Coagulation disordersa clinical approach

Haemophilia is the name given to an increased bleeding tendency. It can be heritable or acquired. The commonest heritable bleeding disorder is mild von Willebrand disease, affecting 1 per few hundred of the population. This heritable disorder is not typically referred to as haemophilia but in the broadest sense of the definition it is a form of haemophilia. 'Classical haemophilia', also termed 'haemophilia A', is due to factor VIII deficiency and affects only 1 per 10,000 male births. It is therefore encountered infrequently in non-haematological practice. The most common acquired form of haemophilia is that due to oral anticoagulant therapy as 1 per 100 of the population of many countries are now taking long-term warfarin or similar anticoagulants.

Conversely, thrombophilia is used to describe an increased tendency to thrombosis. This can also be heritable or acquired. Heritable throm-bophilic defects are often insufficient on their own to cause thrombosis and an additional acquired factor, such as surgery, is often the trigger for an acute thrombotic event.

Bleeding disorders

344 Causes of bleeding—surgery, trauma, non-accidental injury, coagulation disorders (including anticoagulant drugs), platelet dysfunction (including aspirin and other anti-platelet drugs), vascular disorders.

Clinical features—is there a lifelong bleeding history, has the patient been previously challenged, is this an isolated symptom? Type of bleeding problem that led to presentation e.g. mucocutaneous, easy bruising, spontaneous, post-traumatic. Duration and time of onset. Menstrual history is important. Absence of obstetric bleeding may be misleading as haemostatic capacity increases significantly in pregnancy.

Systemic enquiry—do symptoms suggest a systemic disorder, bone marrow failure, infection, liver disease, renal disease?

Past medical history—previous episode, previous known disorder e.g. ITP. Exposure to trauma, surgery, dental extraction, or pregnancies.

Family history—similar bleeding tendency in other family members? Pattern of inheritance (autosomal dominant, sex-linked).

Drugs—thrombocytopenia (ffl p384), platelet dysfunction (ffl p378); not always obvious—aspirin, warfarin. Drug reaction—allergic purpura.

Physical examination

Signs of systemic disease—anaemia, lymphadenopathy ± hepato-splenomegaly?

Assess bleeding site—check palate and fundi. Check size e.g petechiae (pinhead); purpura (larger =1cm); bruises (ecchymoses) =1cm—measure them.

joints—swelling or other signs of chronic arthritis, joint destruction or muscle contractures from previous bleeds?

Vascular lesions—purpura e.g. allergic, Henoch-Schonlein (p376), senile, steroid-related, hypergammaglobulinaemic, HHT—capillary dilatations (blanches on pressure), vasculitic lesions, autoimmune disorders, hyper-sensitivity reactions.

Investigation

• FBC (especially platelet count), film, biochemistry (especially creatinine and LFTs), ESR, coagulation tests (PT and APTT).

• Special tests will be dictated by history. The bleeding time is not a reliable test and is rarely indicated. von Willebrand's disease (vWD) often missed because PT and APTT and platelet count are normal. If history suggestive of vWD then plasma level of von Willebrand factor must be measured.

• Family studies should be considered to identify other family members at risk of bleeding.

Summary

Pre-operative history is most important aspect of identifying clinically significant bleeding risk. If abnormal bleeding does occur exclude surgical bleeding and take blood for testing before blood transfusion compounds 345 the problem. Decide whether platelet or coagulation defect or both? Is it hereditary or acquired?

Treatment

Establish diagnosis and treat as appropriate.

Treatment

Establish diagnosis and treat as appropriate.

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