## Emergency Management of Alkali Chemical Injuries **Key Point:** The first and most critical step in alkali chemical injury is **immediate and copious irrigation** to remove the offending agent and prevent continued penetration into deeper tissues. This is a true ocular emergency where the first 5–15 minutes determine the final visual outcome. ### Why Immediate Irrigation is Paramount **High-Yield:** Alkali burns are **time-dependent injuries**. Unlike acid burns where protein coagulation limits penetration, alkali (especially lime/calcium oxide) continues to penetrate tissue for hours, causing progressive saponification of lipids and destruction of cell membranes. The window for effective intervention is narrow. ### Pathophysiology of Lime Injury 1. **Calcium oxide (CaO) + water → Calcium hydroxide (Ca(OH)₂)** — a strong base that rapidly penetrates ocular tissues. 2. **Saponification** of conjunctival and corneal lipids → loss of cell membrane integrity. 3. **Protein denaturation** → tissue necrosis and ischaemia. 4. **Continued penetration** for 24–48 hours if not irrigated immediately. ### Immediate Management Protocol ```mermaid flowchart TD A[Chemical Eye Injury Presentation]:::outcome --> B[STOP: Immediate irrigation]:::urgent B --> C[Copious irrigation with saline/<br/>Ringer's lactate for 15-20 min]:::action C --> D[Remove particulate matter<br/>with cotton swab/forceps]:::action D --> E[Check pH of tear film<br/>Goal: pH 7-7.4]:::decision E -->|pH still alkaline| F[Continue irrigation until<br/>pH normalizes]:::action E -->|pH normal| G[Topical antibiotics<br/>& cycloplegics]:::action G --> H[Systemic vitamin C<br/>500 mg IV/oral]:::action H --> I[Urgent corneal specialist<br/>referral]:::action I --> J[Monitor for complications:<br/>corneal scarring, symblepharon,<br/>secondary glaucoma]:::outcome ``` **Clinical Pearl:** **Particulate matter removal is essential** — lime particles continue to react with water in the tear film, generating heat and alkali. Gentle removal with a cotton-tipped applicator or jeweller's forceps under topical anaesthesia prevents ongoing chemical reaction. ### Role of Systemic Vitamin C **Mnemonic:** **VIT-C = Vital In Tissue Collagen synthesis; Collagen remodelling prevention** - Vitamin C (ascorbic acid) inhibits collagen cross-linking and reduces scar formation. - Dosing: 500 mg IV or oral, 4 times daily for 7–10 days. - Most effective when started within the first 24 hours. - Reduces the incidence of symblepharon and corneal scarring by ~50%. ### Why Other Options Are Incorrect or Delayed | Intervention | Timing | Role | |--------------|--------|------| | **Irrigation** | **Immediate (within 5 min)** | **First priority — prevents further damage** | | **Topical steroids** | After irrigation | Reduces inflammation; NOT first-line | | **Cycloplegics** | After irrigation | Reduces pain; NOT first-line | | **Bandage contact lens** | After stabilization | Aids epithelial healing; NOT emergency | | **Anterior chamber tap** | Only if IOP > 40 mmHg | Addresses secondary glaucoma, not primary injury | **Warning:** Delaying irrigation to apply topical medications, perform imaging, or manage pain is a **critical mistake**. Every minute of delay increases tissue damage. Irrigation should begin even before formal examination in suspected alkali injuries. ### Grading and Prognosis in This Case The patient has **Roper Hall Grade 3 injury** (opaque cornea, 40% limbal ischaemia). This carries a **guarded prognosis** for visual recovery, but aggressive early management (irrigation, vitamin C, specialist care) can prevent progression to Grade 4 (poor prognosis). [cite:Khurana 7e Ch 8; Parson's 22e Ch 7] 
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