Definition: a group of hereditary genetic disorders that impair the coagulation cascade.
Classification / type of disease:
- Haemophilia A (clotting factor VIII deficiency) is the most common form of the disorder, occurring at about 1 in 5,000–10,000 male births. =80% of haemophilia cases. Often present before age 2yo, unaffected PTT, prolonged APTT.
- Haemophilia B (factor IX deficiency) occurs at about 1 in about 20,000–34,000 male births. = 20% of cases.
- Both diseases span from mild to severe.
Presenting symptoms / signs: prolonged bleeding and re-bleeding, muscle and joint bleeds, easy bruising and mucosal/dental bleeds. Severe symptoms = deep bleeds, intracranial bleeds.
Diagnostic investigations: coag screen, PTT, APTT
Haemophilia lowers blood plasma clotting factor levels of the coagulation factors needed for a normal clotting process. Thus when a blood vessel is injured, a temporary scab does form, but the missing coagulation factors prevent fibrin formation, which is necessary to maintain the blood clot. A haemophiliac does not bleed more intensely than a normal person, but can bleed for a much longer time.
- A recessive sex-linked, X chromosome disorder.
- M>F (females have two X chromosomes while males have only one, so the defective gene is guaranteed to manifest in any male who carries it) – therefore typically women are asymptomatic carriers and males are symtomatic sufferers.
Treatment / management: replete depleted factor. (Haem A = VIII, Haem B = IX). Also desmopressin (as a bizarre side effect) appears to reduce risk of bleeds. Pts should also avoid anti-coagulant / antiplatelet agents and traumatic sports
Differentials: watch out as Von Willebrands can mimic haemophila.
vWD: low platelets and FVIII. P/c: mucosal bleeds, episatxis, bruising. Prolonged PTT and APTT.
Prognosis: with affective Tx, normally about 10 years less than male without haemophillia.
Other haemophillic states = wiskott-aldrich syndrome, bernard-soulier syndrome, leukaemia, Vit K deficiency, warfarin/heparin/aspirin/clopidogrel excess, lupus anticoagulant, liver disease, hypofibrinogenaemia.