Posterior Scleritis

Description

Posterior scleritis is an uncommon form of scleritis – a granulomatous inflammation of the connective tissue sclera. It may be confined to the posterior segment, or develop as an extension of anterior scleritis. Compared with anterior scleritis, there is less association with systemic disease and a higher risk of developing irreversible loss of vision from complications including glaucoma, macular involvement, retinal detachment and optic neuropathy. Posterior scleritis may be associated with conditions such as collagen-vascular diseases, rheumatoid arthritis and syphilis.

Symptoms

The typical presentation is severe ocular pain – classically sufficient to disturb sleep – accompanied by blurred vision. The pain may radiate to the forehead, temple, jaw or sinuses. Other possible symptoms include photophobia, lacrymation and diplopia. There may be a history of connective tissue disease or previous episodes of scleritis. One form of scleritis associated with rheumatoid arthritis – scleromalacia perforans – is often relatively painless.

Signs

Inflammation and edema of the sclera and surrounding tissues may cause proptosis, eyelid edema or limited eye movements. Signs of anterior scleritis co-exist in approximately half of patients (e.g., tender, edematous, vascular sclera with a violaceous hue). Several forms of keratitis are associated with scleritis and require urgent medical attention.

On fundoscopy, a variable amount of vitreous haze may be present. Elevation of the choroid and retinal pigment epithelium due to scleral thickening & edema often produces an orange-yellow mass with associated chorioretinal folds. Choroidal lymphoid hyperplasia occasionally produces scattered, pale nodules on its surface. These signs may resemble an intraorbital tumor.

Optic nerve edema occasionally results from inflammation or congestion of the optic nerve sheath. Similarly, fluid leakage and exudation may produce macular edema and serous or exudative retinal detachment.

Elevated intraocular pressure may occur secondary to congestion of outflow channels, angle closure or corticosteroid therapy. Patients with posterior scleritis have an increased incidence of cataract.

Incidence

Rare (less than 20 percent of cases of scleritis).

Significance

The clinical presentation of posterior scleritis is often suggestive of an intraorbital tumor. Sight-threatening complications include retinal detachment, macular edema, optic neuropathy, glaucoma and cataract.

Differential Diagnosis

Choroidal tumor, Choroidal Detachment, Thyroid Eye Disease, Optic Neuritis, Systemic Lupus Erythematosis; [Orbital Tumors, Orbital Inflammatory Pseudotumour – not in this series].

See Also

Choriodal Folds and Retinal Folds, Retinal Detachment – Classification; [Scleritis- Classification, Scleritis- Thinning and Necrosis – see Anterior Eye Disease and Therapeutics A-Z].

Management

Additional investigations

Modern imaging techniques –B-scan ultrasonography, CT scan and fluorescein angiography – facilitate timely diagnosis and management of this often painful and potentially sight-threatening condition.  Ultrasound characteristically reveals scleral thickening with fluid in Tenon’s space. Fluorescein angiography allows assessment of capillary nonperfusion or disc leakage, and assists with excluding differential diagnoses.

Blood tests

Baseline blood tests include full blood examination, renal function and screening tests for vasculitis. Chest x-ray and syphilis serological tests are often indicated.

Oral medication

• Patients often require regular analgesia.
• In an early mild case of posterior scleritis, oral non-steroidal anti-inflammatory medications (NSAIDs) and oral corticosteroids (e.g., prednisolone) are common initial therapy. Intravenous steroids and other immunosuppressive agents may be required in addition, or to allow steroid tapering.
• Retinal detachment associated with scleritis usually resolves with successful treatment of the scleritis. However, vision may be permanently affected if the detachment involves the macula.
• Antibiotics are indicated when an infectious etiology is likely (e.g., syphilis).

Topical medication

Glaucoma may require medical treatment during the inflammatory phase, and usually resolves with successful treatment of the scleritis.

Review

Referral to & liaison with a physician is generally recommended, particularly when an underlying systemic illness cannot be excluded. Decreased pain is a reliable sign of response to treatment.