USMLE 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:

Menstrual disorders, primarily oligo-and amenorrhea, are particularly common among women with eating disorders and are thought to be the result of hypothalamic hypoestrogenism. This patient demonstrates estrogen deficiency (decreased breast size, urogenital atrophy). Her dental caries, oral sores, and hand sores might be a result of self-induced vomiting. Hyperthyroidism would be considered in the differential diagnosis of a young woman with weight loss and menstrual irregularities. In contrast to persons with a medical condition that causes weight loss, those with an eating disorder express a disordered body image and, often, a desire to be underweight. This patient requires additional investigation to assess for the possibility of inpatient admission. Patients with a prolonged, severe eating disorder are at risk for developing dehydration, electrolyte imbalance (especially hypokalemia), cardiac dysrhythmias, and hypothermia. Hospitalization would be considered for those who are severely dehydrated, who have marked electrolyte abnormalities who are <75% of their ideal body weight, or who have a comorbid condition that would require hospitalization, such as a severe psychiatric disorder. Although weight-bearing exercise favors bone formation, when excessive exercise and/or an eating disorder results in amenorrhea, estrogen levels fall. Subsequently, bone mineral density decreases. Persons with eating disorders are at increased risk for comorbid psychiatric conditions including depression, anxiety, obsessive-compulsive disorder, and personality disorders.

Correct Answer: B Section: (none)

Explanation:

Febrile seizures are the most common cause of seizures in childhood. These are classically seen early in an illness and when there is a rapid rise in the child's temperature. These seizures usually last less than 23 minutes (typical febrile seizures last no longer than 15 minutes) and have a very mild, short, postictal phase. Children who have seizures that are the result of bacterial meningitis will not subsequently be normal. For typical febrile seizures, in an otherwise healthy and well-appearing child, no evaluation (outside of treating any underlying cause of the fever) is warranted. Blood and urine cultures would not be necessary in evaluation of the seizures, but they may be warranted in evaluation of the fever. An EEG and head CT will nearly universally be normal and are unwarranted. A single typical febrile seizure routinely does not require any anticonvulsant therapy. If the child has had multiple febrile seizures, or the seizures are not typical, anticonvulsant therapy may be entertained. Prophylactic anticonvulsant therapy is usually initiated after the third febrile seizure. Occasionally, children may have convulsions associated with fevers which do not fall into the typical features. Some criteria which would make a febrile seizure atypical would be prolonged duration (greater than 15 minutes) and a prolonged postictal state