Asymptomatic Kawasaki Disease in a 3-Month-Old Infant.

Kawasaki disease (KD) is the leading cause of acquired heart disease in children in the United States. It is a systemic vasculitis characterized by diffuse inflammation of medium and small blood vessels. If untreated it can lead to myocardial infarction, ischemic heart disease, or sudden death. Early recognition and treatment decrease the incidence of coronary consequences, resulting in improved clinical outcomes. Incomplete KD is much less likely to fulfill major clinical diagnostic criteria. Infants <12 months of age are more likely to have an incomplete presentation, and children <6 months of age are more likely to develop cardiac complications. We present a case of a 3-month-old, previously healthy white boy who was noted to have a new transient cardiac murmur during a routine health assessment. He was completely asymptomatic, and physical examination was otherwise within normal limits. An echocardiogram was performed and showed abnormal dilation of several coronary arteries, consistent with the coronary ectasia associated with KD. Laboratory evaluation was significant for values suggestive of systemic inflammation. Based on these results, a presumed diagnosis of incomplete KD was made and treatment administered. Close surveillance was undertaken, and serial laboratory studies and imaging showed gradual resolution of inflammatory markers and cardiac ectasia. This unique case of incomplete KD without any of the physical signs normally associated with the disease emphasizes the spectrum of presentation and the possibility of missing a diagnosis of incomplete disease, reinforcing the need to remain vigilant.