Endogenous endophthalmitis caused by Streptococcus mitis: A case report

Endogenous endophthalmitis is a rare disease caused by hematogenous intraocular metastasis of bacteria from an infectious source. Diagnosing endogenous endophthalmitis is challenging for non-ophthalmologists. However, ophthalmic diseases can cause irreversible vision loss, making prompt diagnosis and treatment critical. Here we present a rare case of endogenous endophthalmitis initially misdiagnosed as a cataract.

An 84-year-old Japanese man presented to the emergency department with fever and dysmotility. The patient was aware of a left subconjunctival hemorrhage and cloudy cornea upon arrival at the hospital, but he misunderstood it as a fall-induced subconjunctival hemorrhage and age-related cataracts.

On the day following admission, petechial hemorrhage on the eyelid conjunctiva and the detection of Streptococcus mitis in the blood culture results led us to suspect endophthalmitis rather than cataracts. A definitive diagnosis of endophthalmitis was made through ophthalmologic examinations, and endophthalmitis was considered secondary to endocarditis.

Subsequently, antimicrobial treatment was continued.

However, the patient developed myocardial infarction and died on the ninth day of hospitalization.

Two important lessons were learned from the examination of this case of endogenous endophthalmitis caused by S mitis. First, endophthalmitis and cataracts can be misdiagnosed. Because the symptoms of endophthalmitis and cataracts, such as decreased vision, photophobia, and blurred vision, are similar, the eye must be cautiously examined. Second, endocarditis caused by S mitis may lead to endogenous endophthalmitis. Although S mitis is not pathogenic, endogenous endophthalmitis may occur in patients with certain risk factors, such as older age, cancer, and immunosuppression.