Multisystem Inflammatory Syndrome in Adults

A Case Report and Review of the Literature

Fardad Behzadi; Nicolas A. Ulloa; Mauricio Danckers

J Med Case Reports. 2022;16(102)

Abstract and Introduction

Abstract

Background: The current coronavirus disease pandemic has brought recognition of multisystem inflammatory syndrome in adults as a de novo entity, temporally associated with severe acute respiratory syndrome coronavirus 2 viral infection in adults. Hypothesis about its true pathophysiology remains controversial.

Case Report: The patient was a 22-year-old African American female presenting to the emergency department with fever, sore throat, and neck swelling for the past 3 days. During her initial emergency department visit, her blood pressure was stable at 110/57 mmHg, temperature of 39.4 °C, and heart rate of 150 beats per minute. While in the emergency department, she received broad-spectrum antibiotics (vancomycin and ceftriaxone) and 30 cc/kg bolus of normal saline. Originally, she was admitted to a telemetry floor. The following night, a rapid response code was called due to hypotension. At that time, her blood pressure was 80/57 mmHg. She appeared comfortable without signs of respiratory distress. She received intravenous fluids and vasopressors, and was transferred to the intensive care unit. The patient had reported a previous coronavirus disease infection a few weeks prior. She was diagnosed and treated for multisystem inflammatory syndrome in adults. Intravenous immunoglobulin infusion was initiated and completed on hospital day 5. She was weaned off vasopressors by day 6, and discharged home on day 11.

Conclusion: Our case report is an example of the presentation, diagnosis, and management of multisystem inflammatory syndrome. Our research into previous case reports illustrates the wide range of presentations, degree of end organ damage, and treatment modalities. This diagnosis needs to be considered in the presence of recent coronavirus disease infection with new-onset end organ failure, as prompt diagnosis and treatment is crucial for better outcomes.

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Table 1. Infectious and immunologic panel
Test	Result	Test	Result
Hepatitis A IgM antibody	Negative	Human metapneumovirus (PCR)	Not detected
Hepatitis B surface antigen	Negative	Syphilis serology	< 0.2 AI
Hepatitis B core IgM antibody	Negative	Adenovirus (PCR)	Not detected
Hepatitis C antibody	Negative	Bordetella holmesii (PCR)	Not detected
HSV I IgG antibody	< 0.2 AI	Bordetella pertussis DNA (PCR)	Not detected
HSV II IgG antibody	< 0.2 AI	Bordetella pertussis/bronchoscopy PCR	Not detected
HIV-1 and HIV-2 antigen and antibody	Nonreactive	Coxsackie type B (1) antibody	1:32 A
Influenza A (RT-PCR)	Not detected	Coxsackie type B (2) antibody	1:16 A
Influenza A H1 subtype (PCR)	Not detected	Coxsackie type B (3) antibody	1:16 A
Influenza A H3 subtype (PCR)	Not detected	Coxsackie type B (4) antibody	1:16 A
Influenza type B (PCR)	Not detected	Coxsackie type B (5) antibody	1:32 A
Parainfluenza 2 (PCR)	Not detected	Coxsackie type B (6) antibody	1:32 A
Parainfluenza 3 (PCR)	Not detected	CMV DNA (PCR)	Negative
Parainfluenza 4 (PCR)	Not detected	RSV type A (PCR)	Not detected
Group A strep screen	Negative	RSV type B (PCR)	Not detected
Anti-streptolysin O antibody	42 IU/mL	Rhinovirus (PCR)	Not detected
SARS-CoV-2 IgG antibody	Positive	EBV DNA	Positive
SARS-CoV-2 IgM antibody	Negative	Rheumatoid factor	Negative
IgG total	4247 mg/dL	ANA	Negative
IgG1	1545 mg/dL	C-ANCA	< 0.2 AI
IgG2	639 mg/dL	P-ANCA	< 0.2 AI
IgG3	110 mg/dL	dsDNA antibody	< 1 IU/mL
IgG4	44 mg/dL	Complement C3	70 (L) mg/dL
IgA	63.6 mg/dL	Complement C4	< 8 (L) mg/dL

RT-PCR reverse transcription-polymerase chain reaction, HSV herpes simplex virus, HIV human immunodeficiency virus, CMV cytomegalovirus, RSV respiratory syncytial virus, EBV Epstein–Barr virus, dsDNA double strain DNA antibodies, ANA antinuclear antibody, C-ANCA antineutrophil cytoplasmic antibodies, P-ANCA perinuclear anti-neutrophil cytoplasmic antibodies, IgM Immunoglobulin M, IgG Immunoglobulin G, IgA Immunoglobulin A

Table 2. MIS-A published case reports
Authors	Age, sex, ethnicity	Past medical history	Signs and symptoms at presentation	Previous COVID-19 infection	Initial COVID-19 testing	ICU stay	Laboratory findings	Imaging studies	Treatments	Outcome
Kofman, 2020 [4]	25, female	None	Fever, dyspnea, sore throat, diarrhea, vomiting, cough, and adenopathy	No	PCR (+) IgG (+)	Yes	Increased neutrophils, ESR, CRP, D-dimer, ferritin, Tn, and creatinine; lymphopenia	Chest X-ray and CT: No detected abnormalities CT angiography: dilated main pulmonary artery CT abdomen/pelvis: acute uncomplicated pancreatitis Echo: dilated IVC then right ventricular dysfunction	Aspirin, IVIG	Recovery
Fox, 2020 [9]	31, female, African-American	HTN, DM, and obesity (BMI 36.1 kg/m²)	Fever, tachycardia, left-sided neck pain, nausea, vomiting, and parotitis by examination	Yes, 12 days prior	PCR (−)	NR	Elevated D-dimer, lactic acid, CRP, and creatinine	CT neck: bilateral parotid enlargement and swelling of the posterior nasopharynx to the oropharynx CT chest: bilateral basal GGO plus anterior mediastinal lymphadenopathy	NR	Deceased
Shaigany, 2020 [8]	45, male, Hispanic	No PMH BMI of 26.6 kg/m²	Fever, diarrhea, sore throat, painful lower extremities, diffuse exanthema, conjunctivitis, periorbital edema, left neck swelling with lymphadenopathy, plaques and papules diffuse, hypotension, tachycardia, and atrial fibrillation	No	PCR (+)	No	Increased neutrophils, low lymphopenia, ESR, CRP, D-dimer, ferritin, Tn, AST, ALT, PCT (3179 ng/mL), IL-6 (117 pg/mL)	Chest X-ray: diffuse interstitial haziness CT neck with contrast: inflamed edematous lower eyelids and preseptal spaces, reactive lymphadenopathy ECG: anterolateral ST segment elevation PCI: normal coronary TTE: global hypokinesia of the left ventricle with reduced EF of 40 Slit-lamp examination: conjunctivitis and uveitis	Full dose enoxaparin, IVIG (2 g/kg over 2 days), and single dose of IL-6 inhibitor (tocilizumab)	Recovery
Ahsan, 2020 [13]	28, male	Thalassemia minor. BMI of 28.48 kg/m²	High-grade fever (40.6 °C), anorexia, vomiting, nausea, lower limb pain, generalized weakness, red eye, difficult urination, and constipation. Bilateral facial nerve palsy, optic neuritis	Yes, 2 weeks before Ab (+), PCR (−)	Not done	NR	Anemia hypoalbuminemia leukocytosis with neutrophilia Elevated ESR, ferritin, and CRP	ECG: normal Chest X-ray: normal MRI brain and orbit: normal	Ceftriaxone 2 g daily and prednisolone 1 mg/kg/day orally for 6 weeks	Recovery
Bettach, 2021 [14]	54, female	None	Fever, septic shock, GI symptoms, skin rash, heart failure, bilateral acute anterior uveitis	No	PCR (−) IgG (+)	Yes	NR	Slit-lamp examination: bilateral corneal edema with Descemet's membrane and keratin precipitates Fundus examination: small localized intracranial bleed Fluorescein angiography: no vascular abnormalities	Antibiotics, corticosteroids, and vasopressors. After 2 weeks, topical dexamethasone	Recovery
Razavi, 2020 [15]	23, male, African-American	BMI of 35.4 kg/m²	Fever, fatigue, myalgia, dyspnea, orthopnea, watery diarrhea, and temporal headache. Hypotension, bilateral scleral, and conjunctival injection	Yes, 1 month prior	PCR (−) IgG (+)	NR	Leukocytosis, lymphocytopenia, high Tn I and BNP (NSTEMI) High CRP, D-dimer, ferritin, and fibrinogen	Echo: global hypokinesia with reduced EF (40–45%) Chest X-ray: no focal consolidations CT chest with contrast: no abnormalities Cardiac MRI: pericardial effusion and borderline EF (54%)	Antibiotics, IVIG, methylprednisolone, aspirin, enoxaparin	Recovery
Gulersen, 2021 [18]	31, female	Obesity, asthma, pregnant (28 weeks)	Fever, left-sided pleuritic chest pain, shortness of breath. Late-onset hypotension and tachypnea	Yes, 4 weeks prior. PCR (+)	PCR (−) IgG (+)	Yes	Leukocytosis. Elevated CRP, normal lactate, ferritin, PCT, late-onset increased in cardiac enzymes and inflammatory markers	CT angiography of the chest: normal with no pulmonary embolism or lung pathology detected TTE: On admission, EF 65–70% with a hyperdynamic left side, rim pericardial effusion, and well-functioning right ventricle. On day 4: global dysfunction of the right and left ventricles with rim pericardial effusion Non-stress test: reactive fetus	Intravenous heparin, IVIG, dexamethasone (10 mg every 6 hours), mechanical ventilation, inotrope and vasopressor	Extubated on day 8, elective delivery, and discharged home on day 15
Malangu, 2020 [19]	46, male	History of pneumonia	Fever (39.1 °C), atrial fibrillation, mild hypoxia (SatO₂ 91% on room air), bilateral exudative conjunctival injection, oral mucositis, bilateral cervical lymphadenopathy, and macular skin rash	No	PCR (−) IgG (+)	NR	Leukocytosis and thrombocytopenia. Elevated D-dimer, CRP, ferritin, LDH fibrinogen. Mildly elevated ALT, AST, kidney injury with hematuria, and proteinuria	CT angiography of the chest: bilateral apical patchy consolidations Chest X-ray: basal and middle lobe opacities TTE: left ventricular dysfunction with EF 31% and eccentric hypertrophy Cardiac MRI: perihilar lymph nodes with no infiltrative lesions Bronchoscopy: no malignant cells	Antibiotics and apixaban	Recovery
Othenin-Girard, 2020 [20]	22, male, East African	None	Five days of chills, myalgia, asthenia, diarrhea, and abdominal pain. Three weeks of loss of taste and smell sensations, and 1 day of dry cough, odynophagia, and rash (over trunk, extremities, palms)	Yes, 3 weeks prior. IgG (+)	PCR (+) IgG (+)	Yes	Leukocytosis, elevated CRP (275 mg/L), fibrinogen (8.5 g/L), D-dimer (3322 ng/mL), and creatinine (1.5 mg/dL) Autoimmune workup: negative ANA, ANCA, and rheumatoid factor	CT abdomen and chest: normal lung parenchyma with pulmonary embolism and inflamed mesenteric lymph nodes TTE: biventricular dysfunction/endomyocardial biopsy: myocarditis with necrotic foci Nerve conduction study: mononeuritis multiplex	IVIG, tocilizumab, rituximab, corticosteroids, and cyclophosphamide. Mechanical ventilation and extracorporeal membrane oxygenation (ECMO)	Recovery
Moghadam, 2020 [16]	21, male, Caucasian	None	Seven days of fever (40 °C), watery non-bloody diarrhea, chest tightness, vasoplegic shock, rash, tachypnea, bilateral conjunctivitis, and truncal and palmar rash	No	PCR (−) IgG (+)	Yes	Leukocytosis, CRP (365 mg/L), PCT (3.4 ng/mL), ferritin (1.282 mg/L), high lactate, Tn (55n ng/L)	Skin biopsy: inflammatory infiltrates TTE: hyperkinetic left ventricle with preserved EF CT scan chest and abdomen: compatible with congestive heart failure	Fluid resuscitation, noradrenaline, antibiotics (amikacin and ceftriaxone)	Recovery
Lidder, 2020 [5]	45, male	None	Five days of fever, red eyes, diarrhea, sore throat, eyelids edematous rash, nonexudative conjunctivitis, and abnormal perioral mucosa	No	PCR (+)	NR	Lymphopenia, elevated CRP, ESR, ferritin, D-dimer, and elevated Tn	TTE: global hypokinesia with reduced EF (40%) CT neck: unilateral lymphadenopathy	Eye-lubricating medications, topical prednisolone acetate 1%, IVIG, tocilizumab, and triamcinolone ointment for the rash	Recovery
Tung-Chen, 2021, Spain [6]	25, male	None	One-day history of nausea and abdominal pain. One week of fever (38 °C), sore throat, fatigue, anosmia, and orthopnea. Shock at presentation	No	PCR (−) IgM (+) IgG (+)	Yes	Lymphopenia (0.43 × 109/L), elevated fibrinogen (> 1200 mg/dL), CRP (337.1 mg/L), TnT I, and BNP	TTE: global hypokinesia with severely impaired left ventricular function (EF 29.7%) and rim pericardial effusion. EF improved after 8 days CT chest: no abnormalities Chest X-ray: no abnormalities ECG: sinus tachycardia with no other abnormalities	Antibiotics, ganciclovir, norepinephrine, milrinone, and diuretics	Recovery
Uwaydah, 2021 [7]	22, male	None	Four days of fever (39 °C), sore throat, diarrhea, nausea, vomiting, myalgia, headache, fatigue, erythematous rash involving the torso, tachycardia, hypotension, edema, and proteinuria	Yes, 40 days prior PCR (+)	PCR (−) IgG (+)	Yes	Leukocytosis, elevated creatinine, AST (53 U/L), ALT (81 U/L), direct bilirubin, CRP (249 mg/L), ferritin (4357 ng/mL), D-dimer (14 mg/mL), PCT (9 ng/mL), IL-6 (90 pg/mL), low platelets (122) and albumin (16 g/L)	TTE: severe tricuspid regurgitation, pulmonary HTN (46 mmHg), left ventricle dysfunction (EF 45%), and rim pericardial effusion. Normal echo after recovery CT chest: bilateral moderate pleural effusion and basilar atelectasis	Antibiotics, intravenous hydrocortisone	Recovery
Ahmad, 2021 [21]	26, male, Caucasian	None	Fever, abdominal pain, loose stool, nausea, reduced urine output, hypotension tachypnea (38 breath/minute) and hand/feet rash	PCR (+)	PCR (+) Abs (+)	Yes	Leukocytosis. Elevated lactic acid (9.7 mg/dL), CRP (246 mg/L), PCT (105.12 ng/mL), D-dimer (2.03), LDH (236 U/L), creatinine (4.66 mg/dL), and urea (38 mg/dL)	Lower limb doppler: left peroneal DVT Chest X-ray: peribronchial thickening Noncontrast CT abdomen: perinephric edema and mesenteric lymphadenopathy TTE: severely impaired left ventricular function (EF 15–20%) as well as right ventricular dysfunction. EF increased to 60% after 10 days	Vasopressors, IVIG, methylprednisolone (250 mg/6 hours), aspirin, anakinra (IL-1 receptor antagonist), mechanical ventilation, and CRRT	Recovery
Li, 2021 [10]	28, male	None	Five days of right-sided neck pain and swelling, enlarged tonsils, tenderness of the right submandibular fever, malaise, tachycardia, pruritic rash	4 weeks prior, PCR (+)	PCR (−) IgG (+)	NR	Leukocytosis (13,800/mm³), anemia (10.7 g/dL). Elevated hs-Tn I (11,908 ng/L), BNP (1661 pg/mL), CRP (304.2 mg/L), and ferritin (1588 mg/L)	CT neck: cervical lymphadenopathy, more on the right side TTE: mildly impaired left ventricular function (EF 45–55%) Cardiac MRI: rim pericardial effusion and slightly impaired right ventricular function	Broad-spectrum antibiotics, fluid resuscitation, beta-blocker, ACE inhibitor	Recovery
Veyseh, 2021 [23]	43, female	None	Fever, hypotension, tachycardia, erythematous rash, diarrhea, and cramping abdominal pain	No	PCR (−)	Yes	High WBCs, CRP, ferritin, D-dimer, fibrinogen, LDH, AST, and ALT	TTE: reduced EF (toxic cardiomyopathy), EF improved after IVIG and steroids	Antibiotics, vasopressors, IVIG, and intravenous solumedrol	Recovery
Diakite, 2021, [17]	33, male	HTN	Fever, diarrhea, chest pain, dyspnea, conjunctivitis, and cheilitis. Hypotension, tachycardia, and elevated hepatojugular reflux	Possible 6 weeks prior	PCR (−) IgG (+)	NR	Leukocytosis (21,000/mm³), anemia (10.7 g/dL), high AST, ALT, creatinine, CRP, D-dimer, BNP, and Tn	TTE: global hypokinesia, reduced EF (20%), and dilated IVC. Cardiac MRI revealed improved cardiac function after a week of treatment Coronary CT: aneurysms involving the right coronary, interventricular artery, and the left circumflex	Dobutamine, norepinephrine, IVIG, aspirin, prednisolone	Recovery
Bastug, 2021, Turkey [24]	40, male, Caucasian	None	Fever (39 °C), tachycardia, tachypnea, abdominal pain, diarrhea, and skin rash	23 days prior	PCR (−) IgM (+) IgG (+)	NR	Lymphopenia, leukocytosis as well as high liver function tests, ferritin, D-dimer, troponin, BNP, CRP, fibrinogen, PCL, and IL-6	CT abdomen: inflamed intestine and mesentery, mesenteric lymphadenopathy, and effusion TTE: global hypokinesia, reduced left ventricle function (EF 45%), and mild pericardial effusion. EF increased to 60% and the effusion resolved after treatment	Antibiotics, methylprednisolone, IVIG, full-dose enoxaparin	Recovery
Sokolovsky, 2021, [31]	36, female, Hispanic	None	Fever, vomiting, abdominal pain, diarrhea, arthralgia, rash hypotension, and tachycardia	No	PCR (+) Abs(+)	NR	Elevated liver enzymes, direct bilirubin, albumin, CRP, ferritin, D-dimer, ESR, and hyponatremia (115 mmol/L)	TTE: normal EF (65%) and moderate tricuspid regurgitation CTA coronaries: normal with rim pericardial effusion CT chest: trace pleural effusion	Steroids, acetylcysteine, IVIG, aspirin	Recovery
Julius, 2021, [11]	59, female, Caucasian	HTN and dyslipidemia	Fever, right cervical lymph node swelling, odynophagia, hypotension, and rash (neck and chest)	20 days prior, PCR (+)	PCR (+)	Yes	Slightly elevated AST, ALT; high Tn, CRP, and ferritin	CT neck: enlarged right nodes with one exhibiting liquefaction EKG: ST elevation in V1 and V2	Antibiotics, steroids, norepinephrine, epinephrine, terlipressin mechanical ventilation	Deceased
Parpas, 2021 [32]	67, male	HTN, cirrhosis	Dyspnea weakness, weight loss, anorexia, nausea, extremities edema, tachycardia, and cognitive impairment	68 days prior	PCR (−) Abs (+)	NR	Low sodium (109 mEq/L) and albumin (3 g/dL), leukocytosis (35,000/mm³). High D-dimer, LDH, and PCL	Chest X-ray: bilateral basal infiltrative lesions CT chest: lung atelectasis/collapse TTE: Pulmonary HTN, and grade I diastolic dysfunction Duplex of lower limbs: no DVT Renal biopsy: moderate to severe acute tubular necrosis	Antibiotics, unfractionated heparin, dexamethasone, and hemodialysis	Recovery
Pérez, 2021, [25]	88, male	HTN, dyslipidemia, essential tremors	Hypoxia (saturation 87%), dyspnea, and peripheral edema	54 days prior PCR (+) Abs (+)	PCR (−) IgM (+) IgG (+)	NR	Creatinine (2.14 mg/dL), proteinuria (> 600 mg/dL), and low albumin 3 g/dL High LDL, CRP, and D-dimer	Chest X-ray: typical COVID-19 picture and pleural effusion Renal biopsy: findings suggesting acute IgA-dominant infection-associated glomerulonephritis	Intravenous furosemide, intravenous methylprednisolone	Recovery
Balan, 2021, [33]	46, male	Obesity (BMI 42 kg/m²)	Hypotension, hypoxia tachypnea, right hemiparesis, ataxia, and left hemianesthesia	60 days prior	PCR (−) Abs (+)	Yes	Elevated ferritin, CRP, LDH, PCT, high creatinine (4.1 mg/dL) and Tn	TTE: normal EF and elevated right ventricular pressures CT chest: bilateral apical and basal as well as right middle ground-glass opacities	Norepinephrine, antibiotics unfractionated heparin, dexamethasone, tocilizumab, hemodialysis	Deceased
Mieczkowska, 2021, [22]	32, male	None	Fever, tachycardia, right-sided swollen groin lymph nodes, diarrhea, and palms and soles rash	Two months prior	PCR (−) IgG (+)	No	Elevated AST, ALT, and direct bilirubin. Elevated inflammatory markers (CRP, ferritin, PCL, IL-6, ESR, and D-dimer)	TTE: EF 55% and pericardial effusion CT: lymphadenopathy of the right groin	Enoxaparin and intravenous methylprednisolone	Recovery
Mieczkowska, 2021, [22]	43, female	None	Fever, myalgia, headache, cough, and skin rash. Hypotension, cardiomyopathy, and acute kidney injury	No	PCR (−) Serology (+)	NR	Leukocytosis (21,500/mm³). Elevated ESR, CRP, ferritin, and D-dimer. Elevated AST, ALT, and ALP	Chest X-ray: right basal pneumonia Abdominal ultrasound: pericholecystic fluid, hepatomegaly, and steatosis TTE: EF 40%	Vasopressors, antibiotics, intravenous heparin, methylprednisolone	Recovery
Hékimian, 2021 [12]	40, male	DM (BMI 26 kg/m²)	Apyretic, dyspnea, severe asthenia	No	PCR (+) IgG (−)	Yes	Elevated PCT, CRP, ferritin Elevated AST, ALT, and ALP Elevated LDH, CPK Peak troponin 439 ng/L Peak BNP 6025 pg/mL	Chest CT: severe multifocal PNA TTE: EF 45%	Mechanical ventilation, dobutamine, norepinephrine, ECMO	Recovery
Hékimian, 2021 [12]	19, female	None (BMI 24 kg/m²)	Fever, dyspnea, cough	No	PCR (−) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak troponin 10,652 ng/L Peak BNP 2585 pg/mL	Chest CT: mild infiltrates TTE: EF 30%	Mechanical ventilation, dobutamine, norepinephrine, ECMO	Recovery
Hékimian, 2021 [12]	22, male	DM, asthma (BMI 38 kg/m²)	Fever, dyspnea, cough, severe asthenia	No	PCR (−) IgG (−)	Yes	Elevated CRP, ferritin, LDH Peak troponin 166 ng/L	Chest CT: severe infiltrates TTE: EF 30%	Mechanical ventilation, ECMO	Recovery
Hékimian, 2021 [12]	19, male	None (BMI 22 kg/m²)	Fever, headache, diarrhea, dyspnea, severe asthenia	No	PCR (−) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak troponin 806 ng/L Peak BNP 26,956 pg/mL	Chest CT: negative TTE: EF 15%	Dobutamine, norepinephrine	Recovery
Hékimian, 2021 [12]	16, male	None (BMI 18 kg/m²)	Fever, anosmia, abdominal pain, rash to hands and feet, conjunctivitis, strawberry tongue, adenopathy, severe asthenia, chest pain	No	PCR (+) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak Troponin 2545n ng/L	Chest CT: mild infiltrates TTE: EF 20%	Mechanical ventilation, dobutamine, norepinephrine, IVIG	Recovery
Hékimian, 2021 [12]	16, female	None (BMI 24 kg/m²)	Fever, headache, abdominal pain, rash to hands and feet, dyspnea, severe asthenia	Yes, anosmia and cough 1 month prior	PCR (−) IgG (+)	Yes	Elevate CRP, ferritin, and LDH Peak troponin 64 ng/L Peak BNP 1689 pg/mL	Chest CT: negative TTE: EF 45%	None	Recovery
Hékimian, 2021 [12]	17, male	Moderate aortic regurgitation (BMI 32 kg/m²)	Fever, headache, abdominal pain, diarrhea, dyspnea, severe asthenia, conjunctivitis	No	PCR (+) IgG (+)	Yes	Elevated ferritin and LDH Peak troponin 138 ng/L Peak BNP 35,000 pg/mL	Chest CT: mild pulmonary edema TTE: EF 20%	Mechanical ventilation, dobutamine, norepinephrine, IVIG, corticosteroids 2 mg/kg/day	Recovery
Hékimian, 2021 [12]	25, female	None (BMI 23 kg/m²)	Fever, headache, abdominal pain, dyspnea, severe asthenia, myalgias, arthralgias, adenopathy	No	PCR (−) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak troponin 2542 ng/L Peak BNP 24,540 pg/mL	Chest CT: negative TTE: EF 50%	Nasal cannula	Recovery
Hékimian, 2021 [12]	17, female	None (BMI 18 kg/m²)	Chest pain, dyspnea	No	PCR (+) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak troponin 4905 ng/L Peak BNP 3362 pg/mL	Chest CT: pulmonary edema TTE: 20%	Mechanical ventilation, dobutamine, norepinephrine, ECMO, IVIG, corticosteroids 2 mg/kg/day	Deceased
Hékimian, 2021 [12]	37, male	HTN (BMI 35 kg/m²⁾	Fever, headache, diarrhea, severe asthenia	No	PCR (−) IgG (+)	Yes	Elevated ferritin, LDH Peak troponin 1164 ng/L Peak BNP 35,000 pg/mL	Chest CT: Negative TTE: EF 45%	IVIG, corticosteroids 2 mg/kg/day	Recovery
Hékimian, 2021 [12]	29, female	None (BMI 22 kg/m²)	Fever, abdominal pain, diarrhea, rash, conjunctivitis, severe asthenia	Yes, 1 month earlier	PCR (−) IgG (+)	Yes	Elevated CRP, ferritin, LDH Peak troponin 200 ng/L Peak BNP 21,298 pg/mL	Chest CT: negative TEE: EF 50%	IVIG	Recovery

PMH past medical history, HTN hypertension, BMI body mass index, BPM beats per minute, MIS-A multisystem inflammatory syndrome in adults, PCT procalcitonin, AST aspartate transaminase, ALT alanine transaminase, ALP alkaline phosphatase, CRP C-reactive protein, ESR erythrocyte sedimentation rate, LDH lactate dehydrogenase, EKG electrocardiogram, CAP community-acquired pneumonia, PNA pneumonia, HD hospital day, ANA antinuclear antibodies, ANCA antineutrophil cytoplasmic antibodies, OD once daily, Tn troponin, BNP brain natriuretic peptide, DVT deep vein thrombosis, TTE transthoracic echocardiogram, EF ejection fraction, MRI magnetic resonance imaging, MV mechanical ventilation, CRRT continuous renal replacement therapy, IVIG intravenous immunoglobulins, LMWH low molecular weight heparin, Abs antibodies, SatO₂ saturation of O₂