BASICS

DESCRIPTION

• Noninfectious/immune mediated: Peripheral cornea is 2 mm from the limbus and is susceptible to vasculitis because of its dependency and proximity to the limbal vascular arcade. Compromised blood flow, immunoglobulin/complement deposition create inflammation, which leads to peripheral ulcerative keratitis (PUK) (1). Necrotizing scleritis can occur with PUK if an aggressive vasculitis exists.

• Infectious: Peripheral epithelial defect provides entry of organism.

– Bacterial: If inferiorly: possible lagophthalmos debilitated state, e.g., Moraxella infections (alcoholics) and Pseudomonas (hospitalized comatose patients)

– Fungal: Similar to central ulcers

– Viral: Herpes simplex—May not be hypesthetic, more refractory to treatment

– Herpes zoster (2)

EPIDEMIOLOGY

Incidence

Infectious—fungal keratitis 24% (3)

RISK FACTORS

• Connective tissue (CT) diseases/vasculitides: Rheumatoid arthritis, Wegener’s granulomatosis, polyarteritis nodosa; eye trauma(ensuing aberrant immune response)

• Debilitated state-chronic lagophthalmos

PATHOPHYSIOLOGY

Systemic CT disease with deposition of immune complexes in limbal vessels that cause inflammation, stimulate complement release with limbal and corneal infiltration by inflammatory cells with ulceration of the cornea and possible sclera.

ETIOLOGY

Systemic immune-mediated limbal vasculitis that leads to peripheral corneal ulceration. Infrequently trauma/surgery (4). Possible autoimmune response to tissue antigens.

COMMONLY ASSOCIATED CONDITIONS

Rheumatoid arthritis, Wegener’s granulomatosis, polyarteritis nodosa, CT diseases

DIAGNOSIS

HISTORY

• Red, painful eye with photophobia. Sometimes more severe pain, possible “headache” if scleritis is present

• History of rheumatoid arthritis, Wegener’s granulomatosis, polyarteritis nodosa, and other CT diseases. The systemic diseases may not clinically correlate with the severity of the ocular manifestation.

• Infectious—Eye trauma, eye rubbing, surgery, lagophthalmos, possible purulent discharge

PHYSICAL EXAM

• Immune: Intact overlying epithelium in some cases, concentric immune infiltrates that spread concentrically. Hypopyon rare. Microulcerative: less than 2 clock hours and do not progress centrally. Macroulcerative: greater than 2 clock hours; generally ulceration, both central and circumferential progression; undermined central edge, dense infiltration, epithelial breakdown, and melting. Necrotizing scleritis may occur with corneal perforation. If inferior may suggest a dry eye with lagophthalmos.

• Infectious: Epithelial defect that spreads centrally as it worsens. Possible ring corneal infiltrates surround a central infection. Some may advance to perforation if treatment delayed. May have purulent discharge; hypopyon.

• Viral: Peripheral dendrites that coalesce, possible stromal infiltrate. If metaherpetic, may result in corneal thinning.

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Initial lab tests

• Immune: May not be necessary if Dx of CT disease exists. If suspect Wegener’s or polyarteritis: chest X-ray (CXR), U/A, BUN/Cre, antineutrophil cytoplasmic antibodies (ANCAs). Possible CBC, anti-nuclear antibody (ANA), ESR, fluorescent treponemal antibody absorption test (FTAabs), reactive plasma reagin (RPR), hepatitis C serologies, rheumatoid factor (RF). Wegener’s/polyarteritis Dx may require a lung or renal biopsy.

• Infectious: Corneal scrapings for culture and sensitivities if bacteria or fungus are suspected.

• Viral: Immunoassay? Polymerase chain reaction (PCR) for herpes simplex virus (HSV) only if high suspicion and all other studies are negative (5). Viral cultures (Richmond viral transport medium), fluorescent antibody testing (FAB) (No fluorescein stain prior to collection of sample. Fluorescein alters results.) (5)

Follow-up & special considerations

Immune: Consult Rheumatologist or Clinical Immunologist with experience in corneal manifestations of CT disorders.

Imaging

Initial approach

Only if suspect Wegener’s or polyarteritis—Chest X-ray

Follow-up & special considerations

Immune/infectious follow-up frequently, daily if necessary, until some improvement, in the event of an impending perforation.

Diagnostic Procedures/Other

Corneal scrapings for culture and sensitivity

Pathological Findings

• Noninfectious—Peripheral inflammation that can progress to corneal melting and perforation.

• Infectious-–Can progress to corneal thinning and perforation.

DIFFERENTIAL DIAGNOSIS

• Immune—Rheumatoid arthritis, Wegener’s granulomatosis, polyarteritis. Mooren’s ulcer is diagnosis of exclusion. Herpes zoster virus (HZV) sclerokeratitis: limbal vasculitis and ischemia

• Infectious—Bacterial (staph, B hemolytic strep, Pseudomonas, Moraxella, Neisseria gonorrhoeae), HSV, herpes zoster ophthalmicus, systemic hepatitis 83–84, chlamydial (trachoma and inclusion conjunctivitis)

TREATMENT

MEDICATION

First Line

• Immune: Treat underlying disease, suppress inflammation with tectonic support, and promote healing. (Cornea p. 347) Systemic treatment by rheumatologist—corticosteroids and immunosuppressive medications, e.g., methotrexate, cyclosporine, mycophenolate mofetil (CellCept), azathioprine, and cyclophosphamide. Treatment may increase lifespan (6).

• Provide tectonic support via cyanoacrylate adhesive application to the ulcer bed with a bandage soft contact lens. May need a peripheral lamellar keratoplasty. Treat any underlying dry eye: preservative-free tears, punctual plugs/cautery, bandage soft contact lenses with lubrication, and fluoroquinolone antibiotic coverage or partial tarsorrhaphy if partial lid closure. Avoid corticosteroids if inferior and may be associated with a dry eye. May cause corneal melting.

• Infectious:

– Bacterial: Treat with broad-spectrum antibiotic coverage: Fortified antibiotics or fluoroquinolones. Cultures and sensitivities can guide antibiotic selection.

– Fungal: Treat with broad-spectrum antifungals—pending cultures/fungal stains or corneal biopsies if necessary

– Viral: Topical antivirals, PO Acyclovir

Pregnancy Considerations

Immune: Notify rheumatologist before immunosuppressive oral treatments are given.

Second Line

• Immune/infectious: Provide tectonic support if threat of perforation. Tissue glue; peripheral lamellar grafts.

• Immune: Conjunctival resection adjacent to area of peripheral corneal ulceration and thinning

ADDITIONAL TREATMENT

General Measures

Frequent monitoring until stabilized

Issues for Referral

• Impending perforation

• Recalcitrant to treatment with worsening visual prognosis

COMPLEMENTARY & ALTERNATIVE THERAPIES

• Vitamin C—promotes healing

• Fish oil—helps to normalize meibomian gland secretions and stabilize tear film

SURGERY/OTHER PROCEDURES

• Peripheral lamellar keratoplasties

• Tissue glue for focal perforations

• Conjunctival resection

IN-PATIENT CONSIDERATIONS

Initial Stabilization

Infectious: Begin appropriate therapy immediately upon arrival to the hospital.

Admission Criteria

Inability to administer necessary frequent topical medications and requiring IV meds

IV Fluids

Defer to internist/hospitalist

Nursing

Instruct re: proper drop instillation

Discharge Criteria

Stabilization of ulceration

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Immune: Continued follow up with rheumatologist. Careful ophthalmic monitoring with tapering of systemic meds. May require chronic long-term, low-dose maintenance as determined by the rheumatologist.

• Infectious: May need surgery if scarring involves visual axis. Depth of scarring and location will determine necessity for full-thickness or partial-thickness lamellar keratoplasties.

Patient Monitoring

• Immune: Co-management with rheumatologist as determined by response to treatment

• Infectious: According to response to treatment

DIET

No restrictions

PATIENT EDUCATION

Signs and symptoms of peripheral keratitis for earlier diagnosis

PROGNOSIS

Depends on involvement of visual axis and extent of peripheral thinning—induced astigmatism

COMPLICATIONS

Perforation, thinning, severe scarring, possible recurrences for the immune, and herpetic causes

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