Table 1.

Case definitions of hyper-inflammatory syndromes associated with SARS-CoV-2

Parameter	World Health Organization [16]	Centers for Disease Control and Prevention (United States) [15]	Royal College of Paediatrics and Child Health (UK) [17]
Terminology	Multisystem inflammatory disorder in children and adolescents	Multisystem inflammatory syndrome in children (MIS-C)	Pediatric inflammatory multisystem syndrome temporally associated with SARS-CoV-2 (PIMS-TS)
Age	0–19 years	0–21 years	Pediatric age group
Clinical case definition	Fever and 2 of the following: (i) Rash or bilateral non-purulent conjunctivitis or mucocutaneous signs (oral, hands or feet) (ii) Hypotension or shock (iii) Features of myocardial dysfunction, pericarditis, valvulitis, or coronary abnormalities (including echocardiography findings or elevated Troponin/NT-pro-BNP) (iv) Evidence of coagulopathy (by PT, PTT, elevated d-dimers) (v) Acute gastrointestinal problems (diarrhea, vomiting, or abdominal pain)	Fever for at least 24 h ≥ 38.0 °C and (i) Severe illness necessitating hospitalization (ii) 2 or more organ systems affected (e.g., cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic, and neurological)	Persistent fever and evidence of single or multiorgan dysfunction (shock, cardiac, respiratory, renal, gastrointestinal or neurological disorder) with additional features, which may include children fulfilling full or partial criteria for Kawasaki disease
Laboratory criteria of inflammation	Elevated ESR, CRP, or procalcitonin	Including, but not limited to, one or more of the following: an elevated CRP, ESR, fibrinogen, procalcitonin, d-dimer, ferritin, LDH, or IL-6, neutrophilia, lymphopenia, and low albumin	Neutrophilia, elevated CRP and lymphopenia
Evidence of SARS-CoV-2 infection	Evidence of COVID-19 infection (RT-PCR, antigen test or serology positive), or likely contact with patients with COVID-19	Positive for current or recent SARS-CoV-2 infection by RT-PCR, serology, or antigen test; or COVID-19 exposure within the 4 weeks prior to onset of symptoms	SARS-CoV-2 PCR testing may be positive or negative

CRP C-reactive protein, ESR erythrocyte sedimentation rate, IL Interlukin: LDH lactate dehydrogenase, RT-PCR reverse transcription-polymerase chain reaction

Definitions have been proposed by World Health Organization [16], Centers for Disease Control and Prevention [15] and Royal College of Paediatrics and Child Health [17]