Causes of Abnormal Bleeding
| Cause | Comment |
|---|---|
| Inherited disorders of haemostasis | These are rare in acute medicine If the patient has had previous significant injury, surgery, tooth extraction or childbirth without abnormal bleeding, an inherited disorder of haemostasis is unlikely |
| Acquired disorders of haemostasis | |
| Direct effect of drugs | |
| Warfarin | Inhibits vitamin K-dependent gamma-carboxylation of coagulation factors II, VII, IX and X |
| Direct-acting oral anticoagulants (e.g. dabigatran, rivaroxaban, apixaban) | These drugs are direct inhibitors of factor Xa |
| Unfractionated heparin | Inhibits thrombin |
| Low-molecular-weight heparins | Inhibit factor Xa and thrombin |
| Thrombolytic agents (e.g. alteplase) | Activate plasminogen and thus the fibrinolytic system |
| Antiplatelet agents (e.g. aspirin, clopidogrel, ticagrelor) | Inhibit platelet aggregation |
| Platelet glycoprotein IIb/IIIa-receptor antagonists | Inhibit platelet aggregation |
| Other causes | |
| Thrombocytopenia | Platelet count:
|
| Platelet dysfunction | Most often due to drugs, notably antiplatelet agents, but also NSAIDs and beta-lactam antibiotics Also seen in advanced renal failure and myelodysplasia |
| Coagulation factor deficiency or inhibitor | See Table 102.2. Acquired inhibitors are antibodies to coagulation factors, which may be idiopathic or associated with malignancy, autoimmune disorders, pregnancy and clonal lymphoma proliferative disorders (e.g. Waldenstrom macroglobulinaemia) Typically presents with bleeding into muscles or large ecchymoses |
| Vessel disorder | Corticosteroid therapy, scurvy |