Free USMLE Step 3 Exam Questions and Answers

A 30-year-old man comes to the emergency department because of an acute episode of renal colic. Medical history is remarkable for episodes of painful urination and passing of what he calls "gravel in my urine." Urinalysis demonstrates microscopic hematuria with some crystalluria and no casts. Supine x-ray of the abdomen shows no abnormalities. A 4-mm renal calculus is detected in the distal right ureter on ultrasonography. There is no evidence of dilation of the collecting system. The patient's pain is responsive to narcotic medication. In addition to administering intravenous fluids, which of the following is the most appropriate next step?

• AA. Acidification of urine by drinking cranberry juice
• BB. Cystoscopic removal of the calculus
• CC. Cystoscopic ureteral lavage
• DD. Shock wave lithotripsy
• EE. Straining of the urine

Patient Information Age: 62 years Gender: M, self-identified Ethnicity: unspecified Site of Care: office History Reason for Visit/Chief Concern: "My legs hurt when I walk, and it's getting worse." History of Present Illness: • 3-month history of worsening leg pain • pain exacerbated by walking; peak intensity after 1 block • pain resolves completely with rest • pain rated 4/10 at worst Past Medical History: • hypertension • mild angina • type 2 diabetes mellitus Medications: • lisinopril • metoprolol • furosemide • glyburide • lovastatin Allergies: • no known drug allergies Psychosocial History: • has smoked one-half pack of cigarettes daily for 44 years Physical Examination: | Temp | Pulse | Resp | BP | O2 Sat | Ht | Wt | BMI | | 36.0°C (96.8°F) | 72/min | 14/min | 140/90 mm Hg | – | 164 cm 5 ft 5 in | 90 kg 198 lb | 33 kg/m² | • Appearance: no acute distress • HEENT: funduscopic shows grade 2/4 arteriovenous nicking • Neck: no jugular venous distention • Pulmonary: clear to auscultation; mildly diminished lung sounds • Cardiac: no bruits; distant heart sounds • Abdominal: obese; no tenderness, guarding, masses, bruits, or hepatosplenomegaly • Extremities: no joint erythema, edema, or warmth; no hair on toes; no femoral bruits; dorsalis pedis, radial, and femoral pulses intact • Neurologic: sensation to vibration intact Which of the following is the most appropriate diagnostic study?

• AA. Ankle brachial index
• BB. Arteriography
• CC. ECG
• DD. Echocardiography
• EE. MUGA scan

A 52-year-old man returns to the office for reevaluation of an ulcer on his right great toe. The patient has a 15-year history of diabetes mellitus and takes glipizide and rosiglitazone. He first noticed the ulcer 2 months ago. One month ago, a 14-day course of oral amoxicillin-clavulanate therapy was prescribed. He has smoked one pack of cigarettes daily for the past 37 years. He is 178 cm (5 ft 10 in) tall and weighs 102 kg (225 lb); BMI is 32 kg/m². Today, vital signs are temperature 38.8°C (101.8°F), pulse 96/min, respirations 12/min, and blood pressure 130/85 mm Hg. Physical examination of the right great toe discloses a 1.5-cm nontender ulcer with a depth of 0.5 cm, a moist base, yellow exudate, and surrounding erythema to the level of the malleoli. Vibration sense and sensation to monofilament examination are absent. Pulses are diminished in both feet. Capillary refill time is 2 seconds in the right great toe. Urinalysis discloses 3+ protein. Which of the following historical factors or physical examination findings is most strongly associated with development of this patient's foot ulcer?

• AA. Diminished pedal pulses
• BB. Neurologic findings
• CC. The patient's weight
• DD. Proteinuria
• EE. Tobacco use

A 52-year-old man returns to the office for reevaluation of an ulcer on his right great toe. The patient has a 15-year history of diabetes mellitus and takes glipizide and rosiglitazone. He first noticed the ulcer 2 months ago. One month ago, a 14-day course of oral amoxicillin-clavulanate therapy was prescribed. He has smoked one pack of cigarettes daily for the past 37 years. He is 178 cm (5 ft 10 in) tall and weighs 102 kg (225 lb); BMI is 32 kg/m². Today, vital signs are temperature 38.8°C (101.8°F), pulse 96/min, respirations 12/min, and blood pressure 130/85 mm Hg. Physical examination of the right great toe discloses a 1.5-cm nontender ulcer with a depth of 0.5 cm, a moist base, yellow exudate, and surrounding erythema to the level of the malleoli. Vibration sense and sensation to monofilament examination are absent. Pulses are diminished in both feet. Capillary refill time is 2 seconds in the right great toe. Urinalysis discloses 3+ protein. Which of the following is the most appropriate action at this time?

• AA. Begin aggressive debridement in the office
• BB. Begin intravenous antibiotic therapy
• CC. Refer the patient for transmetatarsal amputation
• DD. Schedule the patient for a third-degree skin graft
• EE. Switch the amoxicillin-clavulanate to oral ciprofloxacin

A 2-year-old girl is brought to the office by her mother for evaluation of fever. You have been the girl's physician since birth. While in the office, the girl stiffens and then has bilateral, symmetrical shaking of her upper and lower extremities; she becomes mildly cyanotic. The episode lasts for approximately 45 seconds, after which she becomes relaxed and appears to fall asleep. Vital signs at this time are temperature 40.0°C (104.0°F), pulse 120/min, and respirations 40/min. On physical examination she has a generally pink complexion and flushed cheeks. She is limp and somnolent and responds with a cry to noxious stimulus. Tympanic membranes are inflamed bilaterally, nose has a scant, clear discharge, and throat is mildly erythematous. Lungs are clear to auscultation except for transmitted upper airway sounds. Heart has rapid rate with a grade 1/6 systolic murmur at the left sternal border. Complete blood count, blood culture, lumbar puncture, and catheterized urine specimen are obtained and sent for stat analysis. Acetaminophen is administered by rectal suppository. Thirty minutes later the patient awakens and is smiling. She is afebrile. Additional history discloses that she was born at term, she had an uneventful neonatal course, she has normal growth and development, and vaccinations are up-to-date. She has never had an episode similar to this. Initial laboratory results are shown: | Blood | | | WBC | 10,400/mm³ | | Neutrophils, segmented | 25% | | Neutrophils, bands | 5% | | Lymphocytes | 65% | | Monocytes | 5% | | Cerebrospinal fluid | 0 RBC/mm³ | | Urinalysis | Normal | Other laboratory studies are pending. In addition to ampicillin for otitis media and acetaminophen, this child also should receive which of the following?

• AA. Oral ethosuximide
• BB. Oral phenobarbital
• CC. Oral phenytoin
• DD. Rectal diazepam
• EE. No additional medications

A 2-year-old girl is brought to the office by her mother for evaluation of fever. You have been the girl's physician since birth. While in the office, the girl stiffens and then has bilateral, symmetrical shaking of her upper and lower extremities; she becomes mildly cyanotic. The episode lasts for approximately 45 seconds, after which she becomes relaxed and appears to fall asleep. Vital signs at this time are temperature 40.0°C (104.0°F), pulse 120/min, and respirations 40/min. On physical examination she has a generally pink complexion and flushed cheeks. She is limp and somnolent and responds with a cry to noxious stimulus. Tympanic membranes are inflamed bilaterally, nose has a scant, clear discharge, and throat is mildly erythematous. Lungs are clear to auscultation except for transmitted upper airway sounds. Heart has rapid rate with a grade 1/6 systolic murmur at the left sternal border. Complete blood count, blood culture, lumbar puncture, and catheterized urine specimen are obtained and sent for stat analysis. Acetaminophen is administered by rectal suppository. Thirty minutes later the patient awakens and is smiling. She is afebrile. Additional history discloses that she was born at term, she had an uneventful neonatal course, she has normal growth and development, and vaccinations are up-to-date. She has never had an episode similar to this. Initial laboratory results are shown: | Blood | | | WBC | 10,400/mm³ | | Neutrophils, segmented | 25% | | Neutrophils, bands | 5% | | Lymphocytes | 65% | | Monocytes | 5% | | Cerebrospinal fluid | 0 RBC/mm³ | | Urinalysis | Normal | Other laboratory studies are pending. Two weeks later the patient is brought to the office for a follow-up visit. Her mother says that she is doing well and she has had no recurrence of her symptoms. Examination of the ears shows resolution of the otitis media. Which of the following is the most important diagnostic step at this time?

• AA. Audiology testing
• BB. Cognitive testing
• CC. CT scan of the head
• DD. EEG
• EE. No additional testing

A 27-year-old man is brought to the emergency department by his roommates because of an inability to walk. He began to notice some problems with his balance 2 days ago, and his walking has become progressively worse since then. He had an episode of optic neuritis in the right eye 3 years ago. He is 157 cm (5 ft 2 in) tall and weighs 55 kg (121 lb); BMI is 22 kg/m2. His temperature is 37°C (98.6°F), pulse is 55/min, respirations are 10/min, and blood pressure is 110/70 mm Hg. Examination shows spastic lower extremities and moderate weakness of the left lower extremity, more prominently in the flexor than in the extensor muscles. Deep tendon reflexes are normal in the upper extremities but hyperactive in the lower extremities, especially on the left. There is clonus at the left ankle. Proprioception and sensation to vibration are absent over the left lower extremity and decreased over the right lower extremity to the level of the hip. Sensation to pain and temperature is decreased at the lower costal margin and below, most pronounced on the right. Which of the following cell types is most affected by this patient's condition?

• AA. Astrocytes
• BB. Ependymal cells
• CC. Neurons
• DD. Oligodendrocytes
• EE. Schwann cells

A 2-year-old girl with sickle cell disease is brought to the emergency department by her parents because of painful swelling of her feet for the past 3 hours. Her temperature is 37.0°C (98.6°F). Physical examination shows swelling and tenderness of her feet; no other abnormal findings are noted. Results of laboratory studies are shown: | Hemoglobin | 7.8 g/dL | | WBC | 13,000/mm3 | | Neutrophils, segmented | 60% | | Lymphocytes | 40% | Which of the following is the most likely diagnosis?

• AA. Bone infarction
• BB. Escherichia coli sepsis
• CC. Osteomyelitis
• DD. Pneumococcal sepsis
• EE. Staphylococcal sepsis

A 54-year-old woman with severe rheumatoid arthritis comes to the office for a routine follow-up examination. Rheumatoid arthritis was diagnosed at age 35 years, and the patient has been unable to work for the past 10 years. She has difficulty bathing and dressing, but she is able to stand and walk independently. Medical history is otherwise unremarkable. Medications include etanercept, methotrexate, prednisone, and tramadol. She tells you that her husband of 30 years left her 6 months ago. She appears depressed. Vital signs are normal. Physical examination discloses marked joint deformities in the hands, wrists, shoulders, and feet; the findings are unchanged from previous visits. The patient says, "I cannot continue to live as I am. I've had it." Which of the following is the most appropriate response?

• AA. "Do you think you're depressed? I can help with that."
• BB. "Have you considered moving to an assisted living facility where your quality of life could be much better?"
• CC. "I know just how you feel."
• DD. "I'd like to refer you to a counselor."
• EE. "Would you like to tell me more about why you feel this way?"

A 17-year-old boy is brought to the emergency department by a caregiver after sustaining a large knife wound to his left arm. The caregiver reports that the patient cut himself with a knife, but it is unknown whether this was a suicide attempt. The patient lives in a group home with three other individuals and the caregiver; it is apparent from talking to the patient that he has limited intellectual capacity. He has an appointed legal guardian who has been contacted and is due to arrive at the hospital in approximately 45 to 60 minutes. The patient's vital signs are temperature 36.5°C (97.7°F), pulse 134/min, respirations 22/min, and blood pressure 70/40 mm Hg. He appears pale and he has a large, blood-soaked towel wrapped around his left forearm. Removal of the towel discloses a 9-cm laceration with obvious arterial hemorrhage and tendon exposure. Examinations of the chest and abdomen are unremarkable. A pressure bandage is immediately applied and consultation is obtained with a surgeon, who wants to take the patient immediately to the operating room. Which of the following statements is most accurate regarding consent for this patient?

• AA. The caregiver can legally provide consent
• BB. The need for consent can be waived
• CC. The patient is emancipated and can legally give consent
• DD. Psychiatric clearance should be obtained for patient consent
• EE. Surgery must be delayed until the guardian arrives