A 70-year-old man presents with a complaint of fatigue. There is no history of alcohol abuse or liver disease; the patient is taking no medications. Scleral icterus is noted on physical examination; the liver and spleen are nonpalpable. The patient has a normocytic, normochromic anemia. Urinalysis shows bilirubinuria with absent urine urobilinogen. Serum bilirubin is 12 mg/dL, AST and ALT are normal, and alkaline phosphatase is 300 U/L (three times normal). Which of the following is the best next step in evaluation?A) Ultrasound or CT scan of the abdomen
Patients with jaundice should be characterized as having unconjugated (indirect reacting) or conjugated (direct) hyperbilirubinemia. Causes of unconjugated hyperbilirubinemia include hemolysis, ineffective erythropoiesis, or enzyme deficiencies (the commonest in adults being Gilbert syndrome). The patient, however, has conjugated hyperbilirubinemia, which almost always indicates significant liver dysfunction, either hepatocellular or cholestatic (obstructive); this patient’s predominant elevation of alkaline phosphatase suggests a cholestatic pattern. Normal transaminases rule out hepatocellular damage (such as viral or alcoholic hepatitis). Instead, a disease of bile ducts or a cause of impaired bile excretion should be considered. Ultrasound or CT scan will evaluate the patient for an obstructing cancer or stone disease versus intrahepatic cholestasis. Ferritin values would evaluate for hemochromatosis, but this disease typically causes transaminase elevation and hepatomegaly. Primary biliary cirrhosis (PBC, evaluated by the antimitochondrial antibody test) might be considered if imaging studies show a nondilated biliary system (suggesting intrahepatic cholestasis), but PBC is usually seen in middle-aged women.