Synopsis
Recognise complete and incomplete Kawasaki disease, exclude dangerous mimics without delaying treatment, give complete IVIG and aspirin regimens, and stratify coronary surveillance and thrombosis risk.
- Kawasaki disease is an acute systemic medium-vessel vasculitis, usually in children under 5 years, with a particular tendency to inflame and dilate coronary arteries.
- Classic diagnosis is fever for at least five days plus four of five features: bilateral non-exudative conjunctivitis, oral change, polymorphous rash, hand or foot change and usually unilateral cervical lymphadenopathy.
- Features evolve rather than appearing together. Perineal erythema, marked irritability, sterile pyuria, gallbladder hydrops, arthritis and later periungual peeling support the diagnosis.
- Incomplete Kawasaki disease means prolonged fever with fewer criteria but supportive inflammation, laboratory or echocardiographic findings; young infants deserve a low threshold for this pathway.
- Initial tests include blood count, CRP or ESR, renal, liver, albumin, sodium, urinalysis and culture, blood culture, ECG and echocardiography, plus targeted tests for sepsis, scarlet fever, measles, adenovirus, toxic shock and PIMS-TS.
- Echocardiography assesses coronary dimensions using age- and body-size-adjusted z scores, ventricular and valve function and pericardial fluid. A normal first scan does not exclude disease.
- Preferred acute treatment is IVIG 2 g/kg as one IV infusion over 12 hours, started as early as possible and ideally within 10 days; treat later if fever or inflammation persists.
- NNUH aspirin regimen is 30–50 mg/kg/day orally in four divided doses until afebrile for 48–72 hours, maximum 14 days, then 3–5 mg/kg once daily until the 6–8-week coronary review if imaging is normal.
- High-risk disease, shock, early aneurysm or IVIG resistance requires cardiology and rheumatology or infectious-disease input for corticosteroid, repeat IVIG or other immunomodulation rather than repeated empirical antibiotics alone.
- Coronary aneurysm changes antithrombotic intensity and lifelong follow-up. Giant aneurysm may require aspirin plus anticoagulation and urgent specialist plans for thrombosis or ischaemia.
- Families need aspirin safety advice, urgent contact after influenza or varicella exposure or illness, and an immunisation plan because high-dose IVIG changes the timing of some live vaccines.
Key red flags
Fever for five days or longer with bilateral non-exudative conjunctivitis, oral change, rash, extremity change or cervical lymphadenopathy should trigger Kawasaki assessment.
Infants under 6 months can have prolonged unexplained fever with few classic signs yet carry greater coronary risk; incomplete presentation must not be dismissed.
Hypotension, cool peripheries, altered consciousness, significant abdominal symptoms, breathlessness or myocardial markers suggests shock, PIMS-TS, myocarditis or severe Kawasaki disease.
A normal early echocardiogram does not exclude Kawasaki disease and must not delay IVIG when clinical and inflammatory evidence is convincing.
Persistent or recurrent fever at least 36 hours after IVIG completion indicates treatment resistance and needs urgent specialist reassessment.
Chest pain, pallor, collapse, new ECG changes or ventricular dysfunction in a child with coronary aneurysm may represent coronary thrombosis or myocardial ischaemia.
Investigation priorities
Support the syndrome, grade severity and identify safe treatment parameters.
Management branches
Fever reaches five days with classic features, or incomplete disease is supported by inflammation or coronary findings.
- Admit under paediatrics, document each feature and onset, and involve cardiology for prompt echocardiography.
- Obtain inflammatory, organ, urine, culture and cardiac tests and actively assess sepsis, toxic shock and PIMS-TS.
- Do not wait for peeling, thrombocytosis or an abnormal first echo when the clinical case supports treatment.