Fungal scleritis

Introduction to fungal scleritis Fungal scleritis manifests as a slowly progressive necrotizing anterior scleritis. The onset is slow. The main symptoms are redness, photophobia, tearing, eye pain, decreased vision and conjunctival sac secretion. Compared with bacterial scleritis, the irritation symptoms are milder and the course of disease is longer. Most patients with fungal scleritis have pain, can be confined to the eye, can also be transmitted along the trigeminal nerve branch to the temporal head and frontal, easily misdiagnosed as migraine, sinusitis, and even brain tumors. basic knowledge Sickness ratio: 0.00005%-0.0001% Susceptible people: no specific population Mode of infection: non-infectious Complications: intraocular inflammation eyeball retraction

Cause of fungal scleritis

(1) Causes of the disease

The fungus causing scleritis is a eukaryotic microorganism that is widely distributed in air, soil and nature. It can be divided into yeast (yeast), fungi (mold) and dimorphic (dimorphic). The most common cause of scleritis is filiform. Filamentous, such as aspergillus, acremonium; other scleral infections are two-dimensional filamentous fungi such as sporothrix schenckii, rhinosporidium seeberi Etc., most of the parasitic bacteria, opportunistic infections occur when systemic or local trauma and low immunity, risk factors are: accidental trauma, especially vegetal and soil factors of the sclera and / or corneal trauma, ophthalmology Surgery such as pterygium excision with -ray irradiation, retinal detachment scleral buckling (Figure 1) and total ocular inflammation, systemic bacterial and viral infections, immune system abnormalities, chronic wasting diseases, long-term wear contact lenses, Intravenous drug users, long-term medication for chronic diseases, including glucocorticoids, immunosuppressants, etc.

(two) pathogenesis

Most pathogenic fungi of deep mycosis are opportunistic fungi. Only when the immune function of the body is reduced, especially when the cellular immune function is reduced, they invade the tissue and cause disease. Superficial fungal infection rarely induces immune response. Individuals may develop delayed allergic reactions, which usually manifest after 10 to 14 months of infection. This is important for the host to obtain specific antifungal infections. Sensitized T lymphocytes can activate and enhance macrophage pairs. The phagocytosis and killing effect of fungi, the specific cellular immune function is perfect, the primary fungal infection is often localized, and granuloma is formed locally; the specific cellular immune function is low, it is prone to serious disseminated infection, and further It can weaken the body's anti-infective ability, cause mixed infection of bacteria, deep infection can stimulate the body to produce specific antibodies, and whether this kind of organism can prevent fungal reinfection, there is no definite evidence. It is generally believed that the antibody induced by fungal infection should not be obtained antifungal immunity. An important mechanism.

Fungal scleritis prevention

Fungal infections are opportunistic infections. In the case of long-term application of antibiotics and hormones, eye inflammation should be thought of as a fungal infection and should be treated promptly.

Fungal scleritis complications Complications , endophthalmitis, eyeball retraction

Mixed bacterial infections cause inflammation of the eye contents and cause eyeball atrophy.

Fungal scleritis symptoms Common symptoms Eye pain, tears, scleral edema, photophobia

Fungal scleritis is a slow-developing necrotizing anterior scleritis with slow onset. The main symptoms are redness, photophobia, tearing, eye pain, decreased vision and conjunctival sac secretion. Compared with bacterial scleritis, the symptoms are more irritating. Light, long course, most patients with fungal scleritis have pain, can be confined to the eye, can also be transmitted along the trigeminal nerve branch to the temporal head and forehead, easily misdiagnosed as migraine, sinusitis, and even brain tumor Etc. Clinical signs: early scleral localized inflammatory infiltration, color dark red, scleral lesions and surrounding areas may appear flaky avascular zone, is a key sign of necrotizing anterior scleritis, should be carefully examined, lesions can be different Direction development, can absorb limitations, can also progress to a large area of necrosis, affected sclera can be necrotic and thin, scleral edema around the necrotic area, surface scleral vasodilation, distortion, displacement, necrosis area after healing, the sclera is thin, gray-blue appearance, It can expose the uveal membrane, but it rarely occurs. It is accompanied by fungal infection of adjacent tissues. It is more common in keratitis and is expressed as the isolated or scattered base in the central or lateral center of the cornea. Internal abscess, leukocyte infiltration or superficial ulcer, dull with mossy scale, ulcerative margin with feathery annular infiltration or shallow ditch, obvious boundary with surrounding tissue, surrounded by isolated circular point infiltration, called "satellite stove" Sometimes there is an immune ring around the ulcer, and 50% of patients with fungal keratitis can form a thick anterior chamber empyema.

Fungal scleritis

Laboratory inspection

Gram staining or Giemsa staining of the cornea or scleral area can show the morphology of the fungus (the mycelial fragments with the membrane), the detection rate of Gram stain is about 55%, and the detection rate of Giemsa stain is about 66. %, the fungus needs to be cultured, and it takes a long time to culture the fungus. In order to increase the positive rate of culture, several different media are inoculated at the same time. The commonly used fungal medium such as Sabro glucose agar is suitable for fungal growth; blood agar medium Suitable for most yeasts; dimorphic fungi grow in 37 ° C incubator; chocolate agar, brain-brain infusion (BHI), Löwenstein medium suitable for acid-resistant fungal growth; Thioglycolate medium suitable for mycobacterial growth, Two plates were used: one was incubated at room temperature and the other was routinely cultured at 35 °C.

If the cornea undergoes a phlegm-like change, the clinical manifestations of fungal keratitis, fungal culture and scleral or corneoscleral biopsy negative, ineffective for broad-spectrum antibiotic treatment, fungi can invade the anterior chamber through the complete Descemet membrane, causing the prophase Pus, the cornea has not been perforated, anterior chamber puncture, immediately with blood agar or SDA, or BHI culture at room temperature to determine the fungus, but the wound in the anterior chamber puncture may inoculate bacteria and other microorganisms in the anterior chamber, must be cautious.

If the fungal infection is first suspected in the clinic, but stained or cultured (48h) negative, and early broad-spectrum antimicrobial therapy is ineffective, a biopsy of scleral or corneoscleral lesions is required, which can be removed under the operating microscope including the conjunctiva or horn. The sclera, superficial sclera and fascial sac lesions were sent to the microbiology laboratory. The tissue fragments were mixed into 1 ml broth. One drop of the sample was cultured in different medium including blood agar at room temperature, SDA, BHI. The fungus; the other half was immersed in formaldehyde and sent to the pathology laboratory for special staining with PAS, GMS, CFW to determine the fungus.

Diagnosis and diagnosis of fungal scleritis

According to the medical history, clinical manifestations, staining or culture fungi positive, typical cases are not difficult to diagnose, culture or biopsy of pathogenic fungi, can be clearly diagnosed, due to the long time of fungal culture, and the visual prognosis of fungal scleritis, and decided In the morning and evening of the start of treatment, as long as the fungus cells or hyphae are found on the scraper, fungal scleritis can be diagnosed and antifungal treatment should be carried out immediately. If conditions are met, antifungal drug sensitivity test should be carried out.

It should be differentiated from bacterial or viral scleritis. Fungal scleritis usually has mild symptoms of eye irritation, but the course of disease is long and the drug treatment effect is poor. The positive result of laboratory examination is still needed for identification.

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