This case series describes clinical and laboratory characteristics of 58 critically ill children who developed an inflammatory multisystem syndrome during the coronavirus disease 2019 pandemic.

All patients were admitted to one of 8 hospitals in England between March 23 and May 16, 2020, with persistent fever and laboratory evidence of inflammation meeting published definitions for pediatric inflammatory multisystem syndrome temporally associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PIMS-TS). Clinical and laboratory characteristics were abstracted by medical record review, and were compared with clinical characteristics of patients with Kawasaki disease (KD) (n = 1132), KD shock syndrome (n = 45), and toxic shock syndrome (n = 37) who had been admitted to hospitals in Europe and the US from 2002 to 2019.

The authors found a wide spectrum of presenting signs and symptoms and disease severity, ranging from fever and inflammation to myocardial injury, shock, and development of coronary artery aneurysms. Of the 58 children who met criteria for PIMS-TS:

• The median age was 9 years [IQR 5.7-14]
• 33 were girls [57%]
• 15 (26%) had positive results from SARS-CoV-2 polymerase chain reaction tests
• 40 of 46 (87%) had positive SARS-CoV-2 IgG test results
• 45 of 58 (78%) had evidence of current or prior SARS-CoV-2 infection
• All children presented with fever and nonspecific symptoms, including vomiting (26/58 [45%]), abdominal pain (31/58 [53%]), and diarrhea (30/58 [52%])
• Rash was present in 30 of 58 (52%), and conjunctival injection in 26 of 58 (45%) cases.
• Laboratory evaluation was consistent with marked inflammation, for example, C-reactive protein (229 mg/L [IQR, 156-338], assessed in 58 of 58) and ferritin (610 μg/L [IQR, 359-1280], assessed in 53 of 58)
• 29 developed shock (with biochemical evidence of myocardial dysfunction) and required inotropic support and fluid resuscitation (including 23/29 [79%] who received mechanical ventilation)
• 13 met the American Heart Association definition of KD
• 23 had fever and inflammation without features of shock or KD
• 8 (14%) developed coronary artery dilatation or aneurysm

Comparison of PIMS-TS with KD and with KD shock syndrome showed differences in clinical and laboratory features, including older age (median age, 9 years [IQR, 5.7-14] vs 2.7 years [IQR, 1.4-4.7] and 3.8 years [IQR, 0.2-18], respectively), and greater elevation of inflammatory markers such as C-reactive protein (median, 229 mg/L [IQR 156-338] vs 67 mg/L [IQR, 40-150 mg/L] and 193 mg/L [IQR, 83-237], respectively).