Introduction:

Kawasaki disease (KD) is an acute multisystemic febrile syndrome that causes small and medium caliber vasculitis with a predilection for the coronary arteries. It usually occurs in children between six months and five years of age. In younger children, its diagnosis is difficult, but it increases the risk of developing aneurysms in coronary arteries.

Presentation of the case:

A 45-day-old male, in whom the diagnosis of KD was confirmed on day 30 after the onset of the clinical picture. The patient had persistent fever and, subsequently, rash and desquamation. During the first weeks of the illness, the patient was treated for pharyngotonsillitis and urinary tract infection, with no resolution of the fever. The diagnosis was confirmed by echocardiogram, which documented coronary aneurysms, one fusiform (z-score +7.7 and 7.1), and the other saccular (z-score +9.2) with a thrombus inside.

Conclusions:

At a very young age, KD can be challenging to reach a diagnosis. In these cases, the echocardiogram can be of great help in identifying patients with this condition.