MIS-C Tool: Pediatric Evaluation & Treatment Pathway

1

Screen: does MIS-C fit?

CDC 2023 criteria

Age (years)

Weight (kg)

Fever subjective or documented ≥ 38.0 °C

New organ-system involvement: at least 2 categories

Mucocutaneousrash, oral mucosal inflammation, conjunctivitis or conjunctival injection, extremity changes Gastrointestinalabdominal pain, vomiting or diarrhea Shockclinician-documented CardiacLVEF < 55%, coronary dilation, aneurysm or ectasia, or troponin above normal Hematologicplatelets < 150,000/µL or lymphocytes < 1,000/µL · set from step 3

SARS-CoV-2 link

Positive PCR, antigen (≤ 60 days) or serology Close contact with COVID-19 ≤ 60 days Neither

A more likely alternative diagnosis for example Kawasaki disease, toxic shock, bacterial sepsis, strep or other infection

Definition (CDC/CSTE, 2023): under 21 years, fever, illness severe enough to need hospitalization, CRP ≥ 3.0 mg/dL, new involvement of at least 2 of the categories above, a SARS-CoV-2 link, and no more likely alternative diagnosis. Test for common alternatives (for example rapid strep, influenza) as indicated.

2

Hemodynamic status

Every patient

Hemodynamically stable Unstable or in shock

3

Tier 1 labs

Stable patients

Send: CBC with differential, comprehensive metabolic panel, CRP, ESR, and SARS-CoV-2 PCR and/or serology.

CRP ≥ 5 mg/dL

ESR ≥ 40 mm/h

Lymphocytes < 1,000/µL

Platelets < 150,000/µL

Sodium < 135

Albumin lowHypoalbuminemia

Neutrophils highNeutrophilia

Move to tier 2 if CRP ≥ 5 mg/dL and/or ESR ≥ 40 mm/h, and at least one of: lymphocytes < 1,000/µL, platelets < 150,000/µL, sodium < 135, neutrophilia, or hypoalbuminemia. The CDC definition itself uses CRP ≥ 3.0 mg/dL.

4

Discharge screen

If tier 1 isn't abnormal

Safe to go home while other causes are pursued? All must be true.

Well appearing with a reassuring exam Tolerating oral intake Reliable reassessment within 24–48 hours, with return precautions

5

Tier 2 workup and disposition

Abnormal tier 1, or not safe for discharge

Tier 2: ECG and echocardiogram, troponin, BNP, ferritin, procalcitonin, D-dimer, fibrinogen, PT/PTT, LDH, urinalysis, blood smear. Blood culture and antibiotics if bacterial infection is possible.

Features needing intensive care: check any

Shock or need for vasoactive support Significant cardiac dysfunction or arrhythmia Respiratory failure or potential airway compromise Altered mental status

Disposition: admit anyone who meets the definition or has abnormal tier 2 results, to a center with pediatric cardiology and intensive care. Involve rheumatology, cardiology and infectious diseases early. Waiting for a SARS-CoV-2 result should not delay care or transfer.

6

First-line treatment summary

For the admitting team

Usually started once MIS-C is diagnosed and infection is reasonably excluded. Confirm with rheumatology, cardiology and pharmacy.

Therapy	Guidance	For this weight

Follow-up echocardiograms at diagnosis, 7–14 days, and 4–6 weeks; longer if abnormal.

Suspected MIS-C: ED Evaluation Navigator

Start with the screen

Screen: does MIS-C fit?

Hemodynamic status

Tier 1 labs

Discharge screen

Tier 2 workup and disposition

First-line treatment summary