CONJUNCTIVA - Clinical Questions

SECTION A: Signs & Reactions

Answer: This is conjunctival injection, typical of bacterial conjunctivitis. It must be distinguished from ciliary injection (perilimbal redness), which is seen in iridocyclitis/uveitis. - Kanski's Clinical Ophthalmology, p. 185

Answer: Chemosis is conjunctival oedema appearing as a translucent swelling that may protrude through the eyelids. Acute chemosis indicates a hypersensitivity response (e.g. pollen) or severe infective conjunctivitis. Subacute/chronic chemosis has broader causes:

• Local: thyroid eye disease, post-surgery, trauma
• Systemic: nephrotic syndrome (low oncotic pressure), SVC syndrome, right heart failure, vasculitis, meningitis
• Kanski's, p. 185

Answer:

• Pseudomembrane: Coagulated exudate adhering to conjunctival epithelium; can be peeled without bleeding. Caused by adenoviral conjunctivitis, gonococcal infection.
• True membrane: Involves superficial layers of epithelium; removal causes bleeding/tearing. Caused by Corynebacterium diphtheriae, Stevens-Johnson syndrome, ligneous conjunctivitis.
• Kanski's, p. 186

Answer: Follicles are multiple discrete, slightly elevated, translucent lesions resembling grains of rice, most prominent in the fornices. Blood vessels run around them, not through them. Histology: Subepithelial lymphoid germinal centre with immature lymphocytes centrally and mature lymphocytes peripherally. Causes: Viral conjunctivitis, chlamydial infection, Parinaud oculoglandular syndrome, topical medication hypersensitivity; also normal in childhood (folliculosis). - Kanski's, p. 187

Answer: Papillae have a central vascular core (unlike follicles where vessels run around). They form a mosaic-like pattern of elevated red dots. Giant papillae (>1 mm) occur with prolonged inflammation (e.g. vernal keratoconjunctivitis, contact lens wear). They can only develop where palpebral conjunctiva is attached to deeper fibrous tissue. - Kanski's, p. 187

SECTION B: Conjunctivitis - Bacterial & Viral

Answer: Painless, unilateral or bilateral mucopurulent discharge that causes lid adhesion on waking. Conjunctiva is injected; cornea is clear. Chemosis is common. Preauricular lymphadenopathy is absent (except in gonococcal infection). Most common pathogens: Staphylococcus and Streptococcus species. - Tintinalli's Emergency Medicine, p. 1582

Answer: A fluoroquinolone (e.g. besifloxacin, moxifloxacin, ofloxacin) or aminoglycoside (tobramycin) should be used to cover Pseudomonas aeruginosa, which contact lens wearers are at risk for. Trimethoprim-polymyxin B is effective for routine cases but does not cover Pseudomonas. - Tintinalli's, p. 1582

Answer: Viral conjunctivitis (Epidemic Keratoconjunctivitis - EKC), most commonly caused by adenovirus. Treatment: cool compresses, ocular decongestants (e.g. Naphcon-A), artificial tears. Highly contagious; patient should wash hands and use separate towels. Course: 1-3 weeks. Always check for herpetic dendrite with fluorescein stain. - Tintinalli's, p. 1582-1583

Answer: Preauricular lymphadenopathy is most common in viral conjunctivitis. It can also occur in:

• Chlamydial conjunctivitis
• Severe bacterial conjunctivitis (especially gonococcal)
• Parinaud oculoglandular syndrome
• Kanski's, p. 187

SECTION C: Allergic & Cicatricial Conjunctivitis

Answer: Key feature is itching plus watery discharge, redness, papillae on inferior fornix, possible chemosis and eyelid oedema.

• Mild: Artificial tears alone
• Moderate: Topical antihistamine/decongestant, mast cell stabilisers, NSAIDs
• Severe: Topical steroids (with ophthalmology consult only, due to risk of occult herpes)
• Tintinalli's, p. 1583

Answer:

1. Early: Papillary conjunctivitis, diffuse hyperaemia, oedema, subtle fibrosis
2. Intermediate: Fine subconjunctival fibrosis, forniceal shortening, symblepharon (adhesion between bulbar and palpebral conjunctiva)
3. Severe: Necrosis, keratinization of caruncle, dry eye (goblet cell destruction)
4. End-stage: Total symblepharon, corneal opacification

• Kanski's, p. 205

Answer: Dapsone (diaminodiphenylsulfone) - approximately 70% of patients respond. It is contraindicated in G6PD deficiency. Sulfasalazine is an alternative if dapsone is poorly tolerated. Antimetabolites (azathioprine, methotrexate, mycophenolate mofetil) are used for refractory disease. - Kanski's, p. 205

SECTION D: Trachoma

Answer: Caused by Chlamydia trachomatis serovars A, B, Ba, C. Stages:

1. Active: Follicles on upper tarsal conjunctiva, inflammatory thickening
2. Cicatricial: Conjunctival scarring, progressive; can cause trichiasis and corneal abrasion
3. Late complications: Corneal scarring and blindness

• Goldman-Cecil Medicine; Jawetz Microbiology

Answer: Surgery may remove many goblet cells or compromise lacrimal gland ductules traversing the conjunctiva. This can leave the patient with a painful dry eye that may compromise vision. - Robbins, Cotran & Kumar Pathologic Basis of Disease

SECTION E: Degenerative & Neoplastic Lesions

Answer: A pterygium is a chronic inflammatory fibrovascular hypertrophy of conjunctiva in the palpebral fissure, triggered by chronic exposure to ultraviolet light (actinic damage). It is typically triangular, apex pointing toward the cornea. Located in sun-exposed regions. - Robbins Pathology; Rosen's Emergency Medicine

Answer:

• Pinguecula: Yellow-white mound on bulbar conjunctiva adjacent to the limbus; does not extend onto the cornea; elastotic degeneration of conjunctival stroma; asymptomatic and innocuous
• Pterygium: Extends onto the cornea; fibrovascular tissue in palpebral fissure; may affect vision if it covers the visual axis Both result from actinic (UV) damage. Biopsy may be needed to exclude neoplasm. - Kanski's; Robbins & Kumar

SECTION F: Specific Clinical Scenarios

Answer: Gonococcal conjunctivitis causes hyperacute, profuse purulent discharge (not just mucopurulent). Unlike typical bacterial conjunctivitis, preauricular lymphadenopathy IS present. It can cause corneal perforation if untreated. It is also a cause of ophthalmia neonatorum. Systemic antibiotics (IV/IM ceftriaxone) are required. - Tintinalli's, p. 1582

Answer: Infiltration is recognized by loss of detail of normal tarsal conjunctival vessels, especially on the upper lid. It represents cellular recruitment to chronic inflammation and typically accompanies a papillary response. - Kanski's, p. 186

Answer: In Sjögren syndrome, the conjunctiva shows squamous metaplasia, loss of goblet cells, and chronic stromal inflammation. This leads to dry eye (keratoconjunctivitis sicca). Subjective symptoms may correlate poorly with objective signs. - Rheumatology, 2-Volume Set (Elsevier)

Answer: Subconjunctival cicatrization refers to fibrotic scarring of the conjunctival stroma. It is seen in:

• Trachoma
• Ocular cicatricial pemphigoid
• Stevens-Johnson syndrome
• Other severe forms of conjunctivitis Severe scarring leads to loss of goblet cells and accessory lacrimal glands, causing dry eye and may result in cicatricial entropion. - Kanski's, p. 186