Introduction: Infective endocarditis is an infection of a heart valve or other cardiac structure at a site of endothelial damage. Infective endocarditis is associated with a broad array of complications and has a high fatality rate. Some autopsy case reports regarding causes of death have previously been published. These cases reported that the condition of patients with infective endocarditis worsened drastically, and they suddenly died from fatal complications, such as acute severe heart failure, cerebrovascular major embolism, and hemorrhage or acute coronary embolism. In these cases, early diagnosis did not necessarily have an important role because of the unpredictable and relatively rare situation.
Case Report: A 47-year-old male was transferred to our hospital due to fever and severe fatigue. Although he had been experiencing symptoms for several months and visited doctors near his home several times, his condition was not diagnosed and he took antimicrobial drugs for a few days. On admission, he presented with typical clinical findings of infective endocarditis. Although intensive medical treatment was administered, his severe infection was not controlled, and it led to multi-organ failure. On day-15 of hospitalization, the patient succumbed to multi-organ failure. An autopsy also revealed multi-organ failure.
Conclusion: This case illustrates the fatal outcome of undiagnosed infective endocarditis in a patient who did not have fatal complications, such as acute heart failure, cerebrovascular major embolism, and hemorrhage or acute coronary embolism, which have been reported in past cases. In this case, early diagnosis could have avoided the unfortunate outcome. We report this case to emphasize the importance of early diagnosis of infective endocarditis.

Keywords: Autopsy, Early diagnosis, Infective endocarditis, Multi-organ failure