From the Guidelines
Elevated bilirubin levels are primarily caused by conditions that either increase bilirubin production or impair its elimination from the body, with the most common causes including liver diseases, biliary obstruction, genetic disorders, hemolytic anemias, and certain medications, as noted in the most recent study 1.
Causes of Elevated Bilirubin
The causes of elevated bilirubin can be broadly categorized into:
- Conditions that increase bilirubin production, such as hemolytic anemias, which can be due to various factors including autoimmune disorders, infections, or medications 1.
- Conditions that impair bilirubin elimination, including liver diseases like hepatitis, cirrhosis, and alcoholic liver disease, which reduce the liver's ability to process bilirubin 1.
- Biliary obstruction from gallstones, tumors, or strictures, which can block bilirubin excretion into the intestines 1.
- Genetic disorders like Gilbert's syndrome and Crigler-Najjar syndrome, which affect bilirubin metabolism, leading to higher levels 1.
Key Points to Consider
- The most common cause of an isolated elevated bilirubin concentration is Gilbert’s syndrome, an inherited disorder of metabolism that leads to impaired conjugation via reduced activity of the enzyme glucuronyltransferase 1.
- In newborns, physiological jaundice occurs because their immature livers cannot process bilirubin efficiently, but this condition is usually self-limiting and resolves on its own 1.
- Symptoms of elevated bilirubin include yellowing of the skin and eyes (jaundice), dark urine, light-colored stools, and in severe cases, neurological symptoms 1.
- Treatment depends on addressing the underlying cause, which may involve medication adjustments, treating infections, managing liver disease, or surgical intervention for obstructions 1.
From the Research
Causes of Elevated Bilirubin Levels
Elevated bilirubin levels can be caused by various factors, including:
- Disorders of bilirubin metabolism, such as Gilbert's, Crigler-Najjar, Rotor, or Dubin-Johnson syndromes 2
- Acquired diseases, including alcoholic/non-alcoholic fatty liver disease, hepatotropic hepatitis, cirrhosis, or hepato-biliary malignancy 2
- Hemolytic anemia, which can lead to an increase in unconjugated bilirubin 3
- Liver cirrhosis, which can cause a decrease in hepatic clearance of bilirubin and an increase in portosystemic shunting, leading to elevated bilirubin levels 4
- Obstructive jaundice, which can cause a buildup of bilirubin in the blood 5
Types of Hyperbilirubinemia
There are two main types of hyperbilirubinemia:
- Unconjugated hyperbilirubinemia, which is associated with conditions such as Gilbert's syndrome and hemolytic anemia 2, 3
- Conjugated hyperbilirubinemia, which is associated with conditions such as liver cirrhosis and obstructive jaundice 4, 5
Clinical Significance of Elevated Bilirubin Levels
Elevated bilirubin levels can have significant clinical implications, including: