High bilirubin levels are caused by conditions that affect the production, processing, or excretion of bilirubin, a yellow pigment formed from the breakdown of red blood cells. Key causes include:
- Liver dysfunction: Diseases such as hepatitis, cirrhosis, liver cancer, alcoholic liver disease, and autoimmune hepatitis impair the liver’s ability to process and remove bilirubin from the blood
- Hemolysis: Increased breakdown of red blood cells, due to autoimmune disorders, infections, or genetic conditions, leads to excess bilirubin production
- Bile duct obstruction: Blockages from gallstones or inflammation in bile ducts prevent bilirubin from being excreted into the intestines, causing it to accumulate in the blood
- Genetic conditions: Gilbert’s syndrome is a common inherited disorder where the liver enzyme that processes bilirubin is deficient, leading to mild, intermittent high bilirubin levels
- Other factors: Temporary stress on the liver from medications, alcohol, illness, strenuous exercise, or pregnancy-related cholestasis can also raise bilirubin levels
In summary, high bilirubin results from increased bilirubin production (e.g., hemolysis), impaired liver processing (e.g., hepatitis, cirrhosis, Gilbert’s syndrome), or blocked excretion pathways (e.g., gallstones, bile duct obstruction).
