S100 Levels Guided Treatment Options in a Teenage Boy with Relapsing Pericarditis or Atypical Still and #8217;s Disease

Abstract

Abstract: Unraveling the etiology of recurrent pericarditis in children is often challenging. Here, we describe the case of a previously healthy, 15-year-old boy who presented with fever, cough and thoracic pain due to Pericarditis with a large pericardial effusion. After insertion of a pericardial drainage over 1600 ml of pericardial fluid were collected over a 48-hour period. Laboratory investigations revealed systemic inflammation and negative autoantibodies, but displayed no evidence of an infectious disease. Autoimmune pericarditis was therefore suspected and a combination of glucocorticosteroid and NSAID therapy was initiated. Steroids were able to be gradually tapered. However, the patient suffered a recurrence of pericarditis after six weeks of low-dose steroids and NSAIDs. As with the first episode, arthritis, rash, lymphadenopathy and hepatosplenomegaly were absent. Retrospective analysis of the serum from the initial episode showed significant elevation of S100 protein levels (S100A8/S100A9). As a result, we assumed an atypical presentation of Still´s disease (systemic onset juvenile idiopathic arthritis or SoJIA) and initiated therapy with anakinra, an interleukin-1-receptor antagonist. This treatment led to rapid improvement, and pericardiocentesis was able to be avoided. Four months after the relapse and subsequent initiation of anakinra therapy, no disease reoccurrence has transpired. Treatment with ibuprofen and steroids could be suspended. The patient developed mild arthritic signs during follow-up supporting the diagnosis of SoJIA. A potential differential diagnosis in this case is idiopathic recurrent acute pericarditis (IRAP), a disease of unknown etiology that shows features consistent with an autoinflammatory pathogenesis where recent reports indicated good clinical response to anakinra treatment as well. This case highlights the predictive value of S100 protein levels for the diagnosis of autoinflammatory disorders such as SoJIA - particularly when there is an atypical or oligosymptomatic presentation. Moreover, it illustrates the therapeutic potential of anakinra for autoimmune-mediated pericarditis.