Post-traumatic endophthalmitis involves infection of the anterior and posterior segments of the eye after a traumatic open globe injury.
It is a devastating complication of ocular trauma and accounts for one-third of all infectious endophthalmitis cases irrespective of the cause. Infection is reported in approximately 1-3 in 100 cases of penetrating eye injuries. The infection rate is higher in presence of intraocular foreign bodies (IOFBs) or if the wound is contaminated with organic matter.
The infectious micro-organism enters the eye through the open wound during trauma. Most of the cases of post-traumatic endophthalmitis are caused by bacteria present in the environment. Causative organisms are most often gram-positive, including Staphylococcus, Bacillus, Streptococcus, and Enterococcus species; 10% –15% are due to gram-negative organisms including Pseudomonas aeruginosa and some species of Enterobacteriaceae; 10-30% are polymicrobial. High incidence of Bacillus infections are seen in the setting of IOFB or soil contaminated wounds. Candida species, Aspergillus and Fusarium are fungal entities that have been identified in chronic indolent cases.
Factors that may increase the risk of infection in open globe eyes include:
- Delayed primary repair of open globe injury by greater than 24 hours
- Retained intraocular foreign body
- Contaminated injury with soil, rural or organic matter
- Ruptured lens capsule
- Large wound size
- Vitreous prolapse through the open globe wound
It can be difficult to diagnose early infection immediately after open globe injury due to trauma-related ocular tissue disruption and inflammation. Detailed history regarding the nature of the injury is important. Detailed anterior and posterior segment examination should be performed. B-scan ultrasonography of the eye or CT of the orbit may be needed to evaluate for the presence of an IOFB.
- Anterior chamber reaction with hypopyon +/- fibrin membranes
- Vitritis identified on clinical examination of B-scan ultrasonography
- Purulent discharge
- Corneal edema
- Eyelid edema
- Severe conjunctival injection with chemosis
- Possible periorbital erythema and proptosis
Symptoms can range from mild to excruciating pain, photophobia, tearing and decreased vision. Pain may be out of proportion to the injury. The worsening of symptoms and progression of infection depends on the type and virulence of the organism.
Diagnosis can be very difficult in early infection in traumatized eyes. Symptoms and many signs of infection overlap those of traumatic injury and inflammation. However, increasing pain with hypopyon and vitritis suggests an infection until proven otherwise. It is important to distinguish bacterial from fungal infection since the treatment is different. Bacterial infections, the most common cause, typically have a relatively rapid onset and progression to panophthalmitis with severe pain and inflammation. Bacillus endophthalmitis is classically associated with very fast (within hours) onset of severe inflammation and is associated with poor outcome. On the other hand, fungal infection after open globe injury may not present acutely. Patients instead may develop subacute symptoms of discomfort, worsening vision and indolent signs of infection starting days to weeks after the initial injury. These should be suspected in tree branch or vegetable matter injuries. In occult, missed, or self-sealed globe lacerations, endophthalmitis may be the presenting sign of injury.
B-scan may be beneficial to evaluate for vitreous opacities, IOFB and status of retina and choroid. Open globe injuries are often associated with retinal detachment and hemorrhagic choroidal detachment, entities which are important to assess for if pars plana vitrectomy is planned. Thin-slice CT scan should be performed to evaluate for retained IOFB if the history is suspicious.
Cultures should be obtained from the wound, vitreous and possibly anterior chamber for identification of aerobic or anaerobic bacteria and fungus. Gram stain, KOH preparation of vitreous sample and blood and chocolate agar should be plated. Samples should be cultured on Sabaroud’s dextrose for fungal organisms. Only 70% of vitreous cultures usually yield positive results. PCR assays of vitreous for identification of bacterial and fungal strains should be considered.
- Post-traumatic non-infectious inflammation
- Phacoanaphylactic endophthalmitis
Emergent admission to the hospital for emergent surgical repair of open globe injury (if not already performed), intravitreal antibiotic injection, and possibly systemic antibiotics.
- Perform expedited vitreous biopsy with empiric intravitreal vancomycin 1 mg/0.1 mL and ceftazidime 2.25 mg/0.1 mL injections in cases where emergent pars plana vitrectomy cannot be performed. If vitrectomy is performed, consider injection intravitreal antibiotics at the conclusion of the case.
- Systemic broad spectrum antibiotics can be used including vancomycin 1 g q12h and ceftazidime 1g q8h. The addition of clindamycin (300 mg every 8 hours), amikacin (240 mg q8hr) or gentamycin (80 mg q8hr) should be considered in severe cases suspicious for Bacillus (history of IOFB) or anaerobic bacteria. Systemic fluconazole (200 mg bid) or more recently, voriconazole (200mg bid) is recommended intravenously for fungal infections.
- Topical fortified vancomycin (50 mg/mL) with ceftazidime (100 mg/mL) every hour.
Medical follow up
- Inpatient stay of 3-5 days for intravenous antibiotic treatment with daily follow-up for clinical examination and B-scan of the vitreous cavity is often recommended.
- Once hypopyon resolves and vitritis improves, the antibiotics are switched to oral and the patient is discharged from the hospital. Oral fluoroquinolones (e.g. ciprofloxacin 750 mg q12hr) are widely used for bacterial infections and oral voriconazole (200 mg bid) for fungal infections. Culture results and sensitivities, once available, can be used to narrow antibiotic therapy.
- Semiweekly to weekly follow-ups with B-scans are performed until the infection fully resolves.
- Pars plana vitrectomy (PPV) with intravitreal antibiotics is the mainstay of treatment for post-traumatic endophthalmitis. Bacterial and fungal cultures of undiluted vitreous samples are obtained. For mild suspicious cases of traumatic endophthalmitis, intravitreal antibiotics (without vitrectomy) with vitreous cultures can be considered. Emergent removal of intraocular foreign bodies, if present, should be performed.
- Empiric intravitreal vancomycin 1 mg/0.1mL and ceftazidime 2.25 mg/0.1 mL injections are given during PPV. Avoid aminoglycosides for gram negative coverage due to high risk of retinal toxicity. Bacillus cereus is resistant to cephalosporins. In cases where Bacillus is suspected, a meticulously prepared low dose gentamycin 40ug intravitreal injection may be considered in eyes with average volume vitreous cavity with no choroidal detachment. Intravitreal corticosteroid (dexamethasone, 0.4 mg / 0.1 ml) may be considered.
- Consider amphotericin (5 ug/0.1 mL) or voriconazole (50-100 µg in 0.1 mL) intravitreal injection if vegetable matter contamination is suspected. Use of intravitreal corticosteroids is not recommended if fungal infection is suspected.
Surgical follow up
- Daily follow-up until marked improvement of infection noted. If no improvement is seen in 48-72 hours, repeated intravitreal antibiotic injection can be considered. As with endophthalmitis of any etiology, vitreous inflammation and debris may initially worsen before improving. Vitreoretinal tractional bands may form especially if a limited vitrectomy was performed initially due to media opacity.
- Secondary procedures are common to address retinal detachment, proliferative vitreoretinopathy, vitreous hemorrhage, choroidal detachment, and cataract. Corneal opacification (due to laceration, suture repair, and scarring) may limit visualization of the posterior segment. In such cases, combined penetrating keratoplasty/temporary keratoplasty or endoscopic vitrectomy are options.
- Vitreous hemorrhage
- Recurrent endophthalmitis
- Retinal tears
- Retinal detachment
- Choroidal detachment
- Drug induced retinal toxicity
- Secondary glaucoma
Unfortunately, visual prognosis is often poor and depends on the virulence of the infecting organism, presence of retinal detachment, timing of treatment, presenting visual acuity, and the extent of initial injury.
- Expedited closure of the open globe wound
- Expedited removal of IOFB
- Use of intravitreal antibiotics in cases of IOFB
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