Bilirubin is the yellow-orange pigment we can find in the bile. It comes from the breakdown of hemoglobin when red blood cells are old and degrade. Bilirubin is what gives a dark color to your stools, and it is processed by the liver. Thus, when you have liver disease, one of the symptoms is jaundice, a yellowish coloration of the skin resulting from bilirubin accumulation in healthy tissues.
Jaundice is a sign of high bilirubin levels in the blood, also known as bilirubinemia. There are different reasons why bilirubin levels increase in the blood. Depending on what part of the liver is involved, we can have two types of bilirubin in the blood: conjugated bilirubin and unconjugated bilirubin. The difference is that the liver metabolizes conjugated bilirubin, and the liver has not changed unconjugated bilirubin as of yet.
In this article, we will break down hyperbilirubinemia into two types and consider each one, what do they mean, what parts of the liver are involved, and what is the treatment.
As noted above, conjugated bilirubin has gone through the liver, and this organ has performed different metabolic reactions, changing the structure of bilirubin. It is still bilirubin and has the same pigment, in any case. But if you have a high level of conjugated bilirubin in the blood, it means that your liver enzymes are working correctly. Otherwise, they could not have metabolized bilirubin in the first place.
Thus, the problem is not in the metabolic functions of the liver. The problem is likely a transportation blockade in the bile ducts, usually due to gallbladder stones. Such blockade is known as cholestasis. A hepatocellular disease (liver cancer) may also increase bilirubin levels in the blood because the tumor grows causes a similar blockade.
Conjugated hyperbilirubinemia is diagnosed in liver function tests by looking at the measure of conjugated bilirubin, also known as direct bilirubin. More than 2 mg/dL of direct bilirubin will diagnose this disease. Even if you don’t have 2 mg/dL, you might also have the diagnose if direct bilirubin makes up more than 20% of your total bilirubin levels.
After diagnosing this problem, your doctor will likely evaluate different causes in the liver (intrahepatic) and outside of the liver (extrahepatic).