Kawasaki Disease

Question 1

Define

Answer 1

Acute self-limiting vasculitis that predominantly affects infants and children

Aetiology

• One of the MOST COMMON vasculitides in childhood
• It affects large-medium vessels
• The aetiology is UNKNOWN
• Mainly affects children 6 months- 4 years with a peak at the end of the 1st year of life
• More common in Japanese/ Black-Caribbean children

Question 2

Symptoms and signs

Answer 2

The diagnosis is CLINICAL

Mucocutaneous systemic inflammation

Non-specific prodrome of respiratory or GI symptoms (about 7-10 days before)
* Diarrhoea, vomiting, abdominal pain, irritability, cough or rhinorrhoea

Cardinal Features: CRASH and Burn

1. Conjunctivitis (bilateral, non-exudative)
2. Rash (polymorphous)
3. Adenopathy (usually cervical)
4. Strawberry tongue (erythema and cracking of lips + erythema of oral and pharyngeal mucosa)
5. Hand- oedema or erythema of the hands and feet
6. Burn- fever (> 5 days)

This fever is usually difficult to control

Children are strikingly irritable with a high fever

Arthritis

Coronary arteries are affected in about 1/3 of children within the first 6 weeks of the illness

Question 3

Investigations

Answer 3

ECG

Bloods: anaemia, raised CRP, ESR, WCC, platelet count rises in the 2nd week of the illness, U&Es (hyponataraemia), LFTs (elevated transaminases and gGT), abnormal lipids

Urine- MC&S (often shows WBCs)

Echocardiography- aneurysms identified

Question 4

Management

Answer 4

ADMISSION

Initial Treatment

IVIg infusion- single dose
* Give 2nd dose if failure to respond after 36 hours after completion of infusion

High-dose aspirin (reduces thrombosis risk)
* Give high dose until 24-72 hours after fever or for maximum of 24 days
* Low dose then given until echocardiography review at 6-8 weeks
* Kawasaki disease is one of the few indications for the use of aspirin in children. Due to the risk of Reye’s syndrome aspirin is normally contraindicated in children.

If IVIg resistance or persistent fever/ inflammation, consider: corticosteroids, cyclosporine

Echocardiography- initial screening test to identify aneurysms

Risk assessment for myocardial ischaemia and coronary artery aneurysms carried out:
* Low risk (normal echo): stop aspirin, repeat echocardiogram in 12 months
* Moderate risk: low dose aspirin until aneurysm regression is demonstrated, ECG and echo follow up annually
* High risk: long term low dose aspirin, ECG and echo follow up 6 monthly
* Need long term warfarin (INR target: 2-3)
* May need clopidogrel

Question 5

Complications and prognosis

Answer 5

Complications

Coronary artery aneurysms

Depressed myocardial contractility

Heart failure

Myocardial infarction

Arrhythmias

Peripheral artery occlusions

Prognosis

Self-limiting condition

Young infants are more severely affected and are more likely to have incomplete symptoms (i.e. not the full list of cardinal features)

Prompt treatment reduces incidence of aneurysms