Antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a multisystem autoimmune disease characterised by thrombus formation (arterial and venous), cardiac disease, neurological features and pregnancy-related complications. APS can result in a wide range of pulmonary complications including pulmonary thromboembolic disease, PH and DAH, clinically mimicking idiopathic disorders. The interpretation of antiphospholipid antibody screening relies on an understanding of the background prevalence of these antibodies and factors increasing the likelihood of false-positive results such as age, recent infection and malignancy. Respiratory physicians should be discouraged from the use of direct anticoagulant therapies in the management of APS. This chapter outlines the major clinical and laboratory features of APS. A practical approach to the assessment and management of APS-related pulmonary disease will be presented. The extrapulmonary clinical and laboratory features that raise the possibility of underlying APS are highlighted to ensure that respiratory physicians are equipped to consider, diagnose and treat APS-related pulmonary disease in a timely fashion.