Comprehensive Clinical Science Test

Question 1

A clinical trial of a potentially valuable medical treatment is planned.
It is unlikely that it will directly benefit the study subjects but very likely that it will benefit future patients.
There is a risk for short-term minor gastric discomfort but essentially no risk for long-term adverse effects.
The investigator concludes that disclosure of the risks may discourage participation in the trial.
Which of the following is the most appropriate next step?

Accepted Answer

Proceed with the trial only with disclosure, because informed consent is an absolute requirement

Answer

Proceed with the trial only with disclosure, because the trial will not directly benefit the subjects

Answer

Proceed with the trial using only subjects who agree to participate without disclosure

Answer

Proceed with the trial without disclosure, because the risks to subjects are outweighed by the possible benefits to many patients

Answer

Proceed with the trial without disclosure, because the probability of long-term harm to subjects is remote

Question 2

A 25-year-old man comes to the emergency department because of a 1-month history of fever, chills, nonproductive cough, and progressive shortness of breath; he now becomes short of breath after walking 20 feet. He has had a 4.5-kg (10-lb) weight loss during this period. He has not seen a physician for 10 years, and he takes no medications. He has a 10-year history of intravenous heroin use and shares needles. He is in mild respiratory distress while sitting. His temperature is 38.6°C (101.4°F), pulse is 92/min, respirations are 24/min, and blood pressure is 110/70 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 90%. There is no jugular venous distention. Diffuse crackles are heard bilaterally. There is no peripheral edema. An x-ray of the chest shows diffuse interstitial infiltrates bilaterally. This patient is most likely to have which of the following immunologic abnormalities?

Accepted Answer

Decreased CD4+ T-lymphocyte count

Answer

Decreased B-lymphocyte count

Answer

Decreased serum complement concentrations

Answer

Decreased serum IgA concentration

Answer

Decreased splenic opsonization

Answer

IgG autoantibodies

Question 3

A 27-year-old man is brought to the emergency department 20 minutes after his roommate found him unconscious on their bathroom floor. The patient has a history of intravenous heroin use. He has no history of serious illness and takes no medications. On arrival, he appears cyanotic. He is unresponsive to verbal and painful stimuli. His temperature is 37.1°C (98.8°F), pulse is 80/min, respirations are 4/min, and blood pressure is 110/60 mm Hg. Examination shows new and old needle tracks over the upper and lower extremities. Cardiopulmonary examination shows no abnormalities. Arterial blood gas analysis on room air shows: pH 7.20 PCO2 80 mm Hg PO2 50 mm Hg HCO3 - 29 mEq/L Which of the following is the best explanation for this patient’s hypoxemia?

Accepted Answer

Hypoventilation

Answer

Decreased inspired oxygen tension

Answer

Impaired diffusion capacity of the lung for carbon monoxide

Answer

Right-to-left shunt

Answer

Ventilation-perfusion mismatch

Question 4

A 15-year-old boy has had pain in the knee since sustaining an injury in a high school football game 6 weeks ago. The high school trainer has been treating him with heat and ultrasound, without significant improvement. Physical examination shows tenderness of the medial femur approximately 7.5 cm above the joint. There is no ligamentous instability, joint swelling, or effusion. Which of the following is the most appropriate next step in diagnosis?

Accepted Answer

Anteroposterior and lateral x-rays

Answer

Arthrography

Answer

Arthroscopy

Answer

Measurement of serum calcium concentration

Answer

Ultrasonography

Question 5

A 2-week-old boy is brought to the physician because of a 3-day history of persistent discharge from his eyes. He was born at term following an uncomplicated pregnancy and delivery. Examination of the eyes shows tarsal inflammation and a thin mucopurulent discharge. Testing of scrapings from the tarsal conjunctivae is positive for Chlamydia trachomatis. The remainder of the examination shows no abnormalities. Which of the following is the most likely mode of transmission of this patient’s infection?

Accepted Answer

Contact with maternal cervical secretions

Answer

Aerosol exposure

Answer

Exposure to household pets

Answer

Poor hand washing by caregivers

Answer

Transplacental transmission

Question 6

A 62-year-old man comes to the physician because of blood in his urine for 24 hours. Vital signs are within normal limits. Examination shows no abnormalities. Tissue obtained on bladder biopsy shows transitional cell carcinoma. Abstinence from which of the following is most likely to have prevented this condition?

Accepted Answer

Tobacco

Answer

Alcohol

Answer

Coffee

Answer

Diet soda

Answer

Tea

Question 7

A 21-year-old nulligravid woman who is not using contraception has had irregular menstrual periods since menarche at age 13 years. She has noted increased hair growth on her face and lower abdomen. On pelvic examination, there is copious cervical mucus and slightly enlarged irregular ovaries. Which of the following is the most likely cause of these findings?

Accepted Answer

Polycystic ovarian syndrome

Answer

Adrenal adenoma

Answer

Idiopathic hirsutism

Answer

Ovarian tumor

Answer

Pituitary adenom

Question 8

A 50-year-old man has a 1-hour history of unremitting chest pressure and “gassiness.” He has no history of cardiac problems but does have a history of peptic ulcer disease. Physical examination shows no abnormalities except for a blood pressure of 140/80 mm Hg. Which of the following is the most appropriate initial step in diagnosis?

Accepted Answer

ECG

Answer

Test of the stool for occult blood

Answer

X-ray series of the upper gastrointestinal tract

Answer

Echocardiography

Answer

Endoscopy of the upper gastrointestinal tract

Question 9

A 32-year-old nulligravid woman comes to the physician because of a 20-minute episode of shortness of breath when she awoke this morning. Her only medication is an oral contraceptive. She has smoked one pack of cigarettes daily for 10 years. She is sexually active with multiple partners. Physical examination shows erythema, swelling, warmth, and tenderness behind the right knee; a cord-like mass can be palpated. Which of the following is the most likely diagnosis?

Accepted Answer

Pulmonary embolism

Answer

Corticosteroid-induced arthritis

Answer

Gonococcal arthritis

Answer

Steroid-induced asthma

Answer

Systemic lupus erythematosus

Question 10

A 4030-g (8-lb 14-oz) newborn has internal rotation of the left upper extremity at the shoulder, extension at the elbow, pronation of the forearm, and flexion of the fingers following a low forceps delivery. He was born at term following an uncomplicated pregnancy. Passive range of motion of the left upper extremity is full; the newborn does not cry or grimace when the left arm, shoulder, or clavicle is palpated. Examination shows no other abnormalities. Which of the following is the most likely underlying mechanism of this condition?

Accepted Answer

Traction on the brachial plexus during delivery

Answer

Anterior dislocation of the left shoulder

Answer

An inherited skeletal dysostosis

Answer

Intracerebral hemorrhage

Answer

Posterior dislocation of the cervical vertebrae