Incomplete Kawasaki Disease in an Infant: A Case Report and Literature Review

The term "incomplete Kawasaki Disease (IKD)" was first used to describe patients with coronary complications who did not fulfill the classical diagnostic criteria for Kawasaki Disease (KD). The risk of coronary artery involvement is similar if not greater in cases of IKD. However, the recognition of IKD is challenging and often delayed, especially in infants. Multiple algorithms have been formulated to identify cases of IKD utilizing supplemental clinical, echocardiographic, and laboratory features. Although fever is not required for a diagnosis of KD in the Japanese guideline, most of the current guidelines, including those of the American Heart Association (AHA), consider the presence of fever for at least seven days a requirement for the diagnosis of both KD and IKD in infants. We present a case of IKD in a four-month-old female who presented with fever for less than three days and did not follow the current AHA algorithm for IKD. An echocardiogram obtained 10 days later revealed a coronary artery aneurysm, and a retrospective diagnosis of IKD was made. A review of the literature identified similar cases with a growing consensus on the need to redefine the role of fever. Pediatricians should search for coronary artery lesions in cases of high clinical suspicion, even if the fever period is short, particularly in those less than six months. Additionally, further innovative research is directly needed to identify immunological and cellular markers that could be tested early in the course of the disease and guide the management.