Part 7 (1629 -1661 ) ( 1530- 1784) Pogba KH 4

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?

41) 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?

150) A 6-year-old Asian boy is brought by his parents to the office due to high-grade fever and rash for the last 9 days. A brick-red, maculopapular rash first appeared on his face and subsequently spread to his trunk and extremities. Prior to the outbreak of the rash, he had a non-productive cough, tearing of eyes, runny nose, sneezing, and intermittent nasal obstruction. Laboratory findings are as follows: Hct 46%, WBC 2,000/mm3, Platelets 160,000/mm3. Which of the following has been shown to reduce the morbidity and mortality rates of patients with this kind of infection?

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?

1) An African-American boy is in the newborn nursery with a bulge on his abdomen that was identified immediately after birth and is most pronounced during crying. The patient was born to an 18-year-old woman who did not receive prenatal care or take prenatal vitamins. Vitals are normal. Examination shows a soft swelling at the umbilical ring. Which of the following is the most likely diagnosis and best course of action for this patient?

2) A 14-year-old girl is brought to the physician’s office because of irregular menstrual periods. She had her menarche at age 13, and since then her periods have been irregular with the cycles varying from 3 to 6 weeks. She has no other symptoms. Physical examination is unremarkable. She has age appropriate secondary sexual characteristics. A urine pregnancy test is negative. Serum prolactin and thyroid stimulating hormone levels are normal. Administration of micronized oral progesterone results in withdrawal bleeding in 3 days. Which of the following most likely explains her irregular periods?

3) Parents bring their 17-year-old son to the emergency department due to his strange behavior at times during the past few weeks. The boy is normally polite and soft-spoken, but he has recently become irritable, impatient, and rude. His parents initially dismissed his behavior as a “phase” with the expectatioin that he would grow out of it. However, they became very concerned on discovering that he had stolen money from their wallets and was sleeping erratically. When questioned by his father about his strange behavior, the boy responsed, “I’m on a secret mission. The king of Norway has sent me here to spy on the US government.” His temperature is 36.6 C, BP is 144/94 mmHg, pulse is 118/min, and respirations are 18/min. On physical examination, the patient appears to be irritated. He is sweating profusely and his pupils are dilated. He is observed in the emergency department for several hours, his condition improves, and he is discharged to the care of his parents. Which of the following is the most likely diagnosis?

4) A 10-year-old boy presents to the emergency room with chief complaints of fever and increasing fatigue. He was well until 2 weeks ago when he had an upper respiratory illness (URI). He has a decreased appetite and has lost 2 lbs over the last 2 weeks. He has some shortness of breath when he climbs the stairs. His past medical history is unremarkable. On examination his vital signs are normal, and his height and weight are at the 80th percentile. His conjunctiva are pale, and he has bilateral, mobile (about 1-2cm) and non-tender nodes in the cervical, axillary, and inguinal regions. Hepatosplenomegaly is present, and skin shows no lesions. Labs are Hemoglobin 7.3g/dl, platelet count 20,000/mm3, WBC count 42,100/mm3, with 24% lymphoblasts, 70% lymphocytes, and 6% atypical lymphocytes. Chest X-rays show clear lung fields but a wide mediastinum. Which of the following is the most likely diagnosis in this patient?

5) A 7-year-old boy is referred by his school for psychiatric evaluation. The teachers have noticed that, in the past year, he has been unable to sustain attention in class, and has been fidgeting and talking to his peers during class. He seems unable to wait for others to finish speaking and keeps interrupting and blurting out answers before questions are completed. At home, his parents state that he is forgetful and losses things easily. Which of the following is the most likely diagnosis?

6) An 8-year-old boy falls on his right hand with the arm extended, and he breaks his elbow by hyperextension. X-ray films show a supracondylar fracture of the humerus. Which of the following complications is of greatest concern with this type of injury?

7) An 18-year-old girl has hepatosplenomegaly, an intention tremor, dysarthria, dystonia, and deterioration in her school performance. She also developed abnormal urine with excess glucose, protein, and uric acid. She has a several-year history of elevated liver enzymes of unknown etiology. Which of the following best explains her condition?

8) The 7-year-old boy now in your office was last seen 2 weeks ago with a mild viral upper respiratory tract infection. Today, however, he presents with fever, ataxia, weakness, headache, and emesis. In the office he has a 3 minutes left-sided tonic-clonic seizure. You send him to the hospital and order a magnetic resonance imaging (MRI) of the brain, the results of which show disseminated multifocal white matter lesions that enhance with contrast. This boy’s likely diagnosis is which of the following?

9) A 15-year-old girl presents to a pediatric cardiology clinic with a complaint of chest pain. She states the pain has come and gone over the past year, but has increased in frequency over the past few weeks. She describes it as a sharp pain over her left chest. Physical examination reveals a healthy-appearing 15-year-old girl. Her temperature is 37.2 C (99 F), pulse is 90/min, and respiratory rate is 20/min. Lung examination is normal. Cardiac examination reveals a late systolic murmur preceded by a click at the apex. No heave or rub is present. An electrocardiogram and chest x-ray film are unremarkable. Which of the following is the most likely diagnosis?

11) A 1-year-old Caucasian boy is brought to your office with necrotic periodontal infection. The past medical history is significant for recurrent cutaneous and sinus infections revealing S. Aureus and P. Aeruginosa isolates. The separation of the umbilical cord was delayed (4 weeks). CBC shows leukocytosis and increased neutrophils. The number of peripheral lymphocytes is normal. Gamma-globulin level is increased on plasma protein electrophoresis. The Nitroblue tetrazolium (NBT) test is normal. Which of the following is the most likely defect present in this patient?

12) A 2-year-old girl is brought to the emergency department due to severe, sudden-onset abdominal pain. She has nausea and vomiting, and her stools contain blood and mucus. Her parents say that she was in her usual state of health when she developed this problem. Her pulse rate is 116/min, blood pressure is 90/60mm Hg, temperature is 37.7C (100F), and respirations are 28/min. She looks lethargic and ill. She is crying and drawing her knees towards her chest. Her abdomen is tender to palpation, and there is a palpable, sausage-like abdominal mass. The bowel sounds are increased, and rectal examination reveals bloody mucus. What is the most likely cause of her symptoms?

13) A 9-year-old boy presents with a 3-month history of multiple episodes of sudden awakening at night. His mother states that when he wakes up suddenly, he screams, "Go! Get away! Go!" and does not respond to the parents. His eyes are wide open, and he sweats heavily and looks scared. The parents have had to struggle to awaken him. After the episodes, he has no memory of what happened. Which of the following is the most likely diagnosis?

14) A 16-year-old girl presents with lower abdominal pain and fever. On physical examination, a tender adnexal mass is felt. Further questioning in private reveals the following: she has a new sexual partner; her periods are irregular; she has a vaginal discharge. Which of the following is the most likely diagnosis?

15) A 6-year-old girl with acute lymphocytic leukemia (ALL) is admitted to the hospital with a generalized vesicular rash and high fever. She has no previous history of chickenpox and has never received immunization for varicella. Her 4-year-old sister recently recovered from chickenpox that started about 10 days ago. On admission, her temperature is 38.4 C (101.1 F), blood pressure is 94/58 mm Hg, pulse is 80/min, and respirations are 20/min. Which of the following is the most serious complication of varicella that might occur in this patient?

16) An 18-year-old male college student is seen in the student health clinic for urinary frequency, dysuria, and urethral discharge. Which of the following is likely to explain his condition?

17) A 1-year-old girl is brought to the emergency department by her mother because the child's "eyes and feet are dancing." On physical examination, the girl is well developed and in no acute distress. Her temperature 37.0 C (98.6 F), blood pressure is 100/55 mm Hg, pulse is 100/min, and respirations are 20/min. The patient has opsoclonus, myoclonus, and ptosis of the right eye. On history, the mother notes the child was born "looking like a blueberry muffin" and has had a persistent cough since the age of 2 months. Which of the following is the most likely diagnosis?

18) A 15-day-old male infant is brought to the emergency department by his mother due to vomiting and bloodstained stools since yesterday. The vomitus is green. Recently, the neonate has been feeding poorly. His birth history is not significant: he was absolutely normal and passed meconium within the first 12 hours of life. He has been breastfed since birth. His pulse rate is 122/min and blood pressure is 80/50mm Hg. He is irritable, his mucous membranes are dry, and his abdomen is distended. Based on these findings, what is the most likely diagnosis?

19) A married couple brings their 2-week-old infant to the office for the evaluation of lethargy, poor feeding and hypotonia. The infant was "fine" until yesterday, when he started to present with these symptoms. The mother's medical history is unremarkable, and her pregnancy was uneventful. On examination, hypotonia, poor reflexes and bulging fontanel are noted. There are no focal neurological signs. He is hypotensive and tachycardiac. His temperature is 39.4 C (103F). Initial investigation reveals a WBC count of 16,000/mm3 with 18% bands. What is the most likely diagnosis?

20) A 5-week-old infant is brought to the clinic for a 4-week history of noisy breathing that has not improved. She has otherwise been healthy except for a current upper respiratory infection for the past 4 days, which according to the parents, has worsened the noisy breathing. On examination, she has inspiratory stridor. The noisy breathing improves when the infant is asleep. Which of the following is the most likely diagnosis?

21) A 1-day-old infant who was born by a difficult forceps delivery is alert and active. She does not move her left arm spontaneously or during a Moro reflex. Rather, she prefers to maintain it internally rotated by her side with the forearm extended and pronated. The rest of her physical examination is normal. This clinical scenario most likely indicates which of the following?

22) A 2-year-old girl is brought to the physician because of protracted irritability, crying, and loss of appetite. She recently had a sore throat. Her temperature is 38.5 C (101.3 F). Physical examination is unremarkable, except for abnormalities of the tympanic membrane detected on otoscopic examination. Which of the following signs or symptoms correlates best with a diagnosis of acute otitis media?

23) A 5-year-old boy is brought to the emergency department with high-grade fevers, irritability, dyspnea and difficulty swallowing that started just hours ago. His mother reports that he had been well before going to bed, but then awoke in the middle of the night with respiratory distress. His vaccination history is uncertain. On physical examination, his temperature is 39. 1 °C (102 .4°F), pulse is 130/min, and respirations are 46/min. He appears anxious and restless, and he is drooling. While observing his respirations, you note that inspiring causes him particular distress. There is no stridor. Sitting upright with his neck hyperextended seems to give the child some relief. Which of the following is the most likely diagnosis?

24) A 3-year-old boy is brought to the clinic due to an abdominal mass that his mother noted while she was bathing him. She seems distressed about the matter, and seeks your "expert opinion." The patient does not have any significant past medical history. On examination, he is calm and quiet. A firm abdominal mass is palpated in the left quadrant, which does not cross the midline. The mass is tender on deep palpation, but is not pulsatile Urinalysis reveals a trace amount of blood. What is the most likely diagnosis?

25) A pediatrician is called to the delivery room because a full-term infant has developed cyanosis and respiratory distress immediately after birth. A brief examination of the infant reveals cyanosis on room air not completely relieved by oxygen administered by mask, subcostal and intercostal retractions, absent air entry on the left with audible bowel sounds in the left chest, and poor air entry on the right chest. The heart is best heard in the right hemithorax; the abdomen is flat without organomegaly. Which of the following is the most likely diagnosis?