Royal College of Ophthalmologists Guidelines (Focus)

Management of endophthalmitis

Endophthalmitis is one of the most devastating eye complications that can occur following intraocular surgery. If the outcome is to be successful, it is essential that the diagnosis is recognised and not denied. Once the diagnosis is made, treatment should begin without delay to avoid further erosion of visual acuity.

Signs and symptoms

Symptoms may include pain, loss of vision, swelling or redness of the eye and discharge following surgery, but some cases may be asymptomatic. Signs may include injection or chemosis, corneal oedema, flare and cells or frank hypopyon, or fibrin clot in the anterior chamber. A relative afferent defect may be found. Vitreous cells or abscess may be seen but often no view of the posterior segment is possible; sheathing of retinal vessels may occasionally be seen. When the signs are pronounced, the diagnosis is not in doubt, but sometimes only a relatively low-grade inflammation is observed. If these signs cannot be explained, or if there is any doubt, the eye should be treated as if it were infected.

Treatment

A 'therapeutic trial of steroids' can be particularly misleading since, even in endophthalmitis, there may be an initial favourable response. If in doubt proceed to vitreous biopsy and anterior chamber tap.

To date, there has only been one large prospective randomised study on the management of endophthalmitis. The Endophthalmitis Vitrectomy Study (EVS)¹, recently completed in the USA, has greatly simplified our approach to treatment, which should begin immediately diagnosis is made.

In all cases, where the acuity is better than light perception, a single-port vitreous biopsy via the pars plana should be performed using a vitreous cutting-suction device. (Disposable devices are now available which allow the procedure to be done outside the operating theatre if necessary with even less delay. this can be useful in outreach clinics). The specimens are directly smeared, for Gram stain etc, and plated for culture.

The space created by the biopsy is sufficient for direct intravitreal injection of antibiotics. In the EVS, amikacin and vancomycin were used. Gentamicin and cefuroxime would have supplied virtually the same degree of broad spectrum cover. The study showed that there was no advantage in the concurrent administration of intravenous antibiotics. The antibiotics may be made up as detailed later.

Only when the visual acuity is perception of light is there an advantage in performing a formal three port vitrectomy, from the point of view of both final acuity and media clarity. Intensive topical antibiotics are not required, unless there are specific wound-related problems or co-existing microbial keratitis.

The EVS did not address the specific question of intravitreal steroids and to date their use remains unsubstantiated. In general terms, high dose systemic prednisolone may be given eg 60-80mgs daily, rapidly reducing to zero over a week to 10 days. Steroids are contraindicated if there is a fungal infection. If the clinical course warrants it, the biopsy and intravitreal antibiotic injection may be repeated after 48 to 72 hours. this may allow review of the choice of antibiotic in light of the culture results as well as the clinical progress.

Prophylaxis

No study to date has effectively looked at the question of antibiotic prophylaxis. Proper pre-assessment of the patient, identifying and treating risk factors such as blepharitis, mucocoele of the lacrimal sac, or conjunctivitis is probably more useful than blunderbuss prophylaxis.

Skin and conjunctival sac preparation with 5% aqueous povidone iodine, at least five minutes before surgery, is safe and effective in significantly reducing ocular surface flora. Instillation of this material into the sac at the end of the procedure may be additionally effective.

The use of antibiotics in irrigating solutions has been widely condemned and the choice of vancomycin can be especially criticised from a public health stance because resistance to vancomycin has been encountered in MRSA.

Active prophylaxis by intravitreal injection of antibiotics after repair of penetrating trauma is probably beneficial.² The EVS did not consider the management of endophthalmitis developing other than post-operatively. It may be reasonable, however, to adopt a similar approach to management in these other cases but no firm guidelines can be given.

References

1. Results of the Endophthalmitis Vitrectomy Study. The Endophthalmitis Vitrectomy Study Group. Arch Ophthalmol 1995; 113; 1479-1496.

2. The criteria for intravitreal antibiotics during surgery for removal of intraocular foreign bodies. Seal DV, Kirkness CM. Eye 1992; 6: 465-468.

1. Gentamicin 200µg in 0.1ml 1. Take 0.5ml from a vial of gentamicin containing 40mg/ml 2. Make up to 10mls with normal saline or balanced salt solution (BSS) in a syringe. 3. 0.1ml of this solution=200µg NB Minims of gentamicin are unpreserved and contain 3000µg per ml. These may be used.

2. Amikacin 0.4mg in 0.1ml 1. Reconstitute one vial - 500mg - and make up to 10ml with BSS 2. Withdraw 0.8ml (using 1ml syringe) and make up to 10ml with BSS 3. Withdraw 0.1ml of this - 0.4mg

3. Cefuroxime or Vancomycin 1000µg in 0.1ml 1. Reconstitute a 250mg vial with 8mls of saline or BSS 2. Withdraw entire contents and make up to 10mls with saline or BSS 3. Inject 2mls back into vial and make up to 5mls in the vial with saline or BSS 4. 0.1ml of this solution - 1mg (1000µg) For smaller doses adjust the volumes accordingly.

4. Amphotericin 5µg in 0.1ml 1. Reconstitute a 50mg vial with 10mls of saline or BSS 2. Withdraw 0.1ml of this and make up to 10mls in a syringe. 3. 0.1ml of this = 5µg Alternatively inject entire contents of a 50mg ampoule into a 1 litre bag of Ringer-Iactate and 0.1ml of this contains 5µg.

5. Clindamycin 1000µg in 0.1ml 1. Draw up the contents of a 2ml ampoule (300mg) and make up to 3ml in a syringe with normal saline or BSS 2. Withdraw 1ml of that and make up to 10ml in another syringe with normal saline or BSS 3. 0.1ml of that contains 1000µg

Intravitreal Drugs

NB The intravitreal dose is given in 0.1ml except when combination therapy is used and 0.2ml are given. In emergencies it may be necessary to prepare drugs for intravitreal injection without the assistance of the pharmacist. Avoid solutions or preparations containing preservatives. The quantities for intravitreal injection may be drawn up in 1ml syringes, and injected with a 25 or 27 gauge needle. Make sure to fill the dead space with antibiotic solution.

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