Episcleritis
Background
- Inflammation of the episclera (thin fibroelastic structure that lies between the conjunctiva and sclera)
- Usually mild and self-limiting
Pathophysiology and aetiology
- Most cases are idiopathic
- Up to a third of patients have an underlying systemic conditions e.g. rheumatoid arthritis, inflammatory bowel disease, SLE, vasculitic disease, dermatological disease etc
- There are two forms of episcleritis
- Simple episcleritis
- intermittent bouts of mod-severe inflammation that often recur at 1-3 month intervals. Usually last 7-10 days
- Nodular episcleritis (more commonly associated with systemic disease)
- Often more severe and prolonged attacks
- Characterised by a discrete, elevated area of inflamed episcleral tissue
- Simple episcleritis
Presentation
- General
- Diffuse or localised, bright red/pink bulbar injection (cf scleritis which is darker/violet)
- Usually unilateral
- Some may report other symptoms such as discomfort, photophobia or tenderness
- Severe pain and discharge are not common
- Simple
- Often acute redness, occasionally associated with pain (mild-moderate)
- Usually peaks around 12 hours then slowly resolves over 2-3 days
- Tends to recur in same or both eyes at the same time
- With time, attacks become less frequent and can disappear completely
- Often acute redness, occasionally associated with pain (mild-moderate)
- Nodular
Management
- Supportive management i.e. reassurance is all that is required in most cases
- NSAIDs may be helpful (ibuprofen tablets), moreso in nodular episcleritis than simple episcleritis
Scleritis
Background
- In contrast with episcleritis, scleritis is potentially blinding and usually requires referral to ophthalmology
- Inflammation of the sclera
Aetiology
- There is a strong link between autoimmunity and scleritis. In particular, patients with rheumatoid arthritis are at a much higher risk than the general population.
- Also more common in women.
Disease class
- There are two main forms of scleritis which can be further classified as such:
- Anterior scleritis: inflammation anterior to the extraocular recti muscles
- Diffuse: anterior scleral oedema is present with dilation of the deep episcleral vessels. This may be diffuse or localised
- Nodular: a distinct nodule of scleral oedema is present (can be single or multiple). They are often tender.
- Necrotising: most severe form. Severe pain and scleral tenderness. Severe vasculitis as well as infarction and necrosis with exposure of the choroid may result.
- Rarely, necrotising scleritis can occur without inflammation (scleromalacia perforans). The sclera become very pale, avascular and thin.
- Posterior scleritis: rare but potentially more serious. Characterised by flattening of the posterior globe, thickening of the posterior coats of the eye (choroid and sclera) and retrobulbar oedema
- Can manifest as serious retinal detachment, choroidal folds or both
- There can also be loss of vision as well as pain on eye movement
- Anterior scleritis: inflammation anterior to the extraocular recti muscles
Pathophysiology
- Common pathological features include scleral oedema and inflammation, often with a zonal granulomatous (can also necrose) reaction that may be localised or diffuse. Often mediated by type III and subsequent type IV autoimmune reactions involving a variety of cell types (T cells, macrophages, B cells, plasma cells etc)
Presentation
- History
- Redness
- Gradually increases over several days
- characteristic violet/blue tinge
- Pain
- Most describe severe boring/piercing eye pain over several days
- may radiate to surrounding facial areas
- may awaken the patient in the night (cf episcleritis)
- Tender on movement and palpation
- Usually not helped by analgesia
- Most describe severe boring/piercing eye pain over several days
- Tearing may occur secondary to discomfort but discharge is uncommon.
- PMHx
- Remember to ask about any autoimmune/ophthalmological conditions
- Redness
- Examination
- Blue hue is best observed under natural light
- On slit-lamp, inflamed scleral vessels are congested and often have criss-cross pattern and (under green light) there may be areas of capillary non-perfusion and granulation
- Phenylephrine (constrictor) will only constrict the superficial conjunctival/episclera vessels but the florid appearance of scleritis should remain.
Management
- Main aim is to minimise inflammation and reduce any damage
- Topical NSAIDs and corticosteroids may be used. However, ultimately, treatment of any underlying cause may require systemic NSAID/steroid use or even immunomodulatory agents
- Severe (necrotising) disease will require systemic treatment in any case