Endophthalmitis

Endophthalmitis is an inflammation of the internal coats of the eye. It is a possible complication of all intraocular surgeries, particularly cataract surgery, with possible loss of vision and the eye itself. Infectious aetiology is the most common and various bacteria and fungi have been isolated as the cause of the endophthalmitis. Other causes include penetrating trauma, allergic reaction, and retained intraocular foreign bodies. Intravitreal injections expose patients to the risk of endophthalmitis, but with an incidence rate usually less than .05%.

Signs and symptoms

In cases of endophthalmitis, one usually finds a history of recent intraocular surgery or penetrating ocular trauma. In some cases of endogenous endophthalmitis—particularly in immunocompromised patients or those with diabetes—the spread of infection may have been hematogenous (via the blood-stream).

Endophthalmitis is usually accompanied by severe pain, loss of vision, and redness of the conjunctiva and the underlying episclera. Hypopyon can be present in endophthalmitis and should be looked for on examination by a slit lamp.

An eye exam may be indicated in severe forms of candidiasis. 1-3% of cases of candidal blood infections include endophthalmitis.

Causative organisms

• Bacteria: N. meningitidis, Staphylococcus aureus, S. epidermidis, S. pneumoniae, other streptococcal spp., Propionibacterium acnes, Pseudomonas aeruginosa, other gram negative organisms.^[1]
• Viruses: Herpes simplex virus.^[1]
• Fungi: Candida spp.^[1] Fusarium
• Parasites: Toxoplasma gondii, Toxocara.^[1]

Late onset endophthalmitis is mostly caused by Proprionobacterium acne.^[2]

Causative organisms are not present in all cases. Endophthalmitis can emerge by entirely sterile means, e.g. an allergic reaction to a drug administered intravitreally.

Complications

• Panophthalmitis — Progression to involve all the coats of the eye.^[3]
• Corneal ulcer^[3]
• Orbital cellulitis^[3]
• no light perception vision^[3]

Treatment

The patient needs urgent examination by an ophthalmologist, preferably a vitreoretinal specialist who will usually decide for urgent intervention to provide intravitreal injection of potent antibiotics. Injections of vancomycin (to kill Gram-positive bacteria) and ceftazidime (to kill Gram-negative bacteria) are routine. Even though antibiotics can have negative impacts on the retina in high concentrations, the facts that visual acuity worsens in 65% of endophthalmitis patients and prognosis gets poorer the longer an infection goes untreated make immediate intervention necessary.^[4] Endophthalmitis patients may also require an urgent surgery (pars plana vitrectomy), and evisceration may be necessary to remove a severe and intractable infection which could result in a blind and painful eye.

Steroids may be injected intravitreally if the etiology is allergic.

Prevention

A Cochrane Review sought to evaluate the effects of perioperative antibiotic prophylaxis for endophthalmitis following cataract surgery.^[5] Separate studies from the research showed that a periocular injection of penicillin with chloramphenicol-suphadimidine eye drops,^[6] and an intracameral cefuroxime injection with topical levofloxacin^[7] resulted in a risk reduction of developing endophthalmitis following cataract surgery for subjects.

In the case of intravitreal injections, however, antibiotics are not effective. Studies have demonstrated no difference between rates of infection with and without antibiotics when intravitreal injections are performed.^[8] The only consistent method of antibioprophylaxis in this instance is a solution of povidone-iodine applied pre-injection.^[9]

References

External links

• Endophthalmitis at eMedicine
• Fungal Endophthalmitis at eMedicine