Hyperbilirubinemia
Overview
Hyperbilirubinemia is a medical condition characterized by elevated levels of bilirubin in the blood. Bilirubin is a yellowish substance produced during the normal breakdown of red blood cells. Normally, the liver processes bilirubin and excretes it in the bile. However, if the liver is unable to process bilirubin or if there is an excessive production of bilirubin, it can build up in the bloodstream and cause hyperbilirubinemia.
Causes
There are several causes of hyperbilirubinemia, which can be broadly categorized into pre-hepatic, hepatic, and post-hepatic causes. Pre-hepatic causes are related to excessive production of bilirubin, hepatic causes are related to impaired uptake, processing, or excretion of bilirubin by the liver, and post-hepatic causes are related to obstruction of the bile ducts or impaired excretion of bile into the intestine.
Pre-Hepatic Causes
Pre-hepatic causes of hyperbilirubinemia include conditions that lead to increased destruction of red blood cells (hemolysis), such as hemolytic anemias, sickle cell disease, and thalassemia.
Hepatic Causes
Hepatic causes of hyperbilirubinemia include conditions that affect the liver's ability to process bilirubin, such as hepatitis, cirrhosis, Gilbert's syndrome, and Crigler-Najjar syndrome.
Post-Hepatic Causes
Post-hepatic causes of hyperbilirubinemia include conditions that block the bile ducts or impair the excretion of bile, such as gallstones, pancreatic cancer, and primary biliary cirrhosis.
Symptoms
The primary symptom of hyperbilirubinemia is jaundice, a yellowing of the skin and the whites of the eyes. Other symptoms can include dark urine, pale stools, and itching. The specific symptoms can vary depending on the underlying cause of the hyperbilirubinemia.
Diagnosis
The diagnosis of hyperbilirubinemia is typically made through blood tests that measure the levels of bilirubin in the blood. Other tests, such as liver function tests, complete blood count, and imaging studies of the liver and bile ducts, may also be performed to determine the underlying cause of the hyperbilirubinemia.
Treatment
The treatment of hyperbilirubinemia depends on the underlying cause. In cases where the hyperbilirubinemia is caused by an increased destruction of red blood cells, treatment may involve addressing the underlying cause of the hemolysis. In cases where the hyperbilirubinemia is caused by a liver disease, treatment may involve medications to treat the liver disease, dietary changes, or in severe cases, liver transplantation.