KAWASAKI DISEASE

DEFINITION Kawasaki disease, is an acute, febrile, self-

limiting systemic vasculitis of unkown origin that almost exclusively affects young children.

Medium sized vessel vasculitis

RISK FACTORS Asian ancestry Age 3 months to 4 years

o Peak age: < 5 years Male sex

PATHOPHYSIOLOGY Kawasaki disease is a systemic vasculitis Most serious complication is the

development of an acute coronary artery vasculitis with dilatation or aneurysm formation.

In the early phase of the disease, there is development of oedema and neutrophil infiltration in the coronary arterial wall, with a rapid transition to mononuclear cells.

This is followed by local production of matrix metalloproteinases that cause destruction of the interanal elastic lamina and media, with progress to fibrous connective tissue replacement of the intima and media, leading to aneurysm formation, scarring and stenosis

HISTORY AND EXAMINATION Characterised by fever (more than 5 days)

Plus 4 out of 5: Polymorphic rash

Bilateral (nonlimbal) scleral injectiono Perilimbal sparingo Non exudative (Dry conjunctivitis is

almost pathognomonic with KD in children

Mucosal erythema with strawberry tongue

Peripheral changes e.g. erythema of the palms or soles, oedema of the hands or feet and in convalescence desquamation

o In the acute phase, erythema of palms and soles and oedema of hands and feet

o In the subacute phase, desquamation of hands and feet

Unilateral cervical lymphadenopathyo Painfulo > 1.5 cm in diameter o non-purulent o usually single

The diagnostic features of Kawasaki disease can occur sequentially and may not all be present at the same time.

NOTE: these children are frequently inconsolably irritable.

DIAGNOSTIC CRITERIA: Warm CREAM fever > 5 d (warm) C – conjunctivitis (dry/non-purulent, bilateral)

(i.e. bilateral scleral injection – non-exudative; perilimbal sparing)

R – rash (polymorphic) E – erythema of palms/soles; edema of hands

& feet (= acute); subacute = desquamation of hands/ feet i.e. peripheral changes

A – adenopathy (unilateral, cervical, painful) M – mucosal involvement (red fissured lips,

strawberry tongue, diffuse redness or oral or pharyngeal mucosa)

Other symptoms or signs may include: Fever and extreme irritability Coronary artery aneurysms Arthritis Uveitis Diarrhoeal illness & vomiting Coryza and cough Hydropic gall bladder

PHASES1. acute phase (as long as fever persists, about

10d) most Dx criteria present irritability, aseptic meningitis, myocarditis,

pericarditis, CHF diarrhoea, gallbladder hydrops, pancreatitis,

urethritis, arthritis

2. subacute phase (resolution of fever, peeling of skin(desquamation), elevated ESR & platelets, usually day 11-21/2nd week of illness) arthritis beau’s lines seen on nail growth

3. convalescent phase (lasts until ESR and platelets normalise, >21d) coronary artery aneurysms aneurysm rupture MI, CHF

PREVALANCE Leading cause of acquired heart disease in

children under 5 years of age

INVESTIGATIONS All patients should have:

o Anti-Streptolysin O Titre (ASOT) and Anti DNaseB

Rule out Streptoccocal infection

o Echocardiography At least twice: at initial

presentation and if negative again at 6-8 weeks

Coronary artery aneursym Look for evidence of

myocarditis, valvulitis or pericardial effusion

o Platelet count Marked thrombocytosis

common in second week of illness

Other investigations that are not as useful but may be seen:

o Neutrophiliao Raised ESR and CRPo Mild normochromic, normocytic

anaemiao Hypoalbuminaemiao Elevated liver enzymes –

transaminases o CXR

If pericarditis or pneumonitis is suspected

o ECG Conduction abnormalities

o Urinalysiso LP

Exclude meningitis

MANAGEMENT Hospital admission 1st line: IV Immunoglobulin

o Preferbaly within 10d of onseto Most useful treatment in reducing

the development of coronary aneurysms (from around 30% to 3%)

o This may be repeated if the fever persists or recrs 36 hours or more after the completion of the initial immunoglobulin infusion

Methylprednisoloneo Used if fever persists after a second

dose of IVIg.

o Methylprednisolone may be repeated daily for up to 3 consecutive days.

1st line: High dose Aspirino 3-5mg/kg once a day for at least 6-

8wkso Used in the acute situation. o Continued until 48 hours after the

fever has resolvedo There is a greater risk of clotting so

aspirin is usedo Low-dose aspirin therapy is

continued during the subacute phase when there is marked thrombocytosis

o Aspirin therapy is continued if coronary artery changes are found

o In the absence of coronary artery changes it is normally continued for 3 months.

COMPLICATIONS Coronary aneurysms that develop in 20% to

25% of untreated patients Myocarditis Pericarditis with small pericardial effusions Gall bladder disease Pneumonitis Valvulitis Arthritis Hepatic dysfunction, rarely jaundice Aseptic meningitis Coronary thrombosis/MI

Bowel ischaemia and necrosis

PROGNOSIS Kawasaki disease, is an acute, self-limiting

illness In untreated patients it is associated with

significant morbidity and mortality Overall the mortality rate is less than 0.5%