Abstract
Complement-amplifying events/conditions associated with thrombotic microangiopathy (TMA) include pregnancy/postpartum period, severe hypertension, autoimmune diseases, drug exposures, infections and organ transplantation. Some of these 'triggers' may exist comorbidly with atypical haemolytic uraemic syndrome (aHUS; a complement-mediated form of TMA), unmask previously undiagnosed aHUS, or occur secondary to aHUS, thus creating a considerable diagnostic challenge. A major goal in patients presenting with TMA is to differentiate complement-mediated aHUS from other causes of TMA such that appropriate targeted treatment with complement 5 (C5) inhibitors can be initiated rapidly to avoid irreversible end-organ damage. To this end, nephrologists and haematologists from Australia, Hong Kong, Japan, Korea and Taiwan met virtually to discuss the management of TMA/aHUS in the presence of trigger conditions, focusing on the role of C5 inhibitors. To assist primary healthcare physicians and specialists from other disciplines in identifying and managing aHUS in the presence of triggers, the panel developed diagnostic and treatment algorithms as the main meeting output. Individual algorithms are presented for the settings of pregnancy, hypertension, autoimmune diseases, drug exposures, and kidney transplant. The algorithms combine clinical evidence with the panel's collective expertise to provide practical steps to differentiate aHUS and can be refined by local experts to reflect respective healthcare systems, approval and reimbursement procedures, resources and access to treatments for aHUS in any Asia-Pacific country.