Corneal Ulcer and Ulcerative Keratitis in Emergency Medicine

Updated: Aug 02, 2017
  • Author: Jesse Borke, MD, FACEP, FAAEM; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Overview

Background

A corneal ulcer is a loss of corneal tissue, often associated with inflammation, and ulcerative keratitis is the general term for the group of disease processes leading to corneal ulceration, as well as the term for the inflammation that accompanies ulceration.

Most corneal ulcers are infectious, including bacterial and viral etiologies. Noninfectious ulcers may be due to chemical burns or autoimmune, toxic, neurotrophic, or other causes.

Because of its potential to permanently impair vision or progress to perforation and an open globe, a corneal ulcer is considered an ophthalmologic emergency.

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Pathophysiology

Although corneal ulcers may occasionally be sterile, most are infectious in etiology.

Bacterial keratitis is the most important etiology to exclude in the emergency department (ED). Corneal infections and infectious keratitis are often presumed to be bacterial until proven otherwise.

Bacterial corneal ulcers may follow a break in the corneal epithelium, thereby providing an entry for bacteria. The traumatic episode may be minor, such as a minute abrasion from a small foreign body, or may result from such causes as tear insufficiency, malnutrition, or contact lens use. Increased use of soft contact lenses in recent years has led to a dramatic rise in the occurrence of corneal ulcers, particularly due to Pseudomonas aeruginosa. [1]

Common bacterial isolates cultured from patients with keratitis include P aeruginosa, coagulase-negative staphylococci, Staphylococcus aureus, Streptococcus pneumoniae, and Enterobacteriaceae (including Klebsiella, Enterobacter, Serratia, and Proteus). Klebsiella pneumoniae mucoid phenotype and its ability to form biofilm may be important in producing corneal ulceration. Agents such as N-acetylcysteine, may have a role in treatment because they inhibit biofilm formation.

Ulcers due to viral infection occur on a previously intact corneal epithelium.

Herpes simplex and varicella-zoster viruses can both cause a significant infectious keratitis. [2]

With the introduction of topical corticosteroid drugs in the treatment of eye disease, fungal corneal ulcers have become more common. Fungi (Fusarium and Candida species) and parasitic amoeba (Acanthamoeba) have been found in a small number of patients and frequently present with more severe symptoms.

Peripheral ulcerative keratitis (PUK) is a complication of rheumatoid arthritis (RA) that can lead to rapid corneal destruction (corneal melt) and perforation with loss of vision. An example is shown in the image below.

Peripheral ulcerative keratitis in the right eye o Peripheral ulcerative keratitis in the right eye of a patient with rheumatoid arthritis. Glue has been placed.

Mooren ulcer is an idiopathic ulceration of the peripheral cornea that may result from an autoimmune reaction or may be associated with hepatitis C virus. It is a rapidly progressive, painful, ulcerative keratitis, which initially affects the peripheral cornea and may spread circumferentially and then centrally. Mooren ulcer can only be diagnosed in the absence of an infectious or systemic cause.

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Epidemiology

Incidence

United States

Approximately 25,000 Americans develop infectious keratitis annually. The annual incidence of microbial keratitis associated with contact lens use is approximately 2-4 infections per 10,000 users of soft contact lenses and 10-20 infections per 10,000 users of extended-wear contact lenses. Approximately 10% of these infections result in the loss of 2 or more lines of visual acuity. [3]

International

A study from the United Kingdom reported factors associated with an increased risk of a corneal invasive event in the population studied. The factors included use of extended-wear hydrogel lenses, male gender, smoking, and the late winter months. [4]

Morbidity

Corneal scarring and vision loss are possible consequences.

Sex

Studies from the United Kingdom suggest that males who wear extended-wear contact lenses are at increased risk of forming a corneal ulcer.

Other studies suggest that males are at increased risk due to the higher probability of sustaining ocular trauma.

Age

Corneal injury or infection can affect people of all ages. A bimodal distribution is observed. The age groups with a higher prevalence of disease are likely tied to risk factors, those in the first group (< 30 y) who are more likely to be contact lenses wearers and/or sustain ocular trauma, and those in the second group (>50 y) who are more likely to undergo eye surgery.

Contact lenses

Infectious keratitis is significantly more common in contact lens wearers.

Authors from the United Kingdom also report an 8 times higher incidence of corneal invasive event in contact lens wearers who sleep in contact lenses compared with wearers who use lenses only during the waking hours. [5]

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