31
75.
A 47-year-old woman comes to the emergency department because of a 2-week history of intermittent abdominal pain,
nausea, and vomiting. She has had similar episodes sporadically during the past 4 years. Physical examination shows
dehydration, jaundice, and upper abdominal distention. Laboratory studies show hyperbilirubinemia. A CT scan and upper
gastrointestinal series of the abdomen with oral contrast are shown; the arrows indicate the abnormality. Which of the
following is the most likely cause of these findings?
(A) Annular pancreas
(B) Cirrhosis of the liver
(C) Duodenal constriction by the portal vein
(D) Duodenal constriction by the superior mesenteric artery
(E) Pyloric stenosis
76.
An 8-year-old boy is brought to the office by his mother because of a 3-day history of fever, sore throat, and itchy eyes. He
just returned from a weeklong summer camp that included hiking trips and swimming lessons in the camp-owned swimming
pool. He has no history of major medical illness and receives no medications. He appears tired. His temperature is 39.4°C
(102.9°F); other vital signs are within normal limits. Physical examination shows conjunctival injection and discharge and
oropharyngeal erythema. The public health department reports an outbreak of similar symptoms among the other campers
and camp volunteers. Which of the following is the most likely cause of this patient’s symptoms?
(A) Adenovirus
(B) Cytomegalovirus
(C) Epstein-Barr virus
(D) Influenza virus
(E) West Nile virus
32
77.
A 36-year-old man with profound intellectual disability is brought to the physician by staff at his facility because of
increasing abdominal girth during the past 2 weeks. He is unable to speak, and no medical history is currently available.
Physical examination shows a protuberant abdomen with a fluid wave and shifting dullness. There are no signs of trauma to
the area. Laboratory studies show no abnormalities. A CT scan of the abdomen is shown. Fluid is present in which of the
following areas as indicated by the arrow?
(A) Epiploic foramen
(B) Gastrosplenic ligament
(C) Hepatorenal pouch (of Morison)
(D) Omental bursa (lesser sac)
(E) Sulcus pericolicus
78.
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
79.
A 56-year-old man comes to the emergency department because of a 4-day history of colicky right flank pain that radiates to
the groin and hematuria. Ultrasound examination of the kidneys shows right-sided hydronephrosis and a dilated ureter.
Which of the following is most likely to be found on urinalysis?
(A) Erythrocyte casts
(B) Glucose
(C) Leukocyte casts
(D) Oval fat bodies
(E) Uric acid crystals
33
80.
A 62-year-old man comes to the physician for a follow-up examination after he was diagnosed with chronic inflammatory
interstitial pneumonitis. Following pulmonary function testing, a biopsy specimen of the affected area of the lungs is
obtained. Compared with a healthy man, analysis of this patient's biopsy specimen is most likely to show which of the
following patterns of changes in the cell populations of alveoli?
Type I Pneumocytes
Type II Pneumocytes
Fibroblasts
(A)
↑
↑
↑
(B)
↑
↑
↓
(C)
↑
↓
↑
(D)
↑
↓
↓
(E)
↓
↑
↑
(F)
↓
↑
↓
(G)
↓
↓
↑
(H)
↓
↓
↓
34
USMLE STEP 1 SAMPLE TEST QUESTIONS
BLOCK 3, ITEMS 81-117
81.
Six healthy subjects participate in a study of muscle metabolism during which hyperglycemia and hyperinsulinemia is
induced. Muscle biopsy specimens obtained from the subjects during the resting state show significantly increased
concentrations of malonyl-CoA. The increased malonyl-CoA concentration most likely directly inhibits which of the
following processes in these subjects?
(A) Fatty acid oxidation
(B) Fatty acid synthesis
(C) Gluconeogenesis
(D) Glycogenolysis
(E) Glycolysis
(F) Oxidative phosphorylation
82.
A 72-year-old woman who has smoked 20 cigarettes daily for the past 38 years begins using eyedrops for glaucoma. Three
days later, she has a marked increase in shortness of breath while walking up a flight of stairs. Which of the following drugs
is the most likely cause of the development of shortness of breath in this patient?
(A) Acetazolamide
(B) Apraclonidine
(C) Epinephrine
(D) Latanoprost
(E) Timolol
83.
A 54-year-old man comes to the physician because of episodes of fainting for 3 months. He also has had difficulty
performing daily tasks because he is easily fatigued. He had a myocardial infarction 12 years ago. His pulse is 40/min,
respirations are 18/min, and blood pressure is 138/85 mm Hg. Physical examination shows evidence of cannon a waves. An
ECG shows a P-wave rate of 90/min, and an R-wave rate of 40/min, with no apparent relation between the two. Which of the
following is the most likely diagnosis?
(A) First-degree atrioventricular block
(B) Right
bundle branch block
(C) Second-degree atrioventricular block, type I
(D) Second-degree atrioventricular block, type II
(E) Third-degree atrioventricular block
84.
A 15-year-old boy is brought to the emergency department by his parents because of a 2-hour history of confusion and
agitation. He also has had fever, headache, stiff neck, and vomiting since he returned from summer camp 2 days ago. His
parents say he does not use illicit drugs. On arrival, he is combative and there is evidence of hallucinations. His temperature
is 40°C (104°F), pulse is 80/min, respirations are 17/min, and blood pressure is 100/70 mm Hg. A lumbar puncture is
performed. Results of cerebrospinal fluid analysis show cysts and trophozoites. The most likely portal of pathogen entry into
this patient's central nervous system is which of the following?
(A) Cavernous sinus
(B) Facial nerve
(C) Frontal sinus
(D) Mastoid sinus
(E) Olfactory nerve
(F) Trigeminal nerve