Causes Thrombophilia

1 causes

1.1 congenital
1.2 acquired
1.3 unclear

causes

thrombophilia can congenital or acquired. congenital thrombophilia refers inborn conditions (and hereditary, in case hereditary thrombophilia may used) increase tendency develop thrombosis, while, on other hand, acquired thrombophilia refers conditions arise later in life.

congenital

the common types of congenital thrombophilia arise result of overactivity of coagulation factors. relatively mild, , therefore classified type ii defects. common ones factor v leiden (a mutation in f5 gene @ position 1691) , prothrombin g20210a, mutation in prothrombin (at position 20210 in 3 untranslated region of gene).

the rare forms of congenital thrombophilia typically caused deficiency of natural anticoagulants. classified type , more severe in propensity cause thrombosis. main ones antithrombin iii deficiency, protein c deficiency , protein s deficiency. milder rare congenital thrombophilias factor xiii mutation , familial dysfibrinogenemia (an abnormal fibrinogen). unclear whether congenital disorders of fibrinolysis (the system destroys clots) major contributors thrombosis risk. congenital deficiency of plasminogen, instance, causes eye symptoms , problems in other organs, link thrombosis has been more uncertain.

blood group determines thrombosis risk significant extent. blood groups other type o @ two- fourfold relative risk. o blood group associated reduced levels of von willebrand factor – because of increased clearance – , factor viii, related thrombotic risk .

acquired

a number of acquired conditions augment risk of thrombosis. prominent example antiphospholipid syndrome, caused antibodies against constituents of cell membrane, particularly lupus anticoagulant (first found in people disease systemic lupus erythematosus detected in people without disease), anti-cardiolipin antibodies, , anti-β2-glycoprotein 1 antibodies; therefore regarded autoimmune disease. in cases antiphospholipid syndrome can cause arterial venous thrombosis. more associated miscarriage, , can cause number of other symptoms (such livedo reticularis of skin , migraine).

heparin-induced thrombocytopenia (hit) due immune system reaction against anticoagulant drug heparin (or derivatives). though named associated low platelet counts, hit associated risk of venous , arterial thrombosis. paroxysmal nocturnal hemoglobinuria (pnh) rare condition resulting acquired alterations in piga gene, plays role in protection of blood cells complement system. pnh increases risk of venous thrombosis associated hemolytic anemia (anemia resulting destruction of red blood cells). both hit , pnh require particular treatment.

hematologic conditions associated sluggish blood flow can increase risk thrombosis. example, sickle-cell disease (caused mutations of hemoglobin) regarded mild prothrombotic state induced impaired flow. similarly, myeloproliferative disorders, in bone marrow produces many blood cells, predispose thrombosis, particularly in polycythemia vera (excess red blood cells) , essential thrombocytosis (excess platelets). again, these conditions warrant specific treatment when identified.

cancer, particularly when metastatic (spread other places in body), recognised risk factor thrombosis. number of mechanisms have been proposed, such activation of coagulation system cancer cells or secretion of procoagulant substances. furthermore, particular cancer treatments (such use of central venous catheters chemotherapy) may increase risk of thrombosis further.

nephrotic syndrome, in protein bloodstream released urine due kidney diseases, can predispose thrombosis; particularly case in more severe cases (as indicated blood levels of albumin below 25 g/l) , if syndrome caused condition membranous nephropathy. inflammatory bowel disease (ulcerative colitis , crohn s disease) predispose thrombosis, particularly when disease active. various mechanisms have been proposed.

pregnancy associated increased risk of thrombosis. results physiological hypercoagulability in pregnancy protects against postpartum hemorrhage.

the female hormone estrogen, when used in combined oral contraceptive pill , in perimenopausal hormone replacement therapy, has been associated two- sixfold increased risk of venous thrombosis. risk depends on type of hormones used, dose of estrogen, , presence of other thrombophilic risk factors. various mechanisms, such deficiency of protein s , tissue factor pathway inhibitor, said responsible.

obesity has long been regarded risk factor venous thrombosis. more doubles risk in numerous studies, particularly in combination use of oral contraceptives or in period after surgery. various coagulation abnormalities have been described in obese. plasminogen activator inhibitor-1, inhibitor of fibrinolysis, present in higher levels in people obesity. obese people have larger numbers of circulating microvesicles (fragments of damaged cells) bear tissue factor. platelet aggregation may increased, , there higher levels of coagulation proteins such von willebrand factor, fibrinogen, factor vii , factor viii. obesity increases risk of recurrence after initial episode of thrombosis.

unclear

a number of conditions have been linked venous thrombosis possibly genetic , possibly acquired. these include: elevated levels of factor viii, factor ix, factor xi, fibrinogen , thrombin-activatable fibrinolysis inhibitor, , decreased levels of tissue factor pathway inhibitor. activated protein c resistance not attributable factor v mutations caused other factors , remains risk factor thrombosis.

there association between blood levels of homocysteine , thrombosis, although has not been reported consistently in studies. homocysteine levels determined mutations in mthfr , cbs genes, levels of folic acid, vitamin b6 , vitamin b12, depend on diet.