Patient
Principal clinical features (now or at any time during this illness)
Assessment
Labs
Initial: CBC with differential, CRP, ESR, CMP, UA (bag or clean catch; a catheter specimen misses urethritis). Consider blood culture, urine culture if pyuria, rapid strep or culture, respiratory pathogen panel.
Supplemental laboratory criteria (incomplete KD)
Echocardiogram
Initial treatment
Response and subsequent treatment
Responsive: afebrile (< 38.0°C) and improving about 48 hours after IVIG (or adjunctive treatment). Resistant: fever > 38.0°C or lingering symptoms more than 24–36 hours after IVIG finishes. Fever in the first 24 hours after IVIG is typical and does not prompt retreatment.
Discharge and follow-up
- Low-dose aspirin until cardiology says to stop (longer with coronary abnormalities). Avoid ibuprofen and other NSAIDs while on aspirin.
- If steroids were given: finish the 2–3 week oral taper.
- PCP within 2–3 days. Cardiology with a repeat echo in about 2 weeks (sooner with significant coronary findings). Rheumatology in 1–2 weeks if steroids were given. Book appointments before discharge if possible.
- Check the temperature daily for 1–2 weeks; return to the ED for > 38°C or returning KD signs before the cardiology or rheumatology visit.
- No live vaccines for 11 months after IVIG. In flu season, give the (inactivated) flu shot before discharge if not already given.
Pitfalls and special situations
Consider KD in: infants under 6 months with prolonged fever and irritability; prolonged fever with unexplained aseptic meningitis; prolonged fever with unexplained or culture-negative shock, cervical lymphadenitis or retro/parapharyngeal phlegmon not responding to antibiotics. A documented viral or bacterial infection (e.g., strep) can coexist with KD.
KD with shock or macrophage activation syndrome: consult rheumatology and cardiology, give IVIG and additional treatments promptly, and consider ICU consult or management.
MIS-C: review the MIS-C pathway; consult as needed about further labs and imaging.
After IVIG: don't recheck the ESR (IVIG raises it). After 2 or more IVIG doses, check for hemolysis (CBC, reticulocytes, LDH, LFTs) 12–24 hours later. Discuss with immunology first if IgA deficient.