Active cardiac sarcoidosis in a patient with adult-onset Kawasaki disease

Adult-onset Kawasaki disease is a rare condition. Cardiac sarcoidosis is an uncommon cardiomyopathy which is characterized by progressive cardiac dysfunction, and abnormality on electrocardiography and morphological aberration of the heart. We report a first case of a combination of these rare conditions. The patient was initially diagnosed with Kawasaki disease based on the coronary artery aneurysms and a past medical history at the age of 20 years which was typical of Kawasaki disease. Decades later, he developed progressive cardiac dysfunction and a sudden-onset atrioventricular block. Laboratory and imaging results revealed severe myocardial damage and inflammation which were unexplainable by coronary artery ischemia. We diagnosed him with cardiac sarcoidosis based on a Japanese guideline to diagnose cardiac sarcoidosis. A cardiac resynchronization therapy defibrillator was implanted and he received oral steroid therapy. This rare combination of adult-onset Kawasaki disease and cardiac sarcoidosis may suggest the causative association of these conditions.