A 30-year-old man comes to the office due to the yellowing of his eyes, which he first noticed after completing a prolonged fast yesterday. He reports a long history of intermittent episodes of mild jaundice that resolve spontaneously. He has no significant past medical history and is not on any medications. Vital signs are within normal limits. Physical examination reveals scleral icterus but is otherwise unremarkable. Laboratory tests reveal the following:
Which of the following is the most appropriate diagnostic step in the management of this patient?
B) No additional testing at this time
Gilbert syndrome is a common, benign, inherited disorder characterized by a mild decrease in the activity of the enzyme UDP-glucuronosyltransferase, which is responsible for the conjugation of bilirubin. This results in intermittent episodes of jaundice, often triggered by stress, fasting, dehydration, illness, or vigorous exercise. The diagnosis is supported by the presence of unconjugated hyperbilirubinemia in the absence of hemolysis (normal hemoglobin and reticulocyte count) and normal liver function tests (AST, ALT, alkaline phosphatase). No further testing is typically required, and no treatment is necessary, as the condition is benign.
Answer choice A: p-ANCA, is incorrect. p-ANCA can be associated with some autoimmune diseases, certain types of vasculitis, and primary sclerosing cholangitis. However, it is not relevant in the evaluation of isolated unconjugated hyperbilirubinemia without other clinical or laboratory abnormalities. In this patient's case, the pattern of isolated elevated unconjugated bilirubin and normal liver enzymes suggests a benign condition like Gilbert syndrome, not an autoimmune disorder.
Answer choice C: Obtain liver biopsy, is incorrect. A liver biopsy is an invasive procedure that is generally reserved for cases where there is diagnostic uncertainty or when other tests suggest significant liver pathology. In this patient's case, the findings of intermittent jaundice with isolated unconjugated hyperbilirubinemia, and otherwise normal liver function tests, are highly suggestive of Gilbert syndrome. This diagnosis can usually be made clinically without the need for invasive procedures.
Answer choice D: Obtain right upper quadrant ultrasound, is incorrect. A right upper quadrant ultrasound is useful for evaluating biliary obstruction or other structural abnormalities of the liver and biliary tree. However, in this patient, the normal levels of alkaline phosphatase, AST, and ALT, along with the pattern of unconjugated hyperbilirubinemia, do not suggest biliary obstruction or other structural liver diseases. Therefore, an ultrasound is not necessary in this context.
Answer choice E: Obtain serology for hepatitis B and C viruses, is incorrect. Hepatitis B and C can cause chronic liver disease and jaundice, but they typically present with elevated liver enzymes (AST and ALT) and a different pattern of liver function test abnormalities. In this patient, the normal liver enzymes and the pattern of isolated unconjugated hyperbilirubinemia make viral hepatitis an unlikely cause of his symptoms.
Key Learning Point
In a patient with intermittent jaundice, isolated unconjugated hyperbilirubinemia, and normal liver function tests, Gilbert syndrome is likely. No additional testing is needed, as the condition is benign and requires no treatment.
