USMLE Pediatry For Student Basic Pédiatrie 212 QCM

1) An infant is born to a woman who has received very little prenatal care. The mother is anxious, complains of heat intolerance and fatigue, and reports that she has not gained much weight despite having an increased appetite. On examination the mother is tachycardic, has a tremor, and has fullness in her neck and in her eyes. The infant is most likely at risk for development of which of the following?

2) An otherwise healthy 7-year-old girl is brought to your office by her father because she has some acne, breast development, and fine pubic hair. Which of the following is the most likely etiology for her condition?

3) A primiparous woman whose blood type is O positive gives birth at term to an infant who has A-positive blood and a hematocrit of 55%. A total serum bilirubin level obtained at 36 hours of age is 12 mg/dL. Which of the following additional laboratory findings would be characteristic of ABO hemolytic disease in this infant?

4) A 14-year-old girl presents to clinic for an annual check up. Her parents are concerned that the child is not meeting normal milestones of adolescent growth. The patient reports no recent illnesses. She is up-to-date on her vaccines, and is not having any trouble in school. She denies drug use and is active in sports. On examination, her vital signs are stable. Her lungs are clear and heart is regular in rate and rhythm. Breast and areolar enlargement is noted with no contour separation of the areola. Pubic hair is noted to be dark. The patient also reports that she started menstruating 8 months ago. Which of the following is the most likely Tanner stage of development in this patient?

5) A 7-year-old boy presents to the physician's office with a 3-week history of left-sided anterior cervical lymph node enlargement. The enlarged nodes are not tender to palpation. A few papules developed on the left forearm at the onset of lymphadenopathy. The boy has a kitten at home. Which of the following is the most likely organism causing lymphadenopathy in this child?

6) A 10-year-old boy comes to the office with fever and chills for 5 days and myalgia. He has recently returned from a 2-week vacation to New England with his family. On physical examination he has mild splenomegaly. Which of the following is the most likely cause of his symptoms?

7) A female infant develops cyanosis. She was delivery vaginally at 43 weeks' gestation, and the amniotic fluid had a greenish color. She has dry, peeling skin, emaciated extremities and long fingernails. Tachypnea, nasal flaring, and sub- and intercostal retractions are observed. Auscultation reveals rales and rhonchi. The chest radiograph reveals flattening of the diaphragm, hyperinflation of the lungs, and patchy opacities diffusely distributed over both lung fields. Arterial blood gases reveal hypoxia and hypercarbia. What is most likely impairing the normal respiratory function of this newborn?

8) A 5-month-old boy is brought in for a routine check-up. He was born at 37 weeks' gestation and has had persistent wheezing since shortly after birth despite inhaled bronchodilator and oral corticosteroid therapy. His diet consists of 32 ounces of iron-fortified cow's milk-based formula daily. On physical examination, the child appears well-nourished and happy. You note moderate relief of his wheezing with neck extension. Which of the following is the most likely mechanism of this infant's wheezing?

9) A mother delivers a neonate with meconium staining and Apgar scores of 3 at 1 and 5 minutes of life. She had no prenatal care and the delivery was by emergency cesarean section for what the obstetricians report as “severe fetal bradycardia.”Which of the following sequelae could be expected to develop in this intubated neonate with respiratory distress?

10) . A neonate is noted to have an abnormally shaped face with a very small jaw. Several hours after birth, the baby develops convulsions and tetany. Serum chemistries show the following: Sodium 1 40 mEq/L, Potassium 4 mEq/L, Chloride 100 mEq/L, Bicarbonate 24 mEq/L, Magnesium 2 mEq/L, Calcium 5 mg/dL, Glucose 100 mg/dL. This child's disorder is associated with aplasia or hypoplasia of which of the following organs?

11) A 1-year-old boy is brought to the physician by his parents for evaluation of bruising and blood in his stool. The child has had multiple episodes of otitis media and has been hospitalized twice with pneumonia, but has never had bleeding or easy bruising in the past. He has been eating and drinking well with no vomiting or diarrhea. He is afebrile with a heart rate of 150/min and a blood pressure of 80/40 mmHg. On examination, he is well-developed, well-nourished, and has a fair complexion. There are dry, scaly patches on his cheeks and lower extremities. He also has bruising and purpura on his lower extremities. His diaper contains a small amount of occult blood positive stool, but no fissures are seen on rectal examination. The remainder of the physical examination is unremarkable. Laboratory studies show: Complete blood count: Hemoglobin 11 .5 g/dL, Platelet count 20,000/mm3, Leukocyte count 6,500/mm3, Neutrophils 76%, Eosinophils 1%, Lymphocytes 13%, Monocytes 10%. A peripheral smear reveals a low number of platelets, and the platelets that are seen are small. Which of the following is the most likely cause of his bleeding?

13) Otitis media occurring during the first 8 weeks of life deserves special consideration, because the bacteria responsible for infections during this time may be different from those that affect older infants and children. Which of the following organisms is the most likely to cause otitis media in these infants?

14) A 3-month-old girl is brought to the pediatrician for a scheduled visit. She has been meeting all development milestones but has been vomiting after each feeding. The infant weighed 3 kg (6 lb 10 oz) at birth and now weighs 6 kg (13 lb 3 oz). She does not have diarrhea and is afebrile. The remainder of the physical examination is unremarkable. Which of the following is the most likely cause of this patient's vomiting?

15) A 16-year-old Asian boy presents with a two-day history of fever, malaise, and painful enlargement of his parotid glands. He has no significant past medical history. He was born in India, and has not received any childhood vaccinations. He recently returned from a one-week vacation in India. His vital signs are stable, except for a mild fever. Examination shows bilateral parotid enlargement. The rest of the examination is unremarkable. Which of the following organs is most likely to be affected by this patient's illness?

16) A pregnant woman has premature rupture of membranes. Her baby is born 3 days later, at 37 weeks' gestation. The 5-minute APGAR score is 4. Lung sounds are reduced, and the infant appears to be in respiratory distress. Peripheral blood smear with differential counts demonstrates a neutrophil count of 30,000/mL, with toxic granules evident in many neutrophils. Gram stain of buffy coat demonstrates small gram-positive cocci in chains. Which of the following is the most likely causative organism?

17) A 14-year-old boy is evaluated for short stature. He has no significant past medical history and is considered otherwise healthy by his parents. He eats a normal diet and has regular meals. His height and weight have been consistently at the 5th percentile since early childhood. His physical examination is normal, with genitalia at Tanner stage 3. Which of the following is the most likely laboratory finding for this boy?

18) The recent suicide of a well-known high school cheerleader in your community has generated an enormous amount of community concern and media coverage. A girl who was close friends with the deceased makes an appointment and comes in to your office to discuss the event with you. You ask, and she denies suicidal ideation, but she has many questions about suicide. Correct statements about adolescent suicide include which of the following?

19) A 2-month-old male is brought to the emergency department for evaluation of cyanosis, which occurred earlier in the day while the infant was taking his bottle. Initially, he became fussy and sweaty, then his mother noticed that his lips turned blue. He became intermittently tachypneic and continued to cry. As the crying continued, the cyanosis worsened. His temperature is 37C (98.6 F), blood pressure is 80/50 mmHg, pulse is 150/min, and respiratory rate is 45/min. On examination, the child is alert, cyanotic, and tachypneic. Cardiac auscultation reveals a normal S 1 followed by a systolic ejection click. A grade 2/6 crescendo-decrescendo systolic ejection murmur is heard at the left upper sternal border. The patient is immediately placed in a knee-chest position. This maneuver will improve this patient's condition by which of the following mechanisms?

20) You are called to the ER to see one of your patients. The father of this 14-year-old mildly retarded child says that he found the child about 20 minutes ago in the neighbor’s garden shed with an unknown substance in his mouth. The child first had a headache, but then became agitated and confused; while you are talking to the father in the ER the child begins to have a seizure and dysrhythmia on the cardiac monitor. The blood gas demonstrates a severe metabolic acidosis. Which of the following agents is most likely the culprit?

21) A 17-year-old sexually active girl comes to your office complaining of acne that is unresponsive to the usual treatment regimen. Physical examination reveals severe nodulocystic acne of her face, upper chest, and back. You consider prescribing isotretinoin (Accutane), but you are concerned about side effects. Reviewing the literature, you find which of the following to be true about isotretinoin?

22) The parents of a 1-month-old infant bring him to the emergency center in your local hospital for emesis and listlessness. Both of his parents wanted a natural birth, so he was born at home and has not yet been to see a physician. On examination, you find a dehydrated, listless, and irritable infant. Although you don’t have a birth weight, the parents do not feel that he has gained much weight. He has significant jaundice. His abdominal examination is significant for both hepatomegaly and splenomegaly. Laboratory values include a total bilirubin of 15.8 mg/dL and a direct bilirubin of 5.5 mg/dL. His liver function tests are elevated and his serum glucose is 38 mg/dL. Serum ammonia is normal. A urinalysis is negative for glucose, but it has a “mouse-like” odor. These findings are consistent with which of the following conditions?

23) After an uneventful labor and delivery, an infant is born at 32 weeks’ gestation weighing 1500 g (3 lb, 5 oz). Respiratory difficulty develops immediately after birth and increases in intensity thereafter. At 6 hours of age, the child’s respiratory rate is 60 breaths per minute. Examination reveals grunting, intercostal retraction, nasal flaring, and marked cyanosis in room air. Auscultation reveals poor air movement. Physiologic abnormalities compatible with these data include which of the following?

24) A 15-year-old girl is seen in your clinic with a sprained ankle, which occurred the previous day while she was exercising in her room. You realize that you have not seen her for quite some time, and begin to expand your examination beyond the ankle. You find relatively minimal swelling on her right ankle. She has dental decay, especially of anterior teeth and a swollen, reddened, irritated uvula. She seems to be somewhat hirsute on her arms and legs, but has thinning of her hair of the head. She has a resting heart rate of 60 beats per minute, and her oral temperature is 35.5°C (96°F). Further questioning suggests that she has developed secondary amenorrhea. Which of the following is the most appropriate next step in the management of this girl?

25) You have been recently named as the medical director of the normal newborn nursery in your community hospital and have been asked to write standardized admission orders for all pediatricians to follow. Which of the following vaccines will you include on these orders?

26) A small-for-gestational-age infant is born at 30 weeks’ gestation. At 1 hour of age, his serum glucose is noted to be 20 mg/dL (normally greater than 40 mg/dL). Which of the following is the most likely explanation for hypoglycemia in this infant?

27) Your sister who lives in another state sends via e-mail photographs of her 6-month-old infant. You note the child has a white reflection from one of his eyes. You hastily assist in arranging an urgent pediatric ophthalmologic evaluation. Your sister immediately accesses the Internet and begins to ask questions of you. Which of the following statements found by your sister is correct?

28) A 2950-g (6.5-lb) black baby boy is born at home at term. On arrival at the hospital, he appears pale, but the physical examination is otherwise normal. Laboratory studies reveal the following: mother’s blood type A, Rh-positive; baby’s blood type O, Rh-positive; hematocrit 38%; and reticulocyte count 5%. Which of the following is the most likely cause of the anemia?

29) A 1-week-old male newborn is seen in the office for "noisy breathing." The mother says that the "noisy breathing" is more prominent when the infant is lying on his back, and improves when he is in a prone position with his chin up. The newborn is afebrile and has no cough, vomiting, or cyanosis. There are no inspiratory retractions or wheezes. On direct laryngoscopy, the epiglottis is rolled in from side to side. Which of the following statements is true about the child's condition?

30) A 2-month-old infant comes to the emergency center with fever for 2 days, emesis, a petechial rash, and increasing lethargy. In the ambulance he had a 3-minute generalized tonic/clonic seizure that was aborted with lorazepam. He does not respond when blood is drawn or when an IV is placed, but he continues to ooze blood from the skin puncture sites. On examination, his anterior fontanelle is open and bulging. His CBC shows a WBC of 30,000 cells/μL with 20% band forms. Which of the infant’s problems listed below is a contraindication to lumbar puncture?

31) A 3-day-old infant, born at 32 weeks’ gestation and weighing 1700 g (3 lb, 12 oz), has three episodes of apnea, each lasting 20 to 25 seconds and occurring after a feeding. During these episodes, the heart rate drops from 140 to 100 beats per minute, and the child remains motionless; between episodes, however, the child displays normal activity. Blood sugar is 50 mg/dL and serum calcium is normal. Which of the following is most likely true regarding the child’s apneic periods?

33) A patient has the sudden onset of fretfulness and pain. He curls up with his legs drawn in to his abdomen. Over the next few hours he continued to have episodes of pain and cries with tears, but between these times he acts normally. The patient's mother fears something is terribly wrong and brings him to the hospital. His past medical history was unremarkable. The previous week he had had a cold with a runny nose. His stools had been normal that day. On examination he is quiet and his abdomen is surprisingly soft and normal. In the emergency room there is a semi-soft stool with some blood mixed with mucus. This classic presentation of intussusception is most likely to occur in which of the following age groups?

34) A 10-year-old girl has bullous target lesions and mucosal erythema, which developed after her third dose of trimethoprim-sulfamethoxazole for a urinary tract infection. Which of the following is a likely associated clinical finding?

35) A 16-year-old boy is brought into the emergency department by his friends. He is semicomatose, with a pulse of 60/min and respirations of 6-8/min. His pupils are constricted. Which of the following will most likely be revealed on a urine toxicology screen?

36) An 8-month-old female infant is brought to the clinic for a well-baby examination. She was born prematurely at 35 weeks gestation. She weighs 2.3kg (5 Ib). She cannot sit unsupported. Physical examination reveals mild facial hypoplasia, epicanthal folds, micrognathia, long nasal philtrum, thin upper lip and short palpebral fissures. Auscultation of the heart reveals an III/ IV harsh holosystolic murmur over the precordium. Her karyotype is normal. What is the most likely cause of these findings?

37) A 12-year-old boy is brought to the clinic by his parents because "he cannot walk anymore." Yesterday, he became irritable, uneasy, and complained of tingling and weakness in both his legs. This morning, he couldn't stand up or move his legs, and complained of pain in his leg and thigh muscles. He denies any headaches, nausea or vomiting. He had an episode of febrile diarrhea 10 days ago. His family history is unremarkable. Physical examination reveals symmetric flaccid paralysis of both legs, absent deep tendon reflexes, and decreased superficial touch and vibratory sense. There is no nuchal rigidity. What structure is most likely affected in this patient's condition?

38) A 5-year-old boy suffers from a condition characterized by recurrent fungal and viral infections, thymic hypoplasia, tetany, and abnormal facies. Serum levels of immunoglobulins are mildly depressed, and lymph node biopsy shows lymphocyte depletion of T-dependent areas. Which of the following is the underlying pathogenetic mechanism?

39) While working in the newborn nursery, you have the chance to counsel a first time mother. She had a healthy pregnancy and good prenatal care. The infant was delivered via normal spontaneous vaginal delivery and is doing well. You are counseling the mother on the benefits of breastfeeding, and she asks you what the differences are between human milk and formula. Which of the following is a true statement?

40) A newborn is diagnosed with congenital heart disease. You counsel the family that the incidence of heart disease in future children is which of the following?

41) An otherwise healthy 13-year-old boy has seasonal allergic rhinitis. He complains of excessive rhinorrhea, frequent sneezing, and nasal congestion. He has a nasal voice and breathes with his mouth. He derives some relief from keeping windows closed at home and spending as litde time as possible outdoors in periods of high pollen concentration. However, he is excessively bothered by nasal congestion. Which of the following drugs would be most effective in relieving nasal congestion?

42) A 7 -year-old Caucasian boy is brought to the emergency room with a severe headache, vomiting, and altered mental status of acute onset. His temperature is 36.7 C (98 F), blood pressure is 130/70 mm Hg, pulse is 60/min, and respirations are 18/min. Neurologic examination reveals nuchal rigidity, but no focal neurologic signs. A CT scan shows blood in the subarachnoid space. Which of the following is the most probable additional finding in this patient?

43) A 3-year-old boy is brought to the office by his parents for the evaluation of dry eyes and photophobia. He has some difficulty in adapting to darkness. He is a very poor eater, and his diet consists mainly of canned foods, and very rarely, fresh vegetables or milk. Examination reveals dry, scaly skin, follicular hyperkeratosis in the extensor surfaces of the extremities, and dry, silver-gray plaques on the bulbar conjunctiva. What is the most likely diagnosis of this patient?

44) An infant is due for her first dose of polio vaccine. Her parents have heard that there are two different types of vaccine for polio. They want to know why their daughter needs to get another shot rather than just taking the oral form of the vaccine. You tell the parents the major advantage of the injectable vaccine is which of the following?

45) An infant can regard his parent’s face, follow to the midline, lift his head from the examining table, smile spontaneously, and respond to a bell. He does not yet regard his own hand, follow past the midline, nor lift his head to a 45° angle off the examining table. Which of the following is the most likely age of the infant?

46) A child is brought to your clinic for a routine examination. She can put on a T-shirt but requires a bit of help dressing otherwise. She can copy a circle well but has difficulty in copying a square. Her speech is understandable and she knows four colors. She balances proudly on each foot for 2 seconds but is unable to hold the stance for 5 seconds. Which of the following is the most likely age of this child?

47) A 16-year-old boy with a history of ulcerative colitis presents to the physician complaining of diarrhea and a rash. He states that his appetite has been decreased recently, and also complains of nausea and abdominal pain in addition to watery diarrhea. He has an erythematous rash on his distal arms and legs that "burns". His mother reports that he has had poor concentration and has been irritable lately. Vital signs are stable. Examination reveals a beefy red tongue that appears swollen. Abdominal examination is normal. The rash resembles a sunburn and is located on his distal arms and legs. It is symmetrical and tender to palpation. Neurological examination is normal. This patient's symptoms are most likely due to a deficiency of which of the following vitamins?

48) A full-term infant is brought to the office on her 6th day of life because her mother noted that she looked "yellow". The mother states that the infant is strictly breast-fed and has been eating every 2-3 hours. On examination, she is noted to be jaundiced over her trunk and face. There is no scleral icterus. She is otherwise healthy. Both the mother and baby are Rh positive. Which of the following is the most likely cause of this infant's jaundice?

49) A 5-year-old pedestrian is hit by a car in a mall parking lot and he is brought to the emergency department. There was loss of consciousness for less than 1 minute. On evaluation, the child has no neurologic deficits and a CT scan of the head reveals no intracranial abnormalities and no obvious skull fractures. The parents want to know what possible long-term problems there might be. You remember that problems after head trauma may include the development of seizures and that the risk of developing posttraumatic epilepsy is increased by which of the following?

50) A one-year-old girl is brought to the office for the evaluation of sickle cell anemia. Both her parents have sickle cell trait, and her elder sister has sickle cell anemia. Her vital signs are stable. Her height and weight are appropriate for age. On examination, she appears healthy and normal. Her birth and past medical histories are insignificant. Hemoglobin electrophoresis reveals 40% hemoglobin S. What is the most common presentation of this condition?

51) A boy is brought to the office by his parents for a routine visit. During the physical examination, he can obey two-step commands, use two- to three-word phrases, and can build a tower of six blocks. According to his mother, he can walk up and down the stairs without help. What is the most likely age of this child?

52) A 12-year-old boy is brought to the emergency department because of severe pain near his left knee. He has sickle cell disease and has been hospitalized previously for sickle cell crisis. Vital signs are notable for persistent fever. Examination of the left lower extremity reveals a normal knee joint with marked tenderness and swelling over the proximal tibia. Laboratory studies show leukocytosis and elevated ESR. Imaging studies confirm the diagnosis of osteomyelitis. Which of the following organisms is the most likely cause of his condition?

53) A child is brought to the physician for a routine visit. On examination, the child can name multiple items in the examination room, and can also combine 2 words into a short sentence. His mother estimates that he knows about 200 words. When his mother tries to help him onto the examination table, he says "me do it." Although his mother seems to understand most of what he says, you can only understand about half of his speech. Which of the following is the most likely age of this child?

54) A 2-year-old boy is brought to the office by his mother because he has not started to walk yet. His birth history is significant for prolonged labor, and his APGAR scores at 1 and 5 minutes were 3 and 5, respectively. His older brother is 4 years old, and has a normal developmental history. On examination, the child has hypotonia, learning disabilities and hyperactive deep tendon reflexes. What is the most likely cause for the child's delayed milestones?

55) A 2-year-old boy is brought to the office by his parents due to severe diarrhea since yesterday. He has had approximately 20 episodes of non-bloody, non-mucoid stool passage in the last twenty hours, and one episode of bilious vomiting. He is also feeding less than usual. He is febrile, tachycardic and moderately dehydrated. What is the most likely cause of his presentation?

56) Routine examination of an otherwise healthy kindergarten child with a history of asthma reveals a BP of 140/90 mmHg. Which of the following is the most likely cause of the hypertension?

57) A 6-year-old boy is seen in the office for evaluation of polyuria. Further questioning reveals several months of headache with occasional emesis. Your physical examination reveals a child who is less than 5% for weight. He has mild papilledema. His glucose is normal, and his first urine void specific gravity after a night without liquids is 1.005 g/mL. Which of the following might also be expected to be seen in this patient?

58) A 2-year-old girl is brought to the clinic due to fever, irritability and lethargy for the past two weeks. Over the past two months, she has complained of intermittent abdominal discomfort and has lost weight. Abdominal palpation reveals a firm nodular mass in the right flank. No bruits are heard. Abdominal x-ray reveals multiple calcifications in the renal area. Urine examination reveals increased levels of homovanillic acid and vanillylmandelic acid. Which embryonic structure has this mass most likely arisen from?

59) A 9-year-old boy is brought to the emergency department due to an episode of seizures during class. His teacher says that the seizure started suddenly, and he fell to the ground with sustained flexion of the arms and extension of the legs, followed by clonic movements of the whole body. He has also been irritable lately, and his school performance has declined. His parents arrive shortly and say that they recently noticed he was lethargic and frequently complained of headaches, especially in the morning. His medical history is unremarkable. Physical examination reveals decreased muscle strength of the left side of the body, with brisk deep tendon reflexes in the left arm and leg. MRI of the head reveals a space-occupying lesion in the right parietal lobe. What tumor is most likely responsible for this patient's symptoms?

60) A 2-year-old boy is brought to the pediatrician for a routine well-child visit. He has been growing and developing normally. He is starting to put words together into 2-word phrases. The boy eats a variety of foods including meats, vegetables, and fruits, and drinks 24-28 ounces (700ml) of whole milk each day. Past medical history is unremarkable. His mother has no concerns at today's visit. His physical examination is within normal limits. Laboratory results are as follows: Complete blood count: Hemoglobin 9.4 g/dl, Hematocrit 28%, Mean corpuscular volume 64 fl, Red cell distribution width 14% (normal 11.5%-16.0%), Reticulocytes 3.0%, Platelets 240,000/μL, Leukocytes 7,500/μL, Blood, plasma, and serum, Ferritin 100 ng/ml (7-140 ng/ml), Iron-binding capacity 300 μg/dl (240-450 μg/dl). Which of the following is the most likely cause for this child's anemia?

61) A newborn is noted to be quite jaundiced at 3 days of life. Laboratory data demonstrate his total bilirubin to be 17.8 mg/dL (direct bilirubin is 0.3 mg/dL). Which of the following factors is associated with an increased risk of neurologic damage in a jaundiced newborn?

62) A 6-year-old boy is brought to the clinic for the evaluation of a large, red, circular rash on his left thigh which has been present since two weeks and has been enlarging. He has a mild headache and myalgia, but is afebrile. Three weeks ago, he and his family visited relatives at a rural farm in Connecticut and went hiking in the woods. His temperature is 37.2 C (99 F) and pulse is 90/min. He is alert, active, appears non-toxic, and not in distress. On the anterior surface of his left thigh, there is a red ring that is 7 cm in diameter with central clearing, and a central brownish-red macule that is 3 mm in diameter. Which of the following measures would have prevented this condition?

63) A 1-week-old female infant is brought to the office by her 30-year-old African-American mother because she has been "crying a lot." She was born at term. Her mother was diagnosed with gestational diabetes mellitus (GDM) at 24 weeks gestation and had been on insulin injections since. During labor, there was a prolonged second stage due to difficulty in delivering the shoulders. Her Apgar scores were 8 and 10 at 1 and 5 minutes, respectively. Her birth weight is 3.8 kg (8.5 Ib). On examination, the infant is active. On sudden extension of the head, there is extension of all the extremities, except for the left upper extremity. There is crepitus over the left clavicular bone. Which of the following statements is true for this baby?

64) A 12-month-old patient has allergies to multiple foods. The child’s mother has eliminated the foods from the diet and wants to know if these allergies will be lifelong. You tell her that some allergies do get better if the food is eliminated for 1–2 years. In which of the following is the allergy most likely to resolve, with elimination of the food from the diet?

65) A 9-year-old boy is brought to the emergency department by his father due to a sudden onset of difficulty with writing and jerky movements. He recently had a mild sore throat which quickly resolved, but now seems to have recurred and have worsened. He also had a low-grade fever last week, but no chills. Physical examination reveals a pericardial friction rub and subcutaneous nodules over the hands. Laboratory studies show an elevated ESR. What is the most likely cause of this child's symptoms?

66) An 18-month-old girl is brought to the hospital with a history of 6 days of bloody diarrhea. She has been drinking well but has not been wetting her diaper. She has been irritable. On physical examination, she has periorbital edema. She appears pale and is tachycardic. Her CBC shows a hemoglobin of 6 g/dL and a platelet count of 100,000/mm3. Her blood urea nitrogen (BUN) is 50 mg/dL and creatinine is 5.5 mg/dL. Her urinalysis shows gross hematuria. Which of the following is the most likely causative organism for her clinical problem?

67) A 1-year-old child with ALL in remission for 3 months is in the office for a health maintenance visit. He is due for multiple vaccinations including hepatitis B vaccine, inactivated polio vaccine (IPV), varicella vaccine H. influenzae B vaccine (Hib), and pneumococcal vaccine (PCV). You remember that some of these vaccines are live attenuated viruses and are contraindicated in immunocompromised patients. Which vaccine will you not give to this patient?

68) A 3-month-old Jewish infant is brought to the emergency department because of a generalized seizure 1 hour ago. He is lethargic, weighs 2.7kg (61b), and has a doll-like face with fat cheeks, relatively thin extremities, and a protuberant abdomen. His liver is felt 5cm (2in) below the right costal margin. His kidneys are enlarged. His blood sugar level is 40mg/dl. His serum uric acid, total cholesterol, triglycerides and lactic acid levels are elevated. The levels of his liver transaminases are normal. What is the most likely cause of this infant's symptoms?

69) A 4-year-old girl is brought to the physician because of a crusted honey-colored erythema resulting from rupture of tiny vesicles and pustules. Her temperature is 37.7 C (102 F). Skin lesions are distributed over the face and extremities. Physical examination reveals enlargement of lymph nodes in the cervical and axillary regions. Which of the following is the most frequent pathogen of this skin infection?

70) A 4-month-old baby is in for a well-child check and routine immunizations. The baby had a fever of 39°C the day he received his 2-month immunizations. The parents have read about the vaccine on the Internet and express their concerns. Which of the following is an absolute contraindication to giving the diphtheria and tetanus toxoids and acellular pertussis (DTaP)?

71) A 4-day-old boy is brought to the physician for an outpatient follow-up visit. His mother's pregnancy and delivery were uncomplicated. The patient weighed 3.4 kg (7.5 lb) and was 48.2 cm (1'7") long at birth. He did well in the newborn nursery and was discharged from the hospital on day 2 of life. His mother reports that he is now exclusively breastfed and nurses for 10 minutes on each breast every 3 hours. He has two wet diapers/day and has not had a bowel movement for 2 days. He weighs 2.95 kg (6.5 lb) and is 48.2 cm (1'7'') long. He appears jaundiced on the face and chest. The remainder of the physical examination shows no abnormalities. Laboratory studies reveal: Total bilirubin 15 mg/dl, direct bilirubin 1 mg/dl, Infant's blood type 0 positive, Mother's blood type A positive. Which of the following is the most likely cause of this infant's hyperbilirubinemia?

72) A 1-week-old infant is brought to the emergency department due to vomiting and poor feeding. The prenatal and birth histories are unremarkable. The infant's pulse is 140/min, temperature is 37 C (98.7 F), and capillary refill is 2 sec. He has sunken eyes, depressed anterior fontanel, and dry mucus membranes; skin elasticity is reduced. Heart and lungs are clear. There is no abdominal mass. Genital examination shows enlarged clitoris, and fusion of the labioscrotal folds. The initial laboratory work-up reveals the following: Sodium 128 mEq/L, Potassium 5.8 mEq/L, BUN 25 mg/dl. If this patient's karyotype is 46 XX, which of the following is most likely to be increased in this patient's serum?

73) A 6-year-old African-American child is brought in by his father for complaints of easy fatigability and pallor. These symptoms occurred after the son was treated with "some medication" for a recent diarrhea. Physical examination is normal except for pallor and multiple petechiae. Laboratory values are as follows: Hb 8.0 g/dL, WBC 12,000/mm3, Platelets 50,000/mm3, Blood glucose 118 mg/dL, Serum Na 135 mEq/L, Serum K 5.3 mEq/L, Chloride 110 mEq/L, Bicarbonate 18 mEq/L, BUN 38 mg/dL, Serum creatinine 2.5 mg/dL, Total bilirubin 3 mg/dL, Direct bilirubin 0.5 mg/dL, PT 12 seconds, APTT 30 seconds, LDH 900 IU/L, Reticulocyte count 6%. A peripheral blood smear reveals giant platelets and multiple schistocytes. What is the most likely underlying pathophysiology for this boy's pallor?

74) A 4-year-old previously well African American boy is brought to the office by his aunt. She reports that he developed pallor, dark urine, and jaundice over the past few days. He stays with her, has not traveled, and has not been exposed to a jaundiced person, but he is taking trimethoprim sulfamethoxazole for otitis media. The CBC in the office shows a low hemoglobin and hematocrit, while his “stat” serum electrolytes, blood urea nitrogen (BUN), and chemistries are remarkable only for an elevation of his bilirubin levels. His aunt seems to recall his 8-year-old brother having had an “allergic reaction” to aspirin, which also caused a short-lived period of anemia and jaundice. Which of the following is the most likely cause of this patient’s symptoms?

75) A 24-month-old child is seen in the pediatrician's office for a regular health supervision visit. He has no history of developmental delay. He was born by an uncomplicated normal vaginal delivery at term, and he has not had any significant illness or injury prior to this visit. Which of the following motor milestones is most consistent with his age?

76) A 2-year-old girl has severe dental caries of the upper and lower incisors. Her teeth are brushed twice daily with a small amount of fluoride-containing toothpaste. What is the feeding practice most likely to result in this pattern of dental caries?

77) A 3-year-old boy is brought to the emergency department three hours after having a seizure. He has been having severe diarrhea for the last three days. His mother recently read about the importance of maintaining adequate hydration during diarrhea, so she had been giving him a lot of milk mixed with water. On examination, his vital signs are stable and mucus membranes are moist. Initial lab results are: Hb 13 g/dl, WBC 6,000/mm3, Platelets 300,000/mm3, Blood Glucose 98 mg/dl, Serum Na 120 mEq/L, Serum K 3.4 mEq/L, Chloride 92 mEq/L, BUN 22 mg/dl, Creatinine 1.2 mg/dl. What is the most likely cause of this patient's seizure?

78) The state laboratory calls your office telling you that a newborn infant, now 8 days old, has an elevated thyroid stimulating hormone (TSH), and low thyroxin (T4) on his newborn screen. If this condition is left untreated, the infant is likely to demonstrate which of the following in the first few months of life?

79) A 1-year-old boy presents with the complaint from his parents of “not developing normally.” He was the product of an uneventful term pregnancy and delivery, and reportedly was normal at birth. His previous health-care provider noted his developmental delay, and also noted that the child seemed to have an enlarged spleen and liver. On your examination, you confirm the developmental delay and the hepatosplenomegaly, and also notice that the child has short stature, macrocephaly, hirsutism, a coarse facies, and decreased joint mobility. Which of the following is the most likely etiology of his condition?

80) A 22-year-old Caucasian female who has received no prenatal care experiences a stillbirth. This is her first pregnancy. The baby has multiple fractures, blue sclerae and short, bent extremities. Her past medical history is significant for a seizure disorder. She has been taking phenytoin regularly and had no seizure episodes during the pregnancy. She admits to eating poorly and occasionally drinking alcohol during the first trimester. She lives with her boyfriend who abuses her physically. She recalls several episodes of abuse during the pregnancy. Which of the following is most likely responsible for fetal abnormalities?

81) A newborn infant has respiratory distress and trouble feeding in the nursery. The mother has no significant medical history, but the pregnancy was complicated by decreased fetal movement. On physical examination, you note that aside from shallow respirations and some twitching of the fingers and toes, the infant is not moving, and is very hypotonic. In the mouth there is pooled saliva and you note tongue fasciculations. Deep tendon reflexes are absent. Spinal fluid is normal. Appropriate statements about this condition include which of the following statements?

82) A 2-week-old infant presents with hepatosplenomegaly and a thick, purulent, bloody nasal discharge. Coppery, oval, maculopapular skin lesions are present in an acral distribution. The neurologic examination is normal, including head circumference. Which of the following is the most likely cause of this congenital infection?

83) A previously healthy 4-year-old child is brought to the physician for a school physical for kindergarten. His mother has brought in his immunization record and reports that received all his immunizations prior to age 2. He has received only a yearly influenza vaccine since age 2. His physical examination is unremarkable. Which of the following immunizations should he be given during this visit?

84) A 2-year-old boy is being followed for congenital cytomegalovirus (CMV) infection. He is deaf and developmentally delayed. The child’s mother informs you that she has just become pregnant and is concerned that the new baby will be infected and may develop serious consequences. Which of the following is true?

85) A 15-year-old female presents to your office with secondary amenorrhea. As part of your evaluation, you find that she is pregnant. After informing her of the pregnancy, you continue to explain that young mothers have a higher risk of several pregnancy-related complications, including which of the following?

86) A 16-year-old boy who is the backup quarterback for the local high school team is in your office complaining of worsening acne. For the last few months he has noted more acne and more oily hair. On his examination, you note gynecomastia and small testicular volume. He is SMR 5. Which of the following drugs of abuse is the likely explanation for all of his findings?

87) A 41-year-old woman who is 32-weeks pregnant presents to the emergency department in labor. Her pregnancy has been complicated by gestational hypertension. Her medical history is otherwise unremarkable. She does not abuse alcohol, tobacco, or illicit drugs. Despite medical interventions, her preterm labor cannot be arrested, and she delivers a 2 kg (41b, 5oz) female infant. Both she and the child do well after delivery. Which of the following is true regarding immunizations for this infant?

88) An adolescent with type 1 diabetes returns for a follow-up visit after his annual checkup last week. You note that his serum glucose is elevated, and his glycosylated hemoglobin (hemoglobin A1C) is 16.7%. This finding suggests poor control of his diabetes over at least which of the following time periods?

89) As part of your anticipatory guidance to new parents of a healthy new-born, you suggest putting the child in which of the following positions for sleep?

90) A 16-year-old Caucasian male presents to the office with pain and limited motion of the right knee. His right knee, as well as his right ankle, has swelled several times before. He has a history of easy bruising since childhood, and an episode of excessive bleeding after a tooth extraction. His uncle had similar problems. Which of the following is the most likely cause of this patient's joint pain?

91) A mother brings her daughter into the clinic for a routine health-care visit. On examination, you note that she walks alone, knows two words, throws objects, and comes when called. What is the most likely age of this infant?

92) Approximately 19 days after having had a severe sore throat, a 10-year-old girl is taken to a pediatrician because she is complaining that her arms and legs hurt. The mother reports that before the extremity pain began, the child had a rash with irregular boundaries that lasted about a day. Physical examination demonstrates mild fever, as well as swelling and erythema around several large joints. Laboratory studies show an elevated erythrocyte sedimentation rate, and ECG demonstrates a prolonged PR interval. Which of the following is the most likely explanation for these findings?

93) At birth, an infant is noted to have an abnormal neurologic examination. Over the next few weeks he develops severe progressive central nervous system (CNS) degeneration, an enlarged liver and spleen, macroglossia, coarse facial features, and a cherry-red spot in the eye. Which of the following laboratory findings most likely explains this child’s problem?

94) The parents of a 2-year-old bring her to the emergency center after she had a seizure. Although the parents report she was in a good state of health, the vital signs in the emergency center reveal a temperature of 39C (102.2F). She is now running around the room. Which part of the story would suggest the best outcome in this condition?

95) A 2-year-old child is brought to the emergency department with sudden onset of unresponsiveness, miosis, bradycardia, and muscle fasciculations. These findings are most suggestive of poisoning with which of the following?

96) A 2-year-old girl presents with fever of 39.3 C and irritability. She has had an upper respiratory tract infection for 4 days. On examination, the right ear is bulging and has poor movement on insufflation. Which of the following organisms is most likely responsible for these findings?

97) A 16-year-old girl presents with a history of primary amenorrhea. On examination, short stature and a short neck with a low posterior hairline are noted. Chromosomal analysis most likely would reveal which of the following?

98) During the examination of a 2-month-old infant, you note that the infant’s umbilical cord is still firmly attached. This finding prompts you to suspect which of the following?

99) A 2-week-old neonate is brought to the office due to poor feeding and persistent vomiting. He had an episode of jerky movements of his limbs this morning. He was delivered at term with no complications and weighed 2.7kg (6 Ib) at birth. He appears lethargic, irritable and jaundiced. On examination, he weighs 2.2kg (5 Ib). His liver and spleen are enlarged. Bilateral cataracts are evident. Which of the following is most consistent with these findings?

100) A 1-day-old infant appears dusky in the newborn nursery during feeding. Oxygen is immediately administered by nasal cannula. Shortly afterward, she develops tachypnea. On physical examination, her blood pressure from the right upper arm is 50/30 mm Hg, her pulse is 180/min, and her respirations are 60/min. An echocardiogram is consistent with hypoplastic left heart syndrome. Which of the following would likely be found on auscultation?

101) A previously healthy 5-year-old girl is brought to the emergency room from a camping trip because her parents are concerned about rabies. This morning, they found a bat in the child's tent. There were no obvious bite marks on the child. Afterwards, the girl helped her father clean animals he had brought back from a hunt, including squirrels, rabbits, and chipmunks. Later, while packing up the campsite, the child was bitten on the arm by a rat. Her encounter with which of the following animals most warrants post-exposure rabies prophylaxis?

102) A 4-week-old boy is brought to clinic by his mother because of a 1 day history of labored breathing. His birth was uneventful and immunizations have been up to date. His mother reports that the patient developed conjunctivitis on the fourth day of life. On physical examination, he is breathing rapidly at 40 breaths per minute and is afebrile. His chest reveals bilateral inspiratory crackles and a slight wheeze. On chest x-ray, bilateral pneumonia is evident. The leukocyte count is elevated at 15,000 with 40% eosinophils. Which of the following is the most likely pathogen causing the patient's symptoms?

103) 6-month-old male is brought to the office due to fussiness and tugging at his right ear for the past 2 days. He has had a fever of 39.4° C (103° F) for the past 2 days. His past medical history is significant for recurrent ear and lung infections, oral candidiasis, and persistent diarrhea by rotavirus. His temperature is 39.4° C (103° F), pulse rate is 150/min, respirations are 28/min, and blood pressure is 80/60mm Hg. Physical examination reveals an erythematous, bulging right tympanic membrane with poor mobility on pneumatic otoscopy. His lymph nodes are not palpable, and his tonsils are not visualized. His B and T lymphocyte levels are markedly reduced. The chest x-ray reveals an absent thymic shadow. What is the most likely etiology of this patient's condition?

104) A 6-year-old boy had been in his normal state of good health until a few hours prior to presentation to the ER room. His mother reports that he began to have difficulty walking, and she noticed that he was falling and unable to maintain his balance. Which of the following is the most likely cause for his condition?

105) A 9-year-old child has developed headaches that are more frequent in the morning and are followed by vomiting. Over the previous few months, his family has noted a change in his behavior (generally more irritable than usual) and his school performance has begun to drop. Imaging of this child is most likely to reveal a lesion in which of the following regions?

106) A 2-year-old boy is rushed to the emergency department by his 21 -year-old white mother because he had a sudden-onset nosebleed which has now subsided. He never had any previous episodes. He is "sickly" and suffers from a productive cough and diarrhea that "refuses to go." His stools are greasy and foul-smelling. His appetite is normal, although his diet consists mainly of milk. His mother's boyfriend lives with them and is a chronic alcoholic. He was delivered vaginally without any complications. His weight is at the 25th percentile for his age. Physical examination reveals dry skin and dried blood at the nasal turbinates. What is the most likely cause of this child's failure to thrive?

107) An 18-month-old male infant is brought to the office by his parents for a follow-up visit. He has a congenital condition that started at the age of 6 months with repeated vomiting and hypotonia, and progressively evolved into choreoathetosis, spasticity and dystonia. Over the past month, he has started biting his hands and arms, pinching himself and banging his limbs against the wall. His family history is unremarkable. On examination, he has several scars, cuts and bruises over his arms and hands. His uric acid levels are elevated. What is the most likely deficient enzyme in this patient?

108) A 16-day-old infant presents with fever, irritability, poor feeding, and a bulging fontanelle. Spinal fluid demonstrates gram-positive cocci. Which of the following is the most likely diagnosis?

109) A 16-year-old boy presents to the emergency center with a 2-day history of an abscess with spreading cellulitis. While in the emergency center, he develops a high fever, hypotension, and vomiting with diarrhea. On examination you note a diffuse erythematous macular rash, injected conjunctiva and oral mucosa, and a strawberry tongue. He is not as alert as when he first arrived. This rapidly progressive symptom constellation is likely caused by which of the following disease processes?

110) An 18-month-old child presents to the emergency center having had a brief, generalized tonic-clonic seizure. He is now postictal and has a temperature of 40C (104F). During the lumbar puncture (which ultimately proves to be normal), he has a large, watery stool that has both blood and mucus in it. Which of the following is the most likely diagnosis in this patient?

112) The mother and father of a newborn come in for the 2-week check-up. The mother complains of “colic” and asks if she can switch to goat’s milk instead of breast milk. Which of the following should be your main concern about using goat’s milk instead of breast milk or cow’s milk?

115) A 4-day-old infant is brought to the physician for an outpatient follow-up visit. The mother's pregnancy and delivery were uncomplicated. The infant weighed 3.4kg (7 .5 lb) and was 19 in (48.2 cm) long at birth. He did well in the newborn nursery and was discharged from the hospital on day 2 of life. Today his mother reports that he is exclusively breastfed, and nurses for 10 minutes every 3 hours. He has 3-4 wet diapers a day, and has not had a bowel movement for two days. On examination, he weighs 2.95 kg (6.5 lb) and is 19 in (48.2 cm) long. He appears jaundiced on the face and chest. The remainder of the physical examination is unremarkable. Laboratory values are shown below. Total bilirubin 15 mg/dl, direct bilirubin 1 mg/dl, Infant's blood type O positive, Mother's blood type A positive. Which of the following is the most likely cause of this infant's hyperbilirubinemia?

116) A 10-year-old presents with 2 months history of heavy menstrual-like bleeding. Menarche occurred 6 months ago and this first menses consisted of spotting for 3-4 days without cramps. Subsequent periods were light in flow but lasted 6 to 8 days. Which of the following is the most likely cause of her bleeding?

117) A 25-year-old woman comes to your office for counseling. She says that her husband has cystic fibrosis, and that she has no family history of this disease. They are planning to have a child. She wonders what the probability is for their baby to have cystic fibrosis. Which of the following is your best response in this situation?

118) An awake, alert infant with a 2-day history of diarrhea presents with a depressed fontanelle, tachycardia, sunken eyes, and the loss of skin elasticity. Which of the following is the correct percentage of dehydration?

119) A newborn infant is brought to the nursery for evaluation after delivery. The mother reports that the pregnancy was uncomplicated, but she had only two prenatal visits. The infant was born via normal spontaneous vaginal delivery and required no resuscitation. The infant has hepatosplenomegaly on examination. While in the hospital, the infant requires treatment for anemia and hyperbilirubinemia. On subsequent examinations, the infant has clear rhinorrhea and ulcerative lesions on his feet. Which of the following congenital infections is most likely in this patient?

120) A 17 -year-old boy is brought to the emergency department by his father after the boy began threatening him at home. Over the last several months, the father reports, the boy has been increasingly abusive. He was recently involved in a fist fight at school. The boy states that there is nothing wrong. He is otherwise healthy. He denies alcohol use, but does admit to occasional marijuana use. On examination he has acne on his forehead and back and his hairline is receding. There is palpable tissue underneath his nipples bilaterally Heart and lung exams are normal. What substance is this boy most likely abusing?

121) A 16-year-old African American male with sickle cell anemia presents complaining of a 1-week history of exertional dyspnea, fatigue, and generalized weakness. He denies fevers, chills, night sweats, or cough. His only medication is oxycodone for chronic pain. On physical examination, he weighs 68 kg (150 lbs) and is 168cm (66 in) tall His temperature is 36.7C (98F), blood pressure is 120/70 mm Hg, pulse is 76/min, and respirations are 18/min. All organ systems appear normal Laboratory studies show: Hematocrit 20%, Mean corpuscular volume 110 fl, Reticulocyte count 1.0%. Which of the following is the most likely mechanism underlying these findings?

122) In the 2nd week of life, a previously healthy newborn develops diarrhea. The stools are watery and voluminous and continue even when the infant is fasting. Which of the following is the most likely pathogen?

123) A 17-year-old girl presents to the office with a 5-day history of a malodorous vaginal discharge. She is sexually active and uses condoms for sexual intercourse. On examination, a thin, white discharge is seen. A "fishy" odor is produced when KOH is added to the discharge. The vaginal fluid has a pH of 5. Which of the following is the most likely finding on a microscopic examination of the vaginal fluid?

124) A 20-month-old male is brought to ER with high fever, confusion and a skin rash suggestive of measles. He has a history of recurrent respiratory infections over the last 6 months. The patient's family has recently emigrated from a rural Russian province. Which of the following forms of vitamin supplementation should be considered in this patient?

125) A 3-year-old male is brought to the emergency department for evaluation of right neck swelling. His parents noticed a lump on his right neck yesterday, which has since increased in size and is now erythematous and tender. He has been previously healthy except for mild upper respiratory tract symptoms last week. His temperature is 38C (100.4F), pulse is 90/min, and respiratory rate is 25/min. On examination, he is nontoxic appearing. A 5-cm anterior cervical lymph node is palpated on the right side. It is poorly mobile, warm, erythematous, and tender to palpation. There is no fluctuance or induration. What is the most likely organism causing these symptoms?

126) A 5-month-old infant is brought to the office for the evaluation of persistent vomiting, failure to thrive, and developmental delay. His antenatal and postnatal histories are not known to his Caucasian foster parents, who adopted him when he was 4 months old. The physical examination reveals an infant with blonde hair, fair skin and blue eyes. His urine has a peculiar musty odor. His plasma phenylalanine level is 40 mg/dl and tyrosine level is normal. His urinary phenylpyruvic and a-hydroxy phenylacetic acid levels are both increased. What is the most likely etiology of this child's symptoms?

127) A 2 1/2-year-old child is evaluated by a neurologist because of difficulty walking. Neurological examination documents ataxia and mental retardation. The neurologist notes the presence of multiple telangiectasias involving the conjunctiva, ears, and antecubital fossae. The child also has a history of multiple respiratory tract infections. Immunoglobulin studies on the child would most likely demonstrate an absence of which of the following?

128) A premature neonate with respiratory distress syndrome is maintained on mechanical ventilation in a neonatal intensive care unit. Two weeks after delivery, the nurses in the intensive care unit notice that higher ventilation settings are needed and that more secretions are being suctioned from the endotracheal tube. A chest x-ray film shows questionable new infiltrates. Which of the following is the most likely pathogen?

129) A 3-year-old boy is brought by his father to the Emergency Department with fever, headache and neck pain that developed over the past several hours. The father states he is not the birth father, and that he and his wife adopted the boy at 18 months of age after his birth mother abandoned him. Physical examination reveals a lethargic male with a temperature of 39.7 C (103.5 F). There is photophobia, and mildly injected conjunctiva are appreciated. Pupils are equal and reactive and funduscopic examination is unremarkable. The patient has neck stiffness with a positive Kernig's sign. A complete blood count reveals a leukocyte count of 24,000/mm3 with 64 segmented neutrophils and 25 bands. A lumbar puncture is performed that reveals elevated CSF pressure, decreased glucose, and elevated protein. A Gram's stain shows gram-negative pleomorphic rods. There is no growth on blood agar. Growth on chocolate agar reveals white colonies. Which of the following is the most likely pathogen?

130) A 2-week-old boy in the neonatal intensive care unit had a birth weight of 1200 g. Ultrasound of the head reveals grade II intraventricular hemorrhage and periventricular leukomalacia. An ophthalmologic examination reveals retinopathy of prematurity of both eyes. In addition, a hearing screen demonstrates bilateral hearing deficits. Which of the following is the most important determinant of this child's neurodevelopmental outcome?

131) A 9-year-old boy is brought to the pediatric clinic by his mother, who noticed that the left side of his mouth has started to droop over the past several days. In addition, he is unable to close his left eye completely and complains of it burning. Review of systems reveals a cold approximately two weeks ago and recent decreased taste sensation. Physical examination reveals a well-nourished male with normal vital signs. There is left eye ptosis and mild erythema of the left conjunctiva. His smile is asymmetrical on the left. Laboratory evaluation, including a complete blood count and chemistry profile, are normal. Which of the following infections is most closely associated with this patient's condition?

132) A 6-week-old child arrives with a complaint of “breathing fast” and a cough. On examination you note the child to have no temperature elevation, a respiratory rate of 65 breaths per minute, and her oxygen saturation to be 94%. Physical examination also is significant for rales and rhonchi. The past medical history for the child is positive for an eye discharge at 3 weeks of age, which was treated with a topical antibiotic drug. Which of the following organisms is the most likely cause of this child’s condition?

133) A 12-year-old girl comes to the physician for an annual examination. She has been in good health for the past year and has no complaints. She began having menses this year and, after a few irregular cycles, is now having a monthly period. Past medical history is significant for multiple episodes of otitis media as a child. Past surgical history is unremarkable. She takes no medications and has no known drug allergies. Physical examination is unremarkable. If not currently immune, which of the following immunizations should this patient most likely receive?

134) An infant is brought to the office for health maintenance visit. On examination, the infant turns when her name is called. She is able to say "mama." Her mother mentions that she also says "dada" at home. She is able to look for her mother when she gets frightened. She also waves bye-bye to the doctor when the doctor steps out of the examination room. What age of this child is most consistent with these developmental milestones?

135) A 4-year-old male is brought to the physician with fever and headache. His symptoms began two days ago with low-grade fever, cough, and congestion. Last night, he developed a temperature of 102 F (38.9 C) and became fussy and less active. Today, he is crying and complaining of a headache. His parents report that he has vomited twice today. In the office, his temperature is 102.5 F (39 C), pulse is 110/min, and respiratory rate is 20/min. On examination, he is irritable and shows signs of photophobia. His oropharynx is erythematous. Nuchal rigidity is present and when the neck is flexed, the patient flexes his lower extremities. The remainder of the physical examination is normal. Lumbar puncture is performed and the results are shown below. CSF: Glucose 60 mg/dL, Protein 80 mg/dL, RBC 10/mm3, WBC 100/mm3, Neutrophils 10%, Lymphocytes 70%, Monocytes 20%, Gram stain negative. Which of the following organisms is most likely responsible for this patient's presentation?

136) A 12-year-old boy is brought to the emergency department with a temperature of 39.1 C (102.4 F) at home, difficulty speaking, and odynophagia for 2 days, Physical examination reveals marked erythema of the right tonsil pillar and edema of the uvula with deviation to the left. In addition to anaerobic bacteria, which of the following organisms is most likely to be isolated from a tonsillar pillar aspirate?

137) A neonate is noted to have many abnormalities, a number of which are located in the midline. The infant has cleft lip and cleft palate. His eyes are very small and have fissures of the iris, shallow supraorbital ridges, and slanted palpebral fissures. He is deaf, and the ears are low set and malformed. Each hand has six fingers and a simian crease. Which of the following congenital abnormalities of the brain is particularly likely to be present in this infant?

138) A 4196 g (9 lb 4 oz) infant is delivered via vaginal delivery to a 31-year-old mother with gestational diabetes. The delivery was complicated by shoulder dystocia. He is taken to the newborn nursery where his initial plasma glucose level is 20 mg/dL. The initial spun hematocrit is 65%. Which of the following congenital anomalies is this baby most likely to have?

139) A 24-month-old girl is brought to the pediatrician's office for evaluation because her mother noticed a yellowish discharge on the girl's underwear for the past 3 days. She had no fever, but her mother said she has been fussier recently. On physical examination, the girl is appears excessively anxious about contact with the physician. Her introitus is inflamed, and the hymeneal edge is jagged at the 8 o'clock position. A vaginal culture is taken. Which of the following organisms, if isolated from the vaginal vault, would constitute the most definitive evidence of sexual abuse?

140) An 8-month-old previously preterm infant with bronchopulmonary dysplasia presents to the emergency department with lethargy. His regular medications include furosemide and spironolactone. His temperature is 37.4 C (99.3 F), blood pressure is 68/32 mm Hg, pulse is 110/min, and respirations are 10/min. He has poor skin turgor and dry mucous membranes. Laboratory chemistry evaluation reveals: sodium, 131 mEq/L; potassium, 3.0 mEq/L; chloride, 84 mEq/L; bicarbonate, 38 mEq/L; blood urea nitrogen, 36 mg/dL; and creatinine, 0.4 mg/dL. An arterial blood gas shows pH, 7.52; PaCO2: 49 mm Hg; and PaO2: 92 mm Hg. Which of the following is the most likely explanation for these findings?

141) An 8-year-old boy with sickle cell disease presents with left leg pain and a high fever. He has been refusing to walk since yesterday. On physical examination, his temperature is 39.8 C (103.6 F), blood pressure is 122/68 mm Hg, pulse is 102/min, and respirations are 20/min. His left femur is tender to palpation 3 cm above the left knee, and there is marked soft tissue swelling. A plain film of his left leg is normal. A bone scan shows increased uptake around the metaphysis of the left femur. Which of the following is the most likely pathogen?

142) A 10-year-old male fell while riding his scooter down a steep hill. In the Emergency Department, his injuries included a fractured wrist and a lacerated spleen, which required surgical removal. Two years later he is diagnosed with bacterial pneumonia. Which of the following bacterial agents is the most likely pathogen for this patient's pneumonia?

143) A 10-year-old boy was healthy until about 10 days ago when he developed 7 days of fever, chills, severe muscle pain, pharyngitis, headache, scleral injection, photophobia, and cervical adenopathy. After 7 days of symptoms he seemed to get better, but yesterday he developed fever, nausea, emesis, headache and mild nuchal rigidity. Cerebrospinal fluid (CSF) shows 200 white blood cells (WBC) per microliter (all monocytes) and an elevated protein. Correct statements about this infection include which of the following?

144) A 12-year-old African American boy is brought to the office due to a 2-day history of high-grade fever and chills. He was apparently well before the onset of fever. He has no bone pain. He has sickle cell disease and has had 4 hospitalizations for painful crises and one episode of osteomyelitis. His blood pressure is 90/60 mm Hg, pulse is 100/min, respirations are 22/min and temperature is 38.9 C (102F). He appears drowsy. His laboratory report shows a total WBC count of 16,000/mm3 with 12% bands and Hb of 9.0 g/dl. Which of the following is the most likely cause of this patient's condition?

145) A 13-year-old comes to your office expressing concern about his height. He had first seen you a year prior for his routine checkup and a preparticipation sports physical for soccer (see growth curve). Now in the eighth grade, all of his friends are taller than he is, and he is at a disadvantage on the soccer field playing against much larger boys. After obtaining height information from his parents shown here, you order a skeletal bone age radiograph. Which of the following results would allow you to assure him of an excellent prognosis for normal adult height?

146) A 16-year-old girl with an incomplete vaccination record received one dose of the measles, mumps, and rubella (MMR) vaccine during a doctor's visit. One month later, she learns that she is 9 weeks pregnant, and she is concerned about potential birth defects resulting from the MMR vaccine. Which of the following most closely approximates the risk of birth defects secondary to MMR vaccine exposure during the first trimester?

147) A 6-week-old male infant, who was born at 32 weeks' gestation with a birth weight of 1500 g, has had an average weight gain of 8 g/day since birth. He takes an iron-fortified formula that is 24kcal/oz. His calorie intake is about 125kcal/day. It is noted that his stool is poorly formed and bulky. Which of the following dietary modifications will most likely result in decreased steatorrhea and improved weight gain?

148) An 8-year-old sickle-cell patient arrives at the emergency room (ER) in respiratory distress. Over the previous several days, the child has become progressively tired and pale. The child’s hemoglobin concentration in the ER is 3.1 mg/dL. Which of the following viruses commonly causes such a clinical picture?

149) A 7 -year-old boy is rushed to the emergency department after falling on his outstretched hand. He immediately complained of right arm pain after the accident, and he currently cannot move his arm due to the pain. He is crying and holding his right arm in flexion. There is ecchymosis just above his elbow. He cries out in pain when his arm is moved. An x-ray reveals a supracondylar fracture. What secondary injury is most commonly associated with this patient's fracture?

152) A 4-month-old infant boy has gained only 10 ounces since birth. He has failed to gain weight with multiple formula preparations. His stools have been loose and fatty. An older sister had similar symptoms and has been repeatedly hospitalized for failure to thrive and recurrent pulmonary infections. Which of the following is the most likely cause of this patient's gastrointestinal symptoms?

153) A term newborn is delivered vaginally following a breech presentation. On physical examination, the Barlow test is positive for bilateral subluxation of the hips. There is decreased abduction of both hips. Besides breech presentation, which of the following infants are most at risk for developmental dysplasia of the hip?

154) A 4-year-old boy, who has a ventriculoperitoneal shunt for congenital hydrocephalus, develops fever, headache, irritability, lethargy, photophobia, and vomiting. His temperature is 39.6 C (103.2 F). He is noted to have nuchal rigidity, with the presence of both Kernig's and Brudzinski's signs. The shunt tract is erythematous on the surface. A lumbar puncture is performed and shows a WBC of 40,000/mm3 with 85% neutrophils, a glucose concentration of 48 mg/dL, and a protein concentration of 169 mg/dL. Which of the following is the most likely pathogen?

155) A 6-month-old male is brought to the office due to fussiness and tugging at his right ear for the past 2 days. He has had a fever of 39.4 C (103 F) for the past 2 days. His past medical history is significant for recurrent ear and lung infections, oral candidiasis, and persistent diarrhea by rotavirus. His temperature is 39.4 C (103F), pulse rate is 150/min, respirations are 28/min, and blood pressure is 80/60mm Hg. Physical examination reveals an erythematous, bulging right tympanic membrane with poor mobility on pneumatic otoscopy. His lymph nodes are not palpable, and his tonsils are not visualized. His B and T lymphocyte levels are markedly reduced. The chest x-ray reveals an absent thymic shadow. What is the most likely etiology of this patient's condition?

156) A 2-year-old child is admitted to your hospital team. The child’s primary care doctor has been following the child for several days and has noted her to have had high fever, peeling skin, abdominal pain, and a bright red throat. You are concerned because two common pediatric problems that could explain this child’s condition have overlapping presenting signs and symptoms. Which of the following statements comparing these two diseases in your differential is true?

157) Two new mothers are discussing their infants outside the neonatal intensive care unit. Both were born at 36 weeks’ gestation. One infant weighs 2600 g (5 lb, 12 oz) while the other infant weighs 1600 g (3 lb, 8 oz). The mother of the second infant should be told that her child is more likely to have which of the following conditions?

158) A 2-day-old male infant is jaundiced. He was born at term from an uncomplicated pregnancy, and was normal at birth. He otherwise appears healthy and is feeding well. Vital signs are stable. Physical examination shows jaundice. There is no organomegaly. Laboratory investigations show: Hemoglobin 17.0 g/L, MCV 88 fl, Platelets 220,000/mm3, Leukocyte count 4,500/mm3, Total bilirubin 7.5 mg/dL, Indirect bilirubin 6.0 mg/dL. What is the most likely cause of this patient's jaundice?

159) An infant in brought to the clinic for a routine healthy visit and vaccinations. She is the product of an uncomplicated pregnancy and has been meeting development mileposts. She is feeding well, and her mother reports that the baby seems to be growing well as well. On physical examination, the infant is afebrile with stable vital signs. She can lift her head to 90 degrees, her eyes follow past the midline, she laughs, regards her own hand and has slight awareness of her mother. Which of the following is the most likely age of this infant?

160) A two-day old infant develops seizures, bulging fontanel, and focal neurologic signs. His temperature is 37 C (98F), pulse is 180/min, and capillary refill is> 2 seconds. The initial work-up reveals a hemoglobin level of 12g/dl. Transfontanel ultrasonography demonstrates a hemorrhage involving the germinal matrix, lateral ventricles, and brain parenchyma. Which of the following is the most significant risk factor for this newborn's condition?

161) A 16-year-old girl, accompanied by her mother, is in your office for a well-adolescent visit. The mother asks about drug and alcohol abuse. You explain that the warning signs of abuse include which of the following?

162) A 3-month-old male infant is brought to the emergency department by his mother because of difficulty in breathing. His mother was admitted in the hospital ten days ago due to a urinary tract infection, and he was cared for by his grandmother during that period. His mother had just been discharged from the hospital yesterday, and noticed that he was constipated and having difficulty with breastfeeding. On examination, he is afebrile. His pulse rate is 110/min, respirations are 36/min with shallow breathing efforts, and blood pressure is 90/50mm Hg. His weight is at the 35th percentile. Examination shows ptosis, dilated pupils with sluggish reaction to light, diminished deep tendon reflexes and decreased muscle tone. What is the most likely mechanism of his illness?

163) A 16-year-old College student presents to the physician's office because of a generalized malaise, sore throat and fever for the past 2 to 3 days. She is given amoxicillin prescription. Twenty-four hours later, she develops a polymorphous rash over her entire body. She has taken amoxicillin in the past for sinus disease and never had any problem. What is the most likely organism that is responsible for her symptoms?

164) 16 An 18-month-old child is brought to the emergency department by his mother due to a one-day history of lethargy and anorexia. He had a fever the whole day yesterday, which responded to Tylenol (Acetaminophen). He then developed a petechial rash over his entire body, which worsened in the last few hours. He is up-to-date with his immunizations, and is an otherwise healthy baby. On examination, he is drowsy and lethargic. He has neck stiffness and appears septic. He flexes his hips when his neck is flexed. What is the most likely organism responsible for the patient's symptoms?

165) A child can walk well holding on to furniture but is slightly wobbly when walking alone. She uses a neat pincer grasp to pick up a pellet, and she can release a cube into a cup after it has been demonstrated to her. She tries to build a tower of two cubes with variable success. She is most likely at which of the following age?

166) A 3-week-old female is brought into the emergency department with a fever and irritability. She was born after a normal pregnancy and delivery. Her mother had routine prenatal care and has no history of sexually transmitted infections. The infant's mother is 14 years old and the father is 17 years old. They are not married, and the father is not involved in the care of the infant. The infant lives with her mother and maternal grandparents at the maternal grandparents' home. You are concerned about meningitis and decide to do a lumbar puncture. The mother and maternal grandparents are present in the emergency department. Informed consent should be obtained from which of the following individuals?

168) A 10-year-old boy is admitted to the hospital because of bleeding. Pertinent laboratory findings include a platelet count of 50,000/μL, prothrombin time (PT) of 15 seconds (control 11.5 seconds), activated partial thromboplastin time (aPTT) of 51 seconds (control 36 seconds), thrombin time (TT) of 13.7 seconds (control 10.5 seconds), and factor VIII level of 14% (normal 38%-178%). Which of the following is the most likely cause of his bleeding?

169) Varicella vaccination is a live virus vaccine. It is generally not recommended in immunocompromised patients. Which of the following is an exception to this rule?

170) The signs and symptoms of meningitis in an infant can be different than those in an adult. Which of the following signs and symptoms of meningitis is more helpful in an adult patient than in a 4-month-old?

171) A woman gives birth to twins at 38 weeks’ gestation. The first twin weighs 2800 g (6 lb, 3 oz) and has a hematocrit of 70%; the second twin weighs 2100 g (4 lb, 10 oz) and has a hematocrit of 40%. Which of the following statements is correct?

172) A 9-month-old African American boy is brought to the office by his parents due to swelling of the feet and hands for the past two days, accompanied by poor feeding and fussiness. His vital signs are stable, except for a temperature of 38.3C (101 F). He appears pale. On examination, the dorsal surface of his hands and feet on both sides are swollen and tender, with restricted range of movement. He is an adopted child, and his family history is not available. Radiography of the feet and hands reveal soft tissue swelling. What is the pathophysiology of this patient's presentation?

173) A 4-year-old child presents in the clinic with an illness notable for swelling in front of and in back of the ear on the affected side, as well as altered taste sensation. Correct statements about this condition include which of the following?

174) A 3-year-old boy is brought to the office by his 27-year-old white mother for the evaluation of recurrent bone fractures. His first fracture was that of the femur, and occured when he was 6 months old. He had a fracture of the wrist 4 months ago. His mother also has a history of multiple fractures since childhood. She lost all her teeth at a very early age and is complaining of deafness. Her husband has a history of severe alcohol abuse. On examination, both mother and son have blue sclerae. What is the most likely involved disease process?

175) A mother brings her infant into the clinic for a routine visit. Examination reveals nothing abnormal. Developmental assessment shows that the infant sits well unsupported, enjoys looking around, babbles, and has a raking grasp. What is the most likely age of this infant?

177) A 6-month-old infant has been exclusively fed a commercially available infant formula. Upon introduction of fruit juices, however, the child develops jaundice, hepatomegaly, vomiting, lethargy, irritability, and seizures. Tests for urine-reducing substances are positive. Which of the following is likely to explain this child’s condition?

178) A term newborn infant from an uncomplicated pregnancy is being examined. He is pink, except for his extremities, which are blue. His heart rate is 150/min, and his respirations are irregular and slow at 40/min. He coughs on nasal stimulation and has some flexion of the extremities. What is his Apgar score?

179) A 2-year-old child is brought to the emergency department because of generalized convulsions that last 15 minutes. He has had a fever for 24 hours, and his current temperature is 39.5 C (103 F). He also has a sore throat, but otherwise looks healthy. His father also had several episodes of febrile seizures in his childhood. Which of the following is the most important factor that will increase the risk of recurrence of febrile seizures?

180) An 8-year-old immigrant from rural Central America presents with complaints of weakness, facial swelling, muscle pain, and fever. A CBC reveals marked eosinophilia. Which of the following parasites is most likely to be responsible?

181) The mother of a 4-year-old child takes her daughter to a pediatrician because she is "scratching all the time." Physical examination demonstrates multiple areas of excoriation, which are worst on the shoulders, buttocks, and abdomen. In the areas where the scratching has occurred, scattered tiny red punctate lesions are also seen. Careful examination of the clothing reveals small, ovoid, grayish-white structures attached to threads on the seams. Which of the following is the most likely causative agent?

182) A previously healthy 6-year-old girl is brought to the office due to a 10-day history of persistent, thick, nasal discharge, nasal congestion, cough, and intermittent low-grade fever. She has had no vomiting, headache, earache, or rash. Her temperature is 37.2 C (98.9 F), blood pressure is 88/50 mmHg, pulse is 90/min, and respirations are 15/min. Physical examination shows clear tympanic membranes, congested posterior nasopharynx with thick, yellow and purulent mucus, and red, swollen nasal turbinates. Transillumination of the sinuses is equivocal. Palpation of the maxillary sinuses shows mild tenderness. Lungs are clearto auscultation. Which of the following organisms is the most common etiologic agent of this condition?

183) A one-month-old infant is brought to the physician for evaluation. His mother reports that for the past two weeks, he has been crying inconsolably for several hours every evening. His mother has tried multiple methods to calm the infant down, but nothing seems to work. The infant was born full term without complications. He takes two ounces of cow's milk-based formula every two hours and is growing well. His mother reports that he is happy and alert the rest of the day. The child's physical examination is unremarkable. Which of the following is a true statement about the child's condition?

184) An 18-month-old male is brought to the hospital because of fever, dyspnea, and productive cough of two days duration. His mother reports that he just recovered from prolonged diarrhea due to Giardia infection. His past medical history is also significant for pneumonia and recurrent ear infections since 6 months of age. On physical examination, his temperature is 38.7°C (101.7°F), pulse is 140/min, and respirations are 40/min. Examination reveals a young child in mild respiratory distress and bronchial breath sounds in the right lower lung lobe. Which of the following is the most likely cause of his recurrent infections?

185) You are called to the nursery to evaluate a newborn infant. The mother is a 24-year-old primigravida. Her pregnancy was complicated by preeclampsia. The infant was delivered at 39-weeks’ gestation via emergent cesarean section due to maternal hypertension and non-reassuring fetal heart tones. On examination, the infant's weight is 2.6 kg (5 lb 11 oz) placing him in the 5th percentile, height is 18 inches (46 em) placing him in the 5th percentile, and head circumference is 13 inches (33 cm) placing him in the 1oth percentile. The infant's head seems large for her body. There is a paucity of subcutaneous fat. The remainder of the physical examination is unremarkable. This infant is at risk for developing which of the following?

186) A 16-year-old girl comes to the physician with headache and vision changes for the past month. The headaches are worse in the morning and are associated with nausea. She takes oral isotretinoin for severe acne. Her temperature is 36.7 C, BP is 130/80 mmHg, Pulse is 70/min, and respirations are 15/min. Eye examination shows papilledema and decreased visual acuity. There is no neck stiffness. Motor examination shows 5/5 strength, 2+ deep-tendon reflexes, and a normal plantar response. Sensory examination is unremarkable. Computed tomography scan of the head is within normal limits. Lumbar puncture shows the following: Opening pressure 280 mm H2O, Cerebrospinal fluid glucose 40 mg/dL, Cerebrospinal fluid protein 40 mg/dL, White blood cell 3/mm3. Which of the following is the most likely cause of this patient’s symptoms?

187) A 3-month-old infant without significant past history was brought to the emergency center by her mother with a generalized tonic-clonic seizure. She is found to have glucose of 5 mg/dL. After correction of her hypoglycemia, she is admitted to your service for further evaluation. Several hours later, her nurse calls to tell you that her bedside glucose check was now 10 mg/dL. You order laboratory work suggested by the pediatric endocrinology team and again correct the infant’s hypoglycemia. The results of the laboratory tests you drew include an elevated serum insulin level of 50 μU/mL, and a low IGFBP-1 (plasma insulin-like growth factor binding protein-1). C-peptide levels are not detectable. Which of the following is the likely cause of this child’s recurrent hypoglycemia?

188) A 10-year-old African American boy is brought to the office for the evaluation of worsening fatigue for the past few weeks. He has sickle cell anemia, and has had several hospitalizations for painful crises. His vital signs are stable. He appears pale. He has a hemoglobin level of 7. 7 g/dl and hematocrit of 22.5%. Which is the most likely type of anemia of this patient?

189) A 6-year-old child has had repeated episodes of otitis media. She undergoes an uneventful surgical placement of pressure-equalization (PE) tubes. In the recovery room she develops a fever of 40C (104F), rigidity of her muscles, and metabolic and respiratory acidosis. Which of the following is the most likely explanation for her condition?

190) A 3-year-old-boy ingests 40 of his older sister's chewable vitamin tablets, as well as 3 tablets of 250 mg of acetaminophen. The ingredients in the multivitamin tablets are as follows: Vitamin A 3000 IU, Thiamine 1 mg, Vitamin C 75 mg, Vitamin B6 1 mg, Vitamin D 400 IU, Iron 12 mg, Fluoride 1 mg. The child is brought to the emergency department in no acute distress. Which of the following complications may occur if appropriate therapy is not undertaken?

191) A 7-year-old boy presents with tenderness and erythema of one knee joint. He has had troubles with infections since about 3 months of age. A brother and a maternal uncle both died of infectious disease at an early age. A detailed immunologic evaluation performed at 2 years of age demonstrated plasma IgG less than 50 mg/100 mL. Normal numbers of circulating T cells and normal cellular immunity were found. The boy had been treated monthly since then with IV immunoglobulin. This therapy had markedly reduced, but not eliminated, the boy's infection rate. Which of the following is the most likely pathogen to cause infectious arthritis in this patient?

192) A 3-week-old African American boy is brought to the Emergency Department because of a generalized seizure 2 hours ago. The infant is highly irritable with incessant high pitched crying. The infant's weight is 2.5 kg (250 gm below birth weight), blood pressure is 70 /40 mm Hg, pulse is 145/min and respirations are 50/min. Laboratory results show: Blood glucose 120 mg/dL, Urea nitrogen 50 mg/dL, Serum sodium 170 mEq/L, Serum calcium 8.5 mg/dL, Serum magnesium 1.5 mg/dL. Which of the following is the most likely cause of this infant’s seizure?

193) A neonate born at term is found to have webbed neck and swollen hands and feet. Ultrasonogram of the abdomen shows a horseshoe kidney. Which of the following is the most likely cause of edema?

194) An 8-year-old girl is being evaluated for short stature. She is at 8th percentile for height and 30th percentile for weight. Vital signs are within normal limits. Examination shows a high arched palate and inverted, widely spaced nipples Karyotyping shows 45 XO. Which of the following is she most at risk of developing?

195) A premature infant has a difficult delivery with episodes of arrhythmia and suspected hypoxiaischemia. After the delivery, the infant is lethargic and has periods of apnea. Intracranial hemorrhage is suspected. No obvious head trauma is noted. Cranial ultrasound identifies blood within the ventricles. Which of the following structures is the most likely source of the hemorrhage?

196) A 16-year-old girl is in your office for a preparticipation sports examination. She plans to play soccer in the fall, and needs her form filled out. Which of the following history or physical examination findings is usually considered a contraindication to playing contact sports?

197) A 15-year-old boy is in the office for a preparticipation sports physical examination before he begins playing with the varsity football team at his school. Although he is a skilled receiver, he will be one of the smallest players on the field and is concerned about the potential for injury. He asks how to bulk up. Appropriate advice to increase muscle mass includes which of the following?

198) A 3-week-old boy presents to the physician's office with a 1-week history of forceful, projectile vomiting. He has been vomiting after almost every feeding. The vomitus contains mostly undigested formula and is non-bilious. On examination, his oral mucosa is dry, his anterior fontanel appears to be depressed, and his capillary refill is 3-4 seconds. An abdominal examination reveals an olive-sized mass in the epigastrium. Which of the following electrolyte findings will most likely be seen?

199) A 3-month-old infant is taken to the emergency department with constipation and behavioral changes. Physical examination demonstrates ptosis and an absence of facial expression. The child appears conscious but has trouble following a toy with her gaze. The crying is very weak, and saliva is pooling in her mouth. She is also developing a generalized hypotonia, and breathing is becoming more shallow. This child's condition is most likely related to ingestion of which of the following food products?

200) A blood type B infant born to a blood type O mother has clinically significant fetal-maternal blood group incompatibility with mild anemia and a weakly positive Coombs test. The infant develops jaundice a few hours after birth, with a bilirubin (measured at 12 hours after birth) of 12 mg/dL (predominately unconjugated) compared with 3.5 mg/dL in cord blood. The physician is concerned that the rising bilirubin levels will damage the infant's nervous system. Which of the following sites is most vulnerable to this injury?

201) A 15-year-old girl is brought to the pediatrician's office because of sudden deterioration of school performance. Over the past month, her mother has noticed an occasional paint stain on the girl's hands. Her mother also noticed six bottles of typewriter correction fluid in her bedroom about a week ago. She raised the concern of inhalant abuse. Which of the following is the most likely consequence of chronic inhalant abuse?

202) A 4-year-old child comes in for a health maintenance visit. His mother is concerned that he is not doing some things that other kids in his preschool do. Which of the following skills would be expected of a 4-year-old?

203) A mother brings her 3-year-old son to the pediatrician because he has had 7 days of fever and a painful swollen lymph node in his right groin. This is the boy's sixth episode of lymph node swelling; previous episodes resolved after drainage and prolonged antibiotic therapy. The child also has a past medical history significant for pneumonia at 12 months of age that required chest tube placement for drainage. His maternal uncle died in childhood from recurrent infections. On examination, the boy is at the 5th percentile for both height and weight His temperature is 38.5 c (101.3 F). There is an enlarged, tender lymph node in the right inguinal area with erythema and warmth of the overlying skin. There are several healed incisions in the inguinal regions bilaterally, as well as around the neck from old drainage sites. Laboratory analyses reveal the following: Hematocrit 35%, Platelet count 350,000/mm3, Leukocyte count 17000/mm3, Segmented neutrophils 65%, Bands 10%, Lymphocytes 25%. Gram stain of fluid aspirated from the affected lymph node reveals numerous bacteria-filled segmented neutrophils. Cultures grow S. aureus. What is the most likely mechanism underlying these findings?

204) A 7-year-old boy has cramping abdominal pain and a rash mainly on the back of his legs and buttocks as well as on the extensor surfaces of his forearms. Laboratory analysis reveals proteinuria and microhematuria. You diagnose Henoch-Schönlein, or anaphylactoid, purpura. In addition to his rash and abdominal pain, what other finding is he likely to have?

205) An infant is brought to a hospital because her wet diapers turn black when they are exposed to air. Physical examination is normal. Urine is positive both for reducing substance and when tested with ferric chloride. This disorder is caused by a deficiency of which of the following?

207) A 23-year-old primigravida comes to the physician for a prenatal visit. She is considering breastfeeding her infant, and the physician discusses the benefits of breastfeeding for both the mother and the infant. She asks if there are any reasons that she should not breastfeed. Which of the following maternal conditions is a contraindication to breastfeeding?

208) A 1-year-old patient is in the office for a health maintenance visit and is ready for immunizations. The child has a mild upper respiratory infection and a low-grade fever. The mother does not want the child to receive vaccine because she has been told that the vaccine could make the illness worse. You tell her the only true contraindication to vaccination is which of the following?

209) An infant comes to the office for his 1-year check-up. His father states that he is worried that his son is smaller than he should be. The child's weight is 8.6 kg (19 lb), and his length is 71 cm (28 in). He appears to be growing appropriately on his growth curve. Which of the following is the most appropriate explanation about growth to be given to the father?

210) A 15-year-old Ashkenazi Jewish boy comes to the office because of pain in his right knee. He gives a history of easy bruising and chronic fatigue. His height and weight are in the 40th percentile mark for his age. The physical examination reveals tenderness over the lower end of the right femur, mildly enlarged liver, and moderately enlarged spleen. X-rays of the right femur reveal an Erlenmeyer flask deformity of the distal femur. Significant lab findings are anemia and thrombocytopenia. A bone marrow examination reveals cells with a wrinkled paper appearance. What is the most likely cause of this patient's condition?

211) A 7-year-old girl is brought to the office by her mother. The mother is worried because she noticed some axillary hair development in her daughter. The girl appears calm, and denies the presence of headaches, visual disturbances or abdominal pain. There has been no change in her behavior. Her medical history is unremarkable. Her older sister's pubertal changes began at age 11. Physical examination reveals scarce and dark axillary hair, absent breast development and absent pubic hair. The rest of the examination is unremarkable. Activation of which of the following structures is most likely responsible for this patient's symptomatology?

212) An 8-year-old boy is seen in the pediatrician's office for a routine health supervision visit. The mother states that he has Duchenne muscular dystrophy. On examination, he is found to have hip waddle and enlargement of both calves. He is ambulatory, but his muscle strength is diminished symmetrically. Which of the following signs is most consistent with Duchenne muscular dystrophy?