Adult onset Still's disease presenting as fever of unknown origin: a case report with review of literature

Adult onset Still's disease (AOSD) is a systemic inflammatory disease with exact etiology and pathogenesis yet to be discovered. AOSD, being an important cause of fever of unknown origin, is diagnosed after ruling out infections, malignancy and other rheumatologic diseases. It may present with fever without typical rash although typical triad is of fever, joint pain and rash. A 35-year-old previously healthy man was referred to our hospital with 6 months of fever, joint pain and weight loss. Examination and investigations revealed anemia, leukocytosis (predominant neutrophilia), lymphadenopathy, hepatomegaly, arthritis and evidence of interstitial lung disease with raised serum ferritin levels. Hematological disorders, infections and other rheumatologic diseases were excluded. The diagnosis of adult onset Still's disease can be very difficult as there are no specific tests and diagnosis is based on symptom complex. AOSD presenting as fever of unknown origin could be a challenge for the physician to diagnose and manage timely.