COVID-19 and multisystem inflammatory syndrome in children: Case

This school-age child has the signature presentation of multisystem inflammatory syndrome in children: persistent fever with multiorgan involvement, shock, and a SARS-CoV-2 exposure three weeks earlier. The negative nasopharyngeal polymerase chain reaction is expected because the syndrome is post-infectious, and her immunoglobulin G serology will be positive. Her elevated troponic and her shock place cardiac involvement at the centre of management, and the echocardiogram is the pivotal next investigation. ^[1]

Clinical findings

The key findings are the persistent fever with multiorgan involvement, the shock with delayed capillary refill and hypotension, the mucocutaneous features of conjunctivitis and red cracked lips, and the elevated troponic signalling cardiac involvement. The markedly raised C-reactive protein and ferritin confirm severe inflammation. The differential is bacterial sepsis, Kawasaki disease with coronary involvement, toxic shock syndrome, and a surgical abdomen given the abdominal pain, but the temporal relationship to a household COVID-19 illness two to six weeks earlier and the multiorgan pattern make multisystem inflammatory syndrome the working diagnosis. ^[1]

The echocardiogram is mandatory and assesses left and right ventricular function, valve regurgitation, pericardial effusion, and the coronary arteries with Z-scores. In a cardiac-dominant phenotype the combination of depressed left ventricular function and coronary arteritis drives management, and the finding of a coronary aneurysm would add therapeutic anticoagulation to the plan. The inflammatory and coagulation panel confirms a markedly raised D-dimer consistent with the prothrombotic state. ^[2]