Multisystem inflammatory syndrome in adults: A systematic review and meta-analysis of the rheumatological spectrum of complications post COVID-19 infection

Multisystem inflammatory syndrome in adults (MIS-A) is a rare but severe complication in adults infected with SARS-CoV-2. However, the pathophysiology remains elusive, as the limited number of reports preclude a broader understanding of this syndrome. We conducted this systematic review to explore the clinical spectrum of MIS-A, in particular its rheumatological manifestations. Meta-analyses of case-series were also performed. We identified 28 patients from 14 case reports and two case series of MIS-A. This disease occurred equally in both genders, with a mean age of 33+10 years old, and predominantly in those of African descent (40%). Rheumatological manifestations consisted of Kawasaki Disease (KD)-like symptoms. Ninety percent of patients had positive COVID-19 serology tests, while 48% of patients were negative for COVID-19 RT-PCR test. Twelve patients were admitted to ICU and unfortunately two died. Although the signs and symptoms of MIS mimicked KD, the gastro-intestinal findings were more prominent in the former group. The demographic make-up was also different, with MIS-A occurring mostly in those of African descent. Importantly, unlike their paediatric counterparts, the adult group did not have coronary artery abnormalities. Long-term monitoring is needed as safety data is scarce. Of note, although the prognosis of MIS-A is excellent, the life-threatening nature of this syndrome demands intensive care unit level of care and mechanical support. During the COVID-19 pandemic, a constellation of KD symptoms in an adult patient should alert the clinician to the possibility of MIS-A. Resumen El espectro clinico del sindrome inflamatorio multisistemico en adultos (MIS-A) es una complicacion rara pero grave en adultos infectados con SARS- CoV-2. Realizamos una busqueda bibliografica en varias bases de datos, tambien se hicieron metanalisis. Identificamos 28 pacientes de 14 informes de casos y dos series de casos de MIS-A. Esta enfermedad se presento por igual en ambos sexos, con una edad media de 33 + 10 anos, y se presento predominantemente en afrodescendientes (40%). Las manifestaciones reumatologicas consistieron en sintomas similares a la enfermedad de Kawasaki (KD). El 90% de los pacientes tuvo pruebas positivas de serologia de COVID-19, mientras que el 48% dio negativo para la prueba de RT-PCR de COVID-19. Doce pacientes ingresaron en UCI y, lamentablemente, dos fallecieron. Encontramos que, si bien, los signos y los sintomas de MIS imitaban a KD, los hallazgos gastrointestinales eran mas prominentes en el primer grupo. Ademas, la composicion demografica fue asimismo diferente, con MIS-A que se presento principalmente en afrodescendientes. Es importante destacar que, a diferencia de sus homologos pediatricos, el grupo de los adultos no experimento anomalias en las arterias coronarias. Se necesita un seguimiento a largo plazo, ya que los datos de seguridad son escasos. Es de destacar que, aun cuando el pronostico de MIS-A es excelente, la naturaleza potencialmente mortal de este sindrome exige el nivel de atencion y el soporte mecanico de la unidad de cuidados intensivos. Durante la pandemia de COVID-19, una constelacion de sintomas de EK en un paciente adulto debe alertar al medico sobre la posibilidad de MIS-A.