Part 7 ( 1729 -1762 ) (1530 - 1784) Pogba KH 7

226) A young infant is noted to have developed constipation over the past week, and then facial diplegia and difficulty sucking and swallowing. The child has been colicky, and the maternal grandmother has been treating the child with a mixture of weak tea, rice water, and honey. Which of the following disorders is the most likely culprit in this child?

227) About 12 days after a mild upper respiratory infection, a 12-year-old boy complains of weakness in his lower extremities. Over several days, the weakness progresses to include his trunk. On physical examination, he has the weakness described and no lower extremity deep tendon reflexes, muscle atrophy, or pain. Spinal fluid studies are notable for elevated protein only. Which of the following is the most likely diagnosis in this patient?

228) A premature neonate develops respiratory distress syndrome several hours after birth. The infant is placed on a respirator and given other appropriate care. However, when the infant reaches a corrected gestational age of 36 weeks, he does not tolerate weaning from the ventilator. A chest x-ray film demonstrates alternating areas of hyperaeration and pulmonary scarring, resulting in parenchymal streaks and hyperexpanded areas. Which of the following is the most likely diagnosis?

229) A neonate has Down syndrome. Maternal hydrammos had been noted prenatally. After the first feeding, the infant has projectile vomiting with bile-stained vomitus. An x-ray film demonstrates a "double-bubble sign" in the abdomen. Which of the following is the most likely diagnosis?

230) A 10-year-old boy is brought to the office by his parents because he is developing dark facial hair, deepening of the voice and a rapid height increase. He also complains of persistent headaches which are resistant to over-the-counter analgesics for the past 2 weeks. He denies nausea, vomiting or visual disturbances. His medical history is unremarkable. Physical examination reveals coarse pubic and axillary hair. Other pertinent findings include lid retraction, paralysis of upward and downward gaze, and poor pupillary reaction to light. His deep tendon reflexes are normal, Babinski sign is negative, and there are no focal neurologic signs. What tumor is most likely responsible for this child's symptoms?

231) A 17-year-old girl comes to the clinic with several weeks of joint pain and rash. The joint pain is most prominent in the hands. She states that the pain is most severe in the morning and tends to improve over the day. She has noted some swelling of her fingers. She has also had a rash on her face that becomes more prominent when she is outdoors. She states that sunlight tends to bother her eyes. On further questioning, she states that she has not felt well for several months. She has had intermittent fever, has been more tired than usual, and has lost weight although she has not been restricting her diet. On physical examination, she looks tired. She has lost 5 lbs since her last visit 1 year ago. She has an erythematous rash on her cheeks. She has several shallow ulcers in her mouth. She has fusiform swelling of her fingers and pain with movement of her fingers. Which of the following is the most likely diagnosis?

232) A full-term newborn develops cyanosis a few hours after birth. Oxygen administration does not improve color or oxygen saturations. Which of the following is the most likely diagnosis?

233) A 6-year-old male presents to the physician with eyelid swelling. His mother noted an insect bite on his left cheek yesterday, and states that this morning his left eyelid was completely swollen shut and painful. He has not had a fever, fatigue, headache, or rhinorrhea. On examination, he is afebrile. The left eyelid is erythematous, tender to palpation, and swollen shut. When trying to clinically distinguish between preseptal and orbital cellulitis, which of the following findings is most likely to be seen with preseptal cellulitis?

234) A 4-year-old Caucasian boy is brought to his physician's office for a health maintenance exam. He will be starting preschool soon, and his parents want to make sure that he is in optimal health. The child has no complaints, and is generally happy. His medical history is significant for pneumonia as a newborn, and three episodes of otitis media since birth. He does not take any medications on a regular basis. His newborn screening test results are normal. His developmental milestones are at par with his age. He lives with his parents in a middle-class, suburban house built in 1981. Which of the following is the most appropriate next step for this child's primary care?

235) Initial examination of a full-term infant weighing less than 2500 g (5 lb, 8 oz) shows edema over the dorsum of her hands and feet. Which of the following findings would support a diagnosis of Turner syndrome?

236) While bathing her newly-received 2-year-old son, a foster mother feels a mass in his abdomen. A thorough medical evaluation of the child reveals aniridia, hypospadias, horseshoe kidney, and hemihypertrophy. Which of the following is the most likely diagnosis for this child?

237) A 7-day-old boy is admitted to a hospital for evaluation of vomiting and dehydration. Physical examination is otherwise normal except for minimal hyperpigmentation of the nipples. Serum sodium and potassium concentrations are 120 mEq/L and 9 mEq/L (without hemolysis), respectively; serum glucose is 40 mg/dL. Which of the following is the most likely diagnosis?

238) A 12-week-old female infant is brought to the office by her mother due to a three-week history of weakness, poor appetite, and choking spells during feeding. Other accompanying symptoms include excessive sleeping, constipation and apathy. Her prenatal history is unremarkable. She was delivered vaginally at 38 weeks of gestation. Her weight and length at birth were within normal range. She is exclusively breastfed. Her mother's family history is unremarkable. The identity and family history of her father are unknown. The pertinent physical findings include apathy, weakness, hypotonia, large tongue, sluggish movement, abdominal bloating, and an umbilical hernia. Based on the given information, what is the most likely diagnosis?

239) While making rounds in the newborn nursery, the nurses ask you to examine a 2-day-old infant who is not feeding well. The nurse reports that the infant is irritable, is not sleeping well, and has had several episodes of vomiting and loose stools today. A review of the maternal history reveals that she had poor prenatal care and the pregnancy was complicated by intrauterine growth restriction. On examination, the infant is diaphoretic and has a high-pitched cry. The infant is also noted to have occasional sneezing and is mildly tachypneic. No dysmorphic features are noted and the remainder of the examination is unremarkable. This infant's symptoms are most likely caused by prenatal exposure to which of the following?

240) A 10-year-old boy is brought to the emergency department due to abdominal pain and bloody diarrhea. The mother says that he was "fine" a few days ago, and then suddenly became ill. Physical examination shows a pale and jaundiced child. There is diffuse abdominal tenderness and 2+ pedal edema. Laboratory studies show anemia, thrombocytopenia and renal insufficiency. What is the most likely cause of the patient's symptoms?

241) A 16-year-old girl is brought to the office due to abdominal pain and bloody diarrhea for the past two days. Her immunizations are up to date. Her past medical history is unremarkable. On examination, she appears lethargic and weak. Her skin turgor is poor, face and extremities are swollen, and skin appears yellow. Abdominal examination shows moderate non-localized, abdominal pain. Laboratory studies show: Hb 64 g/dl, Hct 26.9%, Platelets 45,000/mm3, Creatinine 2.3 mg/dl, Total bilirubin 5.0 mg/dl. What is the most common complication of the patient's condition?

243) A 4-year-old boy, whose past medical history is positive for three urinary tract infections, presents with a blood pressure of 135/90 mm Hg. He is likely to exhibit which of the following symptoms or signs?

245) A 6-year-old boy is brought to the ER with a two-day history of difficulty walking. He is dragging his right leg and seems to have weakness in his right arm. He also complains of headaches. The family just emigrated from Eastern Europe. According to his parents, the child suffers from delayed growth compared to his peers and does not like to engage in active play. His lips and fingers turn blue when he cries. His vital signs today are a blood pressure of 100/70 mmHg, pulse of 90/min, temperature of 38.3 0C (102.0 0F), and respiratory rate of 22/min. Which of the following is most likely responsible for his current complaints?

247) A 4-year-old, apparently healthy child is examined by a pediatrician. The pediatrician hears a loud systolic ejection murmur with a prominent systolic ejection click. He also hears a soft, early diastolic murmur. Both murmurs are heard best at the upper right sternal border. ECG shows left ventricular hypertrophy. Which of the following is the most likely diagnosis?

248) A 19-year-old primiparous woman develops toxemia in her last trimester of pregnancy and during the course of her labor is treated with magnesium sulfate. At 38 weeks’ gestation, she delivers a 2100-g (4-lb, 10-oz) infant with Apgar scores of 1 at 1 minute and 5 at 5 minutes. Laboratory studies at 18 hours of age reveal a hematocrit of 79%, platelet count of 100,000/μL, glucose 41 mg/dL, magnesium 2.5 mEq/L, and calcium 8.7 mg/dL. Soon after, the infant has a generalized convulsion. Which of the following is the 248) A 19-year-old primiparous woman develops toxemia in her last trimester of pregnancy and during the course of her labor is treated with magnesium sulfate. At 38 weeks’ gestation, she delivers a 2100-g (4-lb, 10-oz) infant with Apgar scores of 1 at 1 minute and 5 at 5 minutes. Laboratory studies at 18 hours of age reveal a hematocrit of 79%, platelet count of 100,000/μL, glucose 41 mg/dL, magnesium 2.5 mEq/L, and calcium 8.7 mg/dL. Soon after, the infant has a generalized convulsion. Which of the following is the most likely cause of the infant’s seizure?most likely cause of the infant’s seizure?

249) A 4-year-old child presents with an enlarged submandibular node that is 4 cm in diameter, nontender, and not fluctuant. The node has been enlarged for about 4 weeks, and there is no history of fever or contact with any person who was ill. A CBC is normal, and a Mantoux test with 5 tuberculin units of PPD shows 6 mm of induration. Which of the following is the most likely diagnosis?

250) A 7-month-old patient presents with a history of 3 days of fever to 104°F, which resolved the same day that an exanthem erupted. The exanthem is prominent on the neck and trunk. It is macular, with discrete lesions 3–5 mm in diameter. Which of the following is the most likely diagnosis?

251) A 3-year-old boy’s parents complain that their child has difficulty walking. The child rolled, sat, and first stood at essentially normal ages and first walked at 13 months of age. Over the past several months, however, the family has noticed an increased inward curvature of the lower spine as he walks and that his gait has become more “waddling” in nature. On examination, you confirm these findings and also notice that he has enlargement of his calves. Which of the following is the most likely diagnosis?

252) Your 6-year-old son awakens at 1:00 AM screaming. You note that he is hyperventilating, is tachycardic, and has dilated pupils. He cannot be consoled, does not respond, and is unaware of his environment. After a few minutes, he returns to normal sleep. He recalls nothing the following morning. Which of the following is the most likely diagnosis?

253) A 5-year-old febrile child presents with swelling of the right eyelid. Proptosis and limitation of ocular movements is noted. Which of the following is the most likely diagnosis?

254) A 10-year-old boy is brought in with a chief complaint of multiple colds. On further questioning, you elicit a history of chronic, clear nasal discharge with no seasonal variation. Other symptoms include sneezing, itching of the nose and eyes, as well as tearing and occasional eye redness. Some relief is obtained with an over-the-counter cold medicine containing antihistamine and a decongestant. His history suggests which of the following?

256) A 4-day-old infant presents with yellow discoloration of the skin and sclera. The baby was born at term by a normal vaginal delivery. Pregnancy was uncomplicated; there were no risk factors for sepsis and no history of maternal alcohol or drug use. The baby is breast-fed and has been nursing every 2 hours, about 10 minutes at each breast. The bilirubin level is 15 mg/dL (all unconjugated), the hematocrit is 45%, and the Coombs test is negative. Which of the following is the most likely diagnosis?

257) A previously healthy, active, 18-month-old African American child presents with unilateral nasal obstruction and foul-smelling discharge. The child’s examination is otherwise unremarkable. Which of the following is the most likely diagnosis?

258) A 7-month-old baby presents with a history of constipation for 1 month. He has one hard stool every week. He has been well otherwise. His physical examination is normal. Which of the following is the most likely cause of his problem?

259) A specific pattern of abnormalities has been identified among infants born to mothers who consume moderate-to-large amounts of alcohol during their pregnancies. Which of the following abnormalities is characteristic of these infants?

261) The parents of a previously healthy 2-year-old child note her to be pale and bring her to your clinic for evaluation. She currently has no fever, nausea, emesis, bone pain, or other complaints. Her examination is significant for pallor, tachycardia, and a systolic ejection murmur, but she has no organomegaly. Her complete blood count (CBC) reveals a hemoglobin of 4 g/dL, normal indices for age, a WBC count of 6.5/μL, and a platelet count of 750,000/μL. Her reticulocyte count is 0%. Coombs test is negative. Her peripheral blood smear shows no blast forms and no fragments. Red blood cell (RBC) adenosine deaminase levels are normal. A bone marrow reveals markedly decreased erythroid precursors. Which of the following is this child’s likely diagnosis?

262) On a routine-screening CBC, a 1-year-old is noted to have a microcytic anemia. A follow-up hemoglobin electrophoresis demonstrates an increased concentration of hemoglobin A2. The child is most likely to have which of the following?

263) A 2-year-old child is brought to the office by his parents for the evaluation of failure to thrive and chronic diarrhea. His diarrhea is "almost continuous", and he also has recurrent episodes of fever. He was initially quite well and was on the 60th percentile for weight; however, for the past seven months, he didn't seem to grow and failed to gain weight. Over the past three months, he fell to the 3rd percentile for weight. His parents deny any use of drugs, but they drink occasionally. His mother mentions that her former boyfriend was a heroin addict. Physical examination reveals oral thrush, generalized lymphadenopathy and eczema. What is the most likely diagnosis in this patient?

264) After being delivered following a benign gestation, a newborn infant is noted to have a platelet count of 35,000/μL, decreased fibrinogen, and elevated fibrin spilt products. On examination you note a large cutaneous hemangioma on the abdomen that is purple and firm. Which of the following anomalies might also be expected in this infant?

265) A 6-year-old girl has a low-grade fever, headache, and nasal congestion. She has a flushed face and has developed a lacy reticular rash on the trunk and extensor surface of her arms and legs. Palms and soles are spared. Her mother has been ill with a low-grade fever and some joint stiffness and pain. Which of the following is the most likely diagnosis?

266) A 3-year-old boy has had fever for 4 days. On physical examination he has bilateral cervical lymphadenopathy, injected pharynx, and dry cracked lips. A throat swab is done and the rapid strep test is negative. The child is sent home and advised to follow-up if symptoms worsen. The child is brought back 2 days later with all previous findings including a maculopapular rash, swollen hands, and conjunctivitis. Which of the following is the most likely diagnosis?

267) An 8-year-old Caucasian boy is brought to the office for the evaluation of high-grade fever, flank pain and burning micturition for the last two days. He has had two previous episodes of acute pyelonephritis. Physical examination reveals costovertebral angle tenderness. Urinalysis shows pyuria, significant bacteriuria, WBC casts, positive nitrite and esterase. The voiding cystourethrogram (VCUG) reveals vesicoureteral reflux. What is the most likely complication of this condition, if left untreated?

268) A woman comes to an emergency department because she is in labor. She has had no prenatal care. Her baby is delivered and appears to be of about 32 weeks' gestation. The newborn is very pale and shows severe, generalized edema. Cord-blood hematocrit is 22%, and cord-blood bilirubin is 7 mg/dl. Ultrasound examination demonstrates pleural effusions, ascites, cardiomegaly, and hepatomegaly. Which of the following is the most likely diagnosis?

269) A neonate is examined following a protracted breech delivery. One of the infant's arms is partially paralyzed. The affected arm is adducted and internally rotated at the shoulder, and the forearm is pronated. Which of the following is the most likely diagnosis?

270) A 2-year-old boy presents with refusal to use his right arm for 1 day. He is otherwise well. His mother states she pulled upward on his arm the previous evening to keep him from tripping down the stairs. Which of the following is the most likely diagnosis?

271) A 1-day-old infant who received silver nitrate eye drops in the delivery room is suffering from bilateral purulent conjunctival discharge. Which of the following is the most likely cause of this child’s condition?

272) A 14-year-old girl has a history of red eyes with clear discharge that she suffers from in a seasonal pattern. Together with these symptoms, she reports itching, which is her most bothersome complaint. Physical examination shows conjunctival redness, tearing, and swelling, but there is no purulent discharge. This clinical picture is most compatible with a diagnosis of which of the following conditions?

273) 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?

274) A 14-year-old boy presents with decreased exercise tolerance. He is noted to have a grade III/VI systolic ejection murmur best heard at the left upper sternal border and a grade II/VI mid-diastolic murmur at the lower left sternal border. The first heart sound is normal. The second heart sound is widely split and fixed. A right ventricular impulse is palpated. On a chest roentgenogram, the pulmonary artery segment is enlarged, and pulmonary vascular markings are increased. An ECG shows right axis deviation. Which of the following congenital heart diseases does this boy most likely have?

275) A 7-year-old boy presents with a rash. His mother states that he was well until 3 days ago when he developed fever and malaise. The next day, the rash started as papules on the trunk, which rapidly changed to vesicles. The lesions have spread all over the body. On physical examination, he has no fever and seems well. You note numerous vesicles all over the body, some of which have crusted over. Which of the following is the most likely diagnosis?

276) A 4-year-old boy presents to the emergency department with generalized tonic-clonic seizures. On physical examination, the child is noted to be lethargic. His temperature is 37.4 C (99.3 F), blood pressure is 100/60 mm Hg, pulse is 72/min, and respirations are 16/min. His oral mucosa is moist, and there is no peripheral edema. Laboratory tests show: Blood: Sodium 120 mEq/L, Potassium 4.2 mEq/L, Chloride 96 mEq/L, Bicarbonate 20 mEq/L, Blood urea nitrogen 9.6 mg/dL, Creatinine 0.4 mg/dL, Glucose 88 mg/dL, Urine: Sodium 55 mEq/L, Potassium 16 mEq/L, Osmolality 530 mOsmol/kg. Which of the following is the most likely diagnosis?

277) A 1-month-old, previously healthy infant develops forceful projectile vomiting. No bile is seen in the vomitus. After the infant feeds, gastric peristaltic waves are visible crossing the epigastrium from left to right. Several minutes later, the projectile vomiting occurs. Which of the following is the most likely diagnosis?

278) A 5-month-old girl is brought to the office by her mother, who states that the girl had an episode following feeding during which she began to breathe deeply, became blue, and then lost consciousness. The mother states that she picked her up and held her, and the infant regained her usual color and became alert. Physical examination reveals a harsh systolic murmur. Which of the following is the most likely diagnosis?

279) Physical examination of an infant delivered to a 42-year-old, gravida 3, para 2, woman, is remarkable for slight hypotonia and a poor Moro reflex. Further examination reveals upslanting palpebral fissures, epicanthal folds, excess nuchal skin, an enlarged tongue, clinodactyly of the fifth fingers, and a single transverse palmar crease. Which of the following is the most likely diagnosis?

281) A 10-month-old infant on long-term aspirin therapy for Kawasaki disease develops sudden onset of high fever, chills, diarrhea, and irritability. A rapid swab in your office identifies influenza A, adding her to the long list of influenza patients you have seen this December. Over the next few days, she slowly improves and becomes afebrile. However, 5 days after your last encounter you hear from the hospital that she has presented to the emergency center obtunded and posturing with evidence of liver dysfunction. Which of the following statements about her current condition is correct?

282) The parents of a 7-month-old boy arrive in your office with the child and a stack of medical records for a second opinion. The boy first started having problems after his circumcision in the nursery when he had prolonged bleeding. Studies were sent at the time for hemophilia, but factor VIII and IX activity were normal. At 2 months he developed bloody diarrhea, which his doctor assumed was a milk protein allergy and changed him to soy; his parents note he still has occasional bloody diarrhea. He has seen a dermatologist several times for eczema, and he has been admitted to the hospital twice for pneumococcal bacteremia. During both admissions, the parents were told that the infant’s platelet count was low, but they have yet to attend the hematology appointment arranged for them. The child’s WBC count and differential were normal. Which of the following is the most likely diagnosis in this child?

283) A one-day-old infant with Down syndrome has developed persistent vomiting. He was delivered vaginally at 34 weeks without any complications. On examination, he appears dehydrated and slightly tachypneic. His abdomen is soft and not distended. Abdominal x-ray reveals two large distinct air bubbles, but there are no dilated bowel loops or air fluid levels. What is the most likely diagnosis of this patient?

284) A 10-year-old boy from the Connecticut coast is seen because of discomfort in his right knee. He had a large, annular, erythematous lesion on his back that disappeared 4 weeks prior to the present visit. His mother recalls pulling a small tick off his back. Which of the following is a correct statement about this child’s likely illness?

285) Two weeks ago, a 5-year-old boy developed diarrhea, which has persisted to the present time despite dietary management. His stools have been watery, pale, and frothy. He has been afebrile. Microscopic examination of his stools is likely to show which of the following?

287) A 6-year-old boy is brought to the physician for evaluation of behavior problems. His parents report he is "hyperactive all the time." They cannot get him to sit still. When he does sit, he fidgets and tries to get out of his seat. He is easily distracted and frequently changes from one activity to another. He does not seem to listen when his parents talk to him, and often forgets to do his chores. He talks excessively and often interrupts other people. His parents state that he has been like this for a few years, but they had originally assumed his behavior was normal for his age. His physical examination is unremarkable. Which of the following will be of most help in establishing the diagnosis?

288) An 8-year-old boy is brought to the office due to headaches and impaired walking. These symptoms started seven days ago, and progressed gradually. He just recently recovered from otitis media that was superimposed on an acute respiratory infection. His past medical history is significant for three episodes of otitis media and one episode of pneumonia. His temperature is 36.7C (98F), blood pressure is 100/60 mm Hg, pulse is 110/min, and respirations are 20/min. Physical examination reveals mild right-sided hemiparesis and a slightly dilated left pupil. The funduscopic examination is normal. Which of the following is the most likely diagnosis?

289) A 1-day-old male infant has bilious vomiting after every feeding. He hasn't passed any stools yet. He had no prenatal care, and was delivered vaginally at term. He weighs 3kg (6.61b), and his APGAR scores were 6 and 7 at 1 min and 5 min, respectively. On examination, the neonate is hypotonic, he has a flat facial profile, short ears with downfolding ear lobes, a single palmar crease, and a depressed fontanel. There is abdominal distention which is most prominent in the upper abdomen. His abdominal x-rays show gastric and duodenal gas distension with no air distally. What other anomaly can also be expected in this infant?

290) A 14-year-old boy is brought to the emergency room because of persistent midepigastric pain for two days. The pain is getting no better, yet it is no worse, and radiates to his back. The boy also has had fever, as well as nausea and vomiting that is worse when his temperature rises in the afternoon. On examination, his temperature is 39.2C (102.5F) and there is marked upper abdominal tenderness with guarding. Mild abdominal distention is present with no audible bowel sounds. A complete blood count reveals an elevated leukocyte count and a normal serum amylase. Which of the following is the most likely diagnosis?

291) A baby is born at 34 weeks gestation. The amniotic fluid is brown and murky. The baby has low APGAR scores and appears to be septic, with lethargy, apnea, bradycardia, and temperature instability. The mother lives on a farm and gives a history of a flu-like illness one month before delivery. Gram's stain of a smear from the mother's cervix demonstrates abundant, pleomorphic, gram-variable coccobacillary forms. Which of the following is the most likely diagnosis?

292) A 14-year-old black male comes to the office for the evaluation of pain in his right hip that started several weeks ago. The pain has gradually progressed, and now it limits his daily activities. He has sickle cell disease and was hospitalized three months ago due to a painful crisis that was successfully treated with hydration, oxygen, and analgesics. His temperature is 37.2C (99F), blood pressure is 100/70 mmHg, pulse is 80/min, and respirations are 16/min. Physical examination reveals no local tenderness, but there is restriction of abduction and internal rotation of the hip What is the most likely diagnosis?

293) A 6-year-old Caucasian male is brought to your office with a two-week history of right shoulder pain. Physical examination reveals localized swelling below the shoulder joint, and x-ray shows a single lytic lesion in the right humeral head. Laboratory analyses show mild hypercalcemia but are otherwise within normal limits. Which of the following is the most likely diagnosis?

294) An infant is born prematurely and is small for gestational age. At birth, the infant is obviously ill with jaundice, fever, hepatosplenomegaly, myocarditis, and rashes. Neurologic involvement is prominent, with hydrocephalus, intracranial calcifications, and seizures. The mother has a cat and continued to clean the cat's litter box during the pregnancy. Which of the following is the most likely causative agent?

295) A beekeeper’s previously healthy 6-month-old son develops gradual onset of lethargy, poor feeding, constipation, and generalized weakness. On taking a history, you determine that the child has recently been placed on a homemade formula consisting of evaporated milk, water, and honey. Which of the following is the most likely explanation for this symptom complex?

296) A 12-year-old girl is taken to a pediatrician complaining of a sore mouth. On questioning, the child states that she has been feeling poorly, with fatigue and weakness. She began menstruating briefly and then stopped. Physical examination is notable for focal white crusting of the oral cavity; biopsy of one of these areas later shows candidiasis, Laboratory studies show the following: Sodium 127 mEq/L, Potassium 5.3 mEq/L, Bicarbonate 24 mEq/L, Calcium 7.5 mEq/dL, Phosphorus 5.5 mg/dL, Glucose 87 mg/dL. Which of the following is the most likely diagnosis?

297) A 15-year-old girl presents with a 2-day history of pain and swelling in her left knee. She plays soccer regularly on her school team. There is no history of trauma. On physical examination, there is marked swelling and tenderness over her anterior tibial tuberosity. A radiograph of her left knee reveals irregularities of the tubercle contour and haziness of the adjacent metaphyseal border. Which of the following is the most likely explanation for her symptoms?

299) A 2-day-old male infant presents with multiple episodes of bilious vomiting over the past 24 hours. He has a prominent tongue, flat occiput and slanting eyes. His hands are short, and there are wide gaps between his first and second digits. His abdomen is soft and without any distention, guarding or rigidity. On auscultation of the chest, there is a systolic ejection murmur along the left sternal border, with a wide and fixed splitting of S2. Abdominal x- rays show air trapped in the first portion of the duodenum and stomach. What is the most likely cause of the child's symptoms?

300) A 2-year-old girl presents to the office with a dry cough and a low-grade fever. Over the last two days, she has become very irritable and difficult to feed. She has also had a runny nose. On examination, there is significant wheezing and tachycardia. Evaluation of the nasal discharge confirms the diagnosis of respiratory syncytial virus infection. In the future, which of the following does this child have a slight risk of developing?

301) A 10-month-old boy develops an upper respiratory tract infection 2 days before presentation. On the day of presentation, he has a generalized tonic-clonic seizure lasting 30 seconds. His temperature is 40.0 C (104 F), blood pressure is 90/60 mm Hg, and respirations are 22/min. He is alert and smiling. He has rhinorrhea, and his neck is supple. He has bruises below his knees. Which of the following is the most likely diagnosis?

302) A 4-month-old child presents with a 2-day history of vomiting and intermittent irritability. On examination, “currant jelly” stool is noted in the diaper, and a sausage-shaped mass is palpated in the right upper quadrant of the abdomen. Which of the following conditions is most likely to cause this?

303) A 2-hour-old full-term newborn infant is noted by the nursing staff to be having episodes of cyanosis and apnea. Per nursery protocol they place an oxygen saturation monitor on him. When they attempted to feed him, his oxygen levels drop into the 60s. When he is stimulated and cries, his oxygen levels increase into the 90s. Which of the following is the most important next step to quickly establish the diagnosis?

304) The police bring a 14-year-old boy to the clinic after he was found setting fire to the neighbor's house. He has been previously arrested and warned by the cops twice. The first time was 15 months ago for stealing his neighbor's motorcycle. The second occasion was 6 months ago for a fight with his peers on the roadside. His parents arrive and tell you that he has been behaving this way for the past 3 years, and often argues at home. He steals money from them and tries to hurt the pets. Although they have not seen him using any drugs, they suspect that his behavior could be due to drugs. What is the most likely diagnosis?

305) A 14-year-old girl presents to the emergency room for severe lower mid-abdominal pain that has been increasing over the past 12 hours. She describes it as crampy and sharp. Her last menstrual period was about 2 weeks ago. It was regular with no pain and lasted 4 to 5 days. She has had menstrual periods for nearly 2 years, and over the past 6 months she has noticed some cramping pain the first day or two of her menses. She denies sexual activity and has not had any vaginal discharge. Her bowel movements have been normal and she reports no urinary frequency, urgency, or burning with urination. Which of the following is the most likely diagnosis?

306) A 9-month-old boy is taken to the emergency room because of high fever. Breath sounds are diminished in the lungs, and a chest x-ray film shows lobar pneumonia. Probable streptococcal pneumonia is demonstrated in Gram's stain of sputum and then later confirmed by culture. The child responds to antibiotic therapy. A detailed history is taken during the admission, which reveals that this is the third episode of pneumonia in this young child; the two previous episodes occurred at 6 and 7.5 months of age. One of the mother's brothers had died of infection at age 9. Immunoglobulin studies demonstrate the following: IgG 80 mg/dL [normal 723-1685 mg/dL], IgA 60 mg/dL [normal 81-463 mg/dL], IgM 20 mg/dL [normal 48-271 mg/dL]. Studies of the lymphocyte population demonstrate normal numbers of T cells and markedly decreased B cells. Which of the following is the most likely diagnosis?

307) A newborn baby is noted to have abnormal facies with low-set ears; a small receding jaw; and widely separated eyes. At 30 hours of age, the baby develops multiple muscle spasms. Serum studies are notable for calcium of 4.5 mg/dL. Which of the following is the most likely diagnosis?

308) A 5-year-old girl is being evaluated for generalized swelling. Her blood pressure is 98/60 mm Hg. Her laboratory results show: Creatinine 0.7 mg/dl, Albumin 1.6 g/dL, Cholesterol 360 mg/dL, Triglycerides 400 mg/dL, C3 complement 120 mg/dL (normal, >80 mg/dL), Antinuclear antibody Negative, Urinalysis 1 RBC/hpf, protein 400 mg/dL. Which of the following is the most likely diagnosis?

309) A 10-year-old girl is evaluated by a pediatrician. She is already 5'8" tall and is taller than other members of her family were at this age. Her arms are disproportionately long compared with her trunk, and her sternum is outwardly displaced. Her joints are hyperextensible, particularly at the knees. Ocular examination demonstrates dislocation of one lens. Which of the following is the most likely diagnosis?

310) An 8-year-old boy is brought to the clinic by his mother, who states that he has been complaining of pain in both knees. The mother also states that he had a rash on his leg 3 weeks ago. She said it was there for almost 2 weeks and then went away. She describes the rash as reddish and circular, with a small clear area in the center. She said the rash was not itchy or painful. The child has also complained of headaches and muscle aches over the past several weeks. On questioning, the mother states that they were vacationing in Wisconsin about 1 month ago and the boy was hiking in the woods when he was bitten by a tick. Which of the following is the most likely diagnosis?

311) A male child born to a 25-year-old Caucasian mother by normal vaginal delivery at 36 weeks of gestation is found to have a small face, a small jaw, and a prominence on the back of his head. There are no skin creases on the palmar aspect of his digits. There is overlapping of his fingers bilaterally, along with rocker bottom feet and limited hip abduction. Heart murmur is present. Which of the following cardiovascular abnormality is most likely seen in this patient?

313) A 15-year-old girl is admitted to the hospital with a 6-kg weight loss, bloody diarrhea, and fever that have occurred intermittently over the previous 6 months. She reports cramping abdominal pain with bowel movements. She also reports secondary amenorrhea during this time. Stool cultures in her physician’s office have shown only normal intestinal flora. A urine pregnancy test was negative, while an erythrocyte sedimentation rate (ESR) was elevated. Her examination is significant for the lack of oral mucosal ulcerations and a normal perianal examination. Anti-Saccharomyces cerevisiae antibodies (ASCA) are negative, while anti-neutrophil cytoplasm antibodies (p-ANCA) are positive. You confirm your presumptive diagnosis with a rectal biopsy. In counseling her about her disease, which of the following statements would be true?

314) A 6-year-old boy is brought to the physician by his mother with complaints of "inattentivity." His school teacher frequently complains about him, saying that he, "cannot sit still and just does not listen." He rarely completes his classroom assignments in time. When asked to run errands at home, he appears not to listen and continues to do whatever he is engaged in. He makes poor eye contact and has limited language skills compared to his peers. He usually prefers to play by himself. Which of these is the most likely diagnosis in this case?

316) A 15-month-old Asian girl is brought to the physician's office because of persistent non-productive cough and skin rash. Other accompanying symptoms are a runny nose, sneezing and intermittent nasal obstruction. She has had these symptoms for the past four days. Her parents report that she seems to have lost interest in her usual activities and is irritable all the time. Her pulse is 130/min, temperature is 38.8C (102F), and respirations are 24/min. Her eyes are red and have a watery discharge; there is congestion that is more marked over the canthi; the inner conjunctiva has bluish white lesions on an erythematous background. Throat examination reveals erythema of the posterior pharyngeal wall and tonsillar pillars, and yellowish exudates on the tonsils. The buccal mucous membranes are red with bluish-white lesions. The face has blanching, erythematous "brick-red" maculopapular rash. No rash is present over the extremities. Cervical lymphadenopathy is noted. The lab results are as follows: Hct 46%, WBC count 3,000/mm3, Platelet 160,000/mm3, Urine Dipstick ++ for proteins. What is the most likely diagnosis?

317) A 17-year-old teenage girl presents to your office after having problems during sex with her boyfriend. She also states that she has been developing facial hair, which she has constantly been removing. She started her menstruations at the age of 13 and her cycles have always been regular. On examination she is obese but appears a little masculine and has an enlarged clitoris. Initial lab values are as follows: Serum LH 20 IU/L, Serum FSH 10 IU/L, 17 -hydroxyprogesterone 600ng/ml (Normal is 15ng/ml), Serum testosterone Normal, Serum DHEA 4.0ng/ml (Normal is 4.2ng/ml). What is the most likely diagnosis?

318) A 2-week-old male infant is brought to the office by his 28-year-old primiparous mother for the evaluation of jaundice that was noted two days ago. The infant's stool has a lighter color. He is exclusively breastfed. The pregnancy was uncomplicated, and prenatal screening tests for TORCH organisms were all negative. The infant was delivered vaginally with no complications. His temperature is 37.2 C (99F), pulse is 140/min, respirations are 50/min, and capillary refill is < 2 sec. Examination reveals jaundiced skin and mucous membranes. Abdominal palpation reveals hepatomegaly. The initial investigations show the following: Hb 18.0 g/dl, Hct 52%, Bilirubin, Total 5 mg/dl, Bilirubin, Direct 4 mg/dl, Blood type 0 + (The mother's blood type is B-), Coombs' test Negative. What is the most likely diagnosis?

320) A premature infant develops respiratory distress several hours after birth. The infant is placed in an incubator with supplemental oxygen. The physician instructs the nurse to cover the infant's eyes to minimize the chance of damage by the high oxygen tension. Which of the following is characteristic of eye damage produced by exposure to high oxygen tensions in premature infants with respiratory distress?

321) A 7-year-old boy is brought to the clinic by his mother, who states that he has been complaining of abdominal pain for 2-3 days. He has been afebrile, with no vomiting or diarrhea. His mother states she brought him to the office today because she noticed a rash on his legs that is getting worse, and he is now complaining of knee pain. On examination, there are palpable purpuric lesions on both legs and buttocks. He has pain around his ankle and knee joints with minimal swelling, and no warmth or erythema. Which of the following is the most likely diagnosis?

322) A 7-year-old boy who has had pain in his right leg for 4 months is being evaluated. The pain is worse at night and is unrelenting, but it can usually be relieved with ibuprofen. On physical examination, there is localized tenderness over the anterior aspect of the right thigh. There is also mild atrophy of the affected limb. A radiograph of the femur reveals a radiolucent nidus with surrounding reactive sclerotic bone. Which of the following is the most likely diagnosis?

323) A 2-year-old boy is brought to the emergency department due to a cough and a "whistling" sound with breathing. Two days ago, he developed rhinorrhea, fever, a hoarse cry and a progressively worsening, harsh, "barky" cough. His immunizations are up-to-date. His 6-year-old brother also has cold symptoms. His temperature is 37.5C (99.5F), pulse is 140/min, and respirations are 36/min. On examination, he is alert, in mild respiratory distress, has a dry barking cough, hoarse cry, and some clear mucoid rhinorrhea. His pharynx is slightly injected, but without enlargement or asymmetry. The lungs are clear on auscultation. Lateral neck x-rays reveal a mildly narrowed subglottic region. What is the most likely diagnosis?

324) A 2-year-old child is brought to the physician for a routine visit. He is growing and developing appropriately. He eats a variety of foods including meat, vegetables, and fruits, and drinks 3-4 glasses of whole milk each day. He is starting to put words together into short sentences. His mother has no concerns. Physical examination is unremarkable. Routine laboratory studies show the following: Hemoglobin 9.5 g/dl, RDW 14%, MCV 65 fl, Reticulocyte count 3.0%, Platelet count 212,000/mm3, Leukocyte count 6,500/mm3, TIBC 300 mcg/dl (240-450 mcg/dl), Ferritin 100 ng/ml (7 -140 ng/ml). What is the most likely cause for this child's anemia?

325) A previously healthy 5-year-old girl is brought to the physician for evaluation of night awakenings. She has woken up screaming in each of the past three nights about one hour after going to sleep. When her parents go to her room, she is crying, sweating, and looks frightened. She does not respond to her parents and does not seem fully awake. When her parents hold her, she calms down and goes back to sleep. The next morning, she does not recall the incident. She started kindergarten this week and has just begun going all day without taking a nap. On examination, she is afebrile and her vital signs are within normal limits. A complete physical examination is unremarkable. What is the most likely diagnosis?