How high the bilirubin level is will affect the brain

Bilirubin is an important indicator for diagnosing liver function. When a newborn has jaundice, the child's condition can also be judged by testing bilirubin. Generally speaking, if the bilirubin level is too high, it may be a sign of liver disease. Because many patients do not know much about bilirubin and are worried that it will affect the brain. So, how high is the bilirubin level that affects the brain? Let’s take a look below.

Bilirubin is a type of bile pigment. It is the main pigment in human bile and is orange-yellow in color. It is the main metabolite of iron porphyrin compounds in the body. It is toxic and can cause irreversible damage to the brain and nervous system, but it also has antioxidant function and can inhibit the oxidation of linoleic acid and phospholipids. Generally, when the concentration of unconjugated bilirubin in the blood of newborns is above 307.8-342.0 μmol/L, it can pass through the blood-brain barrier and be deposited in the basal ganglia, thalamus, subthalamic nucleus, fastigial nucleus, ventricular nucleus, caudate nucleus, as well as cerebellum, medulla oblongata, cerebral cortex and spinal cord, inhibiting the brain's utilization of oxygen and causing brain damage, which is called bilirubin encephalopathy, formerly known as nuclear jaundice. Suggestions: Barbiturates or immunoglobulin G are generally used for treatment. At the same time, if there are high-risk factors for bilirubin encephalopathy, symptomatic treatment should be given.

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.