## Clinical Diagnosis: Trachoma (Active Stage, TF) ### Key Diagnostic Features **High-Yield:** Arlt's line (horizontal scarring of upper tarsal conjunctiva) is pathognomonic for trachoma and is one of the most specific signs in ophthalmology. **Key Point:** The WHO simplified grading for trachoma includes: - **TF (Trachomatous inflammation–Follicular):** Active infection with follicles on upper tarsal conjunctiva - **TS (Trachomatous inflammation–Intense):** Intense inflammation with papillae and follicles - **TA (Trachomatous Trichiasis):** Trichiasis (inturned lashes) indicating previous scarring - **TT (Trachomatous Trichiasis):** Advanced scarring and trichiasis ### Clinical Features of Trachoma | Feature | Trachoma (Active) | Allergic | Adenoviral | Bacterial | |---------|------------------|----------|-----------|----------| | **Onset** | Insidious, chronic | Seasonal/chronic | Acute (1–2 days) | Acute (1–2 days) | | **Duration** | Weeks to months | Seasonal | Self-limited (7–14 days) | 5–7 days | | **Tarsal follicles** | Upper tarsal (Arlt's line) | Lower tarsal | Absent | Absent | | **Pannus** | Superior limbal pannus | Absent | Subepithelial infiltrates | Absent | | **Discharge** | Mucopurulent | Ropy, stringy | Watery/mucopurulent | Purulent | | **Preauricular nodes** | Absent | Absent | Present | Absent | | **Corneal scarring** | Yes (chronic) | No | No | No | | **Arlt's line** | Yes (pathognomonic) | No | No | No | ### Pathophysiology of Trachoma 1. **Causative agent:** *Chlamydia trachomatis* serovars A, B, Ba, C 2. **Transmission:** Fomite contact (contaminated fingers, towels, flies in endemic areas) 3. **Chronic infection** → repeated reinfection → progressive scarring 4. **Immune response:** Th1-mediated (IFN-γ, TNF-α) → conjunctival fibrosis and pannus formation 5. **Arlt's line formation:** Horizontal scarring at the level of the superior tarsal conjunctiva due to repeated inflammation **Clinical Pearl:** Trachoma is the **leading infectious cause of blindness worldwide**, endemic in areas with poor sanitation (sub-Saharan Africa, South Asia, Middle East). In India, trachoma remains a public health concern in rural areas. ### WHO Grading System for Trachoma ```mermaid flowchart TD A[Chlamydia trachomatis A-C infection]:::outcome --> B{Clinical stage?}:::decision B -->|Active inflammation| C[TF: Follicles on upper tarsal]:::action B -->|Intense inflammation| D[TS: Intense papillary response]:::action B -->|Scarring phase| E[TA/TT: Trichiasis + scarring]:::action C --> F[Repeat reinfection]:::action F --> G[Progressive scarring]:::outcome G --> H[Entropion, trichiasis, blindness]:::urgent ``` ### Diagnostic Confirmation - **Nucleic acid amplification test (NAAT):** PCR/TMA for *Chlamydia trachomatis* (gold standard) - **Giemsa stain:** Intracytoplasmic inclusions (Halberstaedter–Prowazek bodies) in conjunctival scrapings - **Immunofluorescence:** Monoclonal antibodies to chlamydial antigens ### Management **Key Point:** Early treatment prevents progression to scarring and blindness. 1. **Systemic antibiotics (first-line):** - Azithromycin 20 mg/kg daily for 3 days (single-dose therapy increasingly used) - OR Doxycycline 100 mg BD for 3 weeks (contraindicated in pregnancy/children <8 years) 2. **Topical antibiotics:** Tetracycline ointment 1% BD for 6 weeks (adjunctive) 3. **Surgical intervention (advanced cases):** - Trichiasis correction (electrolysis, cryotherapy, or surgical removal) - Entropion repair - Corneal transplantation (if scarring causes opacity) 4. **Public health measures:** - Mass drug administration (MDA) in endemic areas - Improved sanitation and hygiene education - Facial cleanliness promotion **High-Yield:** Azithromycin 20 mg/kg single dose is now the preferred treatment for trachoma due to improved compliance and efficacy comparable to 3-week doxycycline courses. [cite:Kanski Clinical Ophthalmology 9e Ch 3; WHO Trachoma Elimination Guidelines] 
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.