Adult-Onset Still's Disease in an Elderly Patient Presenting as Aseptic Meningitis: A Case Report.

Adult-onset Still's disease (AOSD) is a rare auto-inflammatory disease of unknown origin characterized mainly by fever, arthritis, and a rash. Aseptic meningitis is a rare complication of AOSD and is seen most commonly in young adults. Here, we report a case of AOSD in a 78-year female with fever and altered sensorium with lymphocyte predominant pleocytosis in the cerebrospinal fluid who was initially managed as tubercular meningitis. Adult-onset Still's disease was diagnosed as there was no response to antitubercular drugs even after 3 months and based on persistent fever, inflammatory arthritis, rash, and highly raised inflammatory markers.