Pediatrie USMLE 201-300

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

202. 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?

203. 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?

204. A 23-year-old man comes to the emergency department (ED) at 2:00 am due to severe pain all over his body for the past few hours. He was diagnosed with sickle cell anemia at 6 months of age, and has had previous episodes of unbearable pain in his chest, abdomen, thighs and lower back. He was hospitalized six times in the past twelve months. He does not have regular follow-up visits up with his physician, and comes to see him "only if required." His blood pressure is 110/80 mmHg, pulse is 80/min, respirations are 16/min and temperature is 37 C (98F). Adequate hydration and analgesics are administered in the ED. What is the best intervention to prevent his painful episodes?

205. A 5-year-old boy is brought to an emergency room because of a painful, swollen knee joint. The boy had fallen while playing, and the joint had subsequently begun to swell. The mother reports that the boy was known to have hemophilia B. Replacement of which of the following is indicated?

206. A 5-month-old male infant has a urine output of less than 0.1 mL/kg/hr shortly after undergoing major surgery. On examination, he has generalized edema. His blood pressure is 94/48 mm Hg, pulse is 140/min, and respirations are 20/min. His blood urea nitrogen is 38 mg/dL, and serum creatinine is 1.4 mg/dL. Initial urinalysis shows a specific gravity of 1.018 and 2+ protein. Microscopic examination of the urine sample reveals 1 WBC per high-power field (HPF), 18 RBCs per HPF, and 5 granular casts per HPF. His fractional excretion of sodium is 3.2 %. Which of the following is the most appropriate next step in diagnosis?

207. An 8-year-old boy is brought to your office with the complaint of abdominal pain. The pain is worse during the week and seems to be less prominent during the weekends and during the summer. The patient’s growth and development are normal. The physical examination is unremarkable. Laboratory screening, including stool for occult blood, CBC, urinalysis, and chemistry panel, yields normal results. Which of the following is the best next step in the care of this patient?

208. 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?

209. 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?

211. A 2-month-old child of an HIV-positive mother is followed in your pediatric practice. Which of the following therapies should be considered for this child?

212. 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?

213. 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?

214. 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?

215. 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?

216. 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?

218. 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?

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

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

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

222. 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 11 0/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?

223. 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?

224. 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 39.2 C (102.5 F) 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? A. Fitz-Hugh-Curtis syndrome

225. 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?

226. 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?

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

228. 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?

229. 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?

230. A 17-year-old adolescent female is 6 weeks postpartum. She presents to the emergency room with the complaints of increased jaundice, abdominal pain, nausea, vomiting, and fever. Her examination is remarkable for jaundice, pain of the right upper quadrant with guarding, and a clear chest. Chest radiographs appear normal. Which of the following tests is most likely to reveal the cause of this pain?

231. An 8-year-old is accidentally hit in the abdomen by a baseball bat. After several minutes of discomfort, he seems to be fine. Over the ensuing 24 hours, however, he develops a fever, abdominal pain radiating to the back, and persistent vomiting. On examination, the child appears quite uncomfortable. The abdomen is tender, with decreased bowel sounds throughout, but especially painful in the midepigastric region with guarding. Which of the following tests is most likely to confirm the diagnosis?

232. A 10-month-old baby boy, recently adopted from Guyana, has a 5-hour history of crying, with intermittent drawing up of his knees to his chest. On the way to the emergency room he passes a loose, bloody stool. He has had no vomiting and has refused his bottle since the crying began. Physical examination is noteworthy for an irritable infant whose abdomen is very difficult to examine because of constant crying. His temperature is 38.8°C (101.8°F). The rectal ampulla is empty, but there is some gross blood on the examining finger. Which of the following studies would be most helpful in the immediate management of this patient?

233. 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?

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

235. A 4-year-old child manifests symptoms of fever, sore throat, and swollen lymph nodes. The spleen tip is palpable. Throat culture and rapid slide (Monospot) test results are negative. The next logical diagnostic procedure would involve which of the following?

236. The mother of a 2-year-old boy comes to the physician because her child awakens at night, with a blank gaze, screaming in bed without recognizing his parents. These episodes have occurred three times in the past 2 weeks, always in the first few hours of the night. The child goes back to sleep and seems to retain no memory of the episode the next morning. Which of the following is the most appropriate next step in management?

237. 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?

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

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

240. 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?

241. A 12-year-old girl with a history of asthma has been admitted to intensive care units two times in the past and has had three emergency department visits during the past 12 months. Her only medication is inhaled albuterol as needed, and she uses it two to three times a day. She has nocturnal symptoms about two times a week. She is free of symptoms now but reports that she gets short of breath easily. Which of the following pharmacologic interventions is most appropriate?

242. 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?

243. A 12-year-old girl with a history of asthma has been admitted to intensive care units two times in the past and has had three emergency department visits during the past 12 months. Her only medication is inhaled albuterol as needed, and she uses it two to three times a day. She has nocturnal symptoms about two times a week. She is free of symptoms now but reports that she gets short of breath easily. Which of the following pharmacologic interventions is most appropriate?

244. A one-month-old child is brought to the office due to persistent vomiting for the last six days. His mothercomplains of increasing episodes of projectile vomiting. These episodes occur every time she attempts tofeed him, and have persisted despite changing formulas. On physical examination, peristaltic waves are seenover the upper abdomen, and an olive-sized mass is palpated. Laboratory studies reveal a potassium level of 3.0mEq/mL. Which of the following is the most appropriate next step in management?

245. A 4-year-old female is brought to the emergency department for evaluation of vaginal discharge. She has had foul-smelling vaginal discharge for 1 week. Her mother has also noted a small amount of vaginal bleeding. The mother called her primary physician and was told to use an over-the-counter cream and to stop letting the child take bubble baths. However, the symptoms have not improved. The child complains of pruritus in her vaginal area. She was potty trained at age 2. While mother is at work, the baby is with her stepfather. On examination, the perineal area is erythematous with a purulent, foul-smelling vaginal discharge. Visual inspection of the vagina reveals a greenish foreign body inside the vagina. Which of the following is the next best step?

246. A 1-year-old child is brought to the physician for a routine visit. He was born full term with a birth weight of 71b 8oz (34 kg) and a birth length of 20 in (50.8cm). He has had no major illnesses or hospitalizations His parents report that he was breastfed exclusively for 6 months. He now eats a variety of baby foods and is being transitioned to whole milk. He can pull up to stand and cruise around holding onto objects, but cannot walk independently yet. He can feed himself small pieces of table food with his thumb and first finger. The only words he knows are mama, dada, and ball. His parents are concerned about his growth because some of the other children in his daycare class are bigger than him. On physical examination, he weighs 221bs (10 kg) and is 30 in (76.2cm) long. A complete examination is unremarkable. Which of the following should you tell his parents?

248. 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?

249. 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?

250. An infant has had repeated pneumonias and middle ear infections that began at about 5 months of age. At 1 year of age, serum electrophoresis demonstrated hypogammaglobulinemia. T cell function was normal. By 2 years of age, the child's infection rate has decreased, and repeat serum electrophoresis is normal. Which of the following immunoglobulins was likely decreased in this child during the period of increased susceptibility to infection?

251. A 12-year-old, previously healthy girl presents to her physician with a chief complaint of early morning headaches. She states that these headaches wake her up from sleep 2-3 days a week. She also complains of some vomiting associated with the headaches. The headaches have been getting progressively worse for the past 2 months. She denies any photophobia, dizziness, or blurred vision. There is no history of a recent respiratory infection, runny nose, or cough. There is no history of recent trauma. In the office, her vital signs are within normal limits. Her examination shows pupils that are equal, round, and reactive, with no maxillary or frontal sinus tenderness. Her tympanic membranes are clear and intact. Her neck is supple with full range of motion. Neurologic examination shows a positive Romberg sign. Which of the following tests would most likely confirm the diagnosis?

(A) CT of the brain (B) MRI of the brain (C) lain film of the skull (D) inus x-ray film (E) Spinal tap

253. 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?

254. During a routine yearly checkup, a 10-year-old boy is found to have 2+ proteinuria on urinalysis. Which of the following would be the most appropriate diagnostic test?

255. An 18-month-old boy has received 5 days of amoxicillin for otitis media. He continues to have fever, and on physical examination, the right tympanic membrane is bulging with purulent fluid behind it. Which of the following is the best antibiotic to use?

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

257. 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?

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

259. A 2-year-old boy with cough and difficulty breathing is brought to the emergency department by his mother. She says that he was well and playing with his toys until 2 hours prior to presentation. He is healthy, but his 6-year old brother has a peanut allergy. The patient's temperature is 36.7 C (98 F), blood pressure is 92/48 mmHg, pulse is 114/min, and respirations are 48/min. The patient's pulse oximetry shows 91 % on room air. Physical examination shows nasal flaring and grunting with both subcostal and intercostal retractions. Wheezing is heard in the right lung field; the left field is clear to auscultation. No rales or rhonchi are noted. The remainder of the physical examination is within normal limits. Supplementary oxygen is applied. Chest x-ray reveals mild hyperinflation of the right lung. Which of the following is the most appropriate next step in management of this child?

260. An 8-year-old boy is brought to the emergency department by his mother. Two weeks ago, he developed a low-grade fever followed by a persistent cough. He occasionally has severe paroxysms of cough that are precipitated by eating and do not resolve with antitussive medications. On physical examination, extensive subcutaneous emphysema over the anterior chest is noted. What is the most appropriate next step in the management of this patient?

261. 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?

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

263. A 2-year-old child was recently adopted from India. She appears to be healthy, and there are no abnormal symptoms. Her weight and height are at 25th percentile for age. Her examination is normal. On screening, you find a positive TB skin test using purified protein derivative (PPD) with 20 mm induration. She has a history of receiving a BCG vaccination at birth. Your management plan is to do which of the following?

264. A baby is born to a mother who is positive for hepatitis B surface antigen (HBsAg). Your plan is to do which of the following?

265. In an adolescent presenting with pityriasis rosea, which of the following would be an appropriate blood test to order?

266. 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?

267. 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 71/2 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?

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

269. 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?

270. An otherwise healthy 5-year-old boy is brought to the emergency department of a small hospital because of a simple 3-cm laceration in his forehead. The patient is crying and frightened. The practitioner decides to perform conscious sedation before suturing the laceration. Support personnel and equipment are available for monitoring the patient's vital status and carrying out resuscitation measures if needed. Which of the following is the most appropriate pharmacologic agent to achieve a safe level of conscious sedation in this situation?

271. A 2-year-old boy has been doing well despite his diagnosis of tetralogy of Fallot. He presented to an outside ER a few days ago with a complaint of an acute febrile illness for which he was started on a “pink antibiotic.” His mother reports that for the past 12 hours or so he has had a headache and is more lethargic than normal. On your examination he seems to have a severe headache, nystagmus, and ataxia. Which of the following would be the most appropriate first test to order?

272. 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?

273. A 13-year-old girl presents with a 1-week history of a sore throat and a nonproductive cough. She has been previously healthy and has not been exposed to any other sick person. She has not been taking any medications. On examination, she has normal oxygen saturation and a low-grade fever. The remainder of the examination is unremarkable. Which of the following is the most appropriate pharmacotherapy?

274. 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?

275. A 6-year-old child is hospitalized for observation because of a short period of unconsciousness after a fall from a playground swing. He has developed unilateral pupillary dilatation, focal seizures, recurrence of depressed consciousness, and hemiplegia. Which of the following is the most appropriate management at this time?

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

277. 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?

278. 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?

280. 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?

281. A 2-month-old female infant born at term is brought to the office for a well-baby visit. Her antenatal and birth histories are unremarkable. Her developmental milestones are all normal for her age. Ophthalmoscopic examination reveals a white reflex in the right eye. The rest of the examination is normal. What is the most appropriate next step in the management of this patient?

282. 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?

284. 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?

285. 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?

286. 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?

288. 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?

289. 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?

290. A 5-year-old boy presents to the emergency department with 2-day history of fever, anorexia, loose stools, and yellow skin color. He attends a large daycare center. On physical examination, his temperature is 38.1 C (100.7 F), blood pressure is 88/56 mm Hg, pulse is 74/min, and respirations are 15/min. Initial laboratory evaluation reveals a total bilirubin of 1.8 mg/dL and alanine aminotransferase of 764 U/L. Which of the following is the most appropriate diagnostic test?

291. A new born infant is in respiratory distress and requires several attempts at resuscitation in the delivery room because of difficulty breathing and frequent cyanosis. The neonatologist notes that during crying, her breathing improves and breath and heart sounds are normal. Direct laryngoscopy is unremarkable as well. Deep inspirations by the neonate are ineffective. Which of the following is the most effective intervention?

292. 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?

293. A previously healthy 12-year-old boy is brought to the physician the day after a nocturnal crisis of difficulty breathing, chest tightness, and cough. He has a history of atopic dermatitis that resolved around 6 years of age. He now has no apparent respiratory distress. His breathing is regular, and his respirations are 12/min. Blood pressure, pulse, and temperature are normal. Chest examination reveals only a few crackles that quickly clear after coughing and mild end-expiratory wheezes. Which of the following is the most appropriate next step in diagnosis?

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

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

297. A 13-year-old girl presents with lethargy, fever, severe headache, and a stiff neck. On examination, a unilateral fixed, dilated pupil and papilledema are noted. Which of the following is the most appropriate initial step in managing this patient?

298. A newborn infant requires repeated resuscitation in the delivery room because of failure to breathe and cyanosis. During spells of crying, which appear to alleviate the cyanosis, his breath and heart sounds are normal, as is direct laryngoscopy. Vigorous respiratory movements appear ineffectual. Immediate management of this infant consists of which of the following?

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

300. 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?