Pathophysiology
Clinical meaning
Kawasaki disease (KD) is diagnosed clinically using the classic diagnostic criteria: fever for 5 or more days PLUS at least 4 of 5 principal clinical features: (1) bilateral non-exudative conjunctival injection (limbic sparing -- redness spares the area immediately around the iris); (2) changes of the oral mucosa (strawberry tongue, erythematous and fissured lips, diffuse oropharyngeal erythema); (3) polymorphous rash (typically maculopapular, can be urticarial or erythema multiforme-like, often accentuated in the groin); (4) changes of the peripheral extremities (erythema and edema of hands and feet in acute phase, periungual desquamation in subacute phase); (5) cervical lymphadenopathy (usually unilateral, at least 1.5 cm diameter). Incomplete (atypical) Kawasaki disease should be considered in children with prolonged unexplained fever and fewer than 4 classic criteria, particularly in infants under 6 months (who are at highest risk for coronary complications but often present atypically). The AHA algorithm for incomplete KD uses supplementary laboratory criteria (CRP ≥3.0 mg/dL or ESR ≥40 mm/hr) combined with supportive findings (albumin ≤3.0 g/dL, anemia for age, platelets >450,000 after day 7, WBC >15,000, urine WBC ≥10/HPF, elevated ALT)...