USMLE USMLE-STEP-2 Online Practice Questions and Exam Preparation

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 361:

  Apreviously healthy 45-year-old man presents with a 9-month history of a slow-growing, painless right neck mass. He is a nonsmoker and has no significant past medical history. On examination, there is a nontender, discrete, 3-cm mass over the angle of the right mandible. Facial muscle function and sensation are normal. An oropharyngeal examination is normal. Which of the following is the best next step in the management of this patient?

  A. antibiotics
  B. excisional biopsy
  C. observation with re-evaluation in 24 weeks
  D. superficial parotidectomy
  E. chest x-ray
  D. superficial parotidectomy

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  Explanation

  The anatomic location of the mass suggests a parotid origin, and the lengthy history and absence of symptoms and signs of inflammation are consistent with a neoplasm of the parotid. The most common salivary gland neoplasm is a benign pleomorphic adenoma. Metastatic carcinoma from a head and neck primary tumor may first present as a neck mass, usually along the anterior or posterior cervical lymph node chain, and often in a patient with such risk factors as a history of smoking. Infectious parotitis may occur in the elderly or diabetic patient, usually presenting with a shorter history, with symptoms and signs of inflammation. Hodgkin's disease can present as a painless neck mass involving the anterior or supraclavicular lymph nodes. Reactive cervical lymphatic hyperplasia is associated with an inflammatory or infectious focus in the head and neck. The optimal management for a pleomorphic adenoma in the lateral lobe of the parotid is a superficial parotidectomy. IV antibiotics are not indicated in the absence of an inflammatory or infectious process. Although an excisional biopsy may be indicated for a mass arising from cervical lymph nodes, enucleation of a neoplastic parotid mass is insufficient and associated with an increased incidence of local recurrence. Observation and re- evaluation are inappropriate in this patient. Achest x-ray would be indicated in the evaluation of a patient with suspected Hodgkin's disease.

• Question 362:

  From the below the clinical indications, choose an option for use of immune globulin (IG) in Hepatitis C prophylaxis

  A. indicated
  B. not proven effective
  C. not routinely indicated
  D. contraindicated
  E. compulsory
  B. not proven effective

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  Explanation

  IG given before exposure or within 14 days of exposure is 7585% effective in preventing symptomatic illness from hepatitis A. IG is produced from the plasma of normal adults and does not contain sufficient antibody to prevent hepatitis B infection. Hepatitis B immune globulin (HBIG) is prepared from plasma known to contain high antibody titers for hepatitis B surface antigen (HBsAg) and is specific for hepatitis B. Given immediately postexposure, and again 1 month later, it has a combined efficacy of about 75% in the prevention of hepatitis B. Postexposure IG has not been found effective in the prevention of hepatitis C infection; on the other hand, treatment of early hepatitis C infection is possible, and thus it is important to monitor exposed individuals to determine whether infection occurs. IG administered to individuals exposed to measles infection who are susceptible to the disease has been shown to be effective if given within 6 days of exposure.

  Recent use of IG is a contraindication to immunization with rubella vaccine. IG is not very effective at preventing in utero infection with rubella, and infants with congenital rubella syndrome have been born to women given IG shortly after exposure. IG is not routinely indicated, as it is indicated only if abortion is not elected.

• Question 363:

  A 28-year-old man has the acute onset of colicky pain in the left costovertebral angle radiating into the groin, as well as gross hematuria. Abdominal x-ray discloses a stone in the left ureter. Which of the following is true concerning this disease?

  A. The majority of renal stones are radiolucent.
  B. Radiolucent stones are usually composed of uric acid.
  C. Staghorn calculi are associated with acid urine.
  D. Radiopaque stones usually contain cystine.
  E. Urate stones are associated with alkaline urine.
  B. Radiolucent stones are usually composed of uric acid.

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  Explanation

  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.

• Question 364:

  A 25-year-old male graduate student presents at a university hospital emergency department complaining of a sudden onset of a pounding in his chest, a feeling of choking, and shortness of breath. He reports that things somehow suddenly seem unreal, and he is afraid he is dying of a heart attack. An electrocardiogram (ECG) shows normal sinus rhythm and no abnormalities.

  Which of the following is the most likely diagnosis?

  A. myocardial infarction
  B. panic attack
  C. hypochondriasis
  D. multiple sclerosis
  E. generalized anxiety disorder
  B. panic attack

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  Explanation

  Panic attacks most frequently have their onset sometime between the late teens and early thirties. Most patients describe their initial panic attack as coming out of the blue. They frequently suffer from palpitations, sweating, trembling, shortness of breath, a feeling of choking, chest pain, nausea, light headedness, derealization (feelings of unreality) or depersonalization (being detached from oneself), fear of going crazy, fear of dying, numbness, and hot flashes or chills. Individuals who suffer from recurrent, unexpected panic attacks with at least 1 month of persistent concern about the attacks or their implications, or a significant change of behavior related to the attacks suffer from panic disorder. If a patient with panic disorder avoids situations in which panic attacks have occurred or endures the situations, such as shopping in a mall, with marked distress or anxiety about having a panic attack, the patient is said to suffer from panic disorder with agoraphobia. This patient's negative ECG makes myocardial infarction an unlikely diagnosis. Hypochondriasis is the term given to a longterm preoccupation with fears of having a serious disease based on the misinterpretation of bodily symptoms; it does not generally present in the sudden manner in which panic attack presents. Multiple sclerosis usually causes many neurologic disturbances which vary across time. Generalized anxiety disorder is not typified by the sudden onset of severe anxiety characteristic of a panic attack.

• Question 365:

  A 55-year-old woman has a bloody discharge from her left breast. A mammogram discloses a cluster of microcalcifications 3 cm beneath her left nipple.

  Which of the following is the most common type of breast cancer?

  A. inflammatory carcinoma
  B. lobular carcinoma in situ
  C. lobular infiltrating carcinoma
  D. infiltrating ductal carcinoma
  E. ductal carcinoma in situ
  D. infiltrating ductal carcinoma

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  Explanation

  Infiltrating (invasive) ductal carcinoma accounts for 6580% of all breast carcinomas. Infiltrating lobular carcinoma accounts for 1014%, and the others 5% or less

• Question 366:

  A 35-year-old pharmacist complains of "hurting all over." Her pain is particularly bad in her upper back and shoulders, and she notes morning stiffness. On examination, her joints are not inflamed, but she has symmetric "tender points" in the posterior neck, anterior chest, lateral buttocks, medial knees, and lateral elbows. You make a preliminary diagnosis of fibromyalgia.

  Which one of the following diagnostic tests should you order?

  A. Lyme titers
  B. electromyelography
  C. sedimentation rate
  D. spine radiographs
  E. screening test for depression
  C. sedimentation rate

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  Explanation

  Sleep disturbance is a characteristic symptom associated with fibromyalgia. Patients awaken feeling tired. The examination, other than tenderness in 14 specific, symmetrical points, is usually normal. Fever, rash on the extremities, muscle weakness, and migratory joint inflammation point to Lyme disease or other rheumatologic disorders. Asedimentation rate should be normal. If elevated, it may point to another diagnosis. Lyme titers are not indicated unless the patient has symptoms or history suggestive of the disease. Electromyelography and spine radiographs are typically normal and unnecessary for help in establishing the diagnosis.

  Depression can be associated with pain, but screening for it early on does not make sense and might offend the patient. Low-dose antidepressants often help to correct the sleep pattern and result in relief of pain. Nonsteroidal anti-inflammatory agents can also be used as needed; low-dose steroid is not indicated. Exercise is also helpful, and patients should be encouraged to stay physically active. Amoxicillin is not used for fibromyalgia. Benzodiazepines have addictive potential and lose their effectiveness

  for sleep after a few weeks.

• Question 367:

  A 70-year-old man is brought to his primary care doctor by the man's son. According to his son, who had not seen his father for about a year, the father seemed to have some personality changes. He was no longer interested in his hobbies and seemed apathetic. He seemed to forget easily, and he repeatedly asked the same already answered questions. On at least two occasions, the father wandered out of the house and was found by neighbors, who thought he was confused. Considering the information learned thus far, which of the following medications would be the most appropriate treatment here?

  A. donepezil
  B. fluoxetine
  C. aspirin
  D. amitriptyline
  E. ginkgo biloba
  A. donepezil

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  Explanation

  Donepezil is a cholinesterase inhibitor used for the treatment of mild-to-moderate impairment in Alzheimer's disease. Fluoxetine is an SSRI antidepressant. Aspirin would decrease clotting. Amitriptyline is a tricyclic antidepressant and with its anticholinergic properties, it would worsen cognition. Ginkgo is an herbal medicine.

• Question 368:

  A 4-year-old child was brought in for evaluation of sleep problems. He cried and screamed within an hour of falling asleep. He seemed disoriented and confused; he did not seem aware of his parents' presence. They were unable to arouse him to comfort him. This resolved spontaneously, and he had no recollection of the event the next morning. You informed the parents that he was most likely experiencing which of the following?

  A. nightmares
  B. night terrors
  C. somnambulism
  D. somniloquy
  E. narcolepsy
  B. night terrors

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  Explanation

  Parasomnias or disorders of arousal include nightmares, night terrors, sleepwalking (somnambulism), and sleep talking (somniloquy). This pattern suggests night terrors and is most common between ages 2 and 6 years. Nightmares occur at any age but peak between ages 3 and 5 years; they occur later in the night during rapid eye movement (REM) sleep. The child usually remembers the dream vividly, is upset on waking, but can be comforted by the parent. Sleepwalking occurs, as do night terrors, during non-REM sleep. It is most common between ages 4 and 8 years; safety of the child is the main concern. Sleep talking is not specific to any stage of sleep and may occur in association with nightmares and night terrors. Narcolepsy is a rare disorder characterized by excessive daytime sleepiness. Confirmation requires referral to a sleep laboratory

• Question 369:

  Select the organism associated with the following clinical findings:

  A 4-year-old child in late summer fell 1 week ago, and now has a crusty, mildly erythematous wound with regional lymphadenitis.

  A. aureus
  B. beta-hemolytic Streptococcus
  C. perfringens
  D. Mycoplasma pneumoniae
  E. Haemophilus pertussis
  F. Helicobacter pylori
  G. Escherichia coli
  H. Rickettsia prowazekii
  I. Giardia lamblia
  B. beta-hemolytic Streptococcus

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  Explanation

  Giardiasis may cause cramping and a chronic diarrheal syndrome, with malabsorption and weight loss. Its distribution is worldwide, particularly where hygienic standards are not high. It also occurs sporadically in high-risk individuals. Streptococcal pyoderma, including erysipelas and impetigo, has been demonstrated to precede acute glomerulonephritis. Even when appropriate antibiotics are given in adequate dosage and duration for these conditions, renal damage may still result. Prevention thus consists of wound care, including cleaning wounds well and removal of crust. Mycoplasma infections are particularly common in families with younger children. They are frequently imported to the family by school-aged children, leading to a low-grade fever and persisting tracheobronchitis in the parents, or more acutely, an atypical pneumonia. G. lamblia is found in up to 20% of homosexual males, and may cause chronic diarrhea, although in these patients it tends to be asymptomatic. E. coli was first reported as a cause of watery diarrhea in nurseries in the 1940s. Although nursery epidemics with enteropathogenic serotypes had decreased in recent years in the United States, the increase of infant- child day care centers has resulted in their relatively frequent occurrence. Furunculosis is most frequently caused by coagulase-positive staphylococcal infections. The public health significance of this largely relates to the hazards of skin infections in food handlers and subsequent staphylococcal toxin in the food, leading to staphylococcal intoxication food-borne disease. H. pylori has been associated with gastric ulcers, but not with duodenal ulcers. Otitis media, whether acute or with effusion, commonly results from viral infection, such as by RSV. Various other organisms may be responsible including Streptococcu pneumoniae, H. influenzae, and others. C. perfringens, with rare exceptions, is transmitted in a meat dish prepared in bulk. Under propitious circumstances for the organism, especially on cooling of the food, bacterial multiplication can be very rapid. Symptoms begin to occur in the affected population in about 12 hours. Epidemic typhus is a rickettsial illness. Man is the host and long-term reservoir. The vectors are body lice (P. humanus corporis). The rickettsia are not present in human excretions and cannot be transmitted by person-to-person contact.

• Question 370:

  A 65-year-old man presents to the physician's office with complaints of abdominal discomfort and jaundice for the past 3 weeks. Past history is pertinent for 30 pack-year smoking history, occasional alcohol intake, and a 5.5-mm ulcerating melanoma removed from his back 21/2 years ago. Examination reveals a mildly jaundiced patient with normal vital signs and a slightly distended abdomen with mild right upper quadrant tenderness and significant hepatomegaly. For above patient with jaundice, select the one most likely diagnosis.

  A. hepatitis A
  B. hemolysis
  C. choledocholithiasis
  D. biliary stricture
  E. choledochal cyst
  F. pancreatic carcinoma
  G. liver metastases
  H. cirrhosis
  I. pancreatitis
  G. liver metastases

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  Explanation

  Liver dysfunction resulting in jaundice may be a manifestation of advanced metastatic disease to the liver. In a patient with a known malignancy at high risk for metastases (i.e., deeply invasive and ulcerative melanoma), metastatic disease must be considered in the evaluation of the jaundiced patient. Hepatomegaly found on abdominal examination is supportive of advanced metastatic disease.