Why is bilirubin high? Why is bilirubin high?

Bilirubin is a very important indicator in clinical practice. It is mainly used in liver function tests and is also an important basis for the differential diagnosis of jaundice. Bilirubin, like other substances in the human body, can also be elevated, which can be divided into two types: physiological increase and pathological increase. We can have a general understanding of the main reasons. So, why is bilirubin high? Let’s take a look below.

The determination of serum bilirubin is an important test item in liver and gallbladder function examination. It can accurately reflect the degree of jaundice and is of great significance for the clinical diagnosis of latent jaundice.

1. Physiological increase

Neonatal physiological jaundice appears 2 to 3 days after birth, reaches a peak on the 4th to 6th day, and disappears on the 7th to 10th day. It lasts longer in premature infants. Except for mild loss of appetite, there are no other clinical symptoms.

Long-term drinking, strenuous exercise, etc. may also cause increased bilirubin. High bilirubin levels caused by physiological factors will generally recover on their own after adjustment.

2. Pathological increase

1. Increased direct bilirubin

It is mainly seen in obstructive jaundice, hepatocellular jaundice, liver cancer, pancreatic head cancer, cholelithiasis, bile duct cancer, etc.

(1) The main symptom is an increase in direct bilirubin, which accounts for more than 30% of the total bilirubin. It is mainly seen in: extrahepatic bile duct obstruction (gallstones, pancreatic head cancer, etc.); intrahepatic bile duct obstruction (extensive intrahepatic bile duct stones, Clonorchiasis sinensis, etc.); intrahepatic cholestasis (hepatitis, drug-induced liver disease, multiple jaundice during pregnancy, etc.).

Patients with elevated direct bilirubin often have symptoms such as fever, abdominal pain, vomiting, etc. The bilirubin concentration gradually increases, generally >170 μmol/L, urine bilirubin is positive, urobilinogen in feces is reduced or absent, and alkaline phosphatase is significantly increased.

2. Increased indirect bilirubin

It is common in acute icteric hepatitis, acute liver necrosis, chronic active hepatitis, cirrhosis, hemolytic anemia, blood type incompatible blood transfusion, hepatocellular jaundice, severe burns, sepsis, malaria, hypersplenism, pernicious anemia, thalassemia, lead poisoning, physiological jaundice of the newborn, drug-induced jaundice, constitutional jaundice, lactation jaundice, etc.

The main symptom is an increase in indirect bilirubin and an increase in total serum bilirubin, of which indirect bilirubin accounts for more than 80%. It is mainly seen in hemolytic jaundice, jaundice caused by certain drugs and examination reagents, and physiological jaundice in neonates.

(1) Patients with elevated indirect bilirubin may have a history of blood transfusion, special medications, infection, or family history of hemolysis.

(2) Increased total serum bilirubin. Serum bilirubin is generally <85 μmol/L, of which indirect bilirubin is the main cause of increase, accounting for more than 80%.

Pathological increase in bilirubin should be taken seriously and the patient should go to the hospital for treatment in time to seize the best time for treatment.