USMLE-STEP-3 Online Practice Questions and Answers
A 64-year-old male has been suffering from lower back pain for over 10 years. You have been following him for this period. You have prescribed stretching exercises and, occasionally, an anti-inflammatory medication to alleviate his pain. Although he has had no neurologic deficits in the past, today he has shown up in your office unexpectedly, complaining of bilateral lower back pain with numbness and tingling over the dorsal aspect of both feet. His symptoms have become progressively worse over the past 2 weeks and he is now unable to stand for more than 5 minutes without developing extreme pain and numbness. His symptoms are much improved by sitting down or kneeling over a chair. Climbing stairs seems to be tolerated well, but walking greatly exacerbates the pain. He denies bladder or bowel incontinence or retention, point tenderness or anesthesia in the lower back along the spinal cord or in the saddle area.
What is the likely diagnosis?
A. spondyloathropathy of the sacroiliac joint
B. age-related early degenerative joint disease (DJD) of the hips
C. spinal stenosis of the lumbosacral area
D. muscle spasm of the lower back
E. cauda equina syndrom
A 49-year-old male presents with crushing substernal pain and rules out for a myocardial infarction. He is noted to have subcutaneous emphysema of the chest and neck and precordial crackles that correlate to his heartbeat but not his respirations.
Which of the following is the most likely diagnosis?
A. spontaneous pneumothorax
B. esophageal perforation
C. pericarditis
D. pneumopericardium
E. pulmonary embolus
A 72-year-old woman undergoes a sigmoid colectomy for diverticulitis. Postoperatively, she develops a wound infection for which she is transferred to the ICU for 2 days because of hypotension. Which of the following would have had the most effect on reducing her risk of developing complications?
A. preoperative treatment of her concomitant urinary tract infection
B. nurses changing gloves in between their patient assessments so they don't have to wash their hands as often
C. using a preoperative antibiotic specific for E. coli, the most common intestinal flora
D. giving preoperative antibiotics immediatel after the skin incision
E. treatment of the infected wound with an antibiotic only
On a Monday morning you see a 12-year-old otherwise healthy boy in the emergency department. The parents brought the boy in because they noticed that he started to have an abnormal gait in the past few days. He seems to be shuffling his feet. The boy complains that his legs feel heavy and are tingling. He relates that his arms feel fine. His past history is significant for attention deficit/hyperactivity disorder (ADHD) for which he is taking methylphenidate. He denies trauma or taking any other medicines or drugs. On examination, he is afebrile with normal vital signs. His entire physical examination is normal with the exception of the examination of is lower extremities. He has 3/5 strength throughout both of his lower extremities with a normal muscle mass. His all joints have a full range of motion, without any pain or swelling. His reflexes are absent and he describes some paresthesias of his feet and ankles
Which of the following is the most appropriate initial management plan?
A. hospitalization and close observation for progression of his weakness
B. high-dose corticosteroids
C. gastric lavage and activated charcoal
D. outpatient family counseling
E. plasmaphoresis
A 16-year-old nulligravid high school student is on your afternoon office schedule for a "talk visit." She was seen last year by one of your colleagues for an initial GYN evaluation. She is healthy and has no medical problems. Today she tells you that she and her new boyfriend had intercourse the night before, and the condom they were using broke.
Your initial course of action should include which of the following?
A. placing an IUD
B. requesting that her parents be told of the situation
C. an examination and offer of sexually transmitted infections testing
D. performing a new obstetric workup
E. empirically treating her with ceftriaxone and doxycycline
A 19-year-old newly married female presents to the emergency room, accompanied by her spouse. She states that she awoke this morning to find that she could not move her legs. She denies any pain but claims that she is unable to feel anything below her abdomen. She denies any trauma or past medical history. She is 24 weeks' pregnant, has had an uneventful pregnancy, and only takes prenatal vitamins. She is concerned if her symptoms will get better and wonders whether the "baby is pulling on my spinal cord." Her neurologic examination is remarkable for 0/5 motor strength in her lower extremities bilaterally, with decreased sensation to light touch and pinprick below the level of her umbilicus. Her cranial nerves and reflexes are normal, and she does not display any upper motor neuron signs. A STAT MRI performed is read as normal.
Which of the following is the most likely explanation for her current symptoms?
A. conscious production of symptoms to assume the sick role
B. conscious production of symptoms to obtain secondary gain
C. pathology involving the central nervous system
D. pathology involving the peripheral nervous system
E. unconscious production of symptoms due to unconscious conflict
A recent study compared two drugs--exemestane and tamoxifen--for the treatment of estrogenreceptor positive breast cancer in postmenopausal women. At the end of the study, 91.5% of the women treated with the drug exemestane and 86.8% of the women treated with tamoxifen were disease free (P < 0.001).
What is the absolute risk reduction (ARR) for the development of recurrent breast cancer for women taking exemestane compared to women taking tamoxifen?
A. 95.3%
B. 72%
C. 64%
D. 36%
E. 4.7%
While you are working in the community health center, a 40-year-old male presents to you as a referral from the dental clinic. The patient reported on the intake history form at the dental office that he had rheumatic fever at the age of 7. The dentist refused to allow him to have a dental examination and cleaning until he was cleared by a medical doctor. Other than rheumatic fever, the patient has no medical history and does not take any medications. He denies chest pain, palpitations, dyspnea, or any other symptoms. On examination, he has normal vital signs and a normal general examination. On auscultation of his heart, you hear a 2/6 systolic ejection murmur at the left upper sternal border without radiation. Review of his chart shows that he had an echocardiogram approximately 9 months ago that revealed mild mitral valve prolapse without evidence of mitral regurgitation, but otherwise normal valves and cardiac function.
Which of the following would be the most appropriate management at this time?
A. Proceed with the dental work.
B. Give the patient a 2 g dose of oral amoxicillin and then perform the dental cleaning an hour later.
C. Delay the dental work until the patient can undergo a repeat echocardiogram.
D. Delay the dental work until the patient is cleared by a cardiologist.
E. Allow the patient to undergo the dental cleaning now, but caution that he will need antibiotic prophylaxis if he requires any fillings.
Your patient who was recently prescribed an antibiotic returns to your clinic for a follow-up visit. Although she was feeling better, the instructions on the bottle were to take the medication for total of 10 days. She wants to know if she still has to take the medication three times daily as she has improved. You explain to her that the dosing regimen is based on the biological half-life of a drug, which is generally related to which of the following?
A. the time for a drug to be absorbed into the blood
B. the time for a drug to take effect following administration
C. the time for the body burden of a drug to be reduced by 50%
D. the serum concentration of a drug that is 50% of the toxic level
E. a value that is half the duration of action of a drug
A 67-year-old female was admitted to the hospital because of chronic fatigue and low back pain. An x-ray of the vertebral column showed diffuse osteoporosis and compression fractures of L1 and L2 vertebral bodies. The complete blood count (CBC) was within normal limits. The peripheral blood smear showed rouleaux formation. The immunoelectrophoresis showed a monoclonal spike of more than 3 g. A bone marrow biopsy was performed and showed an increase of more than 20% in plasma cells see Figure below
Radiographs of the bone and skeletal system in multiple myeloma will more characteristically show which of the following?
A. fractures
B. osteoblastic lesions
C. destructive bone lesions throughout the skeletal system
D. the skeletal system will remain intact
E. changes that resemble Paget disease