WBR0648

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Biochemistry
Sub Category	SubCategory::Gastrointestinal
Prompt	[[Prompt::A 34 year old healthy man presents to the primary care clinic for a general check-up. The man has no complaints except some fatigue during the day, but he relates this to his stressful life style. Physical exam is unremarkable except for mild scleral icterus. The primary care physician decides to order some tests to rule out any serious illness. Lab results return with a normal CBC, reticulocyte count, and blood smear. Transaminases, alkaline phosphatase, and GGT are also all within normal range. Indirect bilirubin is noted to be 2.6 mg/dL with direct bilirubin below the upper limit of normal. The patient remembers that he was noted to have an elevated indirect bilirubin several years earlier but his work-up back then also came back normal. Which of the following pathological mechanisms is involved in this patient's condition?]]
Answer A	AnswerA::Increased hemoglobin breakdown
Answer A Explanation	AnswerAExp::
Answer B	AnswerB::Absent UDP-Glucuronyltransferase
Answer B Explanation	AnswerBExp::
Answer C	AnswerC::Decreased bilirubin uptake in the liver
Answer C Explanation	AnswerCExp::
Answer D	AnswerD::Bile outlet obstruction
Answer D Explanation	AnswerDExp::
Answer E	AnswerE::Hydrolysis of conjugated bilirubin
Answer E Explanation	AnswerEExp::
Right Answer	RightAnswer::C
Explanation	[[Explanation:: Gilbert syndrome is a benign condition leading to elevated indirect bilirubin levels. Its main pathophysiologic mechanism is the decreased uptake of unconjugated bilirubin by the liver, although some decrease in the efficiency of UDP-glucuronyltransferase can be noted in some patients. Usually patients present with asymptomatic jaundice. Fatigue can be present in some patients. The increase in bilirubin is usually triggered by fasting, febrile illness, alcohol, exercise, or stress. It is important to rule out any other disease processes in patients suspected to have Gilbert syndrome. Lab tests include a CBC with reticulocyte count and blood smear for any signs of hemolysis, and liver function tests for any signs of liver disease. Gilbert's syndrome doesn't require treatment. Patients with Gilbert syndrome have an excellent prognosis and the unconjugated hyperbilirubinemia does not cause any health problems. Educational Objective: Gilbert syndrome is a benign condition caused by decreased unconjugated bilirubin uptake by the liver. Reference: Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::Gilbert Syndrome, WBRKeyword::unconjugated hyperbilirubinemia, WBRKeyword::bilirubin
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::