Catastrophic Antiphospholipid Syndrome: A Complex Diagnosis in the Setting of Lupus.

This case report aims to highlight the importance of keeping catastrophic antiphospholipid syndrome (CAPS) high on the list of differentials in patients with lupus who present with digital ischemia and to understand the workup and treatment of the disease. Catastrophic antiphospholipid syndrome is a life-threatening variant of antiphospholipid syndrome (APS), and it is distinguished on the APS spectrum by its increased intensity and extent of thrombotic outcomes. Less than 1% of patients with APS develop CAPS and the demographic of patients affected are primarily females, 37 ± 14 years old, and have underlying primary APS or systemic lupus erythematosus (SLE). This is the case of a young female with lupus and end-stage renal disease secondary to lupus nephritis who presented to the emergency department for shortness of breath and bilateral leg swelling that eventually progressed to catastrophic antiphospholipid syndrome. She developed pulmonary embolisms, axillary hematoma, and bilateral lower extremity digital gangrene. The treatment course consisted of anticoagulation, steroids, intravenous immunoglobulin (IVIG), above-knee amputation, and eventually rituximab. Diagnosis and treatment of digital ischemia can be complex, especially, in the setting of lupus where the differential diagnosis is broad. A high index of suspicion for CAPS is essential for early diagnosis and treatment.