Kawasaki Disease Treatment Algorithm

Initial Diagnosis and Treatment

flowchart TD
    A[Fever ≥5 days] --> B{≥4 principal features?}
    B -->|Yes| C[Complete KD]
    B -->|No| D{2-3 features + Labs support?}
    D -->|Yes| E[Incomplete KD]
    D -->|No| F[Consider alternative diagnosis]

    C --> G[IVIG 2g/kg + High-dose ASA]
    E --> H[Echo + CRP/ESR]
    H --> I{Echo abnormal OR\nCRP≥3 + 3 labs?}
    I -->|Yes| G
    I -->|No| J[Close follow-up]

    G --> K{Afebrile in 36h?}
    K -->|Yes| L[Continue ASA\nEcho at 2 weeks]
    K -->|No| M[IVIG-Refractory]

📋 Text Version (if diagram doesn't render)

**Initial Kawasaki Diagnosis & Treatment** 1. **Fever ≥5 days** → ≥4 principal features? - **YES** → Complete KD → IVIG 2g/kg + High-dose ASA - **NO** → 2-3 features + Lab support? - **YES** → Incomplete KD → Echo + CRP/ESR - Echo abnormal OR CRP≥3 + 3 labs → IVIG 2g/kg + High-dose ASA - Otherwise → Close follow-up - **NO** → Consider alternative diagnosis 2. **After IVIG** → Afebrile in 36h? - **YES** → Continue ASA, Echo at 2 weeks - **NO** → IVIG-Refractory protocol

IVIG-Refractory Management

flowchart TD
    A[IVIG-Refractory\nFever >36h post-IVIG] --> B{Risk factors?}
    B --> C[Second IVIG 2g/kg]
    B --> D[Infliximab 5mg/kg]
    B --> E[IV Methylprednisolone]

    C --> F{Response?}
    D --> F
    E --> F

    F -->|No| G[Combination therapy\nConsider cyclosporine]
    F -->|Yes| H[Continue monitoring]

📋 Text Version (if diagram doesn't render)

**IVIG-Refractory Management** (Fever >36h post-IVIG) Options based on risk factors: - Second IVIG 2g/kg - Infliximab 5mg/kg - IV Methylprednisolone If no response → Combination therapy, consider cyclosporine

Risk Stratification at Diagnosis

Risk Level	Criteria	Initial Treatment
Standard	Complete KD, Z <2, age >6mo	IVIG + ASA
High	Z ≥2.5, age <6mo, high Kobayashi	IVIG + ASA + Steroids
MAS features	Cytopenias, ferritin↑, hepatitis	IVIG + Steroids + consider cyclosporine

Aspirin Dosing

flowchart LR
    A[High-dose ASA\n80-100 mg/kg/day ÷QID] -->|Afebrile 48-72h| B[Low-dose ASA\n3-5 mg/kg/day]
    B --> C{Coronary involvement?}
    C -->|No Z≥2| D[Stop at 6-8 weeks]
    C -->|Z 2.0-2.5| E[Continue until normal]
    C -->|Z ≥2.5| F[Continue indefinitely]

📋 Text Version (if diagram doesn't render)

**Aspirin Dosing** 1. **High-dose ASA** (80-100 mg/kg/day ÷QID) → Afebrile 48-72h → 2. **Low-dose ASA** (3-5 mg/kg/day) → Check coronary involvement: - No Z≥2 → Stop at 6-8 weeks - Z 2.0-2.5 → Continue until normal - Z ≥2.5 → Continue indefinitely

Coronary Artery Management by Z-Score

Z-Score	Classification	ASA	Anticoagulation	Activity	Follow-up
<2 always	Normal	6-8 weeks	None	No restriction	Echo at 6-8 wks
2.0-<2.5	Dilation	Until normal	None	No restriction	Echo q3-6mo
2.5-<5.0	Small aneurysm	Long-term	None	Per stress test	Echo q6mo, stress
5.0-<10.0	Medium aneurysm	Long-term	Warfarin OR LMWH	Limit contact sports	Echo q3-6mo, stress
≥10 or ≥8mm	Giant aneurysm	Long-term	Warfarin + ASA	Restrict exercise	Cardiology q3mo, annual cath

Laboratory Criteria for Incomplete KD

CRP ≥3 mg/dL AND/OR ESR ≥40 mm/hr

PLUS ≥3 of: - Albumin ≤3 g/dL - Anemia for age - ALT elevation - Platelets ≥450,000 (after day 7) - WBC ≥15,000 - Urine WBC ≥10/hpf (sterile pyuria)

Key Decision Points

When to Consider Incomplete KD

• Fever ≥5 days + 2-3 features
• Infants <6 months with prolonged fever
• CRP/ESR elevated without source

When to Treat as High-Risk

• Z-score ≥2.5 at diagnosis
• Age <6 months
• Delayed treatment (>10 days of fever)
• Evidence of MAS
• Coronary artery abnormalities at diagnosis

When to Involve Subspecialty

• Giant aneurysm
• Coronary thrombosis
• IVIG-refractory after 2nd dose
• MAS features
• Cardiac dysfunction

Follow-up Schedule

Coronary Status	2 weeks	6-8 weeks	6 months	1 year	Long-term
Normal	Echo	Echo, stop ASA	-	Risk factor counseling	PRN
Dilation	Echo	Echo	Echo	Echo	Until normal
Small aneurysm	Echo	Echo	Echo, stress	Echo	Annual
Medium/Giant	Echo	Echo, stress	Cath consider	Annual cath	Lifelong