Ophthalmology Spot Diagnosis: Nodular Episcleritis

Nodular Epislceritis
A slightly tender and mobile elevated nodule with epithelial injection is typical for nodular episcleritis

This is a case of nodular episcleritis.

Definition of Episcleritis: Episcleritis is defined as the benign recurrent inflammation of episclera and tenon’s capsule.

Types of Episcleritis:

  1. Diffuse episcleritis
  2. Nodular episcleritis

Epidemiology:

  1. Common in females compared to males
  2. Common in young adults

Etiology:

  1. Non-specific immune response to irritants
  2. Idiopathic (mostly)
  3. Rheumatoid arthritis (RA)
  4. Sjogren’s syndrome
  5. Systemic Lupus Erythematosus (SLE)
  6. Herpes Zoster
  7. Tuberculosis
  8. Syphilis
  9. Coccidiodomycosis
  10. Rosacea

Differential diagnoses:

  1. Phlycten
  2. Inflamed piguecula
  3. Scleritis
  4. Sclerosing keratitis

Episcleritis periodica fugax: Fleeting and repeated attacks of episcleritis

Distinguishing Episcleritis from Scleritis:

PointsNodular episcleritisNodular scleritis
Pain/TendernessMildSevere, generalized, periocular
InjectionAffects superficial episcleral plexusAffects deep sclera plexus
2.5% phenylephrineBlanchesUntouched
Color of involved siteBright redBluish or dusky
NoduleConjunctiva freely mobile over it and traversed by vesselsDiffuse and fixed
Scleral affectionNoYes, repeated attacks may lead to necrosis and ectasia
Corneal complicationsMinimalSeen in 30-40% cases
UveitisOccasional mild iritisPresent in 30% cases

Treatment of Episcleritis:

  1. Artificial tears and/or Topical vasoconstrictor antihistamine drop (naphazoline/pheniramine)
  2. Unresponsive cases: Mild steroid drop
  3. Rarely, oral NSAID may be needed

Note: Warn the patient that episcleritis can recur.

Anatomy of Episclera and Sclera:

EpiscleraSclera
Character“Above” scleraCollagen and proteoglycan in criss-corss arrangement
Loose vascular complex between conjunctiva and sclera within Tenon’s capsuleThickness: 1-1.35 mm near optic nerve and thins anteriorly (thinnest immediately behind extraocular muscle insertion)
Superficial and deep plexus (from anterior and posterior ciliary arteries)
  1. Superficial = radial arrangement
  2. Deep = Non-radial arrangement
AvascularHave endothelial pumps

Posteriorly continuous with dural sheath

FunctionsAs synovial membrane for smooth movement of eyeProtective covering
Nutrition to avascular scleraBlocks extraneous light to enter globe
Site of insertion of Extraocular muscles
InvolvementNearly always in ScleritisNever in Episcleritis

Scleritis: It is the chronic inflammation of sclera proper and is rarer than episcleritis. It is more common in females and elderly patients (40-70 years). The causes of scleritis are:

  1. Collagen vascular disorders: Rheumatoid arthritis, Polyarteritis nodosa, Wegner’s granulomatosis, SLE, Ankylosing spondylitis
  2. Metabolic: Gout, thyrotoxicosis
  3. Infections: Herpes zoster ophthalmicus, Chronic staphylococcal or streptococcal
  4. Granulomatous: Tuberculosis, Syphilis, Sarcoidosis, Leprosy
  5. Miscellanous: Chemical burns, VKH syndrome, Bechet’s disease, Rosacea
  6. Surgical
  7. Idiopathic

Types of scleritis:

A. Anterior scleritis:

  1. Non-necrotizing (commonest): Diffuse or nodular
  2. Necrotizing:
    • with inflammation: severe pain, choroid visible through transparent sclera
    • without inflammation (scleromalacia perforans): usually asymptomatic and associated with rheumatoid arthritis; uveal dehiscence and globe rupture with minor trauma

B. Posterior scleritis: Usually not associated with systemic disease

  • Synonyms: Sclerotenonitis, Periscleritis, Anterior inflammatory pseudotumor
  • May mimic an amelanotic choroidal mass
  • Clinical features: Severe pain, proptosis, restricted extraocular movements, sometimes uveitis, exudative retinal detachment, retinal hemorrhage, choroidal folds, choroidal detachment

Investigations: ESR, Chest X-ray, RF, VDRL, ANA, serum uric acid, mantoux test, USG-B scan (to detect posterior scleritis) etc.

Complications:

  • Scleral melt
  • Corneal ulceration
  • Secondary glaucoma
  • Complicated cataract
  • Exudative Retinal detachment (Posterior scleritis)

Differential diagnosis:

  • Other causes of red eye
  • Posterior scleritis: Masquerade syndrome with malignant melanoma of choroid, lymphoma, multiple myeloma
  • Anterior necrotizing scleritis: Invasive squamous cell carcinoma of conjunctiva

Treatment:

Local and General: Topical steroids, atropine, hot fomentation

If infectious, culture and treat as appropriate

If non-infectious:

  • Oral NSAID (ibuprofen or indomethacin) for 2 months
  • If recalcitrant: Oral steroid (prednisolone) and taper after 2 months
  • If recalcitrant: Steroid sparing immunosuppresants (40-60% success) OR 1 time subconjunctival steroid injection (90% success)
  • Still recalcitrant: Anti-TNF drug

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