COVID-19 and Adult-onset Still’s Disease as part of Hyperferritinemic Syndromes

Abstract

The coronavirus disease (COVID-19) is known to cause hyperferritinemia and hemophagocytic lymphohistiocytosis (HLH). Including this laboratory parameter, clinical symptoms similar to COVID-19 have been observed in adult-onset Still’s disease (AOSD), catastrophic antiphospholipid syndrome (CAPS), macrophage activation syndrome (MAS), and septic shock, which has led to the proposal of a concept called ‘hyperferritinemic syndromes.’ Additionally, high levels of some clinical markers in both COVID-19 and AOSD make them difficult to differentiate. While the efficacy of ciclesonide had been expected for mild pneumonia with COVID-19, the efficacy of tocilizumab, which is a known treatment for AOSD, was not established. Here, we report the first known occurrence of COVID-19, diagnosed in March 2020, preceded by the diagnosis of AOSD, in April 2019, in a 65-year-old, otherwise healthy man. Following the diagnosis of the latter, the patient was first given prednisolone and then tocilizumab, which led to remission. With the recurrence of joint pain and rash in March 2020, accompanied by low oxygen saturation levels (90%), and ground-glass appearance on chest CT, PCR test revealed COVID-19 infection. Ciclesonide was started on day 7 of the disease onset, which led to improved inflammatory markers by day 21. Thus, we infer that while tocilizumab is theoretically useful for COVID-19 due to its inhibition of interleukin 6 (IL-6), additional ciclesonide therapy might be required to prevent worsening of the condition. AOSD and COVID-19 must, therefore, be differentiated by levels of ferritin which differ between the two, and appropriate treatment must be allocated.