Hidden in Plain Sight: Antisynthetase Syndrome Masquerading As Acute Coronary Syndrome and Heart Failure

A middle-aged man presented with fever, generalized myalgia, dyspnea, and worsening chest discomfort. Initial investigations showed elevated troponin and creatinine kinase levels and nonspecific ECG changes. Pulmonary embolism was ruled out, and high-resolution CT (HRCT) revealed ground-glass opacities and nonspecific interstitial pneumonia (NSIP)/organizing pneumonia (OP) overlap pattern. Given the elevated creatinine kinase level, antisynthetase syndrome with rapidly progressive interstitial lung disease (RP-ILD) was suspected. Treatment with pulse-dose methylprednisolone and tacrolimus led to significant clinical improvement, with HRCT showing resolution of the NSIP/OP findings on follow-up. This case highlights the importance of early diagnosis and multidisciplinary management in antisynthetase syndrome.