ABSTRACT

Catastrophic antiphospholipid syndrome (CAPS) is the most severe form of APS with acute multiple organ involvement and small vessel thrombosis. Early diagnosis and aggressive treatment are crucial for the prognosis of CAPS patients. When CAPS is considered in the differential diagnosis of a patient with multiple organ thromboses, several factors can impede the timely diagnosis. The purpose of this paper is to discuss the diagnostic challenges (i.e., false-positive/negative antiphospholipid antibody [aPL] results, overlap with other thrombotic microangiopathies) as well as the updated diagnostic algorithms for CAPS. Important steps of the diagnostic algorithms include: i) history of APS or persistent aPL-positivity; ii) three or more organ new thromboses developing in less than a week; iii) biopsy diagnosis of microthrombosis; and iv) other explanations for multiple organ thromboses and/or microthrombosis.