To conduct a systematic review and meta‐analysis to characterize inflammatory markers in comparisons of multisystem inflammatory syndrome in children (MIS‐C) versus severe/non‐severe COVID‐19, severe MIS‐C versus non‐severe MIS‐C, and among age groups of MIS‐C. Nine databases were searched for studies on inflammatory markers of MIS‐C. After quality checks, data were pooled using a fixed or random effects model. Inflammatory markers included white blood cell count (WBC) or leukocytes, absolute lymphocyte count (ALC), absolute neutrophil count (ANC), platelet count (PLT), C‐reactive protein (CRP), procalcitonin (PCT), ferritin, D‐dimer, lactate dehydrogenase (LDH), fibrinogen, and erythrocyte sedimentation rate (ESR) for comparisons by severity and age. Twenty‐one studies with 1735 participants yielded 787 MIS‐C patients. Compared to non‐severe COVID‐19 patients, MIS‐C patients had lower ALC and higher ANC, CRP, and D‐dimer levels. Compared to severe COVID‐19 patients, MIS‐C patients had lower LDH and PLT counts and higher ESR levels. Severe MIS‐C patients had higher levels of WBC, ANC, CRP, D‐dimer, and ferritin than non‐severe MIS‐C patients. For MIS‐C, younger children (0–5 years) had lower CRP and ferritin levels than middle‐aged/older children/adolescents. Measurement of inflammatory markers might assist clinicians in accurate evaluation and diagnosis of MIS‐C and the associated disorders.

Limited literature exists on Cerebrospinal fluid (CSF) findings in COVID-19 patients with neurological symptoms. In this review, we conducted a descriptive analysis of CSF findings in patients with COVID-19 to understand prognosis and explore therapeutic options. We searched PubMed, Google Scholar, and Scopus databases using the keywords "SARS-CoV-2 in cerebrospinal fluid" and "SARS-CoV-2 and CNS Complications" for reports of CSF findings in COVID-19 related neurological manifestations. Descriptive analyses were conducted to observe the CSF protein and cell counts based on age, gender, severity, fatality of COVID-19, and whether central (CNS) or peripheral nervous system (PNS) was associated. A total of 113 patients were identified from 67 studies. Of these, 7 patients (6.2%) were fatal COVID-19 cases and 35 patients (31%) were considered severe COVID-19 cases. CSF protein was elevated in 100% (7/7) of the fatal cases with an average of 61.28 mg/dl and in 65.0% (52/80) in non-fatal cases with an average 56.73 mg/dl. CSF protein levels were elevated in 74.5% (38/51) patients with non-severe COVID-19 and 68.6% (24/35) in those with a severe COVID-19 infection. CSF cell count was increased in 43% of fatal cases, 25.7% severe cases, and 29.4% of non-severe cases. Our analysis showed that the most common CSF findings situation in COVID-19 infection is elevated protein with, very occasionally, mild lymphocyte predominant pleocytosis. Further studies to elucidate the pathophysiology of neurological complications in COVID-19 are recommended.