Severe Adult-Onset Still's Disease Mimicking Systemic Infection.

Adult-onset Still's disease (AOSD) is an uncommon entity that can mimic infection. Patients present with fever for more than 1-week, joint pain, and rash. We report a case of 22-year-old male who presented with fever, sore throat, and abdominal pain. During hospitalization, he had multiple episodes of tachycardia and tachypnea requiring mechanical ventilation. The patient had elevated white blood cell count, procalcitonin, and troponin. He was extensively investigated and diagnosed as AOSD. He responded to steroids and was discharged on day 20.