An Unusual Presentation of Adult-Onset Still's Disease in a Patient with Recurrent Pleural and Pericardial Effusions.

Adult-Onset Still's Disease (AOSD) usually presents with a salmon-colored skin rash and arthralgias. However, it can also be present with pleural and pericardial effusions. These effusions are often misdiagnosed as having an infectious etiology because AOSD usually present with fever, leukocytosis, elevated inflammatory markers, procalcitonin and CRP. There is usually a delay in giving steroids until the exclusion of all infectious etiologies, including extensive workups. Herein, we present a case report of AOSD in a patient with recurrent pleural and pericardial effusions, with no skin rashes or joint pain. Patient initially presented with fever, pleural and pericardial effusions, which was then treated as pneumonia with parapneumonic effusions. Patient returned for the second time with shortness of breath, productive cough, and fever, with no resolutions of pleural and pericardial effusions. Patient was found to have an extremely high ferritin levels, whereby a diagnosis of AOSD was made after excluding infection, malignancy and other rheumatological disorders based on the Yamaguchi criteria. AOSD is a rare disease with unusual presentation and diagnosis is often delayed. This case aimed to raise awareness among physicians of the multifaceted presentation of AOSD.