Case Presentation: A 36-year-old male presented to the emergency room with complaints of fever, exertional dyspnea, chest pain, and fatigue for two days. He describes his chest pain as sharp, substernal, and aggravated by lying down or inspiration. He denied any previous viral infection, cough, skin rashes, or joint involvement. He states that he has had two similar episodes in the past that have resolved after taking ibuprofen. On presentation, his vitals were blood pressure of 110/72 mmHg, heart rate of 94 bpm, respiratory rate of 20 cpm, saturating 96% on room air and a temperature of 101o F. Physical exam was unremarkable with normal lung sounds, no pericardial friction rub, no skin changes or lymphadenopathy. Labs including complete blood count, basic metabolic profile, and liver function tests were normal. He had an elevated ESR 69 mm/hr, and CRP 179 mg/L. Infective workups were negative for hepatitis viruses, Lyme, tuberculosis, syphilis, and COVID-19 and blood cultures showed no growth. Autoimmune workup revealed a borderline positive ANA titer of 1:80, a speckled pattern but the rest of the work up including complement levels, Anti-Smith antibody, Anti-Sm/RNP antibody, Anti-Ro (SS-A) antibody, Anti-La (SS-B) antibody, Anti ds DNA antibody were unremarkable. EKG showed no significant ST or T changes. The echocardiogram showed moderate pericardial effusion and the CTA chest showed a similar picture with small bilateral pleural effusions. Pericarditis was thought of considering the symptom profile and elevated inflammatory markers. He was started on colchicine 0.5 mg daily (after a loading dose) for three months and ibuprofen 800mg every 8 hours for 2 weeks along with exercise restriction. His inflammatory markers normalized in 10 days. However, within a week of discontinuation of colchicine, his symptoms recurred. Given the recurrence- the diagnosis of idiopathic recurrent pericarditis was thought of and the decision to start anakinra was made. The patient is currently awaiting insurance authorization for anakinra and remains symptom-free on colchicine.

Discussion: Idiopathic recurrent pericarditis (IRP) is a disease that carries significant morbidity, partly driven by corticosteroid or NSAID dependence (1). Pathogenesis includes an auto-inflammatory disease caused by dysregulated production of the pro-inflammatory cytokines IL-1α/β (2). There is a striking clinical resemblance of IRP with autoinflammatory diseases with features of symptomatic serositis, high fevers, and increased inflammatory parameters (3). This is where IL-1 inhibitors like Anakinra play a role in the management of IRP.

Conclusions: Idiopathic recurrent pericarditis (IRP) is a poorly understood sequela of acute pericarditis that impacts significantly on the quality of life. The management remains challenging, with no US guidelines currently in place to aid clinicians. Therefore, with this case report, we aim to raise awareness about the use of IL-1 inhibitors in IRP, especially when conventional therapy with NSAIDs, colchicine, and steroids fails.