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150) A 19-year-old man sustains severe lower-extremity trauma, including a femur fracture and a crush injury to his foot. He requires vascular reconstruction of the popliteal artery. On the day after surgery, he becomes dyspneic and hypoxemic and requires intubation and mechanical ventilation. Which of the following is the most likely etiology of his decompensation?

151) A 19-year-old nulligravid woman at 38 weeks' gestation comes to her physician because she has passed bloody mucus discharge. Her prenatal course was unremarkable including a normal 19-week ultrasound. On speculum examination, there are no vaginal or cervical lesions. On vaginal examination, the cervix is 2 cm dilated and 100% effaced, and the fetus is at +1 station. The fetal heart rate has a baseline of 140 and is reactive. She has painful contractions every 2 minutes. One hour later the patient's cervix is 3 cm dilated, and a small amount of bloody mucus is noted on the examining glove. Which of the following is the most likely diagnosis?

152) A 19-year-old primigravid woman at 34 weeks gestation comes to the physician because of diffuse headache, right upper quadrant pain and visual disturbances. During her last visit two weeks ago she was found to have an elevated blood pressure and 1+ proteinuria. She was advised to follow-up closely and sent home on bed rest. Her blood pressure today is 176/120 mm Hg and pulse is 86/min. Physical examination shows 2+ pitting edema in both legs and right upper quadrant tenderness. Fetal heart tones are audible by Doppler. Urinalysis shows 3+ proteinuria. Serum aspartate aminotransferase (AST) is 88 U/L and alanine aminotransferase (ALT) is 80 U/L. Serum creatinine now is 1.4 mg/dl. Which of the following is the most likely cause of her right upper quadrant pain?

156) A 19-year-old student is referred to the university health center for inability to complete his assignments. He has always been a good student, and was valedictorian of his high school class. However, since starting college, he has found it difficult to keep up with all the work. He audio-records every class, playing the tapes back later in the day to transcribe each entire lecture word for word. He admits to sometimes needing to go over certain sections multiple times to be sure he has heard correctly. He also takes a long time to complete assignments, as he always checks his work multiple times prior to handing it in. Because of this, he has had to ask for many extensions on his assignments. He is sure to complete all his assignments, even after they have been reviewed in class and even though they are not graded. He spends all his time doing his classwork, and is not involved in social activities. What is the most likely diagnosis?

157) A 19-year-old woman comes to the emergency department and reports that she fainted at work earlier in the day. She has mild vaginal bleeding. Her abdomen is diffusely tender and distended. In addition, she complains of shoulder and abdominal pain. Her temperature is 37.2C, pulse rate is 120 beats per minute, and blood pressure is 80/42 mm Hg. Which of the following is the best diagnostic procedure to quickly confirm your diagnosis?

160) A 19-year-old woman makes an appointment to see her primary care physician about a "personal concern." When she comes in for her visit, she says that she has been "deeply depressed" for the past several months because of her "enormous nose." She proceeds to describe in detail the numerous cosmetic aspects of her nose that prove troubling. She says that she is now so embarrassed that she is unwilling to go out with friends because "everyone just stares at my nose." She finds it difficult to concentrate on her studies because she is preoccupied with thoughts about undergoing corrective surgery. On examination, her nose appears completely normal. She pleads for a referral to a good plastic surgeon. Which of the following is the most likely diagnosis?

162) A 2 and a half-year-old child is brought to the office for the evaluation of easy bruising, nosebleeds, and decreased activity over the past week. He had an upper respiratory infection that was treated with an antibiotic 2 weeks ago. On examination, he is well-developed, seems well-nourished, anicteric, and pale. Pertinent findings include some small palpable posterior cervical lymph nodes, sinus tachycardia, a grade I/VI systolic ejection murmur, ecchymoses on his left shoulder and both lower extremities, and petechiae over his extremities and groin. There is no hepatosplenomegaly. The laboratory findings are as follows: Hemoglobin 7.9 g/dl, Hematocrit 24%, Platelet count 12, 000/mm3, WBC 3,000/mm3, Reticulocyte count 0.5%. A bone marrow biopsy reveal a markedly hypocellular marrow with decreased megakaryocytes and precursors of the erythroid and myeloid cell lines. What is the most likely diagnosis?

163) 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?

164) 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?

165) A 2-hour-old male neonate has developed worsening cyanosis over the past few minutes. The infant was vaginally delivered (assisted with forceps) at full term and weighed 4.1 kg (9 lb). The Apgar scores were 7 and 8 at 1 and 5 minutes, respectively. Oxygen is administered by mask but does not relieve the cyanosis. Further examination reveals tachypnea, subcostal retractions, a normal first heart sound, a single and loud second heart sound (S2), and no murmur. Which of the following is the most likely cause of the infant's cyanosis?

166) A 2-month-old girl presents to her pediatrician's office for well-child care. Her mother complains of excessive tearing of the baby's left eye for the past 4 weeks. Each morning, a yellow crusty discharge is noted along the lashes of the left eye. The conjunctiva appears uninflamed. The right eye is not affected. On physical examination, the infant is otherwise well and achieving adequate weight gain on an exclusive breast milk diet. She is developmentally appropriate, including visually tracking 180 degrees. Which of the following is the most likely diagnosis?

167) A 2-month-old infant is brought to the clinic for the evaluation of poor feeding. He was born at 32 weeks of gestation with a birth weight of 1200 g. The pertinent physical findings are pallor, tachypnea, tachycardia, and flow murmurs. The laboratory studies are as follows: Hb 7 g/dl, WBC 7,000/mm3, Platelets 230,000/mm3, Reticulocytes Low. The peripheral smear shows normocytic normochromic RBC. What is the most likely diagnosis?

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

169) A 2-month-old male infant is rushed to the emergency department by his baby sitter. She says that the baby became unresponsive and blue while feeding. The whole episode lasted 45-60 seconds, but the baby still appears pale. She denies any history of coughing or choking. On examination, the infant appears cyanotic and tachypneic. His blood pressure is 90/60 mm of Hg; his pulse rate is 155/min and regular. On auscultation, a harsh pansystolic murmur is noted at the left sternal border, along with a single S2. Hepatomegaly is noted. Pulse oximetry shows an oxygen saturation of 80%. Based on this history and physical examination, what is the most likely diagnosis?

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

172) A 2-week-old infant is noted to be jaundiced. The baby's stools are pale, and his urine darkly colored. Physical examination demonstrates hepatomegaly. Serum studies show elevations of AST, ALT, conjugated bilirubin, and unconjugated bilirubin. By 2 months of age, the baby is notably irritated by pruritus, has retarded growth, and has visible dilated veins in the periumbilical area. Ultrasound fails to demonstrate a gallbladder. Which of the following is the most likely diagnosis?

173) A 2-week-old infant presents with sudden onset of bilious emesis. Plain films of the abdomen show evidence of an intestinal obstruction. An upper gastrointestinal (UGI) contrast series reveals a midgut volvulus with the site of obstruction at the third portion of the duodenum. Which of the following is the most likely diagnosis?