Bilirubin in the blood : the rate of newborns of women and men
Analyses And Studies / / August 12, 2017
- What is bilirubin?
- How is the exchange of bilirubin in the body?
- What indicators of bilirubin levels in the blood are considered to be the norm?
- Factors causing hyperbilirubinemia
What is bilirubin?
Bilirubin is one of the main bile pigments.More than 80% of the compound is formed from the heme - non-protein part of hemoglobin in its decay, which occurs due to destruction of red blood cells.The rest of bilirubin is heme degradation product contained in myoglobin and cytochrome.
whole bilirubin, which is contained in the body of a healthy person, called the general, it is represented by two factions:
- the decay of heme-containing proteins produced unconjugated bilirubin, which is also called unrelated, indirect or non-conjugated.Indirect bilirubin is rather toxic compound capable of increasing it at a level above the norm harm the body.Particularly sensitive in this regard is the central nervous system - even with little giperbelirubinemii person develops weakness, fatigue, lethargy, and poor attention.The unbound bilirubin is insoluble in water and therefore not excreted.
- liver bilirubin in the cells under the action of enzymes associated with glucuronic acid and converted to conjugated bilirubin, which is also called a direct or conjugated.Direct bilirubin, in contrast to the indirect, non-toxic to humans and is highly soluble in water.
How is the exchange of bilirubin in the body?
From hepatocytes conjugated bilirubin through bile capillary enters the bile and then in the intestinal lumen.
His characteristic color owes to the presence of bile in her bilirubin.
In the process of digestion in the conjugated bilirubin affect the microorganisms living in the gut.Under the action of an enzyme produced by bacteria - β-glucuronidase, hydrolysis conjugated bilirubin, resulting again formed unbound bilirubin.Thereafter, the resulting chemical chain reactions, free bilirubin is converted to a number of intermediate compounds consisting of urobilinogenov and urobilinoidov.Subsequently, urobilinogen and urobilinoidy turn into urobilin and stercobilin which are excreted with the faeces, giving them a distinctive color.
In some cases involving violation of receipt of bilirubin into the intestine, the stool may be discolored.Normally, a small part of urobilinogenov excreted in the urine, the concentration is so small that it is not determined by laboratory methods.And only in case of serious liver damage tissue in urine significantly increased levels of bile pigments, and the urine is much darker.20% urobilinogenov not converted in the intestines into the final metabolic products, and are absorbed into the blood and back to the liver, and then removing the process repeats.
What indicators of bilirubin levels in the blood are considered to be the norm?
normal values of bilirubin in the blood differ greatly depending on the age.In children, the first months of life in blood bilirubin content is considerably higher than in adults and older children.Normal bilirubin in the blood of women with normal coincides men.In the adult rate of total bilirubin ranging from 8.5 to 20.5 mmol / l, in the ratio of indirect / direct - 75% / 25%, in absolute terms - about 15.4 / 5.1 mmol / l.At 1 month of life human level of bilirubin is constantly changing, it is associated with physiological processes occurring in the body of the newborn.
norm in the blood of bilirubin in newborns table:
the child's age in days
level content in mmol / l
1 - 2
50 - 60
2 - 7
250 (preterm and 170)
10 - 30
gradual decrease to 20
from the table above it is clear that bilirubin rate atnewborns is significantly higher than in the adult, this phenomenon is known as jaundice in newborns.It is a physiological condition which is observed in the first weeks of life, gradually regressing, and already month old baby normally completely absent.Newborn Jaundice associated with immaturity of the liver enzyme responsible for the transformation of free bilirubin in a related, so the normal ratio in infants indirect / direct 90% / 10%.
Factors causing hyperbilirubinemia
Causes of hyperbilirubinemia diverse.They may be associated with the functional state of the liver, as well as with a variety of extrahepatic factors.Total bilirubin is above normal levels due to the hanging of one of its factions, due to the following factors:
- increase in free bilirubin caused by its increased form, during normal operation of the liver (hepatocytes can not cope with recycling too much);
- increase in free bilirubin caused by impaired liver function in inflammatory or toxic damage of hepatocytes;
- increase of conjugated bilirubin resulting from violations of the formation and excretion of bile from the liver cells;
- increase of conjugated bilirubin caused by a mechanical violation of the outflow of bile on the biliary ways.
hyperbilirubinemia, usually accompanied by jaundice, the severity of which depends on the amount of bilirubin.Its surplus accumulated in all tissues of the body, turning them into yellow color, visually it is shown the yellow of the skin, mucous membranes and sclera.In severe jaundice develops general intoxication and local manifestations, accompanied by itching.The most common cause of jaundice - is to increase direct bilirubin, occurs when the following liver diseases:
- Acute viral hepatitis, especially hepatitis B is A and B, less virus infectious mononucleosis, HCV;
- Bacterial liver disease resulting in infectious diseases: leptospirosis, brucellosis, etc .;
- Toxic hepatitis, arising from the ingestion of hepatotoxic poisons, can be acute - poison plant toxins (death cup) and chemicals (solvents, methylated spirits) and chronic alcoholism;
- drug-induced hepatitis is a special case and there is toxic in overdose or hypersensitivity to certain medications.Most cases antibiotics and nonsteroidal anti-hormones;
- Jaundice in pregnancy can occur in the later stages, and proceed on the type of hepatitis that has holestatitesky character;
- Neoplasms of the liver and primary biliary cirrhosis, hereditary diseases.
cause of hyperbilirubinemia may also be a violation of the outflow of bile, which occurs when the following conditions:
- compression of the bile duct, which occurs when the pancreas increase (chronic pancreatitis, a tumor), liver hydatid disease, diverticulitis 12 duodenal ulcer, hepatic artery aneurysm;
- occurrence of bile outflow obstruction in bile ducts that occurs as a result of inflammatory processes (acute and chronic cholangitis), cholelithiasis (blockage of the duct concrement), tumors of the bile duct.
The bile contains only direct bilirubin, which means that his faction will be enhanced by mechanical jaundice.Increased indirect fraction occurs in the following diseases of the blood system and the normal functioning of the liver:
- Hemolytic anemia, congenital and acquired (autoimmune);
- Hemolytic disease of the newborn (immunological incompatibility between the blood of mother and child);
- Infectious diseases accompanied by destruction of red blood cells: malaria, sepsis, etc .;
- Hemolytic anemia toxic nature: poisoning dyes, salts of heavy metals, plant poisons, bites of some species of snakes and vipers;
- Medicinal toxic anemia as a side effect of the drugs.
Although the level of bilirubin is an important diagnostic indicator reliably judge the reasons that caused its increase, is possible only if there are other indicators that characterize the function of the liver.For this is done, and the biochemical analysis of blood is determined by the level of liver enzymes (AST, ALT), prothrombin index and other indicators, when the content of which is higher or lower than normal can properly assess the big picture.