Evaluation of suspected Kawasaki disease

KD: Kawasaki disease; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; ALT: alanine aminotransferase; WBC: white blood cell; hpf: high-power field.
* KD most commonly occurs in children over 6 months up to 5 years of age, although it can occur in young infants, older children, and adults.
¶ The diagnosis of KD can be made with 4 days of fever if ≥4 clinical criteria are present, particularly the peripheral extremity changes. Rarely, an experienced clinician can make the diagnosis with only 3 days of fever. However, patients who receive early treatment before 5 days of illness are more likely to fail initial IVIG therapy. A significant proportion of children with KD have a concurrent infection; therefore, ascribing the fever to such an infection or to KD requires clinical judgment.
Δ Clinical diagnostic criteria for KD:

• Bilateral bulbar conjunctival injection without exudate
• Oral mucous membrane changes, including erythema and/or fissuring of lips, strawberry tongue, and/or erythema of oropharyngeal mucosa
• Peripheral extremity changes, including erythema of palms and/or soles and/or edema of hands and/or feet (acute phase) and/or periungual desquamation (subacute phase)
• Polymorphous rash (maculopapular, diffuse erythroderma, or erythema multiforme-like)
• Cervical lymphadenopathy (at least one lymph node ≥1.5 cm in diameter, usually unilateral)

◊ Infants ≤6 months of age with KD are more likely to lack clinical features of KD other than fever and are at increased risk for coronary artery aneurysms. Thus, there is a lower threshold for treatment in this population. Some groups include all infants ≤12 months as high risk, although the risks of an atypical presentation and of IVIG resistance decrease significantly between 6 to 12 months of age.
§ Supplemental laboratory criteria:

• Anemia for age
• Platelet count ≥450,000 after the seventh day of fever
• Albumin ≤3.0 g/dL
• Elevated ALT level
• WBC count ≥15,000/mm³
• ≥10 WBC/hpf on urinalysis

¥ Echocardiogram is considered positive if the Z-score of the left anterior descending coronary artery or right coronary artery is ≥2.5, a coronary artery aneurysm is observed, or ≥3 other suggestive features exist including decreased left ventricular function, mitral regurgitation, pericardial effusion, or Z-scores in the left anterior descending coronary artery or right coronary artery of 2 to 2.5.
‡ For patients with incomplete KD and a positive echocardiogram, treatment should be given if the patient is still within 10 days of fever onset, the fever is still present after 10 days, the patient has clinical or laboratory signs of ongoing inflammation, or the coronary arteries are continuing to dilate despite a lack of fever, inflammation, or clinical signs of KD.