Kawasaki Disease

Question 1

Define Kawasaki Disease.

Answer 1

Acute childhood febrile illness with small and medium vessel vasculitis.

Question 2

Explain the aetiology of Kawasaki Disease.

Answer 2

Infectious agent may induce disease in genetically susceptible individuals. Three hypotheses:

• Infectious hypothesis: winter-spring seasonality
• Genetic-susceptibility hypothesis: Japanese individuals more likely to suffer from Kawasaki
• Superantigen hypothesis: inconclusive

Marked cytokine cascade stimulation and endothelial cell activation leads to systemic vasculitis. Coronary artery aneurysms are caused by influx of neutrophils, lymphocytes and IgA plasma cells causing destruction of the internal elastic lamina. Fibroblastic proliferation/remodelling may subsequently lead to coronary artery stenosis

Question 3

What are risk factors for Kawasaki Disease?

Answer 3

1% positive family history. Siblings have a 10-fold risk of developing KD within the next year; in 50% of cases this is within the following 10 days.

Question 4

What are differential diagnoses for KD?

Answer 4

Streptococcal disease (scarlet fever), viral infections (measles, EBV, enterovirus), staphylococcal scalded skin syndrome.

Question 5

Summarise the epidemiology of KD.

Answer 5

Most common acquired heart disease in children – much more common in Japanese children

Question 6

What are the presenting signs and symptoms of KD?

Answer 6

Classic features: High fever 5 days and the presence of 4 of:

1. Erythema/oedema of hands and feet followed by desquamation
2. Diffuse maculopapular rash (usually within 5 days)
3. Bilateral, non-exudative conjunctivitis
4. Erythema of lips and oral mucosa, strawberry tongue
5. Cervical lymphadenopathy (1.5 cm), usually unilateral.

Revised guidelines: Fever persisting 4 days if other clinical features are present.

Question 7

What are appropriate investigations for KD?

Answer 7

Bloods: High WCC, high CRP/ESR, high platelets (subacute phase).

Microbiology: Blood culture, throat, nose and rectal swab, ASOT.

2D-ECHO/coronary angiography: KD may be diagnosed if coronary artery aneurysm, fever and <4 classic features. Make sure to follow-up.

Question 8

What is the management for KD?

Answer 8

Antibiotics: Until bacterial infection has been excluded. IVIG: Decreases the risk of cardiac complications. High-dose (2 g/kg) IVIGshould be administered ≤D10 (ideally D7). Treatment ≤D5 appears no more likely to prevent cardiac sequelae than D5–7, but is associated with an increased need for IVIG retreatment. If ≥D10, IVIG should still be administered if the child is febrile or has raised inflammatory markers. Measles/varicella immunisation should be deferred for 11 months after high-dose IVIG.

Aspirin: High-dose aspirin anti-inflammatory therapy (7.5 mg/kg QDS) until day 14 followed by low-dose antiplatelet therapy (1–2 mg/kg TDS) for 6–8 weeks until ECHO has confirmed no coronary artery involvement. S/E: Reye syndrome (only disease children treated by asp.) ; aspirin should be stopped if child develops influenza or chickenpox.

Steroids: Only considered if two infusions of IVIG have been ineffective.

Question 9

What are complications associated with KD?

Answer 9

Coronary artery aneurysms develop in 15-25% of untreated children and may lead to myocardial infarction, sudden death or IHD (2%).

Question 10

What is the prognosis for KD?

Answer 10

Coronary artery aneurysms develop in 15-25% of untreated children and may lead to myocardial infarction, sudden death or IHD (2%).