Endophthalmitis is a potentially sight-threatening condition that involves intraocular inflammation of any cause. It is either infectious or non-infectious in etiology, but in clinical practice intraocular infections are the commonest.
Eye pain and discomfort are common presenting symptoms sometimes accompanied by blurred vision. Physical examination can reveal swollen eyelids, chemosis, conjunctival injection, corneal edema, reduced red reflex, reduced visual acuity and raised intraocular pressure. Diagnosis is frequently made clinically, in most cases, based on these features.
Bacterial endophthalmitis has been classified as exogenous or endogenous depending on the cause. Exogenous causes frequently include ocular surgery, penetrating injury or spread of periocular infection (i.e. orbital cellulitis).
Endogenous cases comprise only 2-7% of endophthalmitis cases and involve haematogenous seeding of intraocular infection from a primary source. 1
Often shows non-specific features including:
- proptosis (due to raised intraorbital pressure)
- orbital fat stranding
- thickening of the sclera
- choroidal enhancement post-contrast
- often in early disease
- hyperdensity of the vitreous humor
- areas of high FLAIR signal in the vitreous humor
- T1 isointensity or hyperintensity of the vitreous depending on the proteinaceous content
- restricted diffusion on DWI
- similar to an abscess, this is virtually diagnostic of endophthalmitis
- a reducing diffusion restriction is thought to correlate with treatment response 2
- edema within the extraocular tissues
Treatment and prognosis
Intravitreal antibiotics are the mainstay of treatment and vitreal aspiration can be performed to identify the causative pathogen. Severe cases may require surgery with vitrectomy and debridement.