Lower gastrointestinal bleeding during anticoagulant therapy: a life-saving complication?

Warfarin is commonly used in the prophylaxis or treatment of thromboembolic disease. Haemorrhage is a recognised complication which may be life-threatening. This paper describes eight cases in which lower gastrointestinal bleeding while on warfarin therapy resulted in the discovery of previously unrecognised large bowel malignancy. Diagnosis of an otherwise asymptomatic carcinoma in this way enabled surgery to be carried out at an earlier stage and so may have resulted in a better prognosis for these patients. Bleeding while on anticoagulant therapy is caused by a specific organic lesion in 30% to 50% of cases. This may be the case even when the prothrombin time is very prolonged. It is important, therefore, that such cases are fully investigated, especially in the elderly.