Atypical mycobacterial scleritis

Introduction to atypical mycobacterial scleritis In recent years, ocular damage caused by mycobacteria, including scleritis or scleral inflammation, is rare, while ocular infection caused by atypical mycobacteria is increased, and atypical mycobacteria are the most common. Common eye manifestations are scleritis or keratitis. basic knowledge The proportion of illness: 0.003%--0.005% Susceptible people: no special people Mode of infection: respiratory infection Complications: keratitis scleritis

Atypical mycobacterial scleritis etiology

Infection (35%):

As early as 1885, someone isolated the acid-fast bacilli different from Mycobacterium tuberculosis, and later reported it. In 1933, Branch reviewed the literature and thought that there are several types of mycobacteria in the human body, which have increased in the future. Since 1950, the research has been more In-depth, 37 kinds of atypical mycobacteria have been reported so far, including cattle, birds, leprosy and African tuberculosis. According to the pigmentation and growth rate of colonies, Runyon divides it into photochromatogens (M). There are 4 types of dark color (Scotochromatogens.M), non-color (Nonpigmented.M) and fast growth (Acute grown.M).

Infectious aerosol (30%):

Intrapulmonary lesions suggest inhalation of infectious aerosols, indicating the primary route of infection. Many cases are caused by surgery, trauma and allogeneic infection. In adults, the disease usually recurs from primary or resting lesions. It is still unclear.

Low immune function (30%):

Patients with severe immune dysfunction may develop disseminated diseases, including sclera infection, pre-auricular lymphadenitis, suggesting that the pathogen is caused by conjunctival invasion, or scleritis after secondary eye surgery.

Atypical mycobacterial scleritis prevention

Pay attention to eye cleansing in the case of swimming and contact with sewage, and apply antibacterial drugs locally. Prevention should be carried out in response to this feature. Increasing exercise, improving physical fitness, and strengthening nutrition can reduce the prevalence rate. Attention to isolation and protection for infected patients can also reduce the spread of the disease.

Atypical mycobacterial scleritis complications Complications keratitis scleritis

Severe infection may occur with necrotizing anterior scleritis, and may involve the vitreous, caused by Pseudomonas aeruginosa caused by red eye pain, dizziness, conjunctival sac secretion and vision loss, common symptoms are photophobia, often accompanied by keratitis related. If the photophobia is very serious, it often indicates the possibility of scleral tissue necrosis.

Atypical mycobacterial scleritis symptoms Common symptoms Tear tears

After several months of infection, most patients have slow onset and form nodular anterior scleritis. The main symptoms are redness, photophobia, tearing, conjunctival sac secretion, eye pain and decreased vision. The main signs are scleral purple congestion and inflammatory infiltration. With swelling, the formation of bulging nodules, nodular mass, obvious tenderness, push can not move.

The lesion is progressively damaged, forming necrotizing anterior scleritis, which is characterized by localized inflammatory plaque in the sclera. The inflammatory reaction around the lesion is heavier than the center, the eye pain is severe, and it is not proportional to the scleritis sign, followed by the avascular area around the lesion. It is caused by occlusive vasculitis in the outer layer of the sclera. The affected sclera can be necrotic and thin, and the uveal membrane is exposed. If the intraocular pressure continues to rise, scleral staphyloma is formed. If not treated in time, the scleral lesion can be quickly The surrounding spread spread, after the inflammation subsided, the sclera of the lesion was blue-gray, surrounded by thick anastomotic blood vessels, and the most common mycobacteria causing scleritis belonged to type IV Mycobacterium tsuii (M.chelonei), which is a kind Rapidly growing mycobacteria, accompanied by other ocular inflammations such as keratitis or intramuscular injection abscesses, can also be caused by slow-growing type I M. marinum, which can be associated with skin diseases such as sinks Sexual skin granuloma, etc., this type of angular scleritis may also be associated with systemic leprosy infection.

Examination of atypical mycobacterial scleritis

Isolation and culture of atypical mycobacteria by conjunctival sac secretions, Zyhl-Neelsen staining showed the presence of acid-fast bacilli, and Löwenstein-Jeusen cultured in the environment of 30 ° C with acid-fast bacilli growth (less growth at 37 ° C), due to The culture takes a long time and can be positive in a few weeks. As long as the characteristic acid-fast bacilli are found in the biopsy tissue, it can be enough to diagnose the infection of M. sclerotiorum, protein-purified derivative (PPD) skin test. Positive can identify specific atypical mycobacteria, while other bacterial negatives contribute to the diagnosis, and mycobacteria cannot be isolated by standard staining and culture with corneal or scleral biopsy tissue.

Ultrasound examination can reveal the presence of scleral staphyloma.

Diagnosis and differentiation of atypical mycobacterial scleritis

According to the medical history, the clinical manifestations can make a suspected diagnosis, but the isolation of mycobacterial pathogens can confirm the diagnosis. It is worth noting that the diagnosis of various infectious scleritis must consider atypical mycobacteria, especially secondary to scleritis. In the case of eye adnexal infection, soil or contaminated water (pool, aquarium and other water containers) damage caused by eye disease, laboratory examination of scleral or corneoscleral biopsy tissue removed from patients with infectious scleritis must include anti- Acid staining and Löwenstein-Jensen culture at 30 °C to confirm atypical mycobacterial scleritis.

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