Plasma levels of clotting factor VIII or IX determine the severity of this disorder and classify it as severe, moderate or mild depending on whether levels are below 1%, between 1 and 5%, or over 5%, respectively. Spontaneous haematoma during the first few months of life or caused by minor trauma are the key sign of the severe condition.
Although bleeding can be found in any part of the body, it typically occurs within a joint (haemarthrosis), mainly in the ankles, knees and elbows. It generally appears before two years of age and represents 70-80% of all haemorrhages. Repeated bleeding in the same joint ends up causing irreversible damage that affects function (haemophiliac arthropathy). Intramuscular haemorrhaging is the second most common after haemarthrosis, and intracranial bleeding the most serious.
In moderate cases, clinical signs are similar to those of the severe disorder, apart from spontaneous haemorrhaging; and in mild cases diagnosis is reached by spotting an anomaly in blood clotting tests, by bleeding after a tooth extraction or surgery, or following a familial study.
A suspected diagnosis begins by asking about a patient's personal and family history of bleeding. Basic blood clotting tests show increased time for the blood to clot (activated partial thromboplastin time) and it is confirmed by verifying low levels of clotting factors VIII or IX. Genetic testing refines the diagnosis by identifying the mutation causing the disorder. This procedure can also identify potential carriers and may be used for prenatal diagnosis.
Treatment is replacement therapy, which is the intravenous administration of the deficient factor in the case of acute bleeding, before any aggressive exploratory or surgical procedures take place. Factor VIII and IX concentrates may be human plasma or recombinant engineered using biotechnology. In mild cases, other drugs may be used such as desmopressin, a synthetic derivative of vasopressin.
For cases of severe haemophilia, preventative treatment should be started before two years of age or after the first haemarthrosis in order to avoid serious complications in the joints producing repeated haemorrhaging, and also to act as a preventative treatment against brain haemorrhaging. For haemophilia A, factor VIII must be administered three times a week, and twice in the case of haemophilia B. New treatments being developed will allow infusion therapy to be more spread out in the future.
Plasma and recombinant factors currently effectively and safely control and prevent bleeding. The most serious complication of treatment is the possible appearance of an inhibitor. This appears in 30% of severe haemophilia A and in 2-4% of haemophilia B cases.
Because this is a complex and chronic condition, it is advisable to have a multidisciplinary team that includes specialists in haematology, hepatology, infectious diseases, orthopaedic surgery, physiotherapy and rehabilitation, odontology, obstetrics, genetics, psychology and nursing. Educational programmes to show family members how to administer intravenous treatment at home, prenatal diagnosis and genetic counselling are essential.
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