A Mono-Articular Septic Arthritis and Multifocal Avascular Necrosis in Absence of Corticosteroid Use: An Unusual Presentation of Primary Antiphospholipid Syndrome

Abstract

Osteonecrosis (ON) or avascular necrosis results from disruption of blood supply to bone marrow and trabecular bone leading to death of bone. Antiphospholipid Syndrome (APS) may be primary or secondary to other autoimmune disease. The involvement of multiple sites of ON has been documented with APS. Literature suggests that avascular necrosis predispose a septic arthritis in affected joints especially in immunosuppressed patients.A 29-year-old male patient was a heavy smoker with a past medical history of NSAID abuse and antral and duodenal ulcers. He admitted to the hospital with a sudden severe pain on the medial side of right knee associated with erythema and fever. Figure 1: MRI right knee joint showing diffuse altered marrow signal intensity in tibia and patchy areas of altered signal intensity in lower femur suggesting osteomyelitis with bony infarcts. R heuma to lo g y: Curr e n t R e se arch