Diagnostic Pédiatrie Q 101 to 200

102) You are called to examine a one-day-old male neonate who gradually developed cyanosis over the past few hours. The infant was delivered vaginally at full term, assisted with forceps, and weighed 9 lbs. The Apgar scores were 7 and 8 at 1 and 5 minutes, respectively. Oxygen administration by mask does not relieve the cyanosis. Further examination reveals tachypnea, subcostal retractions, a normal S 1, single and loud S2, and no murmur. Which of the following is the most probable cause of the infant's cyanosis?

103) A 29-year-old woman presents to the delivery room in labor at 35 weeks' gestation with a temperature of 40 C (104 F). She lives on a dairy farm and is in the habit of drinking unpasteurized milk from her cows before sending it to the dairy. For the past 3 days she has been unable to attend to her chores because of fever, headache, mild diarrhea, and a general feeling of illness. When her amniotic membranes rupture, the fluid is dark, cloudy, and brownish-green. At birth, the infant has no malformations or edema, but is in severe respiratory distress. Which of the following is the most likely diagnosis?

104) A previously healthy 13-year-old girl presents to the emergency department with an acute onset of red urine after she played soccer in the morning. Her physical examination is unremarkable. Urinalysis shows a red color; pH, 6.2; specific gravity, 1.024; glucose, negative; blood, +4; protein, trace; nitrite, negative; leukocyte esterase, negative; white blood cell, 0/hpf; red blood cell, 1/hpf. Which of the following is the most likely explanation of the red urine?

105) A 1-month-old infant is seen in a well-baby clinic. The mother states that the baby is constipated and feeds poorly. On examination, he is jaundiced, has a large posterior fontanel and an umbilical hernia, and exhibits poor muscle tone. He has gained only 300 g since discharge from the normal newborn nursery. Which of the following is the most likely diagnosis?

106) A 15-year-old girl has a round, 1-cm cystic mass in the midline of her neck, at the level of the hyoid bone. The mass is deep to the skin and moves slightly when the patient swallows. When the mass is palpated at the same time that the tongue is pulled, there seems to be a connection between the two. The mass has been present for at least 10 years, but only recently bothered the patient because it became infected. Which of the following is the most likely diagnosis?

108) A 4-month-old infant is evaluated by a dermatologist because of thick, erythematous skin with fine scaling, principally involving his face. The mother reports that the infant is "always scratching his face." An older brother and a maternal uncle had a similar condition. Screening hematologic studies show the following: Erythrocyte count 5.1 million/mm3, Leukocyte count 12,000/mm3, Segmented neutrophils 80%, Bands 5%, Eosinophils 3%, Basophils 1%, Lymphocytes 5%, Monocytes 6%, Platelet count 35,000/mm3 , with the comment that the platelets are smaller than normal. Serum immunoglobulin studies demonstrate the following: IgA 120 mg/dL, IgE 2300 IU/mL, IgG 900 mg/dL, IgM 15 mg/dL. Patients with this condition have a significantly increased incidence of which of the following?

109) A 15-year-old athlete is in your office for his annual physical examination before the start of football season. He has no complaints, has suffered no injuries, and appears to be physically fit. On his heart examination, you note a heart rate of 100 beats per minute, and a diffuse point of maximal impulse (PMI) with a prominent ventricular lift. He has a normal S1 and S2, with an S4 gallop. He has no murmur sitting, but when he stands you clearly hear a systolic ejection murmur along the lower left sternal edge and the apex. For which of the following conditions is this examination most consistent?

110) A 10-year-old Caucasian boy is brought to the emergency room by his mother with right hemiplegia of sudden onset. The mother says that the child fell on a pencil in his mouth, ten hours before the onset of symptoms. His past medical history is insignificant. Family history is not significant. His blood pressure 110/60 mmHg and heart rate is 90/min. Physical examination reveals dense right hemiplegia, right hemianesthesia, and mild motor aphasia. Cardiac auscultation reveals S3. What is the most probable cause of this patient's condition?

111) A school teacher calls you to report that his 7-year-old student had about 10 episodes of eye blinking and gabbling today, which lasted approximately 30 seconds each. The child sat in his chair and did not have any postictal confusion. The teacher noticed several similar episodes during the last month, as well as a decline in the child's school performance. What type of seizure does this child have?

112) A 10-year-old girl has had a “cold” for 14 days. In the 2 days prior to the visit to your office, she has developed a fever of 39°C (102.2°F), purulent nasal discharge, facial pain, and a daytime cough. Examination of the nose after topical decongestants shows pus in the middle meatus. Which of the following is the most likely diagnosis?

113) A 7 -year-old girl is brought to the physician's office by her mother due to recurrent, prolonged episodes of nausea and severe vomiting for the past 4 days. According to the mother, the vomiting starts in the early morning and recur 7 to 8 times daily. The child denies any headache, abdominal pain, diarrhea, chest pain or respiratory distress. She has had two similar episodes of vomiting and nausea in the past year, which resolved spontaneously. The mother has a history of migraines. On examination, the child is afebrile and has pallor with signs of mild dehydration. The abdomen is soft and non-tender to palpation. What is the most likely cause of this child's symptoms?

114) A 14-year-old boy has pain in his left leg. An x-ray shows a tumor and a biopsy reveals histopathologic features characteristic of neural origin. Which of the following is the most likely diagnosis?

115) A 7-year-old boy arrives at the emergency room in acute distress. Over the past 3 to 4 days he has become progressively ill with generalized fatigue and mild, mid-abdominal pain that have become steadily worse. On physical examination he has a maculopapular rash on his thighs and feet with some spread of the rash to his buttocks. The rash does not blanch and the some lesions near the ankles look petechial or bruised. His temperature is 39.0 C (102.2 F) and he is drawing his knees to his chest for relief of his stomach pains. He is nauseated and vomited once before coming to the hospital. He has semi-soft dark stool, which is guaiac-positive. The boy has not voided since early morning and cannot provide a urine sample. The doctor determines that he is 10% dehydrated and asks the nurse to start intravenous fluids. Which of the following is the most likely diagnosis?

116) A newborn male has oliguria and a midline mass in the lower abdomen. What is the most likely diagnosis?

117) A 22-month-old boy who recently immigrated from Eastern Europe with his family is brought to your office by his mother who is worried that he seems to tire easily. She describes how he becomes short of breath with even mild physical activity and cannot keep up with his peers during play. The boy is at the 40th percentile for height and 20th percentile for weight. On general examination, there is no clubbing, cyanosis, or peripheral edema, but there is a harsh 3/6 holosystolic murmur over the left lower sternal border and a rumbling diastolic murmur over the cardiac apex. Which of the following is the most likely cause of his symptoms?

118) A 5-month-old child was normal at birth, but the family reports that the child does not seem to look at them any longer. They also report the child seems to “startle” more easily than he had before. Testing of his white blood cells (WBCs) identifies the absence of β-hexosaminidase A activity, confirming the diagnosis of which of the following?

119) The family of a 4-year-old boy has just moved into your area. The child was recently brought to the emergency department (ED) for an evaluation of abdominal pain. Although appendicitis was ruled out in the ED and the child’s abdominal pain has resolved, the ED physician requested that the family follow up in your office to evaluate an incidental finding of an elevated creatine kinase. The family notes that he was a late walker (began walking independently at about 18 months of age), that he is more clumsy than their daughter was at the same age (especially when trying to hold onto small objects), and that he seems to be somewhat sluggish when he runs, climbs stairs, rises from the ground after he sits, and rides his tricycle. A thorough history and physical examination are likely to reveal which of the following?

120) A 15-month-old boy is brought into the clinic with a 1-day history of fever, decreased oral intake, and runny nose. His vital signs are within normal limits except for a temperature of 39.5 C (103.1 F). He is active and in no distress. His ears are clear bilaterally. There is a clear nasal discharge. Multiple small (1-2 mm) vesicular lesions are noted on the mucosa of the anterior tonsillar pillars and posterior palate. The rest of his examination is within normal limits. Which of the following is the most likely diagnosis?

121) A 6-month-old infant presents to the emergency department with the new onset of weak cry, decreased activity, and poor feeding. The mother also states that the infant has been constipated for the past 2 days. On physical examination, the infant has a very weak cry, poor muscle tone, and absent deep tendon reflexes. Which of the following is the most likely diagnosis?

122) You are called to examine a 2-day-old male, newborn after he was noted to be cyanotic. He was born at term. His antenatal and birth histories are unremarkable. Auscultation reveals a holosystolic murmur at the left, lower sternal border and a single S2. No rales or rhonchi are heard. Chest radiograph reveals decreased pulmonary vascular markings and a normal-sized heart. EKG reveals left axis deviation. What is the most likely diagnosis?

123) A 2-year-old boy has been vomiting intermittently for 3 weeks and has been irritable, listless, and anorectic. His use of language has regressed to speaking single words. In your evaluation of this patient, which of the following is the most reasonable diagnosis to consider?

124) A 15-year-old boy is seen in the pediatrician's office for a health maintenance physical examination. The boy reports a heavy, dragging sensation in his left scrotum. The sensation is more pronounced after exercise. He denies any scrotal pain. He is not sexually active. Examination of his genitalia indicates Tanner stage 4. There is a palpable fullness over his left scrotum. Both testes are normal in size and smooth in contour. Which of the following is the most likely explanation of these findings?

125) A 5-year-old child undergoes a school entrance physical examination. The pediatrician notices grey-brown pigmentation on the skin of his forehead, hands, and pretibial regions. Subconjunctival areas near the corneoscleral junction show wedge-shaped, yellow-brown discoloration (pingueculae). Enlargement of both the spleen and the liver are noted on abdominal examination. Needle biopsy of the spleen demonstrates the presence of unusually large (20- to 100-mm diameter) reticuloendothelial histiocytes with a "crumpled-silk" appearance. Bone marrow biopsy demonstrates the presence of the same type of cells. Which of the following is the most likely diagnosis?

126) A term male infant is found to be cyanotic shortly after birth and requires endotracheal intubation. On physical examination, his blood pressure is 68/34 mm Hg (equal in all four extremities), pulse is 180/min, and respirations are 32/min. His precordium is dynamic, has a grade III systolic murmur, and a single S2. Chest radiography shows a normal heart size and increased pulmonary vascular markings. An arterial blood gas on an FiO2 of 100% shows pH 7.34; PaCO2: 47 mm Hg; PaO2: 46 mm Hg. Which of the following diagnoses is most consistent with these findings?

127) A 6-month-old boy is found to have bilateral metaphyseal fractures of both proximal and distal ends of the tibia. The mother says that her boyfriend takes care of the infant while she is at work. Her boyfriend explains the injuries as the result of multiple falls from bed. Which of the following is the most likely diagnosis?

129) A 2-year-old child has had red, weeping, crusted lesions of the face, scalp, diaper area, and extremities since about age 2 months, with multiple periods of exacerbation and improvement. Attempts to remove potentially irritating substances have not modified the course of the rashes. The child is noted to be constantly scratching and rubbing involved areas. There is a strong family history of hay fever and asthma. Which of the following is the most likely diagnosis?

130) A 7-year-old Caucasian boy is brought to the clinic because of poor performance in school. His mother says that his teachers have been complaining about his poor attention in the classroom for the past 8 months. They have also complained that he is out of his seat often, fidgets, and talks excessively, gets distracted easily, and interrupts class and other students. His mother has noticed that he often loses his things, and she is having more and more difficulty disciplining him at home. His antenatal and postnatal history is insignificant. His parents never had any similar problems with his 10-year-old sister. What is your clinical diagnosis?

132) A 17-year-old girl presents with a 4-week history of intermittent fever, increasing fatigue, generalized myalgia, and swelling of both her knees and ankles. There is a fine erythematous rash on her back, and she has swollen knees and ankles; the remainder of her physical examination is unremarkable. Initial laboratory evaluation shows: Leukocytes 11,400 cells/mm3, Hemoglobin 8.8 g/dL, Blood urea nitrogen 4 mg/dL, Creatinine 1.4 mg/dL, Glucose 98 mg/dL, C3 complement 36 mg/dL (normal >80 mg/dL), Antinuclear antibody titer 1:3200, Anti-double-stranded DNA titer 1:640, Antineutrophil cytoplasmic antibodies: Negative, Urinalysis Moderate hematuria (50 RBC/hpf), Moderate proteinuria (400 mg/dL). Which of the following is the most likely diagnosis?

133) A vomiting infant is brought to the emergency room. The blood work results reveal a normal blood count, but a hyponatremic, hypochloremic, metabolic alkalosis. Which of the following would be consistent with these findings?

135) A 12-year-old male is brought to your office by his mother because of a several month history of back pain. He also experienced bed wetting recently. His past medical history is insignificant. He tried acetaminophen for pain relief. He does not smoke or consume alcohol. His temperature is 36.7 C (98 F), blood pressure is 110/65 mmHg, pulse is 80/min, and respirations are 16/min. Physical examination reveals a palpable "step off" at the lumbosacral area. Straight-leg raising test is negative on both sides. Perianal sensation tested by pinprick test is decreased, but anal reflex is normal. What is the most probable diagnosis in this patient?

136) A 16-month-old is taken to the emergency room after falling while learning to walk. The toddler has an enlarging, swollen bruise on his forehead, which is now over two inches across. The parents say that the bruise is noticeably larger than it was when they entered the emergency room an hour earlier. A blood sample is drawn, and the child oozes blood at the puncture site for 25 minutes. Clotting studies on the blood sample show a prolonged PTT and a normal PT. Follow-up studies show very low levels of factor VIII. Which of the following is the most likely diagnosis?

137) A previously healthy 8-year-old boy has a 3-week history of low-grade fever of unknown source, fatigue, weight loss, myalgia, and headaches. On repeated examinations during this time, he is found to have developed a heart murmur, petechiae, and mild splenomegaly. Which of the following is the most likely diagnosis?

138) A 10-year-old boy is brought by his parents to the emergency department for the evaluation of headaches, fever, chills, and a rash over his neck, chest, and axillae. The rash appeared today, and for the past two days the child was complaining of a sore throat. He has no history of allergies, and his immunizations are up-to-date. His blood pressure is 112/70 mmHg, pulse is 1 08/min, respirations are 20/min, and temperature is 38.3C (101 F). Examination reveals an erythematous rash with a sandpaper-like texture, and which blanches with pressure. There is submandibular tender lymphadenopathy, and the throat is erythematous with gray-white exudates. What is the most likely diagnosis?

139) A 2-year-old boy is referred to your office for the evaluation of a white eye reflex. His mother suspects a hearing problem because he does not respond when she calls out his name. The physical examination reveals a continuous, machinery murmur over the right 2nd intercostal space and purple lesions on his arms and chest. The initial investigations reveal thrombocytopenia. What is the most likely diagnosis?

140) You find a discrete, whitish polyp that extends through the tympanic membrane in a child with a history of recurrent otitis media. This most likely represents which of the following?

141) A 5-day-old male premature infant in the NICU develops a decreased level of consciousness, hypotonia and decreased spontaneous movements. He was delivered vaginally at 32 weeks of gestation, and his birth weight was 1800g. Examination reveals a lethargic infant with a weak and high-pitched cry, prominent scalp veins, tense fontanels, and eyes directed downward, poor suckling, hypotonia. CT scan reveals dilation of the entire ventricular system, with distinct enlargement of the subarachnoid space over the cerebral cortex. What is the most likely cause of the patient's condition?

142) A 12-month-old infant presents with bilious vomiting and abdominal distention for 10 hours. His mother states that the infant has been constipated since birth and failed to pass meconium during the first 48 hours of life. On examination, he is very irritable. His length and weight are both below the 5th percentile according to his age. His abdomen is moderately distended. After a digital rectal examination, a fair amount of stool ejects out from the anus. Which of the following is the most likely diagnosis?

143) A 9-year-old boy is brought to the pediatrician's office for bed-wetting. His mother states that he has never been dry at night. Occasionally, he has problems controlling his bladder during the day. On physical examination, his blood pressure is 98/56 mm Hg. Both his weight and height are below the 5th percentile for his age. His bladder is enlarged and palpable above the symphysis pubis. Which of the following is the most likely cause of his problem?

144) A 4-day-old female infant presents to the emergency department with vomiting and abdominal distention. The mother states that the vomitus was green. The infant also has had difficulty feeding and has been hard to console. The mother had an uncomplicated pregnancy. The infant passed meconium within 12 hours after birth. She also had several small, seedy, yellowish stools each day since birth. On physical examination, she is very irritable, her anterior fontanelle is slightly depressed. Her abdomen is distended. Which of the following is the most likely diagnosis?

145) A previously healthy 11-year old boy presents to the physician with a fever and persistent vomiting for 4-5 days. Initially, the emesis was clear, but now it contains streaks of bright red blood. Findings on a physical examination, complete blood count, and serum electrolytes are within normal limits. Which of the following is the most likely cause of the hematemesis?

146) A 7 -year-old boy is brought to the emergency department after falling on his outstretched hand. On examination, there is minimal swelling at the right elbow. The skin on the right forearm appears tense, and severe pain is present. The brachial pulses are good bilaterally, and sensations are intact in both upper limbs. X-rays of the right upper limb show a displaced anterior fat pad. Which of the following statements is true about this condition?

147) A 3-month-old infant has a history of chronic constipation. A fulminant watery diarrhea develops over a period of 2 days, and the infant is taken to the emergency department in an obviously severely dehydrated state. Plain x-ray films of the abdomen demonstrate a massively dilated transverse colon. Which of the following is the most likely diagnosis?

148) A mother brings her 9-month-old daughter to the pediatrician with complaints of a rash. The mother states that the infant had a high fever [temperature up to 40.0 C (104 F)] for 3 days prior to developing the rash, but is now afebrile. The mother also says that the infant has had a runny nose and a slight cough for the past 3 days. On examination, there is a fine macular rash on the infant's trunk and neck. The examination is otherwise within normal limits, and the infant is playful and smiling. Which of the following is the most likely diagnosis?

149) A 20-month-old presents to the office with a 2-day history of a harsh, barking cough. His mother states that the cough sounds like a seal. She also states he has not had any fever, although he had a runny nose earlier in the week. On examination, he is notably hoarse with inspiratory stridor. He is not drooling and is sitting on his mother's lap comfortably. The rest of his examination is within normal limits. Which of the following is the most likely diagnosis?

150) A 4-year-old girl is brought to the physician by her mother who is concerned because her child has a vaginal discharge. Starting 2 days ago, the child began scratching her vulva and complaining of burning with urination. The child is otherwise healthy and has never had a similar problem. Examination reveals normal structural anatomy for a 4-year-old girl. There is no evidence of atrophy. There is an inflammatory erythema on the medial aspects of the labia majora and excoriations. There is a mucous discharge with a few flecks of blood intermixed. Which of the following is the most likely cause of a vaginal discharge in this patient?

151) A 1-year-old child presents with failure to thrive, frequent large voids of dilute urine, excessive thirst, and three episodes of dehydration not associated with vomiting or diarrhea. Over the years, other family members reportedly have had similar histories. Which of the following is the most likely diagnosis?

152) A 6-month-old infant has poor weight gain, vomiting, episodic fevers, and chronic constipation. Laboratory studies reveal a urinalysis with a pH of 8.0, specific gravity of 1.010, 1+ glucose, and 1+ protein. Urine anion gap is normal. Serum chemistries show a normal glucose and a normal albumin with a hyperchloremic metabolic acidosis. Serum phosphorus and calcium are low. What is the best diagnosis to explain these findings?

153) A 2-year-old girl is taken to a pediatrician because she has developed a rash and seems unusually unsteady when she tries to walk. Physical examination demonstrates a diffuse rash on body parts exposed to sun. Also noted are short stature, possible mental retardation, and ataxia. Screening studies demonstrate increased total amino acids in the urine. Which of the following is the most likely diagnosis?

155) A 10-year-old boy, the star pitcher for the Salt Lake City Little League baseball team, had a sore throat about 2 weeks ago but did not tell anyone because he was afraid he would miss the play-offs. Since several children have been diagnosed with rheumatic fever in the area, his mother is worried that he may be at risk as well. You tell her that several criteria must be met to make the diagnosis but the most common finding is which of the following?

156) A 6-year-old female is brought to the physician with a rash and joint pains. Her mother reports that she has been previously healthy except for a sore throat a few weeks ago. One week ago, the patient developed pain in her knees. The knee pain resolved after a few days, but now her ankles and wrists are tender. She has also developed a pink rash on her trunk that is non-pruritic. Vital signs are temperature 38.3 c (101 F), pulse 85/min, and respiratory rate 20/min. On examination, there is pain and stiffness during manipulation of the wrists and ankles. A faint, erythematous, centrifugal rash on her trunk and proximal limbs is present. Laboratory studies show: Complete blood count: Hemoglobin 12.5 g/dL, MCHC 32%, MCV 85 fl, Reticulocyte count 0.1%, Platelet count 200,000/mm3, Leukocyte count 6,500/mm3, Neutrophils 56%, Eosinophils 1%, Lymphocytes 33%, Monocytes 10%, C-reactive protein 3.5 mg/dL, Erythrocyte sedimentation rate 38 mm/hr. Which of the following is the most likely diagnosis?

157) A previously healthy 18-month-old male comes to the physician for evaluation of fever. His mother reports that he has had a fever ranging from 1 02.2 F (39.0 c) to 104.0 F (40.0 C) for the past five days. He has also become increasingly irritable with decreased appetite. His mother reports that he does continue to take some liquids. There are no known sick contacts. On examination, the infant's temperature is 102.5 F (39.2 C), pulse is 120/min, and respiratory rate is 20/min. He is irritable during the examination. There is conjunctival erythema bilaterally, with serous drainage from both eyes. His oropharynx is erythematous and his lips are fissured. There is a 2 cm anterior cervical lymph node palpable on the right side. His neck is otherwise supple and he is able to flex his chin to his chest without difficulty. There is mild abdominal tenderness to palpation. His hands and feet are slightly erythematous and edematous and there is a maculopapular rash on the trunk. Which of the following is the most likely diagnosis?

158) A 2-week-old infant is brought to the office for a newborn visit. His mother states that the he has been a very slow eater and that he is constipated, not having had a bowel movement in 3 days. On physical examination, the infant has poor muscle tone, an enlarged tongue, an umbilical hernia, an enlarged anterior fontanelle, and hypothermia. He also looks slightly jaundiced, with slightly dry skin and brittle hair. Which of the following is the most likely diagnosis?

159) A 12-year-old child is brought to his pediatrician for a routine health maintenance visit. He has been well except for occasional attacks of asthma and has met all development milestones. His immunizations are up to date. He occasionally uses theophylline for his asthma. Physical examination is remarkable for a blood pressure of 150/90 mm Hg in both arms. Which of the following is the most likely cause of his hypertension?

160) A 5-year-old boy is brought to the emergency department due to general malaise and a swollen scrotum. His mother noticed the swollen scrotum today, and is sure that "it was not there yesterday." He had a low-grade fever and a cough two weeks ago, and "hasn't been himself ever since." He has no significant past medical history. On examination, he looks ill and lethargic. He has palpable purpura on his buttocks and lower legs. He has a swollen right scrotum which is slightly tender to palpation, and his abdomen is moderately tender to palpation. Urinalysis reveals the presence of a small amount of blood and protein. He is subsequently admitted for observation. Which of the following adverse outcomes is he most likely to develop?

161) A mentally retarded 14-year-old boy has a long face, large ears, micropenis, and large testes. Chromosome analysis is likely to demonstrate which of the following?

162) A 5-month-old child with poor growth presents to the ER with generalized tonic-clonic seizure activity of about 30-minute duration that stops upon the administration of lorazepam. Which of the following historical bits of information gathered from the mother is most likely to lead to the correct diagnosis in this patient?

163) A 13-year-old girl presents with parental concerns of poor posture. She has not had any back pain. On examination, she has unequal shoulder height, asymmetric flank creases, and a forward-bending test that shows rib asymmetry. The physical examination is otherwise normal. Which of the following is the most likely cause of her condition?

164) An 18-month-old boy presents with a history of fever to 39.0°C for 5 days. He has also been irritable and has not been drinking well. Associated symptoms include red eyes, a rash, and some trouble walking. On physical examination, he has a temperature of 39.5°C. He has bilateral bulbar conjunctivitis, a strawberry tongue, an inflamed oral pharynx, edema of the hands and feet, a morbilliform rash, and cervical lymphadenopathy. He is very irritable. His CBC shows a WBC of 15,000/mm3 with 60% neutrophils, 35% lymphocytes, and 5% monocytes. His hemoglobin is 12.0 g/dL and platelet count is 500,000/ mm3. Which of the following is the most likely diagnosis?

165) An infant is delivered at full term by a spontaneous vaginal delivery to a 29-year-old primigravida. At delivery, the infant is noted to have subcostal retractions and cyanosis despite good respiratory effort. The abdomen is scaphoid. On bag and mask ventilation, auscultation of the lungs reveals decreased breath sounds on the left, with heart sounds louder on the right. Which of the following is the most likely diagnosis?

166) A 12-month-old girl has been spitting up her meals since 1 month of age. Her growth is at the 95th percentile, and she is otherwise asymptomatic and without findings on physical examination. Which of the following is the most likely diagnosis?

167) A 14-year-old girl has a 9-month history of diarrhea, abdominal pain (usually periumbilical and postprandial), fever, and weight loss. She has had several episodes of blood in her stools. Which of the following is the most likely diagnosis?

168) A 12-year-old girl complains of intermittent palpitations. She had previously been in excellent health and has met all development milestones. There is no family history of heart disease. She is on no medications and takes no drugs. She states that the palpitations begin and end suddenly and usually last a couple of hours. She is otherwise asymptomatic between episodes. The physical examination is normal. An ECG reveals a shortened PR interval and a slow upstroke of the QRS wave in lead III. Which of the following is the most likely diagnosis?

169) An 11-year-old boy is brought to the office by his mother because "he is sick." He has had headaches for the past several weeks, and has vomited 4 times in the past 5 days. He drinks large amounts of water and goes to the bathroom all the time. He is no longer interested in playing football and going out with his friends. His temperature is 37.0C (98.6F), blood pressure is 118/78 mm Hg, pulse rate is 84/min, and respirations are 16/min. On examination, there is loss of peripheral visual fields. His laboratory findings are as follows: W BC 7,800/mm3, Hemoglobin 12.6 g/dl, Hematocrit 35%, Platelets 199,000/mm3, Sodium 145 mEq/L, Potassium 3.6 mEq/L, Bicarbonate 24 mEq/L, Blood urea nitrogen 18 mg/dl, Serum creatinine 1.0 mg/dl, Blood glucose 88 mg/dl. X-rays of the head reveal a calcified lesion above the sella. What is the most likely diagnosis?

170) A full-term neonate presents with hypotonia, lethargy and poor feeding over the past three hours. The pregnancy was uneventful, but during delivery, the neonate presented with shoulder dystocia and subsequently obtained a fracture of the clavicle. His Apgar scores are 7 and 8 at one and five minutes, respectively. His birth weight is 4000g. His vital signs are normal. Physical examination reveals an enlarged tongue, mild microcephaly, prominent occiput, prominent eyes and omphalocele. Abdominal palpation reveals an enlarged liver and kidneys. The initial work-up reveals hypoglycemia and hyperinsulinemia. What is the most likely diagnosis?

171) Your older sister, her husband, their 2-day-old infant, and their pet Chihuahua arrive at your door. The parents of the child are concerned because the pediatrician noted the child was “yellow” and ordered some studies. They produce a wad of papers for you to review. Both the mother and baby have O-positive blood. The baby’s direct serum bilirubin is 0.2 mg/dL, with a total serum bilirubin of 11.8 mg/dL. Urine bilirubin is positive. The infant’s white blood cell count is 13,000/μL with a differential of 50% polymorphonuclear cells, 45% lymphocytes, and 5% monocytes. The hemoglobin is 17 g/dL, and the platelet count is 278,000/μL. Reticulocyte count is 1.5%. The peripheral smear does not show fragments or abnormal cell shapes. Which of the following is the most likely explanation for this infant’s skin color?

172) A 14-day-old male infant is brought to the emergency department due to spasms involving the whole body. He has been having very poor suckling over the last couple of days. He was delivered vaginally by an untrained birth attendant, and his mother never sought any pre- or antenatal care. The pertinent physical finding is a swollen and erythematous umbilical cord. What is the most likely diagnosis of this patient?

175) A 14-year-old African-American boy presents to your office with difficulty walking for the past several weeks. He complains of pain in the right hip. He describes two episodes of severe hip pain and one previous episode of abdominal pain requiring hospitalization. Physical examination reveals motion restriction in the right hip joint. His joint is not erythematous or tender to palpation. His hematocrit is 22%. This patient's difficulty walking is most likely secondary to which of the following?

176) A 2-year-old girl is brought to her pediatrician by her parents because of increasing lethargy and irritability. She has just started walking, and is teething and likes to chew on the woodwork around the windows. Physicalexamination reveals a tender abdomen. Laboratory studies indicate high iron and ferritin levels. The peripheral blood smear shows basophilic stippling. Which of the following is the most likely diagnosis?

177) A 10-hour-old newborn is noted to have a swelling in the scalp which was not present at birth. The swelling is limited to the surface of one cranial bone. There are no visible pulsations, indentations of the skull, or discoloration of the overlying scalp. What is the most likely diagnosis?

178) A 4-year-old boy is brought to the office because his school teacher thinks that his dusky blue appearance may have something to do with his inability to participate in regular school activities. His mother says that he has always appeared slightly out of breath. He has no history of any trauma, past surgery or medical conditions. His birth history is unremarkable. Physical examination reveals perioral cyanosis and a systolic murmur along the left sternal border. When the child squats, the murmur disappears and the cyanosis slightly improves. What is the most likely diagnosis of this patient?

179) A 2-month-old infant is evaluated by a pediatric cardiologist. The infant was noted at birth to have an upper left sternal border ejection murmur. The infant at that time was not cyanotic, but slowly developed cyanosis over the next two months. At the time of the pediatric cardiologist's examination, an ECG showed right axis deviation and right ventricular hypertrophy. A chest x-ray film showed a small heart with a concave main pulmonary artery segment and diminished pulmonary blood flow. Which of the following is the most likely diagnosis?

180) A 6-year-old boy is brought to the emergency department because of the acute onset of headache, nausea, and vomiting. On arrival, physical examination reveals marked nuchal rigidity and funduscopic evidence of papilledema. A head CT scan reveals a solid tumor in the posterior fossa, centered in the cerebellar vermis and extending to the fourth ventricle. An emergency craniotomy is performed, during which a small sample of the tumor is sent to the pathologist for a frozen section consultation. Which of the following is the most likely diagnosis?

181) A 15-month-old girl is brought to the office by her mother due to failure to thrive. For the past three months, the child has had foul-smelling, non-bloody, loose stools 7 to 8 times daily. On examination, she is irritable and has a protruding belly and trace pre-tibial edema. There are erythematous vesicles symmetrically distributed over the extensor surfaces of her elbows and knees. Preliminary laboratory investigations are significant for hypochromic microcytic anemia, and stool examination is negative for ova or parasites. What is the most likely cause of failure to thrive in this child?

184) A 25-year-old woman brings her 5-day-old infant to the emergency room after noticing that he bruises very easily. Her pregnancy was normal, and the baby was born at term via vaginal delivery at home. This is the child's first visit to the doctor. He is exclusively breast-fed, and there is no family history of bleeding disorders. On physical examination, his vital signs are within normal limits. You note several ecchymotic skin lesions, but his exam is otherwise normal. Laboratory studies show the following: Prothrombin time 20 sec, Partial thromboplastin time 37 sec, Platelets 200,000/mm3. Which of the following is the most likely cause of his current condition?

185) A 7-year-old girl is brought to the physician because of an exanthematous rash associated with malaise and headache for 2 days. On examination, the child shows a fiery red facial rash with a characteristic "slapped cheek" pattern and pallor around the mouth. There is no fever. In immunocompromised patients, the pathogen that causes this condition may result in which of the following manifestations?

186) A 12-year-old boy is brought to the physician because of pain in his right leg for the past 3 weeks. The pain frequently occurs at night and is localized to the tibia, a few centimeters below the knee. The mother reports that the pain is promptly relieved by aspirin and that the child has had no fever. Examination reveals no tissue swelling or redness about the site of pain. X-ray films show a 1-cm radiolucent focus in the tibial cortex surrounded by marked bone sclerosis. Which of the following is the most likely diagnosis?

187) A 7-year-old boy is brought to the physician because of recurrent headaches. The child feels nauseated before and during each attack, and derives some relief from lying down in a dark room. Noises, bright light, and fatigue seem to trigger the episodes. The child frequently complains of headaches at school, and his mother has been occasionally compelled to take him home. The mother is worried about the possibility of a serious illness. She reports that the child's father has similar headaches. The child's growth is normal, and a neurologic examination fails to reveal any abnormality. Which of the following is the most likely diagnosis?

188) A 12-year boy is brought to the emergency room by his parents after a several day history of progressive weakness. He has been a healthy child who has met all development milestones and all his immunizations are up to date. He reports that he had an upper respiratory infection 2 weeks ago. On physical examination, his vital signs are labile with a pulse range of 60-100/ min and systolic blood pressure ranging from 80-120 mm Hg. He is alert and oriented. Neurologic examination is impressive for bilateral weakness in the upper and lower extremities. Deep tendon reflexes are absent and sensation is intact. Which of the following is the most likely diagnosis?

189) A 2-year-old boy is brought to the office due to recurrent skin and soft tissue infections. When he was 2- months-old, he had a perianal furuncle that was incised and drained because it was unresponsive to oral antibiotics. At 7 months of age, he had a left inguinal Klebsiella pneumoniae lymphadenitis. His other past infections include a left calf cellulitis that grew Serratia marcescens and a left inguinal abscess that grew Staphylococcus epidermidis. On examination, he has hepatosplenomegaly, and enlarged axillary and inguinal lymph nodes. The screening tests for humoral, cell-mediated, and complement-mediated immunity are normal. The nitroblue tetra zolium (NBT) slide test is abnormal. What is the most likely diagnosis?

190) A fetus is delivered at 40 weeks' gestation. During labor, the fetal heart monitor shows late decelerations and loss of short- and long-term variability. The membranes are ruptured to expedite the delivery. The fluid is noted to contain meconium. The infant is delivered 45 minutes later. At delivery, the infant appears to be cyanotic and limp. He has poor tone and deep reflexes. Moro's reflex is absent. Ten hours later, he experiences a seizure. Which of the following best explains this infant's perinatal course?

191) A neonate is very small for gestational age, shows hypotonia, marked skeletal muscle, and subcutaneous fat hypoplasia. During delivery, a large volume of amniotic fluid was released at rupture of membranes. The placenta was small, and only a single umbilical artery was noted. The face has a pinched appearance with hypoplastic orbital ridges, short palpebral fissures, and a small mouth and jaw. The head is small with prominence of the occiput. The ears are low set and malformed. The infant's fists are clenched, with overlapping of the third and fourth fingers. The feet are clubbed, and the great toe is shortened. Which of the following is most likely diagnosis?

193) A 17-year-old boy is brought to the emergency department by his parents with the complaint of coughing up blood. He is stabilized, and his hemoglobin and hematocrit levels are 11 mg/dL and 33%, respectively. During his hospitalization, he is noted to have systolic blood pressure persistently greater than 130 mm Hg and diastolic blood pressure greater than 90 mm Hg. His urinalysis is remarkable for hematuria and proteinuria. You are suspicious the patient has which of the following?

194) A 4-year-old boy is being evaluated for short stature. He has a history of multiple bone fractures in the past. He requires a wheelchair to ambulate and has hearing difficulty. On physical examination, his height is below the 5th percentile. His sclerae are blue in color. There is marked deformity of his lower extremities. Which of the following is the most likely diagnosis?

195) The mother of a 2-week-old infant reports that since birth, her infant sleeps most of the day; she has to awaken her every 4 hours to feed, and she will take only an ounce of formula at a time. She also is concerned that the infant has persistently hard, pellet-like stools. On your examination you find an infant with normal weight and length, but with an enlarged head. The heart rate is 75 beats per minute and the temperature is 35°C (95°F). The child is still jaundiced. You note large anterior and posterior fontanelles, a distended abdomen, and an umbilical hernia. This clinical presentation is likely a result of which of the following?

197) A 6-year-old Caucasian boy is brought to the emergency room by his mother with hemiplegia of acute onset. She states that she found the boy unconscious in his room where she had left him playing several minutes ago; and, he slowly gained consciousness, but could not move his right arm and leg. His past medical history is insignificant. Physical examination reveals right hemiparesis with little sensory abnormalities. No meningeal signs are present. The motor function restored spontaneously during 24-hour observation in the hospital. A CT scan of the head is normal. What is the most probable cause of this patient's problem?

198) A 6-year-old female with Down syndrome is brought to the physician for behavioral changes. Over the past few weeks, she has begun refusing to do her usual activities. Her parents also report that she seems dizzy and state that she has developed urinary incontinence. On examination, she is hypotonic but hyperreflexic with a positive Babinski reflex. Her gait is ataxic. Which of the following is the most likely diagnosis?

199) An 8-year-old Cub Scout who returned from an outing 9 days ago is brought to the clinic with the rapid onset of fever, headache, muscle pain, and rash. The maculopapular rash began on the flexor surfaces of the wrist and has become petechial as it spread inward to his trunk. Which of the following is the most likely diagnosis?

200) A 12-year-old girl has had a sore throat over 2 days. She now has a fever of 39.5°C and has difficulty opening her mouth, swallowing, or speaking. Her throat can be visualized with difficulty, the right tonsil is significantly more enlarged than the left, and the uvula is displaced to the left side. Which of the following is the most likely diagnosis?