Adult-Onset Still's Disease and Pulmonary Embolism: A Case Report

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder characterized by fever, rash, arthralgia, and systemic inflammation. Pulmonary embolism (PE), a potentially life-threatening complication, is infrequently associated with AOSD. This report presents a unique case that highlights the importance of considering atypical presentations of PE in this patient population despite the absence of classical risk factors. An 84-year-old male with hypertension, benign prostatic hypertrophy, and AOSD diagnosed six years prior, presented with confusion, fever, and malaise for two days. He denied any recent travel or immobilization. Examination revealed tachycardia and reduced oxygen saturation on room air. D-dimer was elevated, and CT chest angiography (CTCA) confirmed left upper and lower segmental PE without cardiac strain. Investigations for infection were negative. Initial treatment with intravenous heparin was switched to apixaban. The patient was eventually discharged home with stable vital signs. The inflammatory state in AOSD might contribute to hypercoagulability, increasing the risk of PE. This case emphasizes the importance of considering PE in AOSD patients, even in the absence of classical risk factors, to prevent potentially fatal complications. A literature review revealed few cases of AOSD presenting with PE, highlighting the atypical presentation and need for increased awareness. This case underscores the rare, but potentially serious, association between AOSD and unprovoked PE. Clinicians managing AOSD should maintain a high index of suspicion for PE, particularly in patients presenting with unexplained respiratory symptoms.