Kawasaki Disease with Coronary Artery Z Score ≥2.5: When Initial IVIG Fails to Resolve Fever

This protocol applies to children with acute Kawasaki disease who meet high-risk coronary criteria — a Z score ≥2.5 in the left anterior descending or right coronary artery on initial echocardiography, or age under 6 months — and whose fever did not resolve within 36 hours of completing the first IVIG infusion.

High-Risk Criteria for This Scenario

The high-risk designation applies when the coronary artery Z score is ≥2.5 for the left anterior descending or right coronary artery at initial echocardiography, or when the patient is younger than 6 months. A Z score of 2.5 marks the threshold for a true aneurysm.

Previous Treatment — Goal Not Met

The first treatment line for acute Kawasaki disease with high-risk features included IVIG with aspirin and an adjunctive glucocorticoid or nonglucocorticoid immunomodulatory agent. The required goal — resolution of fever within 36 hours after completing the IVIG infusion — was not achieved. This protocol defines the next clinical step after that failure.

Next-Line Approach (Partial Overview)

When fever persists beyond 36 hours after the initial IVIG course, the approach involves either a repeat course of intravenous immunoglobulin or, as a recognised alternative, a glucocorticoid regimen. The complete protocol — including agent selection, sequencing, and the evidence supporting each option — is available via the link below.

Treatment Goal

Resolution of fever.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1002/art.42041

For this recommendation, the Voting Panel defined high-risk features as a Z score of ≥2.5 for the left anterior descending or right coronary artery at the time of the initial echocardiography and age <6 months.

This definition uses the Z score of 2.5 instead of 2.0, since a score of 2.5 is defined as representing a true aneurysm.

For patients with acute KD and persistent fevers after initial treatment with IVIG, a second course of IVIG is conditionally recommended over the use of glucocorticoids.

However, as a conditional recommendation, glucocorticoids are a reasonable alternative (e.g., starting at 2 mg/kg/day and tapering over 15 days or a single dose of 20–30 mg/kg).

For KD patients with persistent fevers after the initial course of IVIG, studies suggest that there is no difference in coronary artery outcomes between repeating the course of IVIG versus a single dose of pulse glucocorticoids (i.e., 30 mg/kg with a maximum of 1 gm).

A second course of IVIG in patients who have persistent fever for >36 hours after the first dose is conditionally recommended, as it is the current standard of care.

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