How this instrument works
Kawasaki disease is an acute, self-limited vasculitis that predominantly affects young children, and its main long-term danger is coronary artery aneurysm formation if the inflammation isn't controlled early. Intravenous immunoglobulin (IVIG) is the cornerstone treatment: a single, weight-based infusion given together with high-dose aspirin, most effective when started within the first 10 days of illness onset — the treatment window during which it most reliably reduces the risk of coronary artery abnormalities.
This calculator applies the standard Kawasaki disease dose specifically: 2 g/kg, given as a single infusion, typically infused slowly over 10 to 12 hours in a monitored hospital setting to reduce the risk of infusion reactions and volume-related complications. This is important to state clearly because IVIG dosing varies enormously by indication — the same drug is dosed very differently for conditions like primary immunodeficiency, Guillain-Barré syndrome, or immune thrombocytopenia. This calculator's 2 g/kg figure applies to Kawasaki disease only and should not be extrapolated to any other IVIG indication.
This is a hospital-based, pediatric-cardiology and inpatient-pediatrics reference tool for a specific, time-sensitive diagnosis — it is not an outpatient or home-use calculator. Kawasaki disease is diagnosed clinically, based on fever duration and a constellation of physical exam findings, and treatment decisions (including whether to treat, timing, and management of IVIG-resistant cases that may need a second dose or additional therapy) require a clinician managing the admission, not a calculator.
- Enter the child's weight in kilograms.
- Read the calculated IVIG dose in grams (2 g/kg), given as a single infusion.
Worked example — a 15 kg child
A 15 kg child with Kawasaki disease: the IVIG dose is 15 × 2 = 30 g, given as a single infusion over 10 to 12 hours alongside high-dose aspirin, ideally started within the first 10 days of fever onset.
A larger 20 kg child would receive 20 × 2 = 40 g under the same weight-based dosing, while a smaller 10 kg child would receive 10 × 2 = 20 g — the dose scales linearly with weight, but the regimen (single infusion, 2 g/kg, given with aspirin, early in illness) stays the same.
Questions
Why is IVIG given together with aspirin for Kawasaki disease?
The AHA's 2017 scientific statement recommends IVIG combined with high-dose aspirin as standard initial therapy — aspirin is used for its anti-inflammatory and antiplatelet effects, while IVIG is the treatment most strongly associated with reducing the risk of coronary artery aneurysms. Aspirin dosing and duration follow separate, weight- and phase-specific regimens not covered by this calculator, which only computes the IVIG dose.
Why does timing (within 10 days of fever onset) matter?
IVIG is most effective at reducing coronary artery aneurysm risk when given within the first 10 days of illness, and ideally as soon as the diagnosis is confirmed within that window. Starting IVIG later than day 10, or in a child who still has ongoing inflammation, may still be appropriate but the evidence for benefit is strongest within that early window — timing is a clinical decision this calculator does not make.
Does this dose apply to other uses of IVIG?
No. This calculator is scoped specifically to Kawasaki disease, where 2 g/kg as a single infusion is standard. IVIG dosing varies enormously across other indications — primary immunodeficiency, Guillain-Barré syndrome, immune thrombocytopenia, and many other conditions each have their own weight-based or fixed dosing regimens that are not reflected here.
What happens if a child doesn't respond to the first IVIG dose?
A meaningful proportion of children with Kawasaki disease have persistent or recrudescent fever after the first IVIG infusion (IVIG resistance) and may need a second IVIG dose or additional therapies such as corticosteroids, per the treating team's protocol. Retreatment decisions and dosing for IVIG-resistant cases are a separate clinical pathway not calculated by this tool.
Who is this calculator for?
Clinicians managing an inpatient child with confirmed or strongly suspected Kawasaki disease — typically pediatric hospitalists, pediatric cardiologists, or pediatric infectious disease specialists. It is a hospital reference tool for a single component of an inpatient treatment plan, not something for a parent to use to dose a child at home.
Why is the infusion given slowly over 10-12 hours rather than quickly?
IVIG at this dose is a large fluid and protein load, and infusing it slowly under monitoring reduces the risk of infusion reactions and volume-related complications such as fluid overload, which is a particular concern in a child who may already have myocardial inflammation from the underlying disease. This is why the infusion is given in a monitored hospital setting rather than as a rapid push.
References
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.