Scleritis and Episcleritis Notes

Scleritis

  • Definition: A rare but serious condition characterized by inflammation of the sclera that can lead to sight-threatening complications like uveitis, keratitis, and secondary glaucoma.

  • Demographics: Predominantly affects elderly patients, with a higher prevalence in females.

  • Associations: frequently linked to systemic diseases:

    • Connective tissue diseases such as rheumatoid arthritis, systemic lupus erythematosus (SLE), and systemic vasculitis (e.g., polyarteritis nodosa).

    • Local causes such as herpes zoster.

Classification of Scleritis

Anterior Scleritis (~98%)

  • Common Symptoms:

    • Red, inflamed eye, often unilateral.

    • Severe pain described as deep and boring, along with slight photophobia.

  • 2.5% phenylephrine: non blanching evident.

  • Management: Refer urgently

    • oral NSAIDS

    • oral steroids, topical steroids.

  • Types:

    • Diffuse: Most common & benign form

      • Widespread redness and inflammation

      • Distortion of normal radial vessel pattern

      Nodular: Appears similar to nodular episcleritis

      • deep red immobile nodules (may be multiple)

      • very painful

      • Can be associated with uveitis

      • can get purulent discharge

    • Necrotizing (with inflammation): The most severe form

      • Deep redness and inflammation, vascular distortion

      • Blood vessel occlusion and dropout can occur, resulting in white avascular patches

      • Results in scleral necrosis and thinning, and exposure of underlying uveal tract

      • Frequently associated with uveitis

      • Can be associated with keratitis (sclerosing keratitis), 2° Glaucoma, cataract

        • Sclerosing keratitis: opacity and thinning of the peripheral cornea adjacent to the site of scleritis. 

      • Prognosis is generally poor

      • management: urgent referral. Oral Prednisolone and immunosuppressive agent.

Sclerosing Keratitis

Necrotizing Anterior Scleritis Without Inflammation (scleromalacia perforans):

  • Characterized by progressive, non-inflammatory scleral thinning with blood vessel dropout and exposure of the underlying uveal tissue

  • Typically observed in longstanding rheumatoid arthritis, especially in elderly female patients.

  • Scleral necrosis can also occur following beta radiation therapy, particularly after pterygium surgery.

  • Can be asymptomatic or present with mild, non-specific irritation.

  • Overlying epithelium may ulcerate, leading to infection or chronic ulceration.

  • Urgent referral generally warranted: Aggressive treatment of the systemic disease is often required.

  • Protect eyes from trauma.

Posterior Scleritis (~2%)

  • Description: Inflammation of the posterior sclera. It may occur independently or alongside anterior scleritis but is often misdiagnosed due to similarities with other conditions (inflammatory or neoplastic).

  • Diagnosis: CT scan needed

    • May simulate tumour and cause choroidal effusions, (fluid collects in suprachoroidal space), angle closure glaucoma due to forward movement of the lens-iris diaphragm.

  • Symptoms: Variable presentation including pain and visual impairment.

  • Signs: Lid oedema, proptosis, ophthalmoplegia (restriction in eye movements), disc swelling, choroidal folds, exudative RD, choroidal detachment, subretinal lipid exudate.

    • associated with anterior scleritis ~ 30%

  • Management: Urgent referral is necessary.

Comparison: Episcleritis vs. Scleritis

  • Episcleritis:

    • Common (20-40 years), mainly females, mild pain (tenderness).

    • Excellent prognosis, with rare complications.

    • occasional systemic associations.

  • Scleritis:

    • Rare (20-60 years), mainly females, real pain.

    • Variable prognosis with common complications; systemic disease association, especially rheumatoid arthritis.

Key Features for Differentiation:

  • Pain Level: Episcleritis (nil to mild), Scleritis (moderate to severe).

  • Vessel Orientation: Episcleritis (straight radiate), Scleritis (crisscross pattern).

  • Response to Phenylephrine: Episcleritis vessels blanch, scleritis vessels do not.

  • Systemic Disease Association: More common and severe in scleritis, often requiring systemic treatment.