A 46-year-old man presented for evaluation of a 3-day history of progressive fatigue, malaise, brown urine, and spontaneous ecchymosis of the right arm associated with anorexia and bilious emesis. He denied any traumatic injury, recent illness, fever, weight loss, night sweats, abdominal pain, or sick contacts.The patient was previously healthy, and his medical history was notable only for obesity and erectile dysfunction. Current medications included sildenafil and varenicline, and he denied any medication allergies. He was a current smoker with a 26 pack-year smoking history and occasionally used alcohol and marijuana (last use, approximately 3 weeks previously). He was married in a monogamous relationship and worked as a real estate broker. He had not traveled outside the United States recently.At presentation, his vital signs were as follows: temperature, 37.4˚C; heart rate, 85 beats/min; respiratory rate, 20 breaths/min; and blood pressure, 140/85 mm Hg. Physical examination was remarkable for a 5 × 5 cm dark ecchymosis on the right medial arm and scattered petechiae on the soft palate and lower extremities. His mucous membranes were dry, the jugular venous pressure was low, and slight scleral icterus was present. Findings on the remainder of the comprehensive physical examination, including mental status and neurologic examination, were within normal limits.Initial laboratory results were as follows (reference ranges provided parenthetically): hemoglobin, 15.4 g/dL (13.5-17.5 g/dL); leukocytes, 10.6 × 10 9 /L (3.5-10.5 × 10 9 /L) with a normal differential; platelets, 6 × 10 9 /L (150-450 × 10 9 /L); reticulocytes, 2.6% (0.60%-1.83%); international normalized ratio, 1.0; partial thromboplastin time, 25 s (21-33 s); blood urea nitrogen, 56 mg/dL (8-24 mg/ dL); creatinine, 3.1 mg/dL (0.8-1.2 mg/dL); alkaline phosphatase, 122 U/L (45-115 U/L); aspartate aminotransferase (AST), 95 U/L (8-48 U/L); alanine aminotransferase, 25 U/L (7-55 U/L); total bilirubin, 5.0 mg/dL (0.1-1.0 mg/ dL); and direct bilirubin, 0.7 mg/dL (0.0-0.3 mg/dL). The urine appeared brown, and urinalysis revealed +3 blood, +3 protein, 3 to 5 nondysmorphic red blood cells per highpowered field, and no leukocytes or casts.
Which one of the following tests would be most appropriate at this time? a. b. c. d. e.Abdominal ultrasonography is a noninvasive study that can identify hepatobiliary obstruction and characterize liver parenchyma in a patient with elevated transaminase and bilirubin levels. However, this patient has an hyperbilirubinemia and not the hyperbilirubinemia characteristic of biliary obstruction. Rhabdomyolysis with accompanying elevated creatine kinase and urinary myoglobin levels can cause brown discoloration of the urine, but acute rhabdomyolysis 1 would likely be associated with a greater elevation in AST levels and would not explain the thrombocytopenia and hyperbilirubinemia. Cryoglobulins are immunoglobulins plus or minus complement components that can be associated with a small-to mediumvessel vasculitis caused by immune co...