We presented a boy with COVID-19 who presented first with acute abdomen features mimicking appendicitis. His fever continued after appendectomy and manifestations including maculopapular rashes, edema of hands and feet, arthritis, punctate erythema, splenomegaly, and increased level of acute-phase reactants were added. The patient was treated with the impression of Kawasaki-like syndrome which was less known at that time. He was resistant to IVIG, therefore he received the second dose of IVIG plus a single dose of IVMP pulse and ASA. With continuing the high-spiky-fever, splenomegaly, and the presence of polyarthritis, salmon-pink patches, and Kobner's phenomenon the final diagnosis was systemic JIA. So, the patient was treated with medications such as three consecutive days of IVMP pulses ( and then oral prednisolone 2 mg/kg/ day), Methotrexate, and Naproxen. His condition improved by time and after 3 months of follow-up, the disease is in remission.
COVID-19 can mimic some aspects of rheumatic diseases. ( Table-1) Furthermore, several hyperinflammatory conditions have been reported in COVID-19 patients. The term pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS) or multisystem inflammatory syndrome in children (MIS-C) was formulated for some aspects of this condition (6).Today, there are increasing reports of this disease from a different area of the world. The patients can be presented with features of complete Kawasaki disease (KD), incomplete KD, atypical KD, KD shock syndrome (KDSS), or multi-organ inflammatory syndrome. There are various clinical presentations: refractory toxic shock syndrome with normal cardiac function, septic and/or cardiogenic shock resembling KD shock syndrome, KD feature, macrophage activation syndrome (MAS), and some with a combination of the above-mentioned features.
Currently, the World Health Organization (WHO) and the US CDC have proposed different and some similar case definition for MIS-C which have shown in table-2 (7, 8, 9): (Table-3)
Verdoni and colleagues reported a 30-fold increased incidence of Kawasaki-like disease from Italy. In contrast with patients before the COVID-19 pandemic disease, these children were older and showed a higher rate of cardiac involvement and features of MAS (3).The cardiac involvement was in the setting of myocarditis, pericardial effusion, and coronary artery involvement. The increasing cases from the USA and European areas are reported (10). It is not yet clear the full spectrum of disease, and whether the geographical distribution in Europe and North America (in contrast to low reported cases from the traditionallyendemic area including North-east Asia) reflects a true pattern, or if the condition has simply not been recognized elsewhere.
Our patient had some manifestations compatible with Kawasaki-like syndrome such as prolonged fever, polymorphous rashes, arthritis, edema of the distal part of the extremities, and elevated acute-phase proteins. Furthermore, he had some features which has been reported in KD-like syndrome and not in classic KD such as splenomegaly, persistent fever, arthritis, and rashes, history of oral ulcer, elevated IL-6, D-dimer, and LDH and decreased fibrinogen.Also, he fulfilled both CDC and WHO criteria for MIS-C which had not been recognized at that time. Eventually, the course of the hyperinflammatory phase of the disease led to a picture named as systemic JIA. To the best of our knowledge, there have been no reports of systemic JIA following COVID-19 in the literature.
Systemic JIA could be triggered with several infectious agents such as viral infections. COVID-19 has been reported to induce imbalance in the immunity system and hyperinflammation. We reported the first systemic JIA patient after COVID-19 in children.