USMLE Step 3 Sample Items – Kaplan Medical

The USMLE Step 3 exam assess the examinee's ability to apply medical knowledge and the understanding of biomedical and clinical science essential for the unsupervised practice of medicine, with emphasis on patient management in ambulatory settings. These sample items are standard USMLE Step 3 type questions.

Question 1

A 31-year-old obese female with a history of asthma comes to your office complaining of severe shortness of breath and wheezing. She produces from her purse a number of active medications including a beclomethasone metered dose inhaler (MDI) and salmeterol MDI. She also appears to be taking zafirlukast daily. She tells you that she has been hospitalized many times for asthma flares and was once intubated. Her review of systems is pertinent for asthma attacks of increasing severity over the past few weeks but she denies any fever, cough, chills, or pleuritic chest pain. On exam, the patient demonstrates audible expiratory wheezes with a markedly prolonged expiratory time. Her respiratory rate is 20-24/min and she is acutely short of breath, using accessory muscles of respiration to breathe. Her vital signs are otherwise stable. Which of the following is the most beneficial management of this patient?

(A) Obtain a chest radiograph to rule out pneumonia
(B) Obtain a peak flow estimate
(C) Albuterol nebulizer therapy in the office
(D) Refer the patient to the local hospital for admission
(E) Refer the patient to the local emergency room for evaluation and treatment

Answer

The correct answer is E. A patient with severe asthma who has had multiple previous admissions for asthma must be treated emergently. Although she presented in an office setting, simply managing her current flare in an outpatient setting is not sufficient, as these patients tend to decompensate rapidly. She is already in mild-to-moderate respiratory distress and will only get worse if appropriate therapy is not initiated. If she worsens, the office setting is no place to manage her.

Getting a chest radiograph to rule out pneumonia (choice A) would be acceptable if this patient's condition were not acute. Since the overriding concern is for impending respiratory collapse, she should be triaged to a local ER and have a chest radiograph taken under more controlled conditions.

Documenting a peak flow estimate (choice B) is not going to alter any management decisions. Even if her flows were not markedly depressed, she is still in moderate respiratory distress and is not moving air well.

Initiating albuterol nebulizer therapy (choice C) may be beneficial, and if the therapy is successful, the acuity of the situation has passed. However, if the therapy fails to be effective, then valuable time has been lost and the patient's condition will likely be more critical.

The ulnar nerve (choice E) crosses the elbow posterior to the medial epicondyle of the humerus. It then passes between the two heads of the flexor carpi ulnaris and courses through the forearm deep to this muscle.

Referring the patient to the local hospital for admission (choice D) is not equivalent to having her seen and evaluated in the emergency room. Given that this patient is in near extremus, she requires evaluation and therapy by the ER team.

Question 2

A 69-year-old man is brought to the clinic for progressively worsening memory loss and confusion. The patient has a long history of hypertension and coronary artery disease. He has not seen a physician in a number of years and has not been taking any medications. The family reports a step-wise decline in his cognitive function over the past few years. He has long periods where he appears stable and then suddenly worsens over a few days. On physical examination, he is a thin but not cachectic appearing man with a blood pressure of 185/110 mm Hg. His physical examination is notable for a faint carotid pulsation on the left with a prominent right carotid bruit. He has an S4 gallop on precordial examination.

Which of the following is the appropriate first step in the management of this patient?

(A) Initiate donepazil therapy
(B) Initiate atenolol therapy
(C) Initiate warfarin therapy
(D) Order a carotid ultrasound study
(E) Order a head CT scan

Answer

The correct answer is B. This patient suffers from a form of dementia known as multi-infarct dementia. The requirements for the diagnosis of dementia include a demonstration in the decline of memory as well as impairment of at least one other cognitive function (aphasia, apraxia, agnosia, executive planning). Multi-infarct dementia is the second most common cause of dementia and is often due to severe carotid disease or embolic disease. This patient has a number of issues on presentation, the most urgent of which is his blood pressure. Although the management of this pressure has subtle details, the best course of management from all of the choices given is to initiate atenolol

Donepazil therapy (choice A) is an anti-cholinesterase inhibitor used in dementia of the Alzheimer's type.

Warfarin therapy (choice C) is generally started in patients with severe carotid disease. However, this patient's most pressing issue is blood pressure control. Starting warfarin in patients with poorly-controlled hypertension predisposes them to catastrophic hypertensive bleeds.

Ordering a carotid ultrasound study (choice D) is a very appropriate intervention to assess the magnitude of this patient's carotid disease. However, the primary medical issue is not urgent revascularization of the carotid vasculature, but control of his severe hypertension.

Ordering a head CT scan (choice E) may be a useful diagnostic study in the evaluation of dementia, however, in a patient with multi-infarct dementia, it is not more useful that carotid studies.

Question 3

A 43-year-old African-American man comes to the clinic for the first time as part of a neighborhood-screening program for hypertension. He reports that he has no past medical history but has not seen a physician routinely for the past ten years. He smokes two packs of cigarettes per day but denies ethanol or any substance abuse. He takes no medicines regularly. The nurse measures his blood pressure as 165/90 mm Hg in the left arm while sitting. The physician has a long discussion with the patient concerning the possibility that his blood pressure has been elevated for some time and that he may need medical therapy in order to lower it to appropriate levels. A careful physical examination is performed looking for possible end-organ manifestations of long-standing untreated hypertension. Which of the following signs is suggestive of long standing hypertension?

(A) S3 gallup
(B) Abdominal bruit
(C) Carotid bruit
(D) S4 gallup
(E) Systolic ejection murmur

Answer

The correct answer is D. Hypertension effects multiple organs adversely. The heart is one of the most severely affected. As a consequence of the long-standing pressure overload on the left ventricle, the initial response of the myocardium is to hypertrophy. As the ventricle enlarges and begins to encroach upon sub-endocardial blood supply, mild ischemia and diastolic dysfunction occur. These consequences are manifest by an audible gallup during diastolic filling (atrial contraction) of a stiffened ventricle.

An S3 gallup (choice A) is the sound heard during rapid diastolic filling of diseased ventricle and results from turbulent blood flow. This is not specific for hypertensive heart disease and is not a characteristic finding.

An abdominal bruit (choice B) or carotid bruit (choice C) are sounds heard over the abdomen and neck respectively. They represent turbulent flow across an artery. The turbulence is most often caused by atheromatous plaques deposited in the arterial intima. Bruits are a sign of severe peripheral vascular disease.

A systolic ejection murmur (choice E) is heard after S1 and during the time of systolic ejection. It is usually caused by a diseased aortic valve, either stenosis or sclerosis. These conditions are not a consequence of long-standing hypertension.