A 62-year-old man with a 15-year history of rheumatoid arthritis presents with chronic bilateral conjunctival injection, foreign body sensation, and reduced tear production. Schirmer test shows < 5 mm wetting in 5 minutes. Rose Bengal staining reveals punctate epithelial keratitis. He denies photophobia or discharge. What is the most likely diagnosis?

Explanation

## Diagnosis: Sjögren Syndrome–Associated Keratoconjunctivitis Sicca (KCS) **Key Point:** Sjögren syndrome is an autoimmune disorder affecting lacrimal and salivary glands, causing severe dry eye (keratoconjunctivitis sicca) in up to 50% of patients with rheumatoid arthritis. ### Clinical Features Supporting Diagnosis | Feature | Finding | Significance | |---------|---------|---------------| | **Systemic disease** | 15-year RA history | Sjögren syndrome associated with RA in 10–30% of cases | | **Tear production** | Schirmer < 5 mm/5 min | Diagnostic threshold for aqueous tear deficiency | | **Ocular surface** | Rose Bengal punctate epithelial keratitis | Vital dye staining indicates epithelial damage from desiccation | | **Symptoms** | Foreign body, no discharge | Chronic dry eye, NOT acute infection | | **Bilateral** | Yes | Systemic autoimmune process | ### Pathophysiology 1. Autoimmune destruction of lacrimal gland acinar cells 2. Reduced aqueous tear secretion 3. Tear film instability → epithelial desiccation 4. Punctate keratitis and potential corneal scarring if untreated **High-Yield:** The **Schirmer test < 5 mm** is the gold standard for diagnosing aqueous tear deficiency and is part of the classification criteria for Sjögren syndrome. **Mnemonic — Sjögren Syndrome Diagnosis (AECG criteria):** **A**bnormal Schirmer, **E**vidence of focal sialadenitis, **C**linical symptoms (dry eye/mouth), **G**landular involvement (biopsy/imaging) ### Diagnostic Confirmation - **Ocular Staining Score (OSS):** Rose Bengal or lissamine green; score ≥ 4 suggests Sjögren-associated KCS - **Tear osmolality:** > 308 mOsm/kg (hyperosmolar tears) - **Tear break-up time (TBUT):** < 5 seconds (unstable tear film) - **Serologic markers:** Anti-SSA/Ro and anti-SSB/La antibodies (present in 40–60% of Sjögren syndrome) ### Management 1. **Topical lubricants:** Preservative-free artificial tears, hyaluronic acid drops 2. **Topical cyclosporine 0.05%:** Reduces inflammation; improves tear production 3. **Punctal plugs:** Conserve remaining tears 4. **Systemic immunosuppression:** If severe; consider hydroxychloroquine or methotrexate 5. **Avoid:** Antihistamines, decongestants (worsen dryness) **Clinical Pearl:** Patients with Sjögren syndrome have increased risk of corneal ulceration, secondary bacterial infection, and vision-threatening scarring if KCS is not aggressively managed. ### Why NOT the Other Diagnoses? - **Bacterial conjunctivitis:** Would present with purulent discharge, acute onset, and positive bacterial culture — absent here - **Allergic conjunctivitis:** Typically unilateral or seasonal, with itching and papillary response; Schirmer test normal - **Viral conjunctivitis:** Acute presentation, watery discharge, follicular response; chronic course and reduced tear production are not typical [cite:Parson's Diseases of the Eye 21e Ch 6; Harrison 21e Ch 328]