Sympathetic Ophthalmitis

Description

Sympathetic ophthalmitis is a rare, bilateral, granulomatous panuveitis that may occur following almost any form of penetrating ocular trauma or surgery. The injured eye is referred to as the exciting eye, and the fellow eye as the sympathising eye. Most cases occur within 3 weeks to 3 months of the initial injury. Trauma – particularly with uveal incarceration or prolapse – is the most common precipitant. It is proposed that the ocular trauma releases uveal antigens which trigger an autoimmune response. Histologic examination of affected eyes reveals granulomatous inflammation of the uveal tract, characterised by aggregations of macrophages surrounded by mononuclear lymphocytes.

Symptoms

Symptoms are often most severe in the exciting eye, and include ocular irritability or pain, photophobia and blurred vision.

Signs

Signs are bilateral, and variable in distribution and severity. The eyes are typically red and irritable. Examination of the exciting eye usually reveals evidence of the initial trauma.

(1) Anterior segment signs include nodules of inflammatory tissue on the iris and large, pale ‘mutton fat’ keratic precipitates on the corneal endothelium, characteristic of granulomatous inflammation. Anterior or posterior iris synechiae may be present.

(2) The posterior uvea is affected by either a diffuse or a multifocal choroiditis, with vitreous cells and flare. Scattered, pale and slightly elevated infiltrates – known as Dalen-Fuchs nodules – are present in up to half of cases, and consist of granulomas situated between Bruch’s membrane and the retinal pigment epithelium. Overlying serous retinal detachments are common. Less common signs include optic disc swelling and exudative retinal detachment.

(3) Progression of the disease may be complicated by the onset of an inflammatory outflow tract glaucoma. Despite aggressive treatment, longstanding advanced disease may lead to cataract and phthisis bulbi (a shrunken, scarred, opaque and blind eye).

Prevalence

Rare; approximately 1 per 7000 following anterior segment surgery.

Significance

Sympathetic ophthalmitis must be excluded whenever inflammation in the fellow eye develops following ocular trauma. Severe cases may blind both eyes. Prompt diagnosis and treatment improve the visual outcome.

Differential Diagnosis

Vogt-Koyanagi-Harada Syndrome, Sarcoidosis, Syphilis, Acute Posterior Multiple Placoid Pigment Epitheliopathy, phacoanaphylactic endophthalmitis.

See Also

Posterior Uveitis, Postoperative Uveitis, Ruptured Globe and Penetrating Ocular Injury.

Management

Sympathetic ophthalmitis is a sight-threatening condition requiring aggressive immunosuppressive therapy.

Additional Investigations

Fluorescein angiography characteristically reveals scattered, small areas of hyperfluorescence with central hypofluorescence, corresponding to the location of granulomas. Other findings include patchy areas of choroidal hypoperfusion and late fluorescein leakage from the optic nerve. When the diagnosis is unclear, other tests may include chest x-ray and screening blood tests for syphilis and sarcoidosis.

Oral and topical medications

The main aim of treatment is to minimise ocular damage by suppressing the immune response. The specific management in each case is influenced by disease severity and the response to treatment. Many patients are commenced on a combination of oral prednisolone with topical steroids and mydriatics. An alternative ocular treatment is sub-Tenon’s injection of triamcinolone. Treatment with steroids may increase the probability of retaining visual acuity of at least 6/30 by approximately 50 percent.

Consideration is given to other immunosuppressive medications (e.g., cyclosporin, cyclophosphamide or methotrexate) when corticosteroids are ineffective or poorly tolerated. Treatment is continued for several months after the signs of inflammation resolve. Periodic review is recommended to detect recurrence and other complications such as elevated intraocular pressure: this can be difficult to control, and may require medical and/or surgical treatment.

Prevention

Although opinions vary, enucleation of a severely traumatized eye – especially with no perception of light – within 3 months of the initial trauma may reduce the incidence of sympathetic ophthalmitis. It is generally agreed, however, that enucleation does not alter the course of established sympathetic ophthalmitis.