Utility of post mortem MRI in definition of thrombus in aneurismatic coronary arteries due to incomplete Kawasaki Disease in infants

Kawasaki disease (KD) is an acute, self-limited vasculitis of unknown etiology that primarily affects the coronary artery (CA) and presents in childhood. The characteristic coronary arterial lesion is an aneurysm, which may lead to thrombosis, dilatation, stenosis, and occlusion. Such an aneurysm is typically calcified and generally develops five or more years after the onset of acute KD. It becomes more noticeable after ten years. KD is sometimes difficult to diagnose because of the limited clinical features, especially in infants younger than 6 months old, where the clinical presentations often do not fulfill the diagnostic criteria for KD. We report a case of Incomplete Kawasaki Disease (IKD) causing unexpected death in infants. A seven-month-old male baby, apparently well nourished and without fever or exanthema that was unexpectedly found agonal in his bed by his parents. He died in an emergency room a few hours later in spite of aggressive resuscitation efforts. Postmortem Magnetic Resonance Images were obtained during the autopsy, with evidence of an occlusive thrombus in left and right coronary artery aneurysms. Laboratory findings were consistent with IKD. The crucial role of postmortem imaging is discussed here in order to improve diagnosis tools for preventable events.