RESUMO
We describe the case of a 50-year-old woman with a history of SLE and APS that presented with a spontaneous subdural haematoma, prolonged aPTT, PT and INR and positive LA. The activity of the coagulation factors II, VIII, IX and XI was extremely low, and anti-prothrombin antibody IgG was positive. LAHS was established, with inhibition of the intrinsic pathway, as an acquired haemophilia. The patient received corticosteroids and cyclophosphamide as treatment. To the best of our knowledge, this is one of the few reports of spontaneous intracranial bleeding, an unusual and initial manifestation of LAHS in an adult patient.HighlightsLAHS is characterised by the presence of LA and hypoprothrombinaemia caused by anti-prothrombin antibodies.Prolonged aPTT and INR, and positive LA are important laboratory findings that help the suspicion of LAHS.Intracranial bleeding is an unusual manifestation of LAHS associated with low factor II activity.Corticosteroids are the first-line treatment of LAHS.The prognosis of LAHS is good with adequate treatment, with a reported mortality of 5%.