Free previewYou're reading the free part of this topic. The rest is included with Clinical.See what's included
Peripheral Ulcerative Keratitis (PUK) And Mooren Ulcer
Cornea
1. Clinical Analogy - Conceptual Foundation
The Moat & The Castle
- Think of the cornea as a walled castle. The peripheral cornea is the moat - closest to the immune machinery of the limbal vasculature.
- PUK is when the immune system's army (neutrophils, MMPs, complement) erroneously breaches the moat wall, dissolving the stromal scaffold.
- Mooren's ulcer is the same battlefield - but with NO identifiable general (systemic disease). The attack is idiopathic, autoimmune, and the cornea itself becomes the antigen.
- The limbal vessels are the supply line: cut them (conjunctival resection) and the attack weakens.
2. Definition & Classification
Peripheral Ulcerative Keratitis (PUK) is a crescent-shaped, destructive inflammatory ulceration of the peripheral corneal stroma (within 2 mm of the limbus), associated with epithelial loss, stromal melting, and often an underlying systemic immune-mediated condition. Peripheral Ulcerative Keratitis (PUK) may result from local or systemic infectious or noninfectious causes; secondary infection can complicate it.
Classification of PUK by Aetiology
| Category | Conditions | Key Mechanism |
|---|---|---|
| Autoimmune (Connective Tissue) | • Rheumatoid arthritis (RA) (most common) • Systemic lupus erythematosus (SLE) • Granulomatosis with polyangiitis (formerly Wegener granulomatosis) (GPA) • Polyarteritis nodosa (PAN) • Relapsing polychondritis • Sjögren syndrome (SS) | • Immune complex deposition • Complement activation • Matrix metalloproteinase production (MMPs) |
| Inflammatory Bowel Disease | • Crohn disease • Ulcerative colitis | • Cross-reactive epitopes • T-cell dysregulation |
| Infectious | • Rosacea keratitis • Herpes simplex virus (HSV) • Herpes zoster virus (HZV) • Tuberculosis (TB) • Syphilis | • Antigen mimicry • Direct invasion |
| Idiopathic | • Mooren ulcer | • Autoimmune mechanism • Molecular mimicry is a proposed trigger or contributing mechanism |
| Post-surgical | • Post-pterygium excision • Post-laser-assisted in situ keratomileusis (LASIK) | • Corneal injury or surgery may expose normally hidden corneal antigens • Exposure may trigger an immune response |
| Category | Conditions | Key Mechanism |
|---|---|---|
| Autoimmune (Connective Tissue) | • Rheumatoid arthritis (RA) (most common) • Systemic lupus erythematosus (SLE) • Granulomatosis with polyangiitis (formerly Wegener granulomatosis) (GPA) • Polyarteritis nodosa (PAN) • Relapsing polychondritis • Sjögren syndrome (SS) | • Immune complex deposition • Complement activation • Matrix metalloproteinase production (MMPs) |
| Inflammatory Bowel Disease | • Crohn disease • Ulcerative colitis | • Cross-reactive epitopes • T-cell dysregulation |
| Infectious | • Rosacea keratitis • Herpes simplex virus (HSV) • Herpes zoster virus (HZV) • Tuberculosis (TB) • Syphilis | • Antigen mimicry • Direct invasion |
| Idiopathic | • Mooren ulcer | • Autoimmune mechanism • Molecular mimicry is a proposed trigger or contributing mechanism |
| Post-surgical | • Post-pterygium excision • Post-laser-assisted in situ keratomileusis (LASIK) | • Corneal injury or surgery may expose normally hidden corneal antigens • Exposure may trigger an immune response |
Free preview ends here
Keep reading Peripheral Ulcerative Keratitis (PUK) And Mooren Ulcer
13 more sections are included with the Clinical plan.
- Epidemiology
- Pathophysiology
- Clinical Features
- Differential Diagnosis - Peripheral Corneal Ulcers
- Investigations
- Management