USMLE-STEP-2 Online Practice Questions and Answers

Correct Answer: C

The typical migraine attack consists of a visual aura with flashes, scintillating scotomata (field loss), or fortification spectra followed by a throbbing unilateral temporal headache. There may be associated vestibular, GI, or neurologic symptoms. Attacks are often precipitated by stress, fatigue, or foods that contain tyramine (e.g., cheese, yogurt, nuts) or phenylethylamine (wine, chocolate). Symptoms peak within an hour of onset and persist for hours to days. A positive family history is found in as many as 50% of cases. Tension headaches are more often bilateral and described as band like or vise like and are not usually associated with visual auras. TIAs more typically present as transient monocular blindness without aura or headache. Temporal arteritis may present as painless loss of vision without aura, but is usually in older people. Cluster headaches are much more common in men. Sumatriptan and the other triptans work by inhibiting the release of vasoactive peptides, promoting vasoconstriction, and blocking brainstem pain pathways. Sumatriptan comes in oral, injectable, and nasal spray form. Ergotamine tartrate, antiemetics, and analgesics may also be used in the acute treatment of migraine headache. Prophylactic medications such as beta-blockers, tricyclic antidepressants, calcium channel blockers, and anticonvulsants are ineffective for acute attacks. Avoidance of known precipitants and control of stress are also important in prevention.

Correct Answer: B

More than 90% of renal stones are visible on a plain abdominal x-ray, and the majority contain calcium oxalate. Staghorn calculi usually contain magnesium ammonium phosphate (triple phosphate or struvite) and are associated with alkaline urine. This is commonly encountered in chronic urinary tract infections with urea-splitting bacteria. Radiolucent stones often contain urea, which is associated with acidic urine. A small percentage (fewer than 10%) of renal stones contain cystine. The most common cause of calcium stone disease is idiopathic hypercalciuria. Almost half these patients will excrete more than 4 mg of calcium/kg body weight/24 h in the absence of hypercalcemia. Causes of hypercalciuria to be ruled out are sarcoidosis, hyperparathyroidism, and Paget's disease of bone. Idiopathic hypercalciuria is believed to result from either increased GI absorption of calcium, increased calcium resorption from bone, or excessive renal calcium leakage into the urine.

Correct Answer: B

Breast discomfort is a problem premenstrually for many women. Simple palliative measures include administration of vitamin E, 600 units daily, and limiting methylxanthines by eliminating coffee and other caffeine-containing substances, although the mechanism of action is not well understood. Danazol (Danocrine), in doses of 200400 mg daily, is often effective in relieving breast pain. Clomiphene may have estrogenic side effects and worsen breast pain. Many women receiving progesterone note breast discomfort secondary to fluid retention. There is no evidence that diuretics such as hydrochlorothiazide relieve breast pain. In one comparison study, tamoxifen (a selective estrogen receptor modulator) was more effective than danazol.

Correct Answer: E

The combination of aging and diabetes suggests the likelihood of a neurologic defect in the bladder, resulting in overflow incontinence. This occurs when the detrusor muscle becomes hypotonic or atonic. Such women complain of voiding small amounts but still having the feeling of a full bladder. In addition, these women are incontinent of small amounts of urine and are unable to stop the flow. This helps to distinguish those with overflow incontinence from those with GSI; the latter are able to voluntarily increase urethral pressure enough to stop urine flow. Cystitis commonly causes urgency and increased urinary frequency, but not incontinence. Urinalysis and urine culture are not likely to be revealing in this patient, but should be done routinely in all incontinent women. Instillation of methylene blue into the bladder after placement of a vaginal tampon should be done when a vesicovaginal fistula is suspected. This occurs most often following gynecologic surgery and should be suspected in women complaining of constant urine leakage. The Q- tip test is useful to demonstrate posterior urethral rotation found in women with GSI.

Correct Answer: D

Maternal hypertension is the most common risk factor for a placental abruption. The relative risk is 3.8 for parous women and 1.6 for nulliparous women. In one published report, half of the women with an abruption severe enough to kill the fetus had hypertension, and half of these had evidence of chronic vascular disease. Advanced maternal age without confounding factors such as diabetes or hypertension is not a risk factor for placental abruption. High parity is associated with an increased risk of placental abruption. Vigorous coitus can cause a vaginal laceration, but not abdominal pain. While blunt abdominal trauma may cause a placental abruption, routine forms of exercise are not a risk factor for placental abruption.

Correct Answer: A

Cutaneous anthrax is associated with a characteristic skin lesion, which becomes infected by the introduction of the bacillus through the skin. Occasionally, an infected carcass is not identified before butchering. A minor wound on the butcher may become infected. Human anthrax is secondary to the disease in animals, primarily mammals. In humans, the disease has three major clinical forms: cutaneous, inhalational, and GI.

Correct Answer: C

Anorexia nervosa is an eating disorder that predominantly affects women in their teens and in early adulthood. It is defined as refusal to maintain a minimal normal weight, at least 85% of that weight considered normal for that person's age and height, and a morbid preoccupation with feeling obese. Common strategies to lose weight include avoidance of all fats and carbohydrates, self-induced vomiting, obsessive physical activity, and abuse of laxatives or diuretics or both. Despite apparent aversion to gaining weight, anorectics frequently take very special care in preparation and consumption of food and may delight in preparing gourmet feasts for others. Menstrual irregularity and amenorrhea are also commonly reported but are not essential factors in making the diagnosis. It is not yet clear whether such menstrual problems are simply secondary to starvation or whether they reflect a more pervasive endocrine dysfunction. Perhaps the most striking clinical feature of this disorder is the misperception of body image. Regardless of the method of confrontation, including use of mirrors or photographs, sufferers see themselves as overweight. The patient often refuses to agree that there is any problem whatsoever.

Numerous factors, including developmental, family, endocrine, and gastrointestinal disturbances have been implicated in anorexia nervosa, but the etiology has yet to be clearly established. Most commonly, the course consists of a single episode followed by remission. Some patients may suffer a series of relapses and remissions. Mortality rates have been estimated to be as high as 20%.

Correct Answer: B

Infantile autism, called a pervasive developmental disorder in DSM-IV, typically is diagnosed when children do not demonstrate the acquisition of communication skills. Ability to form interpersonal relationships also is grossly impaired. Other behavioral manifestations of infantile autism include unusual repetitive mannerisms (e.g., spinning), marked anxiety during environmental changes, and high pain threshold. As to be expected, school performance is poor, though autistic children may display isolated areas (islands) of normal or superior intellectual functioning. Behavioral manipulation is useful in trying to contain the behavior of autistic children. Unlike infantile autism, childhood schizophrenia usually develops later in childhood and follows an intermittent course. Deterioration in social or school functioning is a characteristic presenting feature, along with hallucinations, delusions, and other manifestations of psychosis. Phenothiazine drugs offer effective treatment. Symptoms and signs of depression in children are similar to those in adults. However, children may not be able to recognize depressed feelings. Persistence of puzzling physical problems in association with apathetic, withdrawn behavior is a common presentation. The use of antidepressants is controversial; family and individual counseling often can be quite helpful. ADHD once was called hyperactivity and minimal brain dysfunction. Characteristic signs include impulsivity, distractibility, inattention in school, and (usually but not universally) hyperactivity. A variety of pharmacologic agents, including imipramine, dextroamphetamine, and methylphenidate (Ritalin), have been recommended for treatment of ADHD.

Correct Answer: B

Progressive dysphagia in an older adult warrants evaluation, especially with associated symptoms of weight loss, chest pain, or hematemesis. A barium esophagogram is the first study that should be obtained. The typical carcinoma demonstrates an irregular, rigid narrowing of the esophageal wall with distortion of the lumen. Achalasia demonstrates a narrow, tapering bird's beak appearance of the distal esophagus. Development of an esophageal stricture causes slowly progressive dysphagia, usually after a long history of gastroesophageal reflux disease (GERD). Esophagoscopy and biopsy are mandatory for evaluation of esophageal stenosis and yield a diagnosis of carcinoma in 95% of patients with malignant strictures. CT scanning is the standard technique for staging, once the diagnosis has been made. Bronchoscopy is helpful in patients with upper and middle third carcinomas to exclude invasion of the trachea or bronchi before esophagectomy.

Correct Answer: B

Gastric ulcers present with symptoms of abdominal pain, aggravated by food, and associated with nausea, vomiting, anorexia, and weight loss. The two principal means of diagnosing a gastric ulcer are UGI radiographs and fiberoptic endoscopy, the latter being the most reliable method. CT scan and endoscopic ultrasound may be helpful in staging gastric cancer, but are not routinely used with benign disease. The failure to respond to 12 weeks of medical management is an indication for surgical therapy to avoid potential complications and to exclude malignancy, despite biopsies obtained by endoscopy that show benign disease.