Chorioretinitis

Inflammatory and exudative condition of the choroid and the retina (form of posterior uveitis)

Aetiology

• Most often seen in immunodeficient patients e.g. HIV/AIDS

• Usually a response to viral, bacterial, fungal or protozoal infection

Pathophysiology

Acute retinal necrosis

• Caused by HSV/HZV

Endogenous chorioretinitis

• Very very rare

• 50% bacterial, 50% fungal e.g. candida

• Associated with bacterial endocarditis or indwelling catheters including central lines

Toxoplasma gondii

• Congenital or acquired

• Associated with contaminated soil and undercooked meat

• Results in a mild flu-like illness and rarely causes any further problems

• In immunocompetent patients it enters latent phase with cysts forming, can reactivate

Ocular toxocaracanis (roundworm)

• Ingestion with toxocara eggs (parasite hosted by cats and dogs) leads to systemic and ocular infection

• Reactive inflammatory processes lead to the organism's encapsulation and the formation of eosinophilic granulomas - can cause irreversible visual loss if the egg has migrated to the eye

• No proven treatment

Clinical presentation

• Older patients commonly present with reduced visual acuity with floaters
• Degree of symptoms depends on where the inflammatory lesions lie
• Symptoms are usually unilateral and tend to develop over several days

• Congenital infections may present insidiously, with little history and few symptoms

Investigations

• Swab - culture (bacterial/viral), serology for toxoplasma and toxocara

• Serology for toxoplasma and toxocara

Management

• May involve observation or antimicrobials ± topical steroid treatment - depends on causative pathogen and other criteria

• Toxoplasma gondii requires systemic treatment if sight-threatening (clindamicin/azithromycin +/- steroids)