USMLE Step 3 - Practice Questions

USMLE Step 3-PracticeQuestions

Directions: The USMLE Step 3 tests your ability to apply medical knowledge and your understanding of biomedical and clinical science. It focuses on patient management in ambulatory settings. Try the USMLE Step 3 questions below, pick one best answer from the choices below, then check your answer by clicking on the “get answer” button to see how you did.

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Question 1 – Internal Medicine A 52-year-old woman comes to the emergency department complaining of shortness of breath. She has a medical history significant for a “heart murmur” and hypertension. She is on no medications and describes “throat swelling” with penicillin. Her temperature is 37.0 C (98.6 F), blood pressure is 123/89 mm Hg, pulse is 103/min, and respirations are 28/min. On examination, she has jugular venous distension. There is a loud ejection murmur at the cardiac apex and rales bilaterally in both lung fields. Her chest radiograph shows perihilar air-space disease. An electrocardiogram shows sinus rhythm and left ventricular hypertrophy. The most appropriate next diagnostic step is to order a A. B. C. D. E.

Cardiac stress test CT scan of the chest Transesophageal echocardiogram Transthoracic echocardiogram Ventilation-perfusion scan

Answers and Explanations D On the basis of the available information, this patient has congestive failure from aortic stenosis. It is therefore appropriate to request a transthoracic echocardiogram to investigate this further. A cardiac stress test (choice A) will similarly not provide useful information in the evaluation of aortic valvular disease. A chest CT scan (choice B) will not provide useful information in the evaluation of possible aortic valvular disease. A transesophageal echocardiogram (TEE) (choice C) is typically not used as the first diagnostic tool in the echocardiographic evaluation of aortic stenosis. Because the aortic valve is an anterior structure, the transthoracic approach is able to provide excellent information in the evaluation of aortic stenosis. A ventilation-perfusion scan (choice E) is used in the diagnosis of a pulmonary embolism, which is not consistent with this patient’s clinical picture.


Question 2 – Neurology A 74-year-old man who lives with his sister is brought to the clinic because of behavioural changes and increasing “forgetfulness” over the past year. He often forgets to lock the bathroom door or to change his underwear after he takes a shower. He does some things twice because he has forgotten that he has already done them. Sometimes he accuses his nephew of stealing his money because he cannot find his wallet. He wanted to come to the doctor because he wanted to prove that he was “fine”. He has no history of major medical problems in the past. MiniMental Status examination reveals cognitive deficits with the Folstein score of 21. Additional testing is ordered and findings indicate that diagnosis of dementia of Alzheimer type. He is brought back to the clinic for reevaluation and discussion. His Folstein score on this visit is 20. Further steps are discussed in a family meeting with the patient and his family. Given the present clinical picture of dementia, Alzheimer type, the most appropriate next step in management is to A. Admit him to the geriatric psychiatry unit B. Begin a trial of donepezil and keep the patient at home C. Reassure the family that the addition of vitamins B and E will be sufficient to control the symptoms D. Recommend a brain biopsy E. Recommend a residential facility with close supervision

Answers and Explanations B The best management is to keep the patient at home in a familiar environment and under the supervision of his family. He is not displaying severe behavioral problems that his family wouldn’t be able to manage. Starting donepezil should help the cognitive deficits. His family needs to be educated about the need for closer supervision and safety issues. The focus is initially on the attempt to preserve quality of life. Admitting him to the geriatric psychiatry unit (Choice A) is currently not justified. The workup for dementia has been done and current symptoms are not severe enough to justify inpatient treatment. Starting the patient on vitamins E and B (choice C) could be useful; however, it won’t change the course and prognosis of illness. Available treatment possibilities should be presented instead of misleading reassurance that vitamins-only will produce miracles. Ordering a brain biopsy (choice D) is not a standard diagnostic procedure. In case of dementia of Alzheimer type it would provide patho-histologic proof. Brain biopsy is done in cases of unclear pathology, rather than for the purpose of diagnosing dementia of Alzheimer’s type. Residential facility with close supervision (choice E) is recommended for patients with no family or in a progressed stage of disease when the danger of leaving them unsupervised can lead to tragic consequences and the families are not able to provide sufficient care. It is certainly not the appropriate next step in this patient’s case.


Question 3 – Obstetrics/ Gynecology You are driving to the hospital to evaluate one of your obstetric patients who called and said that she was contracting every 7 minutes. She says that she has no vaginal discharge but has been feeling “lots of fetal movement”. You remember that she is a G2P1001 woman at 38 weeks’ gestation. She was unsure of her last menstrual period, so a first trimester ultrasound was done to establish her due date. There were no abnormalities seen at the time of the ultrasound. Upon arriving on labor and delivery, you learn that on the way to the hospital the patient’s car rear/ended another car at low speed. She was a belted passenger. She has developed moderate vaginal bleeding and more severe contractions that are now occurring “one on top of the other”. Her abdomen is tender with a reddened area from her lap belt. Her temperature is 37 C (98.6 F), blood pressure is 90/60 mm Hg, pulse is 110/min, and respirations are 22/min. The fetal heart rate is being monitored and the baseline is 180/min. Uterine contractions are occurring every 60 seconds and are lasting 45 seconds. At this time you should A. B. C. D. E.

Administer betamethasone Give magnesium sulfate for tocolysis Manage the labor expectantly Prepare for a cesarean section while stabilizing the patient Order an ultrasound to rule out placenta previa

Answers and Explanations D This patient is showing evidence of placental abruption secondary to abdominal trauma. Vaginal bleeding, fetal or maternal distress, and uterine hypertonus are all signs of abruption. Abdominal trauma is a common cause of abruption. Both the patient and the fetus are showing signs of distress from volume loss, and delivery must be accomplished rapidly to prevent fetal death and maternal morbidity from hemorrhage and possible death. The patient should be quickly evaluated for other injuries. IV access should be obtained with determination of blood count and coagulation status. Abruption can commonly cause coagulation abnormalities and even DIC. The patient should also be typed and crossed for blood products. Pregnant women are relatively immune to the usual early signs of volume loss, and the tachycardia, tachypnea, and low blood pressures are all ominous signs of significant blood loss. The amount of vaginal bleeding may or may not correlate with the actual blood loss, so you cannot be reassured by the “moderate” bleeding seen. Betamethasone is indicated to promote fetal lung maturity in preterm infants. This patient is term, confirmend by a first trimenester ultrasound. Therefore betamethasone (choice A) is not indicated. Magnesium sulfate (choice B) can be used in the management of preterm labor, but the contractions this patient is having are not consistent with that diagnosis. The patient was likely in early labor when you spoke to her on the phone, but the increase of contractions is likely secondary to placental abruption and not active


labor. If this patient were close to delivery and hemodynamically stable, expectant management of labor would be reasonable, However, there are signs of me=ternal and fetal compromise therefore, delivery should be expedited and expectant management of labor (choice C) is inappropriate. Placental previa (placental tissue covering or near the cervical os) can cause bleeding in the third trimester. However, placenta previa (choice E) is more commonly seen in early ultrasounds. The majority will resolve through a process called “placental migration”. There is differential growth between the lower uterine segment and the rest of the placenta. This causes the edge of the placenta to gradually move away from the cervical os. If placenta previa was not seen in the patient’s first trimester ultrasound it is unlikely to be present at this time.


Question 4 - Pediatrics You are supervising a third-year medical student who jumps right on to see the first patient of the day, who is a 12-year-old boy complaining of chest pain. The student presents the case to you and states that when the boy took off his shirt for examination there was evident gynecomastia. His lungs, however, were clear to auscultation. The young boy denied that he had any past disease and he reports that he takes no medications, does not smoke marijuana or do drugs, and insists that he hates girls and has never had sex. The boy’s mother could not be found in the waitin room, so the student was unable to obtain her side of the story. His blood pressure is 120/82 mm Hg, pulse is 88/min, and respirations are 18/min. the conscientious medical student also plotted the boy’s height and weight, noting that the boy is greater than 95% in height and 80% in weight. As a supervising physician, you emphasize to the student that the best next step in evaluation of this patient will be A. B. C. D. E.

Bone age Genital examination Serum testosterone To find out from the mother whether there is a family history of gynecomastia Urine screen for drugs

Answers and Explanations B In any male adolescents with gynecomastia it is important to complete the physical exam by examining the genitalia and assessing the Tanner staging or sexual maturity rating (SMR). Usually gynecomastia occurs during Tanner stage II to III. Particularly important in this very tall boy is to rule out any disorder such as Klinefelter syndrome. Characteristically, these patients have gonadal failure with small infantile testes and tall stature. A bone age should not be done before assessing his height and weight together with the Tanner staging (choice A). A normal bone age will most closely correlate with the stage of pubertal development rather than the chronological age. A serum testosterone is not the best next step in evaluating this boy (choice C). Physiocologic pubertal gynecomastia is very common during early puberty in most young males and a family history of gynecomastia is not very helpful (choice D). Knowing that close relatives may have had gynecomastia might make the emotional anguish of having “breasts” less of a worry to this boy, but it is definitely not the best next step. Drug exposure to medications such as hormones (e.g., estrogen, testosterone, anabolic steroids) as well as drugs of abuse (marijuana, opioids, and other street drugs) may be the cause of breast symptoms including pain, gynecomastia, and galactorrhea. However, a urine screen for drugs is not the best next step in evaluation (choice E)


Question 5 - Psychiatry A 45-year-old woman is brought to the emergency department by her family because she is “in a maniac state”. The patient has not slept for several days, has flight of ideas, has maxed out five credit cards, and believes that she is indestructible. She has always been extremely reluctant to seek treatment and has never had consistent outpatient follow-up in the past. She has had two distinct depressive episodes, with consistent sadness, tearfulness, and passive suicidal ideation, and two other manic episodes in the last 6 months. In addition to hospitalization, the most appropriate pharmacotherapy for this patient is A. B. C. D. E.

Amitriptyline Lithium Propanolol Theophylline Valproic acid

Answers and Explanations C Dialectic behavioral therapy was developed by Marsha Linehan at the University of Washington specifically for the treatment of patients with borderline personality disorder and chronic suicidality. The techniques involved in this treatment include the use of confrontation, humor, and self-regulation and exploration of patient affect. Controlled studies of this therapeutic modality confirm its efficacy. Aromatherapy (choice A) has been used experientially for patients with such conditions as anxiety and adjustment-related stress. It is not, however, a wellstudied modality for any mental health condition. Biofeedback (choice B) has been used to treat chronic pain and many medical conditions thought to have a psychosomatic component, such as hypertension and asthma. There is no evidence to suggest that it is an effective treatment for borderline personality disorder. Flooding (choice D) is a cognitive-behavioral technique with documented efficacy for patient with a history of specific anxiety-provoking situations (such as fear of contamination in obsessive-compulsive disorder or fear of riding elevators for agoraphobic patients). Given that this patient does not have a specific stimulus that is anxiety provoking, it is difficult to flood the patient situationally. Hypnotherapy (choice E) has no documented efficacy in the treatment of behavioral disturbances and chronic suicidality associated with borderline personality disorder.


Question 6 - Surgery As you are making afternoon rounds in the hospital, you are informed that one of your patients has a fever of 38.2 C (100.8 F). The patient is a 71-year-old man who is postoperative day 6 from a right hemicolectomy for colon cancer. Upon questioning. The patient tells you that he feels well other than a small amount of pain at his incision site. He has been tolerating his regular diet for 24 hours without any nausea or vomiting. He has passed flatus, but has not had a bowel movement. He has been ambulatory since postoperative day 3. He denies any cough, chest pain, shortness of breath, or dysuria. His Foley catheter has been removed for 3 days now. Physical examination reveals clear lungs with good inspiratory effort and no crackles, normal heart sounds, and nondistended and soft abdomen. There is erythema and increased tenderness around the distal half of the incision site. A small amount of purulent drainage is seen near the erythematous portion of the wound. He has no calf tenderness or lower extremity swelling. The most appropriate next step in the management of this patient’s fever is to A. B. C. D. E.

Apply a dressing to the incision site drainage Begin antibiotic therapy Open, drain, and pack the incision site Order a chest x-ray Schedule a lower extremity venous Doppler study

Answers and Explanations C This patient has a postoperative wound infection. As with all types of infected fluid collections, the primary treatment is drainage of the fluid. In this case, that means removing the outer layer of closing (usually staples), releasing the pus, irrigating the now open wound, and packing the wound. Antibiotic therapy should then be initiated. Once the infection has been removed, daily dressing changes will allow the wound to heal by second intention. Covering the drainage with a dressing (choice A) will prevent the patient from leaking on himself; however, it does nothing to halt the progression of the wound infection. If left untreated, this wound infection may disrupt the integrity of the abdominal fascial closure. Using antibiotics (choice B) without opening the wound is inappropriate and incomplete. It is appropriate to be concerned that any patient suffering from a postoperative fever may have or be developing pneumonia. It would not be inappropriate to order chest x-ray on this patient. However, he has no respiratory distress, his lung examination is normal, and he has an obvious source for his fever (the wound!). Therefore, the chest x-ray should be ordered AFTER the wound is drained (choice D) A lower extremity thrombus may also cause a fever in the postop patient, and this may be evaluated by venous Doppler (choice E). However, the clinical suspicion here is low. There is no extremity edema, palpable cord, or tenderness or respiratory difficulty. Therefore, this test should not be ordered prior to opening the patient infected incision site. Kaplan Test Prep International 3-5 Charing Cross Road, London WC2H 0HA + 44 (0) 20 7930 3130 | www.kaptestglobal.com | [email protected] © Copyright Kaplan Test Prep 2015