Persistent Pancytopenia as a Long-COVID Manifestation in a Patient with Adult-Onset Still's Disease: A Case Report.

Background: Adult-onset Still's disease (AOSD) is a rare rheumatic inflammatory condition with an extremely heterogeneous clinical presentation and systemic impairment. Uncommon manifestations may be challenging to manage, especially in patients with previous severe acute SARS-CoV-2 infection. For the first time, we report the case of a patient affected by refractory AOSD presenting with severe pancytopenia as a long-COVID manifestation. The purpose of this case report is to illustrate the clinical presentation, diagnostic and therapeutic management of this unusual manifestation. Moreover, we examine the mechanisms that are potentially responsible for the onset of the pancytopenia observed in our patient. Case presentation: We describe the case of a 40-year-old male who presented with a history of fever for 2 years, arthralgia, maculopapular salmon-pink rash and a previous SARS-CoV-2 infection which required admission to intensive care. The patient's laboratory results revealed elevated inflammatory markers levels (erythrocyte sedimentation rate and C-reactive protein), hyperferritinemia and severe pancytopenia that needed multiple transfusions. A diagnosis of AOSD was made based on clinical and laboratory presentation after excluding neoplastic, infectious and other rheumatic diseases. The previous empirical treatment was not adequate to control the condition; therefore, treatment with high-dose steroids, canakinumab and epoetin alfa was started and led to the resolution of the man's symptoms and a reduction in inflammatory marker levels, whereas blood cell count remained stable without a need for further blood transfusions. The patient is currently under rheumatologic and hematologic follow-up every month. Conclusions: Neither AOSD nor SARS-CoV-2 infection usually manifests with pancytopenia, except in hemophagocytic syndrome or immunodeficient patients, respectively. Identifying the underlying etiology of pancytopenia is mandatory to establish a prompt treatment that generally resolves the disorder. However, in our case, all common causes of pancytopenia were excluded, suggesting a potential manifestation of the long-COVID syndrome. Despite the resolution of the acute infection and the remarkable treatment of AOSD, pancytopenia persists. Herein, we propose for refractory AOSD patients with previous SARS-CoV-2 infection a novel approach to the diagnosis and treatment of pancytopenia.