USMLE pediatry basic 1

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

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?