Ocular tuberculosis is an extrapulmonary form of tuberculosis, in which the own vascular membrane, conjunctiva or the accessory apparatus of the organ of vision is affected. Clinically, pathology is manifested by “flies” or “black spots” in front of the eyes, decreased visual acuity, pain syndrome. Diagnosis includes biomicroscopy, ophthalmoscopy, visometry, microscopic examination of the biopsy. The treatment regimen consists of drugs of the ansamycin group, aminoglycosides and synthetic antibacterial agents. Surgical tactics are reduced to laser coagulation of large chorioretinal foci and revascularization of the choroid.
General information
Ocular tuberculosis is a disease of the visual organ of a specific etiology, which is characterized by frequent relapses and long–term persistence of the pathogen in the patient’s body. German pathologist Yu . In 1879, Kongame experimentally proved the possibility of the development of the tuberculous process in the eyes. The scientist performed transplantation of small biopsies from other organs (lungs, kidneys) of patients with this pathology into the anterior chamber of the eye. At the same time, the progression of ocular tuberculosis led to the formation of specific tubercles in the structures of the eyeball.
The lesion of the organ of vision occupies the 4th place in the structure of the prevalence of extrapulmonary forms of tuberculosis. According to statistics, the incidence rate increased 2.7 times from 1991 to 2000. Mostly young and middle-aged people are ill. The female sex is more predisposed to the development of this pathology. There is a tendency to increase the incidence of ocular tuberculosis among children and socially well-off classes of the population.
Causes
Mycobacterium tuberculosis is a specific causative agent of ocular tuberculosis. The damage to the organ of vision may be caused by hematogenous dissemination of the pathogen from tuberculous granuloma or by the reaction of the membranes of the eyeball to the course of the pathological process in the body. The metastatic variant of the disease is realized when an infection focus is formed in the choroid, an exudative reaction of surrounding tissues or penetration of mycobacteria into the vascular membrane of the eye by hematogenic path. Damage to the organ of vision can occur in any of the periods of the disease. In this case, the choroid vessels of medium diameter are the first to be affected. The course of ocular tuberculosis acquires an abortive asymptomatic character. Further, the specific inflammatory process spreads to the choriocapillary sections and the retina, which provokes the development of the clinical picture of ocular tuberculosis. The involvement of other structures of the eyeball is due to the perifocal response of tissues to inflammation.
The basis of the tuberculosis-allergic reaction is the increased sensitivity of the eye tissues to the causative agent of the disease. This etiological variant develops with previous sensitization to mycobacterium antigens. The antigen penetrates into its own vascular membrane of the eye. The source of pathological agents are tuberculosis foci (lymph nodes, lung granulomas). Secondary damage to the organ of vision is possible with the localization of a specific tubercle in the central nervous system. At the same time, the clinical picture of eye tuberculosis occurs against the background of intracranial hypertension and is caused by mechanical compression of the tuberculous tubercle of the optic nerve.
Pathanatomy
The nature of morphological changes depends on the stage of the disease. In primary ocular tuberculosis, exudative processes prevail over proliferative ones. At the secondary stage of pathology, proliferation increases, which is manifested by the formation of specific granulomas with caseous necrosis in the central part. Tuberculosis-allergic form is characterized by swelling of the surrounding tissues, their lymphoplasmic infiltration in combination with a histiocytic reaction. In this form of ocular tuberculosis, an increased number of eosinophils is observed in the infiltrate.
Symptoms
Ocular tuberculosis with hematogenous dissemination of the pathogen is characterized by a slowly progressive onset, while the course of the disease acquires a torpid character. Conducting non-specific anti-inflammatory therapy does not bring relief. The acute course is observed in the tuberculosis-allergic form of pathology, while the clinical symptoms of the disease quickly subside. This variant is characterized by the greatest tendency to relapse, due to the action of non-specific allergens. The clinical picture of ocular tuberculosis is determined by the localization of the pathological process.
In ophthalmology, the following variants of eye tuberculosis are distinguished: anterior and peripheral tuberculous uveitis, chorioretinitis, panuveitis. The disease is characterized by an asymptomatic course for a long time. When the anterior choroid is affected, patients complain of the appearance of “fog” in front of the eyes, a feeling of heaviness in the projection area of the orbit, a progressive decrease in visual acuity, photophobia, lacrimation. The dominant signs of peripheral tuberculous uveitis are “floating opacities” in front of the eyes, a decrease in the function of central vision.
With ocular tuberculosis, accompanied by a combined inflammation of the choroid and retina, patients note the appearance of “black spots” or “fog” in front of their eyes, pain in the eye socket, increased sensitivity to light, lacrimation. Panuveitis is manifested by a pronounced pain syndrome, a decrease in visual acuity up to its complete loss. Conjunctival tuberculosis is predominantly unilateral. The symptoms of the disease are absent until the addition of secondary complications or ulceration of tuberculous nodules.
Diagnostics
Diagnosis of ocular tuberculosis is based on biomicroscopy, ophthalmoscopy, visometry, tonometry, histomorphological and cytological examination of the biopsy. By the method of biomicroscopy with a slit lamp, it is possible to visualize large precipitates on the cornea, as well as posterior synechiae. Ophthalmoscopically, rounded chorioretinal foci are detected.
Biopsy is most available when the tuberculous process of the eyelids is affected, chorioretinal endobiopsy is performed less often. Biopsies are subject to histomorphological examination for the detection of mycobacteria. Cytological examination is performed upon receipt of materials during aspiration of the contents of the anterior chamber of the eye or vitreous body after iridectomy.
In tuberculosis of the conjunctiva, a group of gray nodules prone to fusion is visualized by biomicroscopy. After 21-28 days from the moment of formation, they undergo ulceration with the formation of a deep ulcerative surface. The visometry method for conjunctival lesions determines normal visual acuity. In turn, with ocular tuberculosis of other localizations, visual acuity varies from a slight decrease up to complete loss with panuveitis. The etiology of the disease can be confirmed after assessing the local tissue reaction to the introduction of tuberculin. At the same time, for a short time, there is an increase in the clinical manifestations of ocular tuberculosis. Immunological techniques help to confirm the etiology of the lesion of the organ of vision: T-SPOT.TB tuberculosis test and quantiferon test.
Treatment
The tactics of treating ocular tuberculosis depends on the form of pathology. After confirmation of the tuberculous etiology of the disease in the hematogenically disseminated variant, a long course of etiotropic therapy is recommended. The treatment regimen includes drugs of the pharmacological group of ansamycins, aminoglycosides and other synthetic antibacterial agents active against mycobacteria. Throughout the entire period of eye tuberculosis therapy, multivitamin complexes and immunomodulators are indicated. Gastroprotective drugs and hepatoprotectors are prescribed for primary manifestations of decompensation on the part of these organs. The duration of the intensive phase of the course of treatment of ocular tuberculosis ranges from 2 to 5 months.
Antibacterial agents for ocular tuberculosis must be administered in the form of parabulbar injections or by electrophoresis. In the presence of large chorioretinal foci, their laser coagulation or revascularization of the choroid is carried out. In tuberculosis of the conjunctiva, subconjunctival administration of drugs or their instillation is indicated. In the case of tuberculosis-allergic form of ocular tuberculosis, desensitizing agents and nonsteroidal anti-inflammatory drugs should be included in the standard treatment regimen.
Prognosis and prevention
Active specific prevention of ocular tuberculosis consists in vaccination and revaccination. The first administration of the vaccine is carried out by a healthy full-term newborn on day 1-4 of life. Revaccination is carried out only for healthy children at the age of seven. The aim of chemoprophylaxis is to prevent the development of regional forms of tuberculosis in healthy individuals at risk.
All patients with an established diagnosis of tuberculosis of the eye should be registered with an ophthalmologist at the dispensary. Sanitary preventive measures are aimed at breaking the mechanism of transmission of the disease in the focus and include compliance with hygiene rules, regular ventilation, bactericidal ultraviolet irradiation, the use of masks and respirators. The prognosis for life and working capacity in tuberculosis of the eyes with timely diagnosis and treatment is favorable.
