What is the underlying cause of icterus?

What is the underlying cause of icterus?

• A. Ketonuria
• B. Hyperbilirubinemia
• C. Anemia
• D. Hyperhemoglobinemia

Answer: (B)

Icterus appears when bilirubin, a pigment produced from the breakdown of heme, builds up in the blood so tissues turn yellow. Bilirubin is normally processed by the liver, where it is conjugated and excreted in bile. When bilirubin levels rise—hyperbilirubinemia—whether from increased production (as in hemolysis) or impaired liver excretion, the yellow discoloration of the eyes and mucous membranes occurs. The other options describe different metabolic issues that do not by themselves cause the yellow staining seen in icterus: ketonuria is ketones in the urine, anemia is a reduced red blood cell count, and hyperhemoglobinemia is too much hemoglobin.

Icterus appears when bilirubin, a pigment produced from the breakdown of heme, builds up in the blood so tissues turn yellow. Bilirubin is normally processed by the liver, where it is conjugated and excreted in bile. When bilirubin levels rise—hyperbilirubinemia—whether from increased production (as in hemolysis) or impaired liver excretion, the yellow discoloration of the eyes and mucous membranes occurs. The other options describe different metabolic issues that do not by themselves cause the yellow staining seen in icterus: ketonuria is ketones in the urine, anemia is a reduced red blood cell count, and hyperhemoglobinemia is too much hemoglobin.