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. <Learning objective: This is the first report of a rare combination of adult-onset Kawasaki disease and cardiac sarcoidosis. Kawasaki disease is not just a disease of children. Physicians should include Kawasaki disease in the list of differentials for unknown fever or eruptions. In patients with progressive heart failure and atrioventricular block, the possibility of cardiac sarcoidosis should be examined using various imaging modalities even if they had a known cause of cardiac dysfunction.>.