corneal ulcer
Introduction
Introduction Ocular diseases caused by infections such as bacteria, viruses, and fungi. When the pathogenic factors invade the cornea, the limbal vascular network first expands and is congested, called ciliary congestion. Inflammation oozes, white blood cells invade the lesion, causing edema and edema of the epithelium and stroma, called corneal infiltration. If the condition cannot be controlled, the infiltration will continue to worsen, and degeneration, necrosis, and tissue shedding will occur, and corneal ulcers will form. The infiltrated base is grayish white and the edges are unclear. If the treatment is appropriate, the inflammation is controlled, the base and edges of the ulcer are gradually cleaned, the boundary is clear, the surrounding epithelium is regenerated, and the connective tissue proliferates to form different scars. Cellular corneal ulcer is a corneal suppuration caused by pathogens such as Streptococcus pneumoniae, Staphylococcus, Pseudomonas aeruginosa, Neisseria gonorrhoeae, and Moraxella after injury to the corneal epithelium. Crops, nail scratches, iron filings, and contact lens abrasions are the cause of injury in recent years. Pseudomonas aeruginosa in rural areas and Pseudomonas aeruginosa in the harvest season are the main pathogens. Fungal corneal ulcers were first reported by Leber in 1878. In the past, due to the low incidence rate, it is rarely mentioned in the literature. After the 1950s, reports of outside national value gradually increased. In the past 10 years, the disease has also seen an obvious increasing trend in China. In fact, some of the so-called "crowded corneal ulcers" that are not treated with antibiotics may be fungal and worthy of attention.
Cause
Cause
Bacterial corneal ulcers are more common. It is a severe chemora corneal ulcer. Common claudication corneal ulcers and Pseudomonas aeruginosa corneal ulcers. The former is often accompanied by anterior chamber empyema, also known as anterior chamber pyogenic corneal ulcer. More common in elderly patients with chronic malnutrition chronic dacryocystitis. Often caused by infection with S. pneumoniae Morax-Axenfeld's Staphylococcus aureus after corneal trauma. Its clinical features are acute onset. The lesion begins with a yellow-white infiltration in the center of the cornea. Ulcers form quickly and progress to the periphery and deep. There is a cellulosic exudation in the anterior chamber of the iridocyclitis and formation of anterior chamber empyema. The empyema is sterile before the corneal perforation. Finally, corneal perforations can be formed. Perforation in most cases is a contributing factor to recovery. However, perforation in severe cases can lead to intraocular infections, or endophthalmitis or total ocular inflammation. If you have dacryocystitis, you should do the removal surgery as soon as possible.
Examine
an examination
Diagnosis of bacterial corneal ulcers:
1, according to clinical manifestations, combined with ulcer formation, reference etiology and medical history can generally make a preliminary diagnosis.
2, the scraping of the bacteria for bacterial staining, culture, help to confirm the diagnosis. The diagnosis of fungal corneal ulcer is difficult, generally should start from the following three aspects.
1. If the medical history has one of the following conditions, the pathogen should be further examined.
1 Rural patients, before the onset of a history of agricultural trauma such as rice, or a history of keratitis, or picking up a history of foreign bodies.
2 Long-term use or subconjunctival injection of a variety of antibiotics and ulcers failed to control.
2, symptoms and signs
1 often accompanied by white, yellow-white or gray-white ulcers in front of the empyema, the degree of development is compared with the course of the disease, relatively chronic.
2 eye irritation symptoms and ulcer size comparison, relatively minor.
3, the pathogen
1 ulcer necrotic tissue for scraping, can find fungal hyphae; the scraper is inoculated on the fungal medium, there may be fungal growth.
2 cell culture is generally negative, or only bacteria grow.
Fungal examination method: take the nectar examination of the necrotic tissue of the ulcer surface. If the fungal hyphae can be found, or the necrotic tissue can be cultured, and the fungus grows, it is the most reliable diagnosis basis. The specimen method is to first drop the surface anesthetic, and then use a small pointed blade to scrape a small piece of necrotic tissue with a diameter of 0.5 mm in the infiltrated dense area as a specimen. Generally, potassium oxychloride smear is first checked. If there is still a specimen available, fungal culture can be performed at the same time. Sometimes, the rabbit is used to damage the cornea in the pupil area. Do not take specimens deep in the ulcer to prevent ulceration.
When scraping specimens, it is sometimes possible to make a preliminary identification between fungal and bacterial. Generally speaking, the necrotic tissue of the fungal ulcer surface is "tidal scale" or "toothpaste", the texture is loose and lacks viscosity; and the necrotic tissue of the bacterial ulcer surface is "gelatinized" and rich in viscosity.
(1) Fungal smear method Take a small piece of ulcerated necrotic tissue and place it on a slide. Drop a small drop of 5% potassium hydroxide solution onto it, cover it with a cover slip, and gently press it. The fungal hyphae can be detected by high-power microscopy. Many are often full of vision, but a small amount of hyphae needs to be carefully examined to find out. Smear positive, generally can confirm the diagnosis. Specimens need to be inspected at the time and cannot be saved.
(2) Fungal culture method Take a small piece of necrotic tissue and place it on the slope of solid potato or Sabouraud medium. If it can be inoculated on several media at the same time, it will help to increase the positive rate of culture. Place in a 37 degree Celsius incubator and observe daily. Fungal organisms are possible from the next day after inoculation. If there is no growth after one week, it is positive. The culture method can observe the morphology and color of the fungal colonies, and examine the hyphae, spores, etc. under the microscope to identify the bacteria, preserve the bacteria and test the drug sensitivity. The positive rate of culture is generally low.
Diagnosis
Differential diagnosis
Some ulcers are very bacterial in nature and must rely on careful clinical examination and pathogen diagnosis to identify bacterial corneal ulcers.
Diagnosis of bacterial corneal ulcers:
1, according to clinical manifestations, combined with ulcer formation, reference etiology and medical history can generally make a preliminary diagnosis.
2, the scraping of the bacteria for bacterial staining, culture, help to confirm the diagnosis. The diagnosis of fungal corneal ulcer is difficult, generally should start from the following three aspects.
1, medical history. In case of any of the following conditions, the pathogen should be further examined.
1 Rural patients, before the onset of a history of agricultural trauma such as rice, or a history of keratitis, or picking up a history of foreign bodies.
2 Long-term use or subconjunctival injection of a variety of antibiotics and ulcers failed to control.
2, symptoms and signs
1 often accompanied by white, yellow-white or gray-white ulcers in front of the empyema, the degree of development is compared with the course of the disease, relatively chronic.
2 eye irritation symptoms and ulcer size comparison, relatively minor.
3, the pathogen
1 ulcer necrotic tissue for scraping, can find fungal hyphae; the scraper is inoculated on the fungal medium, there may be fungal growth.
2 cell culture is generally negative, or only bacteria grow.
Fungal examination method: take the nectar examination of the necrotic tissue of the ulcer surface. If the fungal hyphae can be found, or the necrotic tissue can be cultured, and the fungus grows, it is the most reliable diagnosis basis. The specimen method is to first drop the surface anesthetic, and then use a small pointed blade to scrape a small piece of necrotic tissue with a diameter of 0.5 mm in the infiltrated dense area as a specimen. Generally, potassium oxychloride smear is first checked. If there is still a specimen available, fungal culture can be performed at the same time. Sometimes, the rabbit is used to damage the cornea in the pupil area. Do not take specimens deep in the ulcer to prevent ulceration.
When scraping specimens, it is sometimes possible to make a preliminary identification between fungal and bacterial. Generally speaking, the necrotic tissue of the fungal ulcer surface is "tidal scale" or "toothpaste", the texture is loose and lacks viscosity; and the necrotic tissue of the bacterial ulcer surface is "gelatinized" and rich in viscosity.
(1) Fungal smear method Take a small piece of ulcerated necrotic tissue and place it on a slide. Drop a small drop of 5% potassium hydroxide solution onto it, cover it with a cover slip, and gently press it. The fungal hyphae can be detected by high-power microscopy. Many are often full of vision, but a small amount of hyphae needs to be carefully examined to find out. Smear positive, generally can confirm the diagnosis. Specimens need to be inspected at the time and cannot be saved.
(2) Fungal culture method Take a small piece of necrotic tissue and place it on the slope of solid potato or Sabouraud medium. If it can be inoculated on several media at the same time, it will help to increase the positive rate of culture. Place in a 37 degree Celsius incubator and observe daily. Fungal organisms are possible from the next day after inoculation. If there is no growth after one week, it is positive. The culture method can observe the morphology and color of the fungal colonies, and examine the hyphae, spores, etc. under the microscope to identify the bacteria, preserve the bacteria and test the drug sensitivity. The positive rate of culture is generally low.
