What is Factor I Deficiency?
Congenital and hereditary forms of fibrinogen deficiency are described as early as 1920. Family afibrinogenemia (absence of fibrinogen in the blood plasma) is a rare disease that is inherited in an autosomal recessive manner. Almost all patients with plasma fibrinogen levels below 0.15 g/l (15 mg%) are homozygous. Their parents usually show a moderate decrease in plasma fibrinogen without any hemorrhagic manifestations.
Symptoms of Factor I Deficiency
Bleeding with afibrinogenemia is usually not very pronounced, microcirculatory. In some patients, wounds do not heal well.
Diagnosis of Factor I Deficiency
In afibrinogenemia, all coagulation tests reveal complete blood coagulation, but the evidence is the absence of clotting when thrombin is added to the recalcified plasma under study (plasma with calcium introduced into it, which takes part in the blood coagulation process). To exclude the effect of anticoagulants that can block thrombin added from the outside, the thrombin sample is repeated in two versions: with the addition of a heparin antagonist – protamine sulfate or polybrene and with the addition of highly purified fibrinogen to the studied plasma. If heparin antagonists do not eliminate incoagulability, and the added fibrinogen normalizes the thrombin time of the plasma under investigation, then the diagnosis of afibrinogenemia is confirmed.
For the final distinction of a- or hypofibrinogenemia and dysfibrinogenemia, quantitative determination of fibrinogen is used. Antifibrinogen serum is used in immunological tests.
In each case of detecting a- or hypofibrinogenemia, the doctor should first of all think not about the genetically determined deficiency of this protein, but about the more frequently acquired forms of the indicated pathology in clinical practice, caused either by DIC or hepatic dystrophy. Only in the complete absence of any clinical and laboratory signs of these syndromes and the diseases that cause them, the diagnosis of a hereditary violation of fibrinogen synthesis becomes eligible. The diagnosis of such hereditary forms is confirmed by stable, life-long insufficiency of factor I, as well as hypofibrinogenemia in the parents and other blood relatives of the patient.
Treatment of Factor I Deficiency
Bleeding from the mucous membranes and after extraction of the teeth is usually prevented and stopped with moderate doses of aminocaproic acid, irrigation with a 5% solution of this preparation of the bleeding surface, tamponade of the tooth hole with a hemostatic sponge with thrombin.
Specific replacement therapy is indicated for large bleedings, as well as during and after surgical interventions, either with concentrated dry plasma or fibrinogen solution. 1 l of plasma is equivalent to 3.0-3.5 g of fibrinogen. To ensure reliable hemostasis, the first dose of fibrinogen should be 0.06 g/kg body weight per day, which increases the plasma concentration of the patient with this protein from 0 to 1.5 g/l. Repeated administration of fibrinogen is done in 2-3 days, since the half-life of this protein in the plasma of the recipient varies from 3 to 4.8 days. Maintenance doses of the drug, administered every 2 days, should be half the original and make up 0.03-0.04 g/kg body weight.