What is the appropriate evaluation and management for a child presenting with fever, bilateral conjunctivitis, dry cracked lips, rash, edema, and erythema of palms and soles, and cervical lymphadenopathy?

Kawasaki Disease: Immediate Echocardiography and Laboratory Evaluation Required

This 4-year-old presents with classic Kawasaki disease (KD) and requires immediate echocardiography, complete laboratory workup including inflammatory markers, and urgent cardiology consultation to prevent coronary artery aneurysms.

Diagnostic Criteria Met

This child meets diagnostic criteria for Kawasaki disease with fever plus at least 4 of 5 principal features 1:

• Bilateral non-purulent conjunctivitis 1
• Oral mucosal changes (dry, cracked lips) 1
• Polymorphous rash 1
• Extremity changes (edema and erythema of palms/soles) 1
• Cervical lymphadenopathy (enlarged anterior cervical node) 1, 2

Immediate Tier 1 Laboratory Evaluation

Send the following screening tests immediately 3:

• Complete blood count (CBC) with differential 3
• Complete metabolic panel (CMP) including sodium, potassium, liver enzymes (AST/ALT), albumin, and renal function 3
• Erythrocyte sedimentation rate (ESR) 3
• C-reactive protein (CRP) 3
• SARS-CoV-2 PCR and serology to rule out MIS-C 3, 4

Tier 2 Cardiac Evaluation (Urgent)

Given the clinical diagnosis of KD, immediately obtain 4, 1:

• Echocardiography to assess for coronary artery abnormalities and ventricular function 4, 1
• Electrocardiogram (EKG) 3
• Cardiac biomarkers: B-type natriuretic peptide (BNP) and troponin T 3, 4

Additional Tier 2 Laboratory Tests

Complete the diagnostic workup with 3:

• Urinalysis (looking for sterile pyuria) 1
• Serum albumin (if not in CMP) 1
• Platelet count (typically elevated in KD, but may be normal early) 3, 4
• Procalcitonin if available 3

Critical Differential Diagnosis Considerations

While this presentation is highly consistent with Kawasaki disease, you must exclude 3, 4:

• MIS-C (Multisystem Inflammatory Syndrome in Children): The SARS-CoV-2 testing is essential because MIS-C presents with overlapping features but requires different management intensity 3, 4. MIS-C patients typically have more prominent GI symptoms, lower platelet counts, and higher CRP levels than classic KD 3, 4.

• Scarlet fever: Would show sandpaper-like rash and circumoral pallor, but lacks conjunctivitis and extremity edema 1, 5

• Rocky Mountain Spotted Fever: Rash typically starts on wrists/ankles after 3-5 days of fever and becomes petechial, with prominent headache 6, 5

Immediate Management Priorities

Admit this child immediately 3, 4. Patients with KD features require hospitalization for 3:

• Multidisciplinary team involvement (pediatric cardiology, rheumatology, infectious disease) 3, 4
• Serial cardiac monitoring 4
• Preparation for IVIG therapy (2 gm/kg) once diagnosis is confirmed 7, 8

Critical Timing Considerations

Time is tissue: Coronary artery aneurysms develop in 20-25% of untreated patients but can be reduced to ~5% with prompt IVIG therapy 1, 7, 8. Treatment should ideally be initiated within 10 days of fever onset 7.

Common Diagnostic Pitfalls to Avoid

• Do not dismiss KD because the child appears relatively well: The clinical presentation can be deceptively benign early in the disease course 1

• Do not wait for all 5 principal features: Incomplete KD is common, especially in infants, and still carries significant risk of coronary complications 1

• Do not attribute symptoms to a viral illness or antibiotic reaction: This is a classic missed diagnosis scenario that delays life-saving treatment 1

• Do not delay echocardiography: Cardiac imaging should be performed at diagnosis, not after treatment initiation 4, 1