Endophthalmitis (plural: endophthalmitides) is a potentially sight-threatening condition that involves intraocular inflammation of any cause. It is distinguished from panophthalmitis in that it does not extend beyond the sclera. It is either infectious or non-infectious in etiology, but in clinical practice, intraocular infections are the commonest cause.
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Clinical presentation
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.
Pathology
Etiology
Bacterial endophthalmitis has been classified as exogenous or endogenous depending on the cause.
Exogenous causes frequently include:
ocular surgery
penetrating injury
spread of periocular infection, i.e. orbital cellulitis
Endogenous cases comprise only 2-7% of endophthalmitis cases and involve hematogenous seeding of intraocular infection from a primary source 1.
Radiographic features
Features of panopthalmitis includes: edema or exudates within the tissues surrounding the sclera, especially in the sub-Tenon's space, extraocular inflammation such as lacrimal gland enhancement and enlargement and subconjunctival abscess. Pre and post-septal stranding indicates orbital cellulitis 5,6.
CT
Often shows non-specific features including:
proptosis (due to raised intraorbital pressure)
intraorbital fat stranding
scleral thickening
choroidal enhancement post-contrast: often in early disease
hyperdensity of the vitreous humor
MRI
areas of high FLAIR signal in the vitreous humor
T1 isointensity or hyperintensity of the vitreous depending on the proteinaceous content
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restricted diffusion on DWI
similarly to an abscess, this is virtually diagnostic of endophthalmitis
a decreasing diffusion restriction is thought to correlate positively with treatment response 2
edema within the extraocular tissues
Treatment and prognosis
Intravitreal antibiotics are the mainstay of treatment. Vitreal aspiration can be performed to identify the causative pathogen. Severe cases may require surgery with vitrectomy and debridement.