According to the RCPCH definition, the child may test positive or negative for SARS-CoV-2, but other possible microbial causes need to be excluded. The CDC case definition for MIS-C comprises individuals "aged <21 years presenting with fever, laboratory evidence of inflammation, and evidence of clinically severe illness requiring hospitalization, with multisystem (>2) organ involvement (cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic or neurological)." It also requires that there should either be a positive antigen/antibody SARS-CoV-2 test or COVID-19 exposure in the 4 weeks before onset of symptoms, along with exclusion of other plausible diagnoses. This case definition is quite broad (it overlaps not only with Kawasaki disease, but also with juvenile rheumatoid arthritis, and various infectious/inflammatory conditions of childhood, including other viral diseases), but not as broad as the RCPCH definition. The CDC advises health providers in the United States to inform their public health authorities of suspected cases, even if they also meet full or partial criteria for Kawasaki disease, and to consider MIS-C after any childhood fatality in which there is evidence of SARS-CoV-2 infection.Further case definitions have been formulated by the British Paediatric Surveillance Unit (BPSU) and the Canadian Paediatric Surveillance Program (CPSP). Some provisional diagnostic guidance has been provided by both the American College of Rheumatology and the American Academy of Pediatrics. In the UK, consensus has been reached for diagnostic investigation of children with suspected PIMS-TS. A clinical pathway for diagnostic evaluation of suspected MIS-C has also been proposed by the Childrens Hospital of Philadelphia.
Spanish flu or Spanish influenza, also known as purulent bronchitis, may refer to:

the 1918 flu pandemic where 500 million people worldwide were infected with H1N1 influenza A virus between 1918 and 1920, killing from 20 to 100 million people
the Influenza A virus subtype H1N1 which caused the influenza pandemic between 1918 and 1920, as well as the 2009 swine flu pandemic and 1977 Russian flu pandemic

See also

Flu (disambiguation)
Influenzavirus, the viruses that cause influenza disease
Influenza pandemic, "the influenza" global mass disease for a given year