Gram-positive cocci and Gram-negative bacilli scleritis
Introduction
Introduction to Gram-positive cocci and Gram-negative bacillary scleritis Infectious scleritis Inflammation caused by pathogen infection, which may be caused by direct invasion of the pathogen or by an allergic reaction caused by the pathogen. basic knowledge The proportion of illness: 0.03% Susceptible people: no specific population Mode of infection: non-infectious Complications: keratitis
Cause
Gram-positive cocci and Gram-negative bacillary scleritis
(1) Causes of the disease
Common pathogens causing bacterial scleritis are: pseudomonas of pseudomonadaceae, streptococcus of streptococcaceae, staphylococcus of the genus Staphylococcus And proteus of the enterobacteriaceae (enterobacteriaceae).
Scleral foreign body, eye surgery or postoperative beta ray irradiation, topical application of immunosuppressive drugs and ocular trauma as scleritis are gradually gaining attention. In recent years, more and more reports at home and abroad are corneal damage caused by long-term wear of contact lenses. In addition, the lens itself and the preservation solution are easily contaminated, causing corneal infection. Pseudomonas aeruginosa (Pseudomonas aeruginosa) is a conditional pathogen, causing eye infections to occur mostly in people with low immunity and Patients, Pseudomonas aeruginosa caused the most common exogenous scleritis, first caused by keratitis and spread to the sclera, 14% to 20% of the conjunctival sac can be isolated from streptococcus, usually not pathogenic, Streptococcus pneumoniae Streptococcus pneumoniae scleritis is also caused by corneal infection or pterygium secondary to beta radiation, Staphylococcus aureus, staphylococcus epidermidis and proteolytic scleritis Rare.
(two) pathogenesis
The normal structure and defense mechanism of the sclera are destroyed and the exogenous bacteria invade the sclera, which can cause local inflammation. The bacterial scleritis is often caused by the infection of the initial conjunctiva and cornea. Risk factors include contact lens damage, recent eyes. Surgery or suture reaction (radiation therapy or topical application of immunosuppressive agents after pterygium excision, scleral cerclage or scleral electrocoagulation of retinal detachment, condensation or strabismus surgery, etc.), making conjunctival regeneration difficult or secondary infection, forming Continuous scleral exposure, scleritis, topical application of drugs (glucocorticoids, interferons, etc.), neovascular glaucoma, ocular adnexal disease, corneal degeneration (herpes simplex or herpes zoster keratitis, corneal exposure) And consumptive systemic diseases (AIDS, diabetes), etc.
Inflammation of the local sclera or superficial scleral blood vessels caused by scleritis, some bacteria such as Pseudomonas, Streptococcus and Staphylococcus can produce immune complex deposition can cause blood vessel wall immune response, scleral microvascular inflammation, self-initiation Immune scleritis followed by systemic manifestations.
Prevention
Gram-positive cocci and Gram-negative bacillary scleritis prevention
During the use of contact lenses, as well as eye redness, eye pain and other symptoms after scleral-related surgery, the presence of various types of scleral inflammation must be ruled out.
Complication
Gram-positive cocci and gram-negative bacillary scleritis complications Complications keratitis
Scleral necrosis, scleral staphyloma and so on.
Symptom
Gram-positive cocci and Gram-negative bacillary scleritis symptoms Common symptoms Tear tear photokeratitis elevated intraocular pressure sclera
Bacterial scleritis mostly diffuse or nodular, acute onset, often accompanied by acute catarrhal conjunctivitis (acute catarrhal conjunctivitis), patients with conjunctival hyperemia, photophobia, tearing, eye pain and decreased vision, inflammatory stimulation A large number of secretions, first mucus, later purulent, 60% of patients with severe eye pain, can be limited, can also be transmitted along the branches of the trigeminal nerve, diffuse anterior scleritis scleral tissue edema, and due to edema to the surface The deep sclera of the sclera, the deep vascular plexus of the sclera is more prominent than the superficial vascular plexus, which is typically dark red. The disease is relatively good, 60% of cases involve part of the anterior sclera, and 40% of cases involve all the anterior sclera, nodules Sexual anterior scleritis lesions are purplish red congestion, scleral inflammation infiltration, tissue edema, nodules, nodules, tenderness, inability to move, nodules are often single, 40% of cases have several, and may be accompanied by sclera Outer layer inflammation.
Severe cases of necrotizing anterior scleritis, and may involve the vitreous, caused by Pseudomonas aeruginosa, red eyes, eye pain, photophobia, tearing, conjunctival sac secretion and vision loss are common symptoms, photophobia, tearing often Associated with keratitis, if photophobia, tearing is very serious, often indicates the possibility of scleral tissue necrosis, 74% of patients with necrotizing anterior scleritis have vision loss, necrotizing anterior scleritis eye pain is severe, can be radiated Around the eyebrow and the eyelids, often affects sleep, the sensory nerve structure through the sclera is destroyed, matrix edema and inflammatory infiltration around the axon are closely related to severe eye pain. Necrotizing anterior scleritis is often accompanied by fasciitis. The nerves of the fascia sac and sclera are also involved in eye pain. The signs of bacterial necrotizing anterior scleritis are early localized inflammatory infiltration, acute congestion, scleral tenderness, edema in some areas of sclera, nearby The surface sclera has a flaky avascular zone, which is a reliable feature of necrotizing anterior scleritis. Inflammation can be a limitation. If not treated, the inflammation spreads until And the entire anterior segment of the sclera, after the scleral necrosis is absorbed, the uveal membrane is exposed, if there is no increase in intraocular pressure (>30mmHg), no staphyloma will form, and staphylococcal anterior scleritis will also show chronic inflammation changes, forming scleral pain. Nodules, granulomas or fistulas, ulcerative lesions of the sclera and conjunctival tissue.
According to the characteristic clinical manifestations of scleritis, a preliminary diagnosis can be made, and a laboratory examination is needed for the diagnosis.
Examine
Examination of Gram-positive cocci and Gram-negative bacillary scleritis
1. Bacteriological examination Before the use of antibiotics, secretions or tissue scrapings must be carried out for Gram staining, Giemsa staining (Giemsa) and bacteriological culture and drug susceptibility testing, according to the results of staining and isolation culture. Identify pathogens and make a correct diagnosis.
2. Pathological examination If the clinical first consideration of bacterial infection, but staining and culture (48h) negative, the patient is not effective for the initial broad-spectrum antibiotic treatment, need to be scleral or limbal limb tissue biopsy, biopsy tissue after soaking with formaldehyde solution, using Special dyeing methods such as periodic acid-schiff (PAS), acid fast, Gomori methenamine silver (GMS), stilbene fluorescent whitening Histopathological examinations such as calcofluor white (CFW) can also identify infectious pathogens.
No special auxiliary inspection.
Diagnosis
Diagnosis and identification of Gram-positive cocci and Gram-negative bacillary scleritis
Mainly to distinguish between viral infectious scleritis, as well as other types of bacterial infections or non-infectious scleritis.
Bacteriological examination
Before using antibiotics, secretions or tissue scrapers must be used for Gram staining (Gram) Giemsa staining (Giemsa) and bacteriological culture and drug susceptibility tests. According to the results of staining and isolation culture, pathogens can be determined early to make a correct diagnosis.
2. Pathological examination
If the clinical first consideration of bacterial infection but staining and culture (48h) negative patients are not effective for the initial broad-spectrum antibiotic treatment, scleral or limbal biopsy biopsy tissue should be used after soaking with formaldehyde solution, using special staining methods such as periodic acid-Schiff Epigenetic acid-schiffPAS acid fast omomelamine hexamine silver staining (Gomori methenamine silverGMS) stilbene fluorescent whitening agent staining (calcofluor whiteCFW) and other histopathological examination can also identify infectious pathogens .
