USMLE Step 1 Preparation Course

A 27-year-old woman comes to the office for counseling prior to conception. She states that a friend recently delivered a newborn with a neural tube defect and she wants to decrease her risk for having a child with this condition. She has no history of major medical illness and takes no medications. Physical examination shows no abnormalities. It is most appropriate to recommend that this patient begin supplementation with a vitamin that is a cofactor in which of the following processes?

(A) Biosynthesis of nucleotides

(B) Protein gamma glutamate carboxylation

(C) Scavenging of free radicals

(D) Transketolation

(E) Triglyceride lipolysis

(Answer: A)

A study is designed to evaluate the feasibility of acupuncture in children with chronic headaches. Sixty children with chronic headaches are recruited for the study. In addition to their usual therapy, all children are treated with acupuncture three times a week for 2 months. Which of the following best describes this study design?

(A) Case-control

(B) Case series

(C) Crossover

(D) Cross-sectional

(E) Historical cohort

(F) Randomized clinical trial

(Answer: B)

A 26-year-old woman comes to the physician with her husband for counseling prior to conception. Her mother and three of her five siblings have type 2 diabetes mellitus. She is 170 cm (5 ft 7 in) tall and weighs 82 kg (180 lb); BMI is 28 kg/m2. Her blood pressure is 148/84 mm Hg. Physical examination shows no other abnormalities. Her fasting serum glucose concentration is 110 mg/dL. Which of the following is the most appropriate initial statement by the physician?

(A) “Let’s review ways you can optimize your own health before conceiving.”

(B) “We should test you for islet cell antibodies before you try to conceive.”

(C) “You can conceive right away since you are in good health.”

(D) “You should avoid gaining weight during pregnancy because you are already overweight and at risk for type 2 diabetes mellitus.”

(E) “You should have no problems with your pregnancy if you start insulin therapy.”

(Answer: A)

A 55-year-old man has had crushing substernal chest pain on exertion over the past 6 weeks. He had a myocardial infarction 2 months ago. He takes nitroglycerin as needed and one aspirin daily. He has smoked two packs of cigarettes daily for 30 years. Examination shows normal heart sounds and no carotid or femoral bruits. Treatment with a β-adrenergic blocking agent is most likely to improve his symptoms due to which of the following mechanisms?

(A) Decreasing myocardial contractility

(B) Dilating the coronary arteries

(C) Peripheral vasodilation

(D) Preventing fibrin and platelet plugs

(Answer: A)

A 31-year-old woman is brought to the emergency department 45 minutes after sustaining injuries in a motor vehicle collision. Physical examination shows tenderness to palpation of the right upper extremity. An x-ray shows a midshaft fracture of the right humerus. The physician wants to assess the integrity of the radial nerve, but the patient has severe pain with movement of the upper extremity. If this patient has sustained damage to the radial nerve, altered sensation to pinprick of which of the following areas would most likely confirm the diagnosis?

(A) Anterior medial surface of the forearm

(B) Palmar surface of the index finger

(C) Palmar surface of the small finger

(D) Posterior lateral surface of the hand

(E) Posterior surface of the small finger

(Answer: D)