Kawasaki disease

A 5-year-old female child presents to the emergency department with a history of high-grade fever and red eyes for 6 days. Examination reveals red, cracked lips, a strawberry tongue, and a faint maculopapular rash that began on the trunk and has spread to the limbs. Her palms and soles are erythematous and swollen. She also has cervical lymphadenopathy. Laboratory studies show elevated inflammatory markers (CRP and ESR). Echocardiography demonstrates coronary artery aneurysms. Diagnosis?

Diagnosis is Kawasaki disease.

1. Definition

Kawasaki disease is an acute, self-limited medium-vessel vasculitis of unknown etiology that primarily affects children and has a predilection for the coronary arteries.
It is the leading cause of acquired heart disease in children.

2. Etiology

1. Unknown etiology
2. Likely infectious trigger in genetically predisposed individuals
3. Immune-mediated vascular inflammation

3. Pathophysiology

Kawasaki disease involves immune activation with subsequent cytokine release, leading to endothelial injury and inflammation of medium-sized vessels. This results in coronary arteritis, which weakens the vessel wall and predisposes to the formation of coronary artery aneurysms.

4. Clinical Features

4.1 Diagnostic Criteria (CRASH)

Fever ≥5 days + ≥4 of the following:

1. Conjunctivitis (bilateral, non-purulent)
2. Rash (polymorphous, non-vesicular)
3. Adenopathy (cervical lymphadenopathy >1.5 cm, usually unilateral)
4. Strawberry tongue (± red/cracked lips)
5. Hands/feet changes (erythema, edema ± desquamation)

Diagnosis can be made with fewer criteria if coronary artery abnormalities are present.

4.2 Additional Features

1. Occurs in children <5 years
2. Symptoms appear sequentially
3. Irritability
4. Periungual desquamation in subacute phase

5. Diagnosis

Diagnosis is clinical; investigations support and assess complications.

5.1 Laboratory Findings

1. Leukocytosis
2. Elevated CRP and ESR
3. Thrombocytosis (subacute phase)

5.2 Echocardiography

1. Coronary artery aneurysms
2. May show myocarditis

6. Management

1. IVIG: 2 g/kg single infusion (within 7–10 days of fever onset)
2. Aspirin:
• High dose: 80–100 mg/kg/day (acute phase)
• Low dose: 3–5 mg/kg/day after afebrile for 48–72 hours

7. Complications

1. Coronary artery aneurysms (most important)
2. Myocardial infarction
3. Thrombosis

8. Key Clinical Insight

Child with prolonged fever + mucocutaneous findings + extremity changes + coronary involvement → Kawasaki disease

9. Exam Level Pearls

1. Fever ≥5 days is essential for diagnosis
2. Non purulent conjunctivitis distinguishes it from infection
3. Thrombocytosis occurs in the subacute phase
4. IVIG reduces risk of coronary artery aneurysms
5. Do not delay treatment if clinical suspicion is high