A 22-year-old man comes to the clinic with a history of intermittent jaundice, which he has noticed particularly during periods of stress, fasting, or after minor illnesses. He has no significant past medical history and denies alcohol or drug use. He is not on any current medication. Vital signs are temperature 37.1°C (98.6°F), blood pressure 118/72 mmHg, pulse 70 beats/min, and respirations 18/min. His physical examination is unremarkable except for mild scleral icterus. Laboratory tests reveal a total bilirubin level of 3.0 mg/dL, with an indirect (unconjugated) bilirubin of 2.8 mg/dL and direct (conjugated) bilirubin of 0.2 mg/dL. Liver function tests, hemoglobin, and reticulocyte count are within normal limits.
C) Gilbert syndrome
The patient’s presentation of intermittent jaundice, particularly during stress, fasting, or illness, along with an isolated increase in unconjugated bilirubin, is characteristic of Gilbert syndrome. Gilbert syndrome is caused by a reduced activity of the enzyme UDP-glucuronosyltransferase, which is involved in the conjugation of bilirubin.
Answer choice A: Crigler-Najjar syndrome, is incorrect. Cirgler-Najjar syndrome presents with severe jaundice and kernicterus in infancy due to a complete absence of UDP-glucuronosyltransferase.
Answer choice B: Dubin-Johnson syndrome, is incorrect. Dubin-Johnson syndrome is characterized by conjugated hyperbilirubinemia and a darkly pigmented liver.
Answer choice D: Hemolytic anemia, is incorrect. Hemolytic anemia would present with signs of hemolysis such as increased reticulocyte count, low haptoglobin, and elevated lactate dehydrogenase (LDH). This patient has normal hemoglobin and reticulocyte count, making hemolytic anemia less likely.
Answer hoice E: Rotor syndrome, is incorrect. Rotor syndrome also causes conjugated hyperbilirubinemia. However, the laboratory findings would show an increased direct (conjugated) bilirubin.
Key Learning Point
Gilbert syndrome is a common and benign intermittent jaundice seen in young adults that is triggered by stress, fasting, or illness. It is caused by a reduced activity of the enzyme UDP-glucuronosyltransferase, which is responsible for bilirubin conjugation. Liver function tests, hemoglobin, and reticulocyte count are normal. It is typically asymptomatic apart from the jaundice, and there is no need for further intervention.
