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

USMLE USMLE-STEP-2 Online Questions & Answers

• Question 301:

  You evaluate a 38-year-old man who complains of muscle weakness. Her appearance is remarkable for a periorbital heliotrope rash with edema and erythema on his upper chest, neck, and face. Which of the following is the most likely diagnosis?

  

  Which of the following examination findings would this patient most likely have?

  A. proximal muscle weakness
  B. distal muscle weakness
  C. ataxic gait
  D. hyperactive deep tendon reflexes
  E. inflamed small joints
  A. proximal muscle weakness

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  Explanation

  The heliotrope, purple periorbital rash is seen with dermatomyositis and may even precede the muscle involvement. On examination, these patients will usually show proximal muscle weakness and may complain of difficulty getting up from a chair, climbing stairs, and raising the arms over the head. Ataxia may be present with cerebellar lesions. Deep tendon reflexes should be normal and there is no joint inflammation. Polymyalgia rheumatica generally occurs in older people but is not associated with muscle weakness. Spinocerebellar degeneration, vasculitis, and rheumatoid arthritis are not associated with this rash. Creatine phosphokinase is usually markedly elevated and muscle biopsy will confirm the diagnosis. Serum creatinine, sodium, and potassium should be normal, and the rheumatoid factor should not be elevated.

• Question 302:

  A 19-year-old previously healthy man is an unbelted driver of a motor vehicle involved in a front-end collision. On arrival in the emergency department, the patient is noted to have stridor, with marked respiratory distress, and an oxygen saturation of 88% despite 100% oxygen by mask. He has obvious extensive facial injuries, a flail chest, and poor chest expansion. Bag-mask-valve ventilation is ineffective. Which of the following is the most appropriate next step in management?

  A. orotracheal intubation
  B. nasotracheal intubation
  C. cricothyroidotomy
  D. tracheostomy
  E. placement of bilateral chest tubes
  C. cricothyroidotomy

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  Explanation

  This patient has an obstructed airway from maxillofacial trauma. The patient is stridorous, hypoxic, and cannot be ventilated with bag andf mask. Immediate cricothyroidotomy is lifesaving. In the presence of severe facial trauma, orotracheal intubation is likely to be difficult because of distortion of landmarks and excessive oropharyngeal secretions. Nasotracheal intubation is contraindicated in this setting. A definitive tracheostomy is more time consuming than a cricothyroidotomy and requires specific surgical expertise. Stabilization of the airway is the first resuscitation priority, before placement of chest tubes to relieve potential pneumothoraces.

• Question 303:

  The health commissioner asks you to propose a primary prevention program for your community.

  Which of the following should you recommend?

  A. annual sigmoidoscopy
  B. routine immunization
  C. mammography
  D. prostate-specific antigen (PSA) testing
  E. isolation of disease contacts
  B. routine immunization

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  Explanation

  Examples of primary prevention include routine immunization of individuals at risk for infectious disease, or healthy diet and exercise for persons at risk for diabetes; presymptomatic and clinical diseases are not present and are being avoided. Screening, such as by using Pap smears, colonoscopy, or mammography, typifies secondary prevention; disease is recognized earlier than it otherwise would be, making improved management of the disease possible. Efforts to reduce the consequences of existing recognized disease, such as isolation of disease contacts, are termed tertiary prevention.

• Question 304:

  A63-year-old man with chronic bronchitis presents to the emergency department with worsening shortness of breath. He is dyspneic, his respiratory rate is 32/min, and he has peripheral cyanosis. A chest examination reveals increased anteroposterior diameter and scattered rhonchi, but no wheezes or evidence of consolidation. His ABG determinations on room air are pH of 7.36, arterial oxygen pressure (PaO2) of 40 mmHg, and PaCO2 of 47 mmHg. He is given oxygen by face mask while awaiting a CXR.

  His respiratory rate falls to 12/min,but his ABGs on oxygen are now pH of 7.31, PaO2 of 62 mmHg, and PaCO2 of 58 mmHg. Which of the following is the most appropriate next step in the management of this patient?

  A. repeat the ABG
  B. initiate mechanical ventilation
  C. obtain a CXR
  D. check the oxygen delivery system
  E. decrease the fraction of inspired oxygen (FIO2)
  E. decrease the fraction of inspired oxygen (FIO2)

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  Explanation

  Patients with advanced chronic obstructive pulmonary disease (COPD) are at risk for development of acute respiratory failure. Common precipitants are infections, increased secretions, and superimposed bronchospasm. Oxygen therapy is effective in reversing the hypoxemia associated with respiratory failure.

  Arisk of such therapy peculiar to patients with COPD is worsening hypercapnia. Affected patients are thought to have lost their respiratory center's sensitivity to hypercapnia, so that their primary stimulus to breathe is hypoxemia. When the hypoxemia is corrected, they may lose their stimulus to breathe and develop carbon dioxide narcosis with worsening acidosis, confusion, stupor, and eventually coma. Because of this, the usual approach is to begin with a low fraction of inspired oxygen (FIO2) and increase gradually. Serial ABGs are obtained to

  ensure that as PaO2 improves,

• Question 305:

  A15-month-old African American male, who is otherwise healthy, is found to have an emoglobin level of 8 g/dL on routine screening. The mean corpuscular volume (MCV) is decreased. His lead screen is within normal limits. You obtain a diet history, which reveals that he drinks about 3040 oz of whole cow's milk a day. He eats no meat and some fruits and vegetables.

  Which of the following is the most likely cause?

  A. sickle cell anemia
  B. thalassemia major
  C. lead poisoning
  D. iron-deficiency anemia
  E. anemia of chronic disease
  D. iron-deficiency anemia

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  Explanation

  Iron deficiency is the most common cause of microcytic anemia. In children it is often related to excessive consumption of cow's milk, which is low in iron content, and inadequate consumption of iron-rich foods. Allergy to cow's milk may also cause occult GI blood losses. In thalassemia major, there is usually physical evidence of chronic anemia with signs of bone marrow expansion (frontal bossing) and severe anemia often requiring transfusions. Lead poisoning may cause microcytic anemias; it may also be associated with iron-deficiency anemia, which enhances lead absorption and, therefore, should always be excluded. Anemia of chronic disease (renal disease) may be microcytic or normocytic and should be excluded by history and examination.

• Question 306:

  For each of the following scenarios, select the gas exposure responsible for the signs and symptoms.

  Aworker drilling for oil experiences acute tearing, mucous membrane irritation, and onset of a cough while repairing machinery.

  A. carbon monoxide
  B. methane
  C. hydrogen sulfide
  D. ozone
  E. sulfur dioxide
  E. sulfur dioxide

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  Explanation

  Sulfur dioxide is a colorless, pungent gas encountered in drilling for oil, paper production, treatment of fruit, and other processes. Sulfur dioxide is an irritant gas. It causes tearing, mucous membrane irritation, cough, and eventually pulmonary edema. In asthmatics it provokes bronchospasm at low doses. Like other irritant gases, in large quantities, it will damage alveoli and capillary endothelial cells.

• Question 307:

  Select the ONE best lettered option that is most closely associated with the question below. A 38-year-old African American female with shortness of breath and bilateral hilar adenopathy on CXR.

  A. rheumatoid arthritis
  B. SLE
  C. Wegener's granulomatosus
  D. polyarteritis nodosa
  E. Goodpasture syndrome
  F. fibromyalgia
  G. osteoarthritis (OA)
  H. giant cell arteritis
  I. sarcoidosis
  I. sarcoidosis

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  Explanation

  Sarcoidosis is a relatively common disease. In the United States, most patients are African American (ratio ranges from 10:1 to 17:1). The disease is systemic, and the lung is almost always affected (primarily an ILD). Seventyfive to ninety percent of patients have enlarged intrathoracic lymph nodes, usually the hilar nodes

• Question 308:

  A55-year-old retired policeman has had hypertension for about 15 years for which he takes hydralazine. He has a 35 pack-year tobacco history and continues to smoke one pack a day. On his visit, he complains about the appearance of his nose and asks if something can be done to decrease the redness.

  Which of the following statements is correct?

  

  A. Hydralazine does not play a role in his nasal erythema.
  B. Smoking probably aggravates the dilatation of the blood vessels on his nose.
  C. He should avoid alcohol and spicy foods.
  D. There is no effective topical therapy.
  E. Laser therapy will worsen the erythema.
  C. He should avoid alcohol and spicy foods.

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  Explanation

  He should avoid alcohol and spicy foods because these along with the heat, emotional stress, and hot temperature foods can aggravate rosacea. Hydralazine is a vasodilator and could worsen his nasal erythema. Smoking vasoconstricts rather than dilates blood vessels. Metronidazole gel is an effective topical therapy. Laser therapy is usually done after the other interventions have been tried

• Question 309:

  An 83-year-old woman presents to a mammographic facility for a screening mammogram. The technician notices a mass in the lateral right breast. The patient denies any breast pain, nipple discharge, skin changes, or breast trauma. A right breast CC view is shown in

  

  Which of the following is the most appropriate next step in management?

  A. incisional biopsy
  B. needle biopsy
  C. lumpectomy, axillary dissection, and irradiation
  D. total mastectomy
  E. modified radical mastectomy
  B. needle biopsy

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  Explanation

  A new mass in an older woman must be evaluated for malignancy. In this case, the mammogram has characteristics of malignancy, which include a density or mass that is stellate or spiculated, irregular in size or shape, and possessing ill-defined borders. Other features suggestive of malignancy include clustered microcalcifications, asymmetric density, architectural distortion, and skin or nipple retraction. DCIS usually presents as calcifications without a definite mass. Cystosarcoma phyllodes presents much like a fibroadenoma as a well-defined mass with smooth margins. Papillomas are small and not usually palpable or noted by mammography. Fat necrosis can mimic the mammographic features of malignancy and is often associated with trauma.

  However, only when an oil cyst is noted, can an unequivocal diagnosis of fat necrosis be made. The next step is needle biopsy, by FNA, or core biopsy so a histologic diagnosis can be made and options for management (i.e., modified radical mastectomy or lumpectomy, axillary dissection, and irradiation) discussed. Needle biopsy is less invasive and less expensive than incisional biopsy and, therefore, is preferred. Excisional biopsy (not listed) is acceptable, but often requires a two-step procedure, the first to establish the diagnosis and the second for definitive treatment. Aneedle biopsy, especially a core biopsy that renders a histologic diagnosis, can often avoid the necessity of a second surgical procedure.

• Question 310:

  The crude death rate in Sweden was 0.010 per year, while in Costa Rica it was 0.008 per year. All age- specific death rates, except those for the oldest-age category, were higher in Costa Rica than in Sweden. From these data, one can correctly infer which of the following?

  A. The difference is too small for any deductions to be made.
  B. It is healthier to live in Sweden than in Costa Rica.
  C. There is less cardiovascular disease in Costa Rica than in Sweden.
  D. A greater proportion of the Swedish population is in the older-age categories.
  E. There is unexplained progressive deterioration of health indicators in Costa Rica relative to those of Sweden.
  D. A greater proportion of the Swedish population is in the older-age categories.

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  Explanation

  In a crude death rate, all deaths are in the numerator, and the total midyear population in the denominator. In age-specific death rates, the calculation is done using data from specific age intervals. Small differences in crude death rates may enable specific deductions to be made. Ahigher death rate in the older population may indicate that a more fragile population has successfully survived to that age. Of the statements listed, considering that age-specific death rates were greater in all age groups except the elderly, only the fact that a greater proportion of the population in Sweden is in the older age groups could account for the difference in crude mortality rate.