Lipid metabolism — MCQs

A 30-year-old woman is brought to the emergency department by ambulance after being found unconscious in her bedroom by her roommate. The roommate says the patient has type 1 diabetes and takes her insulin regularly. Her pulse is 110/min, the respiratory rate is 24/min, the temperature is 36.6°C (97.9°F), and the blood pressure is 95/65 mm Hg. She is breathing heavily and gives irrelevant responses to questions. Her skin and mucous membranes appear dry. Her breath has a fruity smell to it. Tendon reflexes are slightly delayed. The laboratory findings include: Finger-stick glucose 530 mg/dL Arterial blood gas analysis pH 7.1 pO2 94 mm Hg pCO2 32 mm Hg HCO3 17 mEq/L Serum Sodium 136 mEq/L Potassium 3.2 mEq/L Chloride 136 mEq/L Blood urea nitrogen 20 mg/dL Serum creatinine 1.2 mg/dL Urine examination Glucose positive Ketones positive Leucocytes negative Nitrite negative RBC negative Casts negative Which of the following abnormalities accounts for her sweet smelling breath?

A 43-year-old woman, gravida 2, para 2, comes to the physician because of a 6-month history of heavy, irregular menstrual bleeding. Pelvic examination shows blood and clots in the posterior fornix and normal-appearing internal and external genitalia. An endometrial biopsy specimen shows straight uniform tubular glands lined with tall pseudostratified columnar epithelial cells with high mitotic activity embedded in an edematous stroma. Increased activity of which of the following is directly responsible for the histologic appearance of the biopsy specimen?

A 24-year-old woman with a past medical history of anorexia nervosa presents to the clinic due to heavy menses, bleeding gums, and easy bruisability. She says she is trying to lose weight by restricting her food intake. She has taken multiple courses of antibiotics for recurrent sinusitis over the past month. No other past medical history or current medications. She is not sexually active. Her vital signs are as follows: temperature 37.0°C (98.6°F), blood pressure 90/60 mm Hg, heart rate 100/min, respiratory rate 16/min. Her BMI is 16 kg/m2. Her physical examination is significant for ecchymosis on the extremities, dry mucous membranes, and bleeding gums. A gynecological exam is non-contributory. Laboratory tests show a prolonged PT, normal PTT, and normal bleeding time. CBC shows microcytic anemia, normal platelets, and normal WBC. Her urine pregnancy test is negative. Which of the following is the most likely cause of her condition?

A 54-year-old man presents to his primary care physician with a 2-month-history of diarrhea. He says that he feels the urge to defecate 3-4 times per day and that his stools have changed in character since the diarrhea began. Specifically, they now float, stick to the side of the toilet bowl, and smell extremely foul. His past medical history is significant for several episodes of acute pancreatitis secondary to excessive alcohol consumption. His symptoms are found to be due to a deficiency in an enzyme. Which of the following enzymes is most likely deficient in this patient?

A 2-year-old boy is brought to the emergency department by his parents because of fever and recurrent episodes of jerky movements of his extremities for the past 6 hours. Pregnancy and delivery were uncomplicated, and development was normal until the age of 1 year. The parents report that he has had gradual loss of speech, vision, and motor skills over the past year. During this time, he has been admitted to the hospital three times because of myoclonic seizures. Physical examination shows hypertonicity of the upper and lower extremities. Fundoscopic examination shows pallor of the optic disc bilaterally. An MRI of the brain shows brain atrophy and hyperintensity of the periventricular and subcortical areas. Two days after admission, the patient dies. Histopathologic examination of the brain shows aggregation of globoid cells and loss of glial cells. The patient’s condition was most likely caused by a deficiency of which of the following enzymes?