Recent studies have shown that endophthalmitis caused by liver abscess accounts for an increasing percentage of endogenous endophthalmitis cases each year, particularly in East Asia.12 A study on endogenous endophthalmitis conducted in Korea showed that 25% of primary lesions were liver abscesses,13 whereas a study in Taiwan found that 53% of primary lesions were liver abscesses, and 61% of cases were caused by Klebsiella pneumoniae, and showed the trend of drug resistance.14 In the present study, microbial cultures of the vitreous humor, as well as blood cultures were obtained from all patients. Bacteria could be identified in 11 (69%) cases, 8 (50%) of which were positive for Klebsiella pneumoniae. In Asia, the incidence rate of multidrug-resistant and hypervirulent Klebsiella pneumoniae strains increased.15 We found that there were 3 patients with carbapenem resistance; however, the patients were not included in our study because of the surgery and the discontinued visiting of the patients.
One patient’s endophthalmitis was caused by Serratia marcescens, and the final visual outcome of the 2 eyes was NLP. Endophthalmitis caused by Serratia marcescens is very rare, where most of the cases progress to NLP. Most of the reported cases have a history of interventional surgery, oral surgery, and intravenous drug use.16 Both liver abscess and endophthalmitis caused by Staphylococcus walleriae and Bacillus licheniformis are uncommon, implying they should be paid more attention in the clinics. The ideal condition for performing a bacterial culture is during the absence of antibiotic treatment following disease onset. However, due to the rapid progression of the disease, and the lack of a standardized antibiotic treatment strategy for endogenous endophthalmitis, it is difficult to control this condition, and the results of the culture may be unreliable.17 Therefore, for effective management of endogenous endophthalmitis, blood samples should be collected before starting antibiotic treatment.18
Liver abscess–associated endophthalmitis can significantly impact the visual acuity of patients, and has a poor prognosis. A study conducted in Southern California investigating endophthalmitis caused by Klebsiella pneumoniae showed that approximately half of the patients required enucleation.19 It has been reported that early use of antibiotics combined with timely vitrectomy in patients with endophthalmitis can effectively improve the visual acuity.20 In the present study, we found that while the condition of the patients with liver abscess–associated endophthalmitis could be improved by vitrectomy combined with intravitreal injection, the overall prognosis was poor. Endogenous endophthalmitis caused by liver abscess is a metastatic infection, in which inflammation occurs rapidly and pathogenic bacteria can invade the inner eyes in a short period of time, which makes surgery more difficult. In this study, 44% patients with endogenous endophthalmitis were initially diagnosed with only a liver abscess and fever. Eye symptoms are easily neglected when rescuing critical symptoms and focusing on systemic conditions, thereby missing the opportunity for early diagnosis and effective treatment. Furthermore, the clinical manifestations of liver abscess–associated endophthalmitis are nonspecific, and the condition can easily be misdiagnosed as other diseases, such as uveitis, leading to a delay in diagnosis and treatment. Four patients had NLP vision when they were transferred to an ophthalmology department, and their vision could not be preserved. Therefore, when treating patients with severe liver abscess, especially those in coma, doctors should pay attention to the patients’ eyes.
Vitrectomy is effective for the treatment of retinal detachment, vitreous hemorrhage, and diabetic retinopathy. It is also the most commonly used surgical method that has demonstrated a definitive efficacy for the treatment of endophthalmitis.21-23 Vitrectomy can remove intravitreal inflammatory lesions, bacteria and toxins, and reduce the damage caused by the effect of toxic substances on the retinal function.24 It may also rescue vitreous transparency and reduce or avoid tractional retinal detachment.25,26 Intravitreal injection enables the rapid and effective delivery of antibiotics, to achieve high local drug concentrations. This allows the antibiotics to target the pathogenic bacteria more effectively, thereby inhibiting bacterial growth and controlling inflammation. Concurrent intravitreal vancomycin, ceftazidime and dexamethasone are recommended for patients with infectious endophthalmitis caused by pyogenic liver abscess. According to experimental and clinical observations, most clinicians believe that injection of vancomycin, ceftazidime and dexamethasone into the vitreous cavity is safe and doses not lead to retinal toxicity. Studies have shown that intravitreal antibiotic injection for susceptible pathogens within 48 hours may help in retaining the visual acuity in some patients with liver abscess–associated endophthalmitis, and patients who received antibiotic intervention 48 hours following the disease onset ultimately had poorer visual acuity.27 Despite prompt treatment, the visual sequelae of endogenous endophthalmitis caused by liver abscess are frequent and outcomes are poor. In the current series, only 6 (31%) patients had visual acuity of CF or better at the 6-month follow-up visit. In addition, because some patients who underwent vitrectomy, are accompanied with bacteremia, postoperative infection is still a high-risk factor for blindness. Three patients in this study underwent enucleation as a result of the infection not effectively controlled in time. Repeated intravitreal and periocular injections of antibiotics and dexamethasone could prevent enucleation.26 Therefore, it is necessary to inject antibiotics intravenously according to the results of drug sensitivity after vitrectomy.
The present study showed that upon diagnosis of endophthalmitis caused by liver abscess, treatment should be initiated immediately and include intravitreal antibiotics injections, and vitrectomy. We concluded that vitrectomy combined with intravitreal injection is effective in the treatment of endogenous endophthalmitis. Further, the active treatment of the primary lesions was critical. The administration of systemic antibiotics should be accompanied by active treatment of surgical abscess drainage. Carbapenem can be used when cephalosporins have no effect. Therefore, The disease was effectively mitigated, and progression to panophthalmitis was controlled.
Our study had some limitations. Firstly, the limited case data because of the retrospective nature of the study, secondly, the sample size of this study was small. Future studies may include a larger sample size and a multicentered approach.