Pseudomonas aeruginosa corneal ulcer

Introduction to Pseudomonas aeruginosa corneal ulcer Pseudomonas aeruginosa corneal ulcer is one of the most serious suppurative keratitis. The symptoms are severe and develop rapidly. The entire cornea can be destroyed within 24 to 48 hours. It can be blinded within a few days. It must be rescued in time and disinfected. To prevent cross-infection. The necrotic tissue is sticky and can quickly fall off to form an ulcer. There is a ring-shaped infiltration around the ulcer, which cuts off the connection between the lesion and the limbal vascular network. The disease is mainly caused by Gram-negative aerobic bacillus, Pseudomonas aeruginosa, which is often found in soil and water. It can also be found in normal human skin, upper respiratory tract and normal conjunctival sac, and can also be attached to foreign bodies. As well as contaminated eye drops, especially fluorescein liquid or incompletely disinfected instruments, they can also be found in cosmetics, and even in preserved distilled water. According to statistics, the incidence rate is highest in late summer and early autumn. basic knowledge The proportion of illness: 0.032% Susceptible people: no special people Mode of infection: contact infection Complications: glaucoma corneal ulcer

Causes of Pseudomonas aeruginosa corneal ulcer

Cause:

It is caused by Gram-negative aerobic bacillus, Pseudomonas aeruginosa, which is often found in soil and water. It can also be found in normal human skin, upper respiratory tract and normal conjunctival sac, and can also be attached to foreign bodies and contaminated. In the eye drops, especially in fluorescein or incompletely disinfected instruments, it can also be present in cosmetics, even in distilled water. According to statistics, the highest incidence rate in late summer and early autumn may be related to Pseudomonas aeruginosa. The most suitable breeding temperature is 30~37°C. Although Pseudomonas aeruginosa is very toxic, its invasiveness is weak, only the cornea is damaged (such as surgery, various corneal trauma, corneal foreign body injury) or corneal resistance (such as nutrition). Poor, corneal exposure, paralysis, etc.) can easily cause infection.

Pseudomonas aeruginosa corneal ulcer prevention

There may be Pseudomonas aeruginosa in the skin and conjunctival sac. Once the cornea is traumatized, there is a risk of corneal ulcer. Applying contaminated eye drops (such as fluorescein) and ophthalmic instruments can cause infection. Therefore, it must be in no Remove corneal foreign bodies under the conditions of bacteria, and fluorescein and other eye drops should be replaced regularly.

At present, there are more and more people wearing contact lenses. The incidence of Pseudomonas aeruginosa corneal ulcers is also increased due to wearing contact lenses. The surface of the contact lens usually has adhesion of mucin, which is easy to be contaminated with Pseudomonas aeruginosa. The mirror itself has damage to the corneal epithelium, especially long-term contact lenses, and there are more cases of Pseudomonas aeruginosa corneal ulcers. Therefore, the contact lens must be cleaned and disinfected regularly.

Pseudomonas aeruginosa corneal ulcer complications Complications glaucoma corneal ulcer

This disease is one of the most ferocious corneal ulcers, the prognosis is poor, late treatment or treatment is not timely, often form large spots or white spots, often up to 3 ~ 8 mm in diameter, scars dense, involving the full thickness of the cornea The tissue is thinner, about 1/3 to 3/4 of the normal corneal thickness, the surface is flat, and the fashion is accompanied by new blood vessels, which obviously affects the visual acuity. The diameter of the white spot is more than 8 mm, or accompanied by a pre-adhesion. Vision can be up to light or manual, there is fashion to continue glaucoma, the prognosis is even worse, such as ulcers have been perforated at the time of treatment, accompanied by large iris out, or secondary intraocular infection, eyeball removal or eye Content excavation.

Pseudomonas aeruginosa corneal ulcer symptoms Common symptoms Conjunctival edema and corneal ulcer Corneal ulcer Conjunctival congestion Conjunctival hyperemia exposed...

Sudden onset, rapid development, short incubation period, infection can occur, corneal irritation is severe, secretions are more, vision is decreased, bulbar conjunctiva is highly edematous, and hyperemia is present, corneal stroma can be rapidly damaged and perforated, early infection, in the cornea There is a small area of gray-yellow infiltration in the center, bulging, diffuse edema around and deep in the matrix, and then quickly form a round, semi-annular or ring-shaped translucent oily gray-white necrotic area; necrotic tissue is sticky and can quickly fall off Ulcer, surrounded by an annular infiltration around the ulcer, thus cutting off the relationship between the lesion and the limbal vascular network; plus the invasion of neutrophils and the destruction of collagen fibers by collagenase produced by Pseudomonas aeruginosa in the cornea, The corneal stroma is further accelerated to necrosis. New research data suggest that the protease that destroys the cornea by Pseudomonas aeruginosa is a protein glycoside lytic enzyme, and its degradation can discard the collagen fibers, thereby liquefying the cornea, which can cause the entire corneal necrosis within 1-2 days. And perforation, eventually blinded by endophthalmitis or even full eye inflammation.

Examination of Pseudomonas aeruginosa corneal ulcer

Since Pseudomonas aeruginosa secretes fluorescein and pyocyanin, a large amount of viscous secretion attached to the ulcer surface is pale green, which is one of the characteristics of this disease. In addition, severe iridocyclitis can be found early. Then there is a yellow anterior chamber empyema.

Diagnosis and differentiation of Pseudomonas aeruginosa corneal ulcer

diagnosis

Diagnosis can be performed based on clinical performance and laboratory tests.

Differential diagnosis

Mainly differentiated from bacterial corneal ulcers.

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