A 42-Year-Old Man Comes to the Emergency Department Due to 4

question 87

Multiple Choice

A 42-year-old man comes to the emergency department due to 4 days of nausea, skin rash, progressive weakness, and decreased urine output.  For the past few months he has also had fatigue, tingling in his hands and feet, and occasional joint pains.  The patient has had no fever, chest pain, dysuria, hematuria, or diarrhea.  He has no chronic medical problems and takes no medication.  The patient does not use tobacco or alcohol but used injection drugs during his early 20s.  Temperature is 37.6 C (99.8 F) , blood pressure is 150/90 mm Hg, pulse is 92/min, and respirations are 16/min.  BMI is 24.8 kg/m².  Mucous membranes are dry with no lesions.  Cardiopulmonary auscultation is normal.  The liver edge is palpable 2 cm below the right costal margin.  Bilateral ankle reflexes are absent.  He has mild, bilateral, lower-extremity pitting edema and a palpable, nonblanchable, purpuric rash on both legs.  There is no joint swelling or erythema.  Laboratory results are as follows:

Which of the following is most helpful in establishing the cause of this patient's renal dysfunction?

• A)Antineutrophil cytoplasmic antibodies test
• B)Anti-dsDNA antibody levels
• C)Antiglomerular basement membrane antibody levels
• D)Serum cryoglobulin levels
• E)Streptozyme test

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Definitions:

Major Product

The primary outcome of a chemical reaction, especially when it yields more of one product over any other possible outcomes.

Nucleophilic Aromatic Substitution

A reaction where an electron-rich nucleophile displaces a leaving group attached to an aromatic ring.

1,2-Dibromo-4-Nitrobenzene

A compound containing a benzene ring substituted with two bromo groups and one nitro group, used in organic synthesis and chemical research.

NaOH

Sodium Hydroxide, a strong base used in various industrial and chemical processes.