Why do patients with antiphospholipid syndrome bleed? A clinical paradox

Although worldwide-known criteria of antiphospholipid syndrome include thrombotic and obstetric events, a moderate number of patients manifest with bleeding episodes during course of the disease, which is typically attributed to the long-term anticoagulation. However, these haemorrhagic manifestations sometimes are part of pathophysiological changes that might occur secondary to the disease that involves endothelial activation, platelets dysfunction and blood clot factors misfunction. Recognizing these mechanisms of bleeding is crucial not only due to the need of treatment change or adding, but also because of changes in the disease' prognosis. In this review, we attempted to explain those complications, from its mechanism to a treatment approach, in order for physicians to be able to recognize patients with antiphospholipid syndrome and haemorrhagic manifestations, and to understand that, beyond over-anticoagulation, there are some other mechanisms that can trigger this complication and thus carry out a better diagnostic and therapeutic approach.