USMLE-STEP-3 Exam Questions & Answers

Correct Answer: B Section: (none)

Explanation:

Quinidine can prolong the Q-T interval resulting in the development of polymorphic ventricular tachycardia (torsade de pointes). Hypokalemia, a side effect of thiazide diuretics, increases the risk of torsade de pointes, which can then degenerate into fatal ventricular fibrillation. Thiazide diuretics may decrease the effectiveness of uricosuric agents, insulin, and sulfonylureas and may increase the effects of vitamin D. However, these effects tend not to be life threatening

Correct Answer: D Section: (none)

Explanation:

This patient presents with classic symptoms of a bowel obstruction. The diagnosis is often made by a thorough history and physical examination. Following the initial evaluation, an acute abdominal x-ray series should be obtained, which includes supine and erect views of the abdomen. The diagnosis is confirmed with the presence of dilated loops of bowel with the presence of air-fluid levels. These plain films may also suggest the location of the obstruction (small vs. large intestine). Abdominal ultrasonography has limited role in the diagnosis or management of intestinal obstruction. Serum electrolyte determination helps in identifying the electrolyte disturbances that have taken place. Fluid loss needs to be corrected with rehydration, and nasogastric suction helps in decreasing abdominal distention. Upper GI endoscopy would increase distention, and is contraindicated. Antiemetics should not be given until a definitive diagnosis is made, and then only if indicated; promotility agents have little to no role in the management of a patient with bowel obstruction, and may even be contraindicated.

An annular constricting lesion with overhanging edges is typical of annular carcinoma of the colon. Mechanical small bowel obstruction results in multiple air-fluid levels in distended small bowel loops. Intussusception produces a "corkscrew" appearance on barium enema, and sigmoid volvulus produces a "bird's beak" appearance. In diverticulitis, extravasation of barium outside the lumen of the colon typically is seen.

Correct Answer: B Section: (none)

Explanation:

There are nearly 900,000 victims of child abuse in the United States each year. An inflicted injury is the most common cause of injury in the first year of life. As a child becomes more mobile, falls and motor vehicle accidents become increasingly more common. Other children are a very rare cause of serious injury in childhood. (Department of Health and Human Services, 2002) Brain injury that results from violent shaking of the infant is known as Shaken baby syndrome. These infants can present with seizures, a bulging fontanelle, or irritability presenting a clinical picture similar to that of a septic infant. Intracranial injury is evident on CT or MRI and with a funduscopic examination revealing retinal hemorrhages. Accidental bruises are usually found over bony areas such as shins, knees, elbows, and forehead. Linear fractures of the skull can result from low-energy blunt trauma over a wide surface area of the skull. Nursemaid's elbow is a common condition in young children and generally affects children under 5. It occurs when a child is pulled up too hard by the hand or wrist resulting a in a partial dislocation of the elbow.