Seronegative Catastrophic Antiphospholipid Syndrome in a Young Female Presenting with a Headache

BackgroundCatastrophic antiphospholipid syndrome (CAPS) is a rare disease that causes rapid vascular occlusion in multiple organ systems. Initial presentation varies depending on the organs affected. Although headache is a common complaint in the emergency department (ED), it is a very rare presentation of CAPS.Case ReportA 43-year-old previously healthy woman presented to the ED with severe headache. Subarachnoid hemorrhage was excluded and she was discharged home. She returned 36 h later with diabetic ketoacidosis, hyperthyroidism, and thrombosis in her cerebral venous sinus, aorta and splenic artery. She was treated with heparin, steroids, plasmapharesis, and i.v. immunoglobulin, after which she improved. This constellation of symptoms is highly suggestive of CAPS initiated by a polyglandular autoimmune syndrome, despite negative serology.Why Should an Emergency Physician Be Aware of This?Although a rare cause of headache, CAPS is a potentially fatal disease that requires early identification and initiation of appropriate treatment.