During the COVID 19 pandemic a new childhood inflammatory disorder has emerged with several different clinical presentations such as features of Kawasaki’s disease, toxic shock syndrome, acute abdominal conditions, and encephalopathy, along with other reports of children with fever, raised inflammatory markers and multisystem involvement.

What is Multisystem Inflammatory Syndrome in children (MIS~C)

MIS~C occurs 2 to 4 weeks after infection with SARS-CoV-2. The disorder is uncommon (2 in 100, 000 persons <21 years of age) as compared with SARS~CoV-2 infection diagnosed in persons younger than 21 years of age over the same period (322 in 100, 000).

Most patients with MIS~C have antibodies against SARS~CoV-2 and virus is detected in a smaller proportion. A relatively high proportion of cases have occurred among black, Hispanic, or South Asian persons. Currently, there are approximately 1000 cases of MIS~C reported worldwide.

Clinical condition of the patients

Critical illness leading to intensive care develops in some patients, with prominent cardiac involvement and coronary artery aneurysms in 10 to 20%. Elevated levels of troponin and B type natriuretic peptide are common in severely affected patients, especially those with cardiac dysfunction, and most have elevations in levels of C-reactive protein, ferritin, lactate dehydrogenase, and D-dimers, as well as in neutrophil counts. Anaemia, lymphopenia, hypoalbuminemia, and abnormal coagulation indexes are also common.

Differential diagnosis of MIS~C

Direct comparison of the clinical and laboratory features of MIS~C with those of Kawasaki’s disease shows that the new disorder is different from the latter. Patients with MIS~C are older and have more severe inflammation and greater myocardial injury than patients with Kawasaki’s disease, and racial and ethnic predominance differs between the conditions.

Management and patient recovery

Most patients have recovered with intensive care support and after treatment with a range of immunomodulatory agents such as immunoglobulin, glucocorticoids, anti-tumour necrosis factor, and interleukin-1 or 6 inhibitors. Some patients have been given extracorporeal membrane oxygenation support, and almost 2 to 4% patients have died.

Challenges in management

Clinicians face difficult management issues as they are coming across a wide spectrum of patients. Several issues that need to be considered during the management include treatments that may prevent progression to shock and multiorgan failure, will treatment prevent coronary-artery aneurysms, are children with self-resolving inflammation at risk for aneurysms, and what cardiac follow-up is needed? An understanding of its pathophysiological mechanisms, to develop diagnostics, and to define the best treatment are needed to establish the appropriate therapy.

Resources

1. Levin M. Childhood multisystem inflammatory syndrome-A new challenge in the pandemic. The New England Journal of Medicine. June 29, 2020. DOI: 10.1056/NEJMe2023158.