USMLE USMLE Certifications USMLE Questions & Answers

• Question 571:

  A 26-year-old man is brought to the emergency department by ambulance 30 minutes after being shot in the leg. He is unconscious and appears markedly pale. His pulse is 120/min, respirations are 16/min, and blood pressure is 80/60 mmHg. Compared with a healthy adult, which of the following findings is most likely in this patient?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  E. Option E

  F. Option F

  Correct Answer: D

• Question 572:

  A 17-year-old boy is brought to the emergency department 30 minutes after being found with a "blank stare" and flat facial expression at a party. His pulse is 72/min, and blood pressure is 104/68 mmHg. He is sitting upright and appears catatonic. Physical examination shows rigidity. During the examination, he becomes hostile and attempts to assault the physician. This patient most likely ingested which of the following drugs?

  A. Cocaine

  B. Diazepam

  C. Methamphetamine

  D. Oxycodone

  E. PCP (phencyclidine)

  Correct Answer: E

• Question 573:

  

  During an experiment, a Southern blot analysis is done by digesting DNA samples with a single restriction endonuclease, separating the digestion products by gel electrophoresis, and transferring them to a filter. The investigator probes the filter by exposing it to a cDNA clone that encodes a single immunoglobulinconstant region. The figure shows the resulting pattern with DNA samples isolated from different organs. Assuming there were no technical errors, the Southern blot analysis results demonstrate which of the following processes?

  A. Affinity maturation

  B. Apoptosis

  C. Gene rearrangement

  D. RNA splicing

  E. Somatic hypermutation

  Correct Answer: C

• Question 574:

  During a clinical study examining the effects of exercise, men between the ages of 20 and 30 years are evaluated during a 15-minute session on a treadmill. The average pulse for the last 2 minutes of the session is 175/min. During the last minute of exercise, various measurements are taken. Compared with the measurement before the session, which of the following is most likely to be decreased?

  A. Cardiac output

  B. Oxygen consumption

  C. Pulse pressure

  D. Stroke volume

  E. Systolic blood pressure

  F. Total peripheral resistance

  Correct Answer: F

• Question 575:

  A 55-year-old woman with small cell carcinoma of the lung is admitted to the hospital to undergo chemotherapy. Six days after treatment is started, she develops a temperature of 38°C (100.4°F). Physical examination shows no other abnormalities. Laboratory studies show a leukocyte count of 100/mm3 (5% segmented neutrophils and 95% lymphocytes). Which of the following is the most appropriate pharmacotherapy to increase this patient's leukocyte count?

  A. Darbepoetin

  B. Dexamethasone

  C. Filgrastim

  D. Interferon alfa

  E. Interleukin-2 (IL-2)

  F. Leucovorin

  Correct Answer: C

• Question 576:

  A 37-year-old woman with right lower extremity edema is evaluated because of the sudden onset of shortness of breath and pleuritic chest pain. A diagnosis of pulmonary embolism is made. Which of the following signs, if present on physical examination, would be the most specific indicator of pulmonary arterial hypertension in this patient?

  A. Increased jugular venous pressure

  B. P2 louder than A2

  C. Peripheral edema

  D. Presence of an S3

  E. Pulmonary crackles

  Correct Answer: B

• Question 577:

  A 24-year-old woman comes to the physician for a follow-up examination. One week ago, she was treated in the emergency department after she accidentally spilled hot grease on her left leg while working at a fast-food restaurant. Examination of the left lower extremity shows a 7-cm, pink, soft, granular, edematous wound. The formation of this tissue was most likely caused by increased activity of which of the following?

  A. Complement C3b

  B. Glycosylation-dependent cell adhesion molecule-1

  C. P-selection

  D. Stromelysin

  E. Vascular endothelial growth factor

  Correct Answer: E

• Question 578:

  A 63-year-old woman comes to the physician 1 day after the sudden onset of pain and swelling of her right knee. She has had no injury. Her medications include occasional ibuprofen for mild osteoarthritis of both knees. Her temperature is 37°C (98.6°F), pulse is 97/min, respirations are 19/min, and blood pressure is 129/79 mmHg. Examination of the right knee shows warmth, erythema, and effusion. Exquisite tenderness is produced with minimal range-of-motion testing. Examination of synovial fluid obtained via joint aspiration shows that it is clear, with positively birefringent rhomboids observed under polarized light microscopy. Deposition of which of the following substances is the most likely cause of these findings?

  A. Ammonium urate

  B. Calcium oxalate

  C. Calcium pyrophosphate

  D. Calcium urate

  E. Sodium urate

  Correct Answer: C

• Question 579:

  A 28-year-old man comes to the physician because of a 1-year history of pain with urination that has increased in severity during the past month. He also has had episodes of blood in his urine during the past 5 years. He lived in sub-Saharan Africa until he came to the USA 6months ago for graduate school. His temperature is 38°C (100.4°F), pulse is 80/min, respirations are 16/min, and blood pressure is 110/84

  mmHg. Physical examination shows suprapubic tenderness. Laboratory studies show:

  

  Imaging studies show bilateral hydroureter and hydronephrosis and foci of calcification in the region of the bladder. A biopsy specimen of the bladder shows marked chronic inflammation with fibrosis and scattered granulomas. Which of the following best explains the biopsy findings?

  A. Exposure to a chemical toxin

  B. Interstitial cystitis

  C. Malacoplakia

  D. Schistosomiasis

  E. Vesicoureteral reflux

  Correct Answer: D

• Question 580:

  A 14-year-old boy is brought to the emergency department after being hit with a baseball bat on the lateral side of his leg immediately below the knee. He is unable to dorsiflex his foot. Which of the following nerves is most likely injured?

  A. Common fibular (peroneal)

  B. Femoral

  C. Obturator

  D. Sural

  E. Tibial

  Correct Answer: A