tuberculous uveitis
Introduction
Introduction to tuberculous uveitis Tuberculous uveitis is a common eye lesion of tuberculosis and was one of the major types of uveitis before the 1960s. Mycobacterium tuberculosis can cause uveitis and other ocular lesions by directly invading the uveal membrane or by an immune response. Mycobacterium tuberculosis is transmitted by blood in the primary disease or secondary disease stage, invading the eye tissue, causing inflammation and tissue destruction. It can also cause granulomatous uveitis by inducing type IV allergic reactions. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Mode of infection: non-infectious Complications: glaucoma retinal detachment cystoid edema of the cyst
Cause
Causes of tuberculous uveitis
(1) Causes of the disease
Three types of mycobacteria, such as Mycobacterium tuberculosis, Mycobacterium tuberculosis and Mycobacterium avium, can cause tuberculosis in humans, among which Mycobacterium tuberculosis is the most common.
(two) pathogenesis
Whether or not the disease occurs after infection with Mycobacterium tuberculosis depends on two factors, one is the virulence of the bacteria, and the other is the immune response of the body. In fact, only 10% of the infected people show tuberculosis, and 90% of them are lifelong asymptomatic. It indicates that only when the immune function is affected and the body can not produce an effective response, the large-scale reproduction of M. tuberculosis in macrophages and monocytes can lead to the occurrence of diseases, and -interferon can enhance these cells to tuberculosis. The killing effect of mycobacteria, cytotoxic T cells can identify and dissolve monocytic cells infected with M. tuberculosis, and the body often forms granuloma at the infected lesions, which is a protective mechanism that limits the spread of bacteria.
Mycobacterium tuberculosis can cause uveitis and other ocular lesions by directly invading the uveal membrane or by an immune response. Mycobacterium tuberculosis is transmitted by blood in the primary disease or secondary disease stage, invading the eye tissue, causing inflammation and tissue destruction. It can also cause granulomatous uveitis by inducing type IV allergic reactions.
Prevention
Tuberculous uveitis prevention
Supplemented with sufficient vitamins, vitamin A enhances the body's immunity, vitamin D promotes calcium absorption, vitamin C is beneficial for healing of the lesion and hemoglobin synthesis, and B vitamins have an effect of improving appetite. Fresh vegetables and fruits are also the main source of vitamins. In addition, foods such as milk, eggs, and internal organs are rich in vitamin A, and peanuts, beans, and lean meat are rich in vitamin B.
Complication
Tuberculous uveitis complications Complications glaucoma retinal detachment macular cystic edema abscess
Tuberculous uveitis can cause a variety of complications, such as post-iris adhesion, secondary glaucoma, retinal detachment, cystoid macular edema, subretinal abscess, retinal neovascularization.
Symptom
Tuberculous uveal inflammation symptoms common symptoms uveitis eye congestion granuloma tuberculosis blood line dissemination
Tuberculosis can cause lesions in multiple systems and multiple organs. The most common lesion in tuberculosis infection is uveitis, which can also cause eyelids, conjunctiva, cornea, sclera and sclera, eyelids, optic nerves, etc. More no tuberculosis or other systemic tuberculosis.
Tuberculous choroiditis
Tuberculous choroiditis has different clinical manifestations, and according to its clinical characteristics, it can be divided into five types:
1 exudation type or allergic type, is a non-specific inflammation, mainly occurs in people with high sensitivity or low immunity to tubercle bacilli, and there are 1 or 2 round or oval yellow-white patches of optic disc size in the fundus. May be accompanied by nearby bleeding.
2 Miliary choroidal tuberculosis, is a common tuberculous uveitis, usually affected by both eyes, showing multiple yellow-white nodules with unclear borders, located in the deep choroid, mostly distributed in the posterior pole, and the lesions can be counted up to Hundreds of different, 1 / 6 ~ 1/2 optic disc diameter, occasionally visible miliary nodules merge into a mass, may be associated with optic disc edema, nerve fiber layer bleeding and varying degrees of anterior uveitis.
3 localized choroidal tuberculosis, mostly in the posterior pole, often involving the macula, manifested as localized exudation, grayish white or yellow-white lesions, slightly elevated, unclear borders, with peripheral pigmentation.
4 agglomerate choroidal tuberculosis, also known as focal tuberculous choroiditis, occurs mostly in young children and young adults, single or multiple, 3 to 5 optic disc diameters, lesions are limited to the posterior pole, grayish white, can be gradually increased Large hemispherical bulge, surrounded by satellite-like nodules and small hemorrhagic foci, may be accompanied by serous retinal detachment, and the late lesions are white plaques with peripheral pigmentation.
5 cluster choroidal tuberculosis, very rare, can be formed by agglomerate choroidal tuberculous necrosis, ulcers further developed, the choroid is invaded by tuberculous granulation tissue and appears blurred, often accompanied by retinal detachment, vitreous opacity, acute iris Stomatitis and secondary glaucoma, cheese-like changes, can eventually lead to eyeball paralysis.
2. Chronic granulomatous anterior uveitis
It is also a common type. Of the 40 tuberculosis patients confirmed by pathology, 12 cases show iritis, accounting for 30%. Patients have sheep-like KP, Koeppe nodules and Busacca nodules on the iris surface. Recurrence and remission are alternated, and blood-aquatic barrier function destruction (anterior chamber glint) is often present for a long time, with significant vitreous opacity and cystoid macular edema.
3. Non-granulomatous anterior uveitis
Some patients may present with acute, recurrent anterior uveitis, manifested as ciliary congestion, dusty KP, massive inflammatory cells in the aqueous humor, anterior chamber glint or even aqueous fibrinous exudation and anterior chamber empyema, some patients also Can be expressed as chronic non-granulomatous anterior uveitis, dusty KP, a small amount of aqueous inflammatory cells, anterior chamber flash, and post-iris adhesions.
4. Retinitis
It can be expressed in two forms, one is miliary type, also known as superficial exudative retinitis, which is characterized by multiple small tuberculous nodules, which often end up healing; the other is a wide retina Inflammation, manifested as a wide range of gray-white lesions with significant vitreous opacity.
5. Retinal vasculitis
Patients may have retinal vasculitis, especially retinal vein inflammation. In the early literature, M. tuberculosis infection is considered to be the main cause of retinal vein inflammation. In fact, in the whole retinal vasculitis, by Mycobacterium tuberculosis It is rare to see.
6. Endophthalmitis
In very few patients, it can cause severe inflammation of the tissues in the eye and the clinical manifestations of endophthalmitis.
Examine
Tuberculous uveitis examination
The current diagnostics for ocular tuberculosis mainly include the following laboratory tests and auxiliary tests.
1. Anti-acid staining of specimens
Anti-acid staining of intraocular fluid, sputum, urine, lymph node biopsy and other specimens can quickly obtain results, but the specificity and sensitivity are low. If it is found that acid-fast bacilli in the intraocular fluid is still helpful for diagnosis.
2. Tuberculin skin test
The skin test is usually a purified protein derivative (PPD) of Mycobacterium tuberculosis. The principle is to use PPD as an antigen to examine the corresponding antibody by the following method: injection of 0.1 mm (including 1 or 10 U) of PPD To the skin, the diameter of the skin reaction was measured at 48-72 hours. It is generally considered that the induration of the tuberculin skin reaction is equal to or greater than 10 mm. It is worth noting that this skin test is affected by many factors, so the test is conducted. Attention should be paid to the following aspects: 1 This test can only determine whether the subject has been infected with M. tuberculosis, and is not sure whether or not there is tuberculosis, because only 10% of the infected persons develop tuberculosis; 2 tuberculin skin The test can not distinguish whether it is diseased in the past or is now sick; 3 the results of tuberculin skin test are greatly affected by the immune status of the patient, such as the immune function of the patient is inhibited (glucocorticoid users, patients with acquired immunodeficiency syndrome, etc.) ), false negative results can occur; 4 not all active tuberculosis patients are positive, according to statistics, about 10% to 25% of active tuberculosis patients are cloudy Reaction; 5 tuberculin skin test positive does not indicate that the patient's uveitis must be caused by Mycobacterium tuberculosis, 90% of infected people do not develop tuberculosis, it is clear that many diseases occur in these people It cannot be attributed to Mycobacterium tuberculosis. According to the data of our country, the proportion of patients with uveitis caused by tuberculosis is 0.2% to 1%, and the probability after calculation is only 2.9% to 13%. This indicates that if the patient is positive for PPD, the probability of uveitis caused by Mycobacterium tuberculosis is only 2.9% to 13%. Therefore, what kind of patient is tested for PPD and how to correctly judge the results of the skin test is Problems to be considered in diagnosis.
3. Mycobacterium tuberculosis culture
Incubation on egg medium usually results in 18 to 24 days; on agar medium, positive results may be seen earlier, and should be observed once a week during culture for 6 to 8 weeks. Mycobacteria can now be determined by monitoring the radioactive CO2 produced by mycobacterial metabolism of specific radioactive materials, which reduces the assay time to 9 days.
4. Nucleic acid amplification of Mycobacterium tuberculosis
Aqueous and vitreous specimens can be detected by nucleic acid amplification techniques. There are usually two techniques: one is a transcription-mediated amplification technique, targeting the M. tuberculosis rRNA sequence; the other is PCR technology. The DNA sequence of Mycobacterium tuberculosis is the target gene, and the two amplification techniques combined with acid-fast staining have higher specificity and sensitivity. It is worth noting that when performing nucleic acid amplification examination, care should be taken to avoid false positive results.
5. Histological examination
Histological examination of specimens taken from the lesions revealed that Langerhans giant cells, caseous necrosis and other lesions are important for diagnosis.
6. Chest X-ray examination
It has been found that calcified tuberculosis, fibrotic lesions, multiple nodular infiltration, and cavity formation are helpful for the diagnosis of tuberculosis.
7. Fluorescein fundus angiography
Fluorescein fundus angiography is helpful in the diagnosis of this disease. The choroidal tuberculosis nodules show diffuse fluorescence in the arterial phase, diffuse strong fluorescence in the later stage, and retinal vasculitis can show fluorescein leakage and blood vessel wall staining. Patients with retinal detachment may have fluorescein leakage and dye accumulation.
8. Indocyanine green angiography
Tuberculous choroidal lesions can be found in the following changes in indocyanine green angiography:
1 Early weak fluorescent dark areas, irregular distribution, such weak fluorescent areas can become equal fluorescence in the later stage, but also weak fluorescence.
Multiple small focal focal fluorescence areas appeared in the middle or late stage.
3 The choroidal blood vessels became blurred due to leakage in the middle of the angiography, and sometimes the blood vessels could not be seen, but the diffuse strong fluorescence was observed in the late stage.
4 diffuse choroidal strong fluorescence area, the weak fluorescence area in the early and middle stages of angiography becomes a strong fluorescent area suggesting active choroidal lesions, and local strong fluorescence is associated with long-term disease activity.
Diagnosis
Diagnosis and identification of tuberculous uveitis
Diagnostic criteria
The diagnosis of tuberculous uveitis is generally difficult. There is no satisfactory diagnostic criteria for tuberculous uveitis, but the following conditions should be met in the diagnosis:
1 can exclude uveitis caused by other reasons.
2 meet the clinical features of tuberculous uveitis.
3 intraocular fluids were isolated and cultured to produce Mycobacterium tuberculosis.
4 anti-tuberculosis treatment can reduce eye lesions.
5 There are extraocular tuberculosis lesions or a history of extraocular tuberculosis.
6 tuberculin skin test was positive.
The nucleic acid of Mycobacterium tuberculosis was detected by PCR in 7 intraocular fluid samples.
