DefinitionIdiopathic multisystem diseasecharacterized by vasculitis of small

andmedium blood vessels (coronary

arteries).

It is now the most common cause of acquired heart

disease in children.

Median age of affected children = 2.3 years 80% of cases in children < 4 yrs, 5% of cases in children > 10 yrs

Males 1.7 : 1 Females

Positive family history in 1% but 13% risk of occurrence in twins.

Epidemiology

Annual incidence: 4-15/100,000 children under 5 years of age

Japanese, Chinese, Korean 10-15 time more than others

Seasonal variation: more cases in winter and spring but occurs throughout the year

No causative agent identified, but it could be:Bacterial, retroviral, superantigenic bacterial

toxin

Infectious agent features:Age-restricted susceptible populationSeasonal variationAcute self-limited illness

Etiology

Identified a novel human coronavirus in respiratory secretions from a 6-month-old with typical Kawasaki Disease

Subsequently isolated from 8/11 (72.7%) of Kawasaki

patients & 1/22 (4.5%) matched controls (p = 0.0015)

Suggests association between viral infection & Kawasaki disease

Fever (39-40°) for at least 5 days

(no response to Paracetamol or others NSAIDs)

At least 4 of the following 5 features: 1. Conjunctival injection

2. Erythema or fissuring of lips and oral cavity: strawberry tongue

3. Cervical lymphadenopathy (the least common among those symptoms 60% vs 90%)

Polymorphous exanthem, usually truncal

Changes in the extremities: Edema, erythema, desquamation

Diagnostic Criteria

Present with < 4 out of 5 diagnostic criteria

Compatible laboratory findings

Still develop coronary artery aneurysms (children with incomplete KD are also at risk for cardiovascular sequelae)

No other explanation for the illness

Incomplete (Atypical) Kawasaki Disease

Acute (1-2 weeks from onset)Febrile (39-40°C), irritableOral changes, rash, edema/erythema of feetDesquamation, arthritis or arthralgias

Subacute (2-8 weeks from onset)Temperature decreaseHypercoagulability (> PLT)High risk coronaries artery vasculitis and

aneurysm Gradual improvement even without treatment

Convalescent (Months to years later)

Phase of the Disease

• Acute• Bilateral• Non purulent

• Often unilateral• 1,5-5cm

NeurologicIrritability, aseptic meningitis, facial palsy,

hearing loss

RespiratoryRhinorrhea, cough, pulmonary infiltrate

GIDiarrhea, vomiting, abdominal pain, hydrops

of the gallbladder, jaundice

MusculoskeletalMyositis, arthralgia, arthritis

Others symptoms and signs

InfectiousMeasles & Group A beta-hemolytic strep can

closely resemble KDViral: adenovirus, enterovirus, EBV, roseolaSpirocheteal: Lyme disease, LeptospirosisParasitic: ToxoplasmosisRickettsial: Rocky Mountain spotted fever, Typhus

Immunological/AllergicJRA (systemic onset)Hypersensitivity reactions

Differential Diagnosis

EarlyMild anemia

Leukocytosis

Thrombocytopenia/ Thrombocytosis

Elevated ESRElevated CRPHypoalbuminemia

Elevated transaminases

LateThrombocytosisElevated CRP

Lab tests

MyocarditisPresent in 50% of the patientsTachycardia, murmur, gallop rhythmsDisproportionate to degree of fever &

anemia

ECG changes Prolonged PR and/or QT intervals Low voltage (especially of the R wave) ST-T–wave changes.

Cardiovascular Manifestationof Acute kawasaki disease

PericarditisPresent in 25% although symptoms are rareDistant heart tones, pericardial friction rub,

tamponade

Valves abnormalitiesValves incompetence in 1 % patients

Coronary Arterial changes15% to 25 % of untreated patients

develop coronary artery changes 3 - 7% if treated in first 10 days of fever with IVIG

Most commonly proximal, can be distalLeft main > LAD > Right

May lead to myocardial infarction, sudden death, or ischemic heart disease

Risk FactorsYounger than 6 months, older than 8 yearsMalesFevers persist for greater than 14 daysPersistently elevated ESRThrombocytosisPts who manifest s/s of cardiac involvement

SizeSmall = <5 mm diameter Medium = 5-8 mmGiant = ≥ 8 mm

ShapeSaccularFusiform

Prognosis: about 50% of aneurysms resolve, it depends on:Smaller size= <5 mm diameter Fusiform MorphologyFemale genderwhile, the giant aneurysms have the worst

prognosis Highest risk for sequelae

Other arteries may be involved:renalcerebral arteriesperipheral arteries (upper and lower

extremities)

If the echocardiogram is negative but fever persists, a repeat echocardiogram may be performed. If the echocardiogram is negative and the fever abates, Kawasaki disease is unlikely. If the echocardiogram is positive, the child is treated for Kawasaki disease.

Myocarditis with dysfunctionPericarditis with an effusionValvar insufficiencyCoronary arterial changes

Echocardiographic findings

0.3-2% mortality rate due to cardiac disease10% from early myocarditis32% from MI: principal cause of death in KD

Aneurysms may thrombose, leading to MI/death Most often in the first year Majority while at rest/sleeping About 1/3 asymptomatic

Cardiovascular Sequelae

IVIG: 2g/kg as one-time doseMechanism of action is unclearSignificant reduction in Coronary

arterial Aneurysm in pts treated with IVIG plus aspirin vs. aspirin alone (15-25%3-5%)

70-90% defervesce and resolution within 2-3 days of treatment

Treatment

AspirinHigh dose (80-100 mg/kg/day) for its

antiinflammatory effects (e.g., reduce the duration of fever), until afebrile x 48 hrs (need high doses in acute phase due to malabsorption of ASA)

NOTE Dosage of ASA in acute phase does not seem to affect subsequent incidence of CAA

Decrease to low dose (3-5 mg/kg/day), for its antiplatelet activity, for 6-8 weeks or until platelet levels normalize. NOTE: for patients who have aneurysms, aspirin should be continued until the aneurysm resolves or should be continued indefinitely.

No evidence of effect on CAA when used alone.

Due to potential risk of Reye syndrome instruct parents about symptoms of influenza or varicella

Aggressive support with diuretics & inotropes for some patients with myocarditis

Antibiotics (while excluding bacterial infection)

Steroids conflicting data: higher incidence of aneurysms, KD refractory to IVIG but responsive to high-dose steroids