A case series of acquired haemophilia in a Malaysian hospital: unpredictably rare medical emergency.

Acquired haemophilia (AH) is a rare bleeding disorder characterized by the presence of acquired inhibitors against Factor VIII causing disruption of coagulation cascade. It has no known genetic inheritance, and diagnosis remains a challenge. The peculiar presentations are later age of onset as acute pain in weight-bearing joints and spontaneous muscle haematoma with isolated prolonged activated partial thrombin time (APTT). Prevalence is 1 per million per year affecting both genders equally where blood product transfusion is seen in almost 87% of cases. The direct cause of AH is still unknown, and autoimmune dysregulation has been postulated, which predisposes to the development of the factor inhibitors. Being extremely rare, we are reporting two consecutive patients diagnosed by unusual bleeding episodes with isolated prolonged APTT due to Factor VIII inhibitors. AH deserves a special mention as high index of suspicion is required. More studies are required to provide better guidance in diagnosis and management of this condition.