Paediatric multisystem inflammatory syndrome
|Pediatric multi-system inflammatory syndrome (PMIS)|
|Other names||Multisystem inflammatory syndrome in children (MIS-C);|
multisystem inflammatory disorder in children and adolescents;
pediatric inflammatory multisystem syndrome (PIMS), temporally associated with SARS-CoV-2 infection (PIMS-TS)
Paediatric multisystem inflammatory syndrome (PMIS), or multisystem inflammatory syndrome in children (MIS-C), is a systemic disease involving persistent fever, inflammation and organ dysfunction following exposure to SARS-CoV-2, the virus responsible for COVID-19.
This syndrome resembles Kawasaki disease (a rare disease of unknown origin that affects young children, in which blood vessels become inflamed throughout the body). It can also appear similar to other serious paediatric inflammatory conditions, including toxic shock and macrophage activation syndromes. Failure of one or more organs can occur. Early recognition of this disease is essential, followed by prompt admission to hospital for specialist attention.
Low blood pressure is common. The first symptoms are sometimes acute abdominal pain, diarrhoea or vomiting. Other symptoms can include conjunctivitis, rashes, mucous membrane changes, enlarged lymph nodes, swollen hands and feet, sore throat, cough, fainting, irritability and confusion. Respiratory symptoms are not always present. Cardiological findings may include clinical features of myocarditis, pericarditis, valvulitis, or coronary artery abnormalities, including dilatation and aneurysms.
Oxygen therapy may be needed, and some children require paediatric intensive care. Limited information exists regarding clinical course of this life-threatening disease, which may occasionally be fatal.
- The World Health Organization (WHO) has published a preliminary case definition for diagnosis and tools for standard reporting of cases.
- The Royal College of Paediatrics and Child Health (RCPCH) has issued guidance on diagnosis and clinical management.
- The Centers for Disease Control and Prevention (CDC) has provided recommendations for diagnosis and reporting.
Although the condition is thought to follow SARS-CoV-2 viral infection, antigen or antibody tests are not always positive. Exclusion of other possible microbial (including bacterial) causes is always essential for differential diagnosis.
The biological mechanism of the disease is not known, and no risk factors are known either. The condition is considered rare. The European Centre for Disease Prevention and Control (ECDC) has rated risk to children in Europe as being 'low' overall, based on a 'very low' likelihood of a child developing this 'high impact' disease. So far, reports have regarded children in various parts of Europe and the U.S. It is unclear whether the condition has gone unrecognized elsewhere.
This is a newly-proposed clinical entity, and it has also been argued that cases meeting the criteria for Kawasaki disease or myocarditis should be diagnosed and treated as such.
Paediatric cases of COVID-19 have been relatively uncommon, possibly because children generally appear to display milder symptoms. While cases with severe symptoms are much rarer, they can occasionally require intensive care. Some children with evidence of SARS-CoV-2 infection or exposure to COVID-19 display clinical features corresponding to the diagnostic criteria of Kawasaki disease, sometimes accompanied by shock.
Kawasaki disease is a rare syndrome which mainly affects young children. It is a form of vasculitis, where blood vessels become inflamed throughout the body, and it results in a persistent fever. Recovery typically occurs spontaneously, though some children go on to develop mid-sized or giant coronary artery aneurysms in the heart – a potentially fatal complication. Symptoms of toxic shock occasionally occur – an association sometimes referred to as 'Kawasaki shock syndrome', which is characterized by systolic hypotension or signs of poor perfusion. While the cause of Kawasaki disease is unknown, one possible explanation is that it may stem from an infection triggering an autoimmune (or autoinflammatory) response in children who are genetically predisposed. No specific diagnostic test exists for Kawasaki disease, and its recognition is based on various combinations of clinical and laboratory findings (including persistent fever, widespread rashes, lymphadenopathy, conjunctivitis, and changes to the mucous membranes and extremities).
PMIS is a systemic inflammation, involving persistent fever, inflammation and organ dysfunction, which is suspected to be associated with COVID-19. The condition may match some or all of the diagnostic criteria for Kawasaki disease (i.e. the 'complete' or 'incomplete'/'atypical' subtypes). It can also share clinical features with other paediatric inflammatory conditions, including toxic shock syndrome, septic shock, and macrophage activation syndrome. Some children have a less severe Kawasaki-like disease.
Low blood pressure is common. The condition can present with unusual abdominal symptoms, accompanied by pronounced inflammatory markers. Acute gastrointestinal symptoms can include abdominal pain, and diarrhoea or vomiting. Other symptoms may include conjunctivitis, rashes, mucous membrane changes, enlarged lymph nodes, swollen hands and feet, sore throat, cough and respiratory symptoms, fainting, irritability and confusion. Cardiological findings may include clinical features of myocarditis, pericarditis, valvulitis, or coronary artery abnormalities, such as dilatation. Some patients have coronary artery aneurysms. Shock is often of myocardial origin. Respiratory symptoms are not always present. Breathing difficulties are often linked to shock.
Early recognition of the disease is essential, followed by prompt admission to hospital, with referral to specialists (in paediatric infectious diseases, cardiology, rheumatology, etc). Supplemental oxygen may be required, and paediatric intensive care may also be needed. Limited information currently exists regarding clinical course. Fatalities have been recorded (five, as of 11 May 2020).
Clinicians worldwide have been urged to consider this condition in children who display some or all the features of Kawasaki disease or toxic shock syndrome. Early recognition and specialist referral, including to critical care, is considered essential.
- The World Health Organization (WHO) has released a scientific brief on links between multisystem inflammatory syndrome and COVID-19. The brief, released on 15 May, 2020, includes a preliminary WHO case definition (for 'multisystem inflammatory disorder in children and adolescents'), based on currently available knowledge. The WHO has established a platform for standardized, anonymized clinical data, along with a dedicated case report form. The WHO underlines the "urgent need for collection of standardized data describing clinical presentations, severity, outcomes, and epidemiology."
- Diagnostic guidance originally published by the Royal College of Paediatrics and Child Health (RCPCH) on 1 May, 2020, proposes a case definition which has also been endorsed by an expert panel convened by the American College of Cardiology. 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. Key clinical criteria set out in the RCPHC case definition are: persistent fever, inflammation (indicated by neutrophilia, high C-reactive protein levels and low lymphocyte count), and evidence of single- / multi-organ dysfunction (shock; cardiac, respiratory, renal, gastrointestinal, or neurological disorder), coupled with other clinical, laboratory, imaging and ECG findings. Coronary artery abnormalities, such as dilatation, may be apparent at echocardiography and ECG (or contrast CT of the chest). Biomarkers supporting the diagnosis include abnormal fibrinogen levels, high D-dimers (possible coagulopathy), high troponin, low albumin, and high ferritin.
- The Centers for Disease Control and Prevention (CDC) has also published a case definition. The CDC definition (for MIS-C) comprises individuals
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. The CDC advises U.S. health providers to inform public health authorities of suspected cases.
"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 is essential to exclude other alternative microbial causes, including bacterial sepsis, staphylococcal and streptococcal shock, and infections associated with myocarditis, such as enterovirus. (Of note, coinfection with additional pathogens, such as human metapneumovirus, may sometimes occur.)
The RCPHC has provided guidance on clinical management and treatment.
Little specific information is available regarding therapeutic effectiveness. Anti-inflammatory treatments have been used, including intravenous immunoglobulin and corticosteroids. RCPCH guidance recommends that all affected children should be treated as having suspected COVID-19, and that for mild or moderate disease supportive care alone may be sufficient.
The RCPHC recommends that any administration of a candidate antiviral therapy should − whenever possible − be performed in the context of a registered clinical trial (e.g. the RECOVERY study). In the U.K., ongoing collaborations are aiming to ensure that all infected children are able to take part in a mechanistic study such as DIAMONDS or ISARIC-CCP. (In the European Union, children do not usually participate in clinical trials of new antiviral and monoclonal antibody treatments for severe COVID-19.)
Treatment strategies are being considered to prevent serious long-term complications such as coronary artery aneurysms (the main complication of Kawasaki disease).
Based on laboratory findings, it has been hypothesized that the condition may be related to COVID-19. Further characterization of the syndrome is essential to identify risk factors and help understand causality. Improved understanding will have potential implications for clinical management.
It has been emphasized that the potential link of this rare condition with COVID-19 "is neither established nor well understood." A temporal association between SARS-CoV-2 infection and clinical presentation of the syndrome is plausible. A causality assessment found that 'temporality' was among the five (out of nine) Bradford Hill criteria that supported a causal relationship between SARS-CoV-2 infection and the development of the syndrome.
The pathogenesis is unknown. It has been suggested that, as with Kawasaki disease, one possible mechanism is antibody-dependent enhancement, whereby development of antibodies facilitates viral entry into host cells. It has also been suggested that the condition may be caused by the cytokine storms induced by COVID-19. It has been noted that a leading hypothesis for the pathogenesis of Kawasaki disease also involves a hyperinflammatory response to viral infection in some genetically predisposed children.
On pathophysiological grounds, it has been argued that association of Kawasaki disease with COVID-19 may support the view that SARS-CoV-2 can cause a systemic vasculitis by targeting endothelial tissue via angiotensin-converting enzyme 2 (ACE2), the protein which the virus uses to gain access to cells.
Epidemiological information is scarce. Suspected cases began to be recorded in Europe and the U.S. around April 2020, and several hundred possible cases were recorded by mid-May, along with at least five fatalities.
Clinicians in Bergamo (Italy) reported an apparent 30-fold increase in the incidence of "Kawasaki-like disease" during the first six weeks after the arrival there of SARS-CoV-2 virus infection (at a time when Bergamo was experiencing the highest rates of infections and deaths in the country).
This emerging diagnosis is considered rare. A rapid risk assessment conducted by the European Centre for Disease Prevention and Control (ECDC) concluded that the overall risk to children in the European Union, European Economic Area and the U.K. "is considered 'low', based on a 'very low' probability of [the disease] in children and a 'high' impact of such disease."
Regarding geographical distribution, it is unclear whether currently available reports of cases in Europe and North America reflect a true pattern, or whether the condition has gone unrecognized elsewhere.
This is a newly-proposed clinical entity, and it has also been argued that cases meeting the criteria for Kawasaki disease or myocarditis should be diagnosed and treated as such.
Cases of Kawasaki disease with concurrent SARS-CoV-2 infection have been recorded among children in Europe and the U.S.A. since 7 April 2020, when a report was published by the American Academy of Pediatrics regarding a case of 'classic' Kawasaki disease in a six-month old girl who tested positive for COVID-19. In this case, COVID-19 did not appear to have significant clinical implications.
On 25 April, concerns were initially raised in the U.K. regarding a cluster of children of various ages presenting with a multisystem inflammatory state who required intensive care, and who all displayed "overlapping features of toxic shock syndrome and atypical Kawasaki disease with blood parameters consistent with severe COVID-19 in children." Details of the eight cases which helped trigger this alert (not all with confirmed exposure to COVID-19) were later reported in The Lancet, where the authors summarized the clinical picture as "a hyperinflammatory syndrome with multiorgan involvement similar to Kawasaki disease shock syndrome."
Accounts of analogous cases – including some that appeared less clinically severe – were also being informally shared among clinicians around Europe. In Bergamo, at the heart of the COVID-19 epidemic in Lombardy, a cluster of 20 cases of Kawasaki disease appeared to be roughly equivalent to the number commonly recorded there over the course of three years. In France, the government reported on 29 April that around 15 children were in hospital in Paris with symptoms of Kawasaki disease.
On 1 May, the RCPCH published a preliminary case definition based on review of the characteristics of the cases identified in the U.K., accompanied by some clinical guidance. Two weeks later, on 15 May, two further preliminary case definitions were published separately by the WHO and by the CDC, while the ECDC released a 'rapid risk assessment' of the condition on behalf of the European Union.
On 4 May, the New York City Department of Health and Mental Hygiene issued an alert to identify children with the condition in New York City hospitals, where 15 such cases were already being treated.
By mid-May, several hundred potential cases were being investigated in areas affected by COVID-19 across Europe and the U.S.A. (including 200 or more across the United States, with some 145 in New York, as well as up to 100 in UK, over 135 in France, 20 in the Netherlands,  10 in Switzerland, and 10 in Germany). As of 11 May 2020, five fatalities were reported (1 in France, 1 in the UK, 3 in the US).
- Guidance - Paediatric multisystem inflammatory syndrome temporally associated with COVID-19 (PDF), The Royal College of Paediatrics and Child Health, May 2020
- "Multisystem Inflammatory Syndrome in Children (MIS-C) Associated with Coronavirus Disease 2019 (COVID-19)". emergency.cdc.gov. Centers for Disease Control and Prevention. 15 May 2020. Retrieved 15 May 2020.
- "Multisystem inflammatory syndrome in children and adolescents with COVID-19: Scientific brief". www.who.int. World Health Organization. Archived from the original on 15 May 2020.
- "Rapid risk assessment: Paediatric inflammatory multisystem syndrome and SARS-CoV-2 infection in children". European Centre for Disease Prevention and Control. 15 May 2020. Archived from the original (PDF) on 15 May 2020.
- "Kawasaki Disease". PubMed Health. NHLBI Health Topics. 11 June 2014. Archived from the original on 11 September 2017. Retrieved 26 August 2016.
- Loomba RS, Villarreal E, Flores S (2020). "Covid-19 and Kawasaki syndrome: should we really be surprised?" (PDF). Cardiology in the Young: 1–5. doi:10.1017/S1047951120001432. PMID 32412400.
- Viner RM, Whittaker E (2020). "Kawasaki-like disease: emerging complication during the COVID-19 pandemic". The Lancet. doi:10.1016/S0140-6736(20)31129-6. PMID 32410759.
- Dietz SM, van Stijn D, Burgner D, et al. (2017). "Dissecting Kawasaki disease: a state-of-the-art review". European Journal of Pediatrics. 176 (8): 995–1009. doi:10.1007/s00431-017-2937-5. PMC 5511310. PMID 28656474.
- Brogan P, Burns JC, Cornish J, et al. (2020). "Lifetime cardiovascular management of patients with previous Kawasaki disease". Heart. 106 (6): 411–420. doi:10.1136/heartjnl-2019-315925. PMC 7057818. PMID 31843876.
- Taddio A, Rossi ED, Monasta L, Pastore S, Tommasini A, Lepore L, Bronzetti G, Marrani E, Mottolese BD, Simonini G, Cimaz R, Ventura A (2017). "Describing Kawasaki shock syndrome: results from a retrospective study and literature review". Clinical Rheumatology. 36 (1): 223–228. doi:10.1007/s10067-016-3316-8. PMID 27230223.
- Marrani E, Burns JC, Cimaz R (2018). "How Should We Classify Kawasaki Disease?". Frontiers in Immunology. 9. doi:10.3389/fimmu.2018.02974. PMC 6302019. PMID 30619331.
- McCrindle BW, Rowley AH, Newburger JW, et al. (2017). "Diagnosis, Treatment, and Long-Term Management of Kawasaki Disease: A Scientific Statement for Health Professionals From the American Heart Association". Circulation. 135 (17): e927–e999. doi:10.1161/CIR.0000000000000484. PMID 28356445.
- Dallan C, Romano F, Siebert JN, et al. (2020). "Septic shock presentation in adolescents with COVID-19". The Lancet Child & Adolescent Health. doi:10.1016/S2352-4642(20)30164-4.
- Newburger, JW (15 May 2020). "Pediatric Hyperinflammatory Syndrome and COVID-19: Statement and Recommendations From a Pediatric Intensive Care International Collaborative Conference Call". www.acc.org. American College of Cardiology. Archived from the original on 19 May 2020.
- Belhadjer Z, Méot M, Bajolle F, et al. (2020). "Acute heart failure in multisystem inflammatory syndrome in children (MIS-C) in the context of global SARS-CoV-2 pandemic". Circulation. doi:10.1161/CIRCULATIONAHA.120.048360. PMID 32418446.
- Schroeder AR, Wilson KM, Ralston SL (2020). "COVID-19 and Kawasaki Disease: Finding the Signal in the Noise" (PDF). Hospital Pediatrics. doi:10.1542/hpeds.2020-000356. PMID 32404331.
- Alunno A, Carubbi F, Rodríguez-Carrio J (2020). "Storm, typhoon, cyclone or hurricane in patients with COVID-19? Beware of the same storm that has a different origin". RMD Open. 6 (1). doi:10.1136/rmdopen-2020-001295. PMID 32423970.
- Sardu C, Gambardella J, Morelli MB, et al. (2020). "Hypertension, Thrombosis, Kidney Failure, and Diabetes: Is COVID-19 an Endothelial Disease? A Comprehensive Evaluation of Clinical and Basic Evidence". Journal of Clinical Medicine. 9 (5). doi:10.3390/jcm9051417. PMID 32403217.
- Riphagen S, Gomez X, Gonzalez-Martinez C, Wilkinson N, Theocharis P (7 May 2020). "Hyperinflammatory shock in children during COVID-19 pandemic". The Lancet. doi:10.1016/S0140-6736(20)31094-1. PMC 7204765. PMID 32386565.
During a period of 10 days in mid-April, 2020, we noted an unprecedented cluster of eight children with hyperinflammatory shock, showing features similar to atypical Kawasaki disease, Kawasaki disease shock syndrome, or toxic shock syndrome (typical number is one or two children per week). This case cluster formed the basis of a national alert.
- Edwards, Erika (7 May 2020). "At least 85 kids across U.S." NBC News. Retrieved 10 May 2020.
- Verdoni L, Mazza A, Gervasoni A, Martelli L, Ruggeri M, Ciuffreda M, Bonanomi E, D'Antiga L (2020). "An outbreak of severe Kawasaki-like disease at the Italian epicentre of the SARS-CoV-2 epidemic: an observational cohort study". The Lancet. doi:10.1016/S0140-6736(20)31103-X. PMC 7220177. PMID 32410760.
- Jones VG, Mills M, Suarez D, et al. (2020). "COVID-19 and Kawasaki Disease: Novel Virus and Novel Case" (PDF). Hospital Pediatrics. PMID 32265235.
- Mahase E (2020). "Covid-19: concerns grow over inflammatory syndrome emerging in children". BMJ. 369: m1710. doi:10.1136/bmj.m1710. PMID 32345602.
The alert, which relayed information from NHS England, said, 'It has been reported that over the past three weeks there has been an apparent rise in the number of children of all ages presenting with a multisystem inflammatory state requiring intensive care across London and other regions of the UK.'
- "Rising cases of kids with Kawasaki disease possibly linked to coronavirus". Kyodo News. 30 April 2020. Archived from the original on 30 April 2020.
- Daskalakis, DC (4 May 2020). "2020 Health Alert #13: Pediatric Multi-System Inflammatory Syndrome Potentially Associated with COVID-19" (PDF). NYC Health. Archived from the original (PDF) on 6 May 2020.
- "With over 200 possible cases, doctors warn reports of rare, coronavirus-linked child inflammatory illness likely to rise". ABC News. 15 May 2020. Retrieved 16 May 2020.
- McNamara, Audrey (13 May 2020). "15 states now investigating child illness possibly linked to coronavirus, Cuomo says". www.cbsnews.com. Retrieved 14 May 2020.
- Marsh, Julia; Musumeci, Natalie (18 May 2020). "145 NYC kids have rare Kawasaki-like disease linked to coronavirus". New York Post. Retrieved 19 May 2020.
- "Coronavirus: Children affected by rare Kawasaki-like disease". BBC News. 14 May 2020. Retrieved 24 May 2020.
- d'Adhémar, Margaux (15 May 2020). "Coronavirus : 135 enfants français atteints d'une forme proche de la maladie de Kawasaki, un mort". Le Figaro.fr (in French). Retrieved 16 May 2020.
- "COVID-19 Fragen und Antworten Teil 11". Paediatrica (in German). 12 May 2020. Retrieved 16 May 2020.
- Irmer, Juliette (15 May 2020). "„Kawasaki" durch Covid-19?: Auch deutsche Kinder mit schweren Entzündungsreaktionen". Faz.net (in German). Retrieved 16 May 2020.