What is prothrombin time and what are its norms?
Prothrombin time, the norm of which for adults is 11-15 seconds, and for children - 13-18 seconds, can increase, which becomes a sign of the presence of various kinds of diseases. This indicator is characteristic for I and II plasma homeostasis and is intended to reflect the activity of the prothrombin complex.
If prothrombin time begins to increase, this indicates a tendency to hypercoagulable. There may be several reasons for this:
· If the prothrombin complex is deficient in the development of such coagulopathies as hypoproconvertinemia and hypoprothrombinemia.
· Sometimes this factor increases with amyloidosis, which is caused by a deficiency of factor X. In this case, it is absorbed by amyloid. If the nephrotic syndrome develops, then there is a deficiency of factors VI and V.
Because the synthesis of elements of the prothrombin complex occurs in the liver, because if it is unhealthy, their quantity decreases. In some situations prothrombin time is an indicator of the physiological state of the body.
An increase in this indicator is also observed in the presence of acute and chronic hepatitis, cirrhosis of the liver, and also under the condition of subacute liver dystrophy and other lesions of the hepatic parenchyma. The fact is that these changes are a bad sign and indicate the development of a disease. If mechanical jaundice is diagnosed, the prothrombin time may increase because the amount of bile entering the intestine decreases, which leads to a violation of absorption of vitamin K. It is he who takes an active part in the synthesis of the prothrombin complex.
Also among the reasons that cause an increase in this indicator are enteropathy and intestinal dysbiosis, which lead to chronic vitamin K deficiency. If treatment is carried out with the help of antagonists of this vitamin, the final stage in the synthesis of the main factors of the prothrombin complex is disrupted. It is believed that the use of coagulants can continue if the prothrombin time is doubled.
There are many drugs that can increase the time frame of this indicator. Among them, there are laxatives, antibiotics, aspirin( given a high dose), as well as quinine and anabolic steroids.
In general, with violations of the liver, the prothrombin time indicator tends to increase. Therefore, if you have any diseases of this kind, you need to monitor this indicator.
Sometimes there are situations in which prothrombin time begins to decrease. This indicates that there is a tendency to hypercoagulable. Sometimes this occurs at the initial stage of vein thrombosis in the lower extremities, as well as polycythemia. Very often, the indicator may decrease on the last days of pregnancy or after the use of certain medications, for example, acetylsalicylic acid( in small doses), mercaproturine and oral contraceptives.
When pro-oral coagulant therapy is monitored, prothrombin time is routinely monitored. However, in such a situation, the change in the index can be caused by the thromboplastin used, which is necessary in this case. Therefore, it is very important to conduct research after using various types of thromboplastins. This is considered one of the important tasks of practical medicine. For a patient who is under observation, tests should be performed regularly after the appointment of a new drug.