Optical Coherence Tomography Reveals Clear Categories of Lesions in ECE

A new study of patients with endogenous Candida endophthalmitis (ECE) offers uses pre- and post-treatment optical coherence tomography (OCT) to generate new insights into the disease.

Endogenous endophthalmitis is caused by the spread of hematogenous spread of infectious microbes. It accounts for between 2-10% of all cases of endophthalmitis, and can lead to vision loss. Some research indicates cases of endophthalmitis are increasing among the population of East Asia. Most instances of the disease are related to Candida species, such as Candida albicans.

A team of researchers from China’s Fudan University, in Shanghai, wanted to evaluate the features of ECE using OCT images of retinal lesions. They studied 16 patients (22 eyes) who had sought treatment at the university’s hospital between January 2014 and April 2018. The team used OCT to classify the patients’ lesions into 4 discrete categories. They also found that OCT morphology of lesions correlated with visual prognosis. The findings are reported this month in BMC Ophthalmology.

“There have been very few OCT follow-up studies of ECE after treatment,” wrote corresponding author Gezhi Xu, MD, of Fudan University, noting that another recent study did not include follow-up imagery for most patients. “In our study, all 22 eyes were followed-up by OCT for at least 2 months at the same medical center, and post-treatment changes in the retinal lesions were evaluated using the eye-tracking-based follow-up function of the OCT instrument.”

Xu and colleagues found that major risk factors for ECE included intravenous use of corticosteroids or antibiotics, lithotripsy of urinary calculi, diabetes, endocarditis, gastrointestinal surgery, and abortion. Fourteen of the 22 eyes were treated with vitrectomy, and the authors confirmed previous research which found the positive rate of vitreous fungal culture was higher in vitrectomy samples than in needle biopsy samples.

While earlier work has sought to differentiate between lesion types in patients with ECE, Xu and colleagues were able to come up with 4 categories of lesions using OCT. They are as follows:

• Type 1: subretinal macular lesions.
• Type 2: lesions located in the inner retinal layer.
• Type 3: lesions involving the full-thickness retina and accompanied by macular edema.
• Type 4: sub-inner limiting membrane lesions.

ECE causes vision loss in a high number of patients. A 2012 study found 55% of eyes with ECE suffered vision loss, and 32% of eyes suffered severe vision loss as a result of the infection. Xu and colleagues said poor baseline visual acuity and centrally located fungal lesions have been associated with poor vision outcomes in ECE.

Of the 4 categories, those with Type 2 lesions had the best prognosis, Xu and colleagues found. However, the data also showed that patients with Type 2 lesions also had the best baseline visual acuity. This might explain why all four eyes categorized as Type 2 saw improved visual acuity following antifungal therapy without vitrectomy.

In terms of complications, the team found that epiretinal membrane and subretinal fibrosis were the most common complications among patients with ECE.

Still, Xu and colleagues said the sample size was ultimately too small to draw wide conclusions about the prognoses of patients based on the 4 categories.

Reference

Zhuang, H., Ding, X., Gao, F. et al. Optical coherence tomography features of retinal lesions in Chinese patients with endogenous Candida endophthalmitis. BMC Ophthalmol 20, 52 (2020). https://doi.org/10.1186/s12886-020-01337-9.