Trachoma is a chronic chlamydial infection affecting the conjunctiva and cornea of the eyes. Trachoma is manifested by signs of conjunctivitis, keratitis, the formation of trachomatous grains (follicles) on the conjunctiva. In the outcome, trachoma can lead to scarring of the mucous membrane, destruction of the cartilage of the eyelids and complete blindness. In the diagnosis, biomicroscopy, cytological examination of epithelial scrapings from the conjunctiva, ELISA, RIF, PCR methods are used. Instillation and local application of antibacterial ointments, vitamin therapy, immunotherapy, expression and diathermocoagulation of follicles, eyelash epilation are used in the treatment of trachoma. Complications are eliminated surgically.
The causative agent is Chlamydia trachomatis, an intracellular parasite that multiplies in the cytoplasm of the epithelial cells of the conjunctiva and cornea. The causative agent was discovered by Provacek and Halberstedter in 1907 . Currently, trachoma is massively found among the population of Southeast Asia, South America and Africa; only sporadic cases are registered on the territory of USA. The active course of trachoma is mainly characteristic of children 4-10 years old; severe consequences of infection in the form of trichiasis, eyelid inversion, blindness develop in people over 50 years old. In ophthalmology, trachoma is 3 times more often diagnosed in women.
Trachoma is an anthroponotic infection with an epidemic nature of spread. Transmission of the pathogen occurs by contact through contaminated secretions (tears, mucus, pus) hands, household and hygiene items, clothes. In the epidemiology of trachoma, the leading role belongs to unsatisfactory living conditions and a low level of sanitary culture of the population.
The sources of the spread are both patients with active forms of infection, and carriers of the pathogen, persons with atypical and erased course of the disease. The possibility of mechanical transfer of pathogens by insects (flies) is not excluded. There is a high general susceptibility to trachoma in the epidochages. Immunity after an infection is not developed, therefore, re-infection with trachoma is possible.
The conjunctiva and cornea undergo the most pronounced morphological transformation in trachoma. The initial changes are characterized by diffuse infiltration of the conjunctiva by neutrophils and histiocytes, then (from 10-12 days) by lymphocytic and plasma cell infiltration. Follicles (trachomatous grains) are formed on the mucous membrane of the eyelids, represented by a focal accumulation of lymphocytes. In the future, dystrophic changes, sclerosis and hyalinosis of conjunctival tissues occur in the follicle area. Possible resorption of follicles without scarring. In some cases, a capsule is formed around the follicles, which “immures” cellular infiltrates, contributing to the preservation of the pathogen of trachoma for many years.
In the cornea with trachoma, a diffuse inflammatory process develops with the spread of infiltration and newly formed vessels into the upper part of the limb and the formation of a trachomatous pannus. In severe trachoma, follicles are formed in the corneal stroma; infiltration and scarring spread to the lacrimal organs and deep layers of the cartilage of the eyelids and meibomian glands.
In accordance with pathogenetic changes in the development of trachoma, 4 stages are distinguished.
In the first (initial) stage of the trachomatous process, inflammatory phenomena in the conjunctiva are noted, trachomatous grains appear in the upper eyelid and transitional folds, edema and vascularization of the upper limb develop, superficial subepithelial infiltration of the cornea.
The second (active) stage proceeds with the maturation of follicles, their papillary hyperplasia, the formation of pannus and corneal infiltrates, necrosis of individual follicles and their scarring.
In the third (scarring) stage, the processes of scarring of the conjunctiva and transitional folds of the eyelids, cornea prevail while maintaining the phenomena of inflammation.
The fourth (cicatricial) stage of trachoma is characterized by signs of clinical cure – in the conjunctiva, cornea and cartilage of the eyelids, there is a complete replacement of follicles and infiltrates with scar tissue. In the fourth stage of trachoma, based on the criterion of visual impairment, 4 groups are distinguished: 0 – without vision loss; I – vision loss to 0.8; II – vision loss to 0.4; III – vision loss below 0.4.
Depending on the prevailing pathological elements , I distinguish the following forms of trachoma:
- follicular – with the predominant formation of follicles;
- papillary – with the formation of papillary growths;
- mixed – with a combination of follicles and papillary growths;
- infiltrative – with predominant infiltration of the interested structures of the eye.
The incubation period for trachoma takes 7-14 days. The manifestation of the disease is more often acute, the course of trachoma is long, chronic. Both eyes are usually involved in the trachomatous process. There is an appearance in the eyes of a burning sensation and sensations of a foreign body. With the acute onset of trachoma, the symptoms of conjunctivitis are pronounced – hyperemia and swelling of the eyelid mucosa, copious mucopurulent discharge, photophobia. Follicular or papillary growths are detected on the mucous membrane of the eyelids.
In a quarter of cases, the erased course of trachoma is possible, which can be regarded as chronic conjunctivitis. The course of trachoma in young children resembles blennorrhea. Frequent exacerbations of trachoma in children lead to scarring of the cornea, which are detected by biomicroscopy of the eye.
The severity of trachoma is associated with the degree of infiltration of the conjunctiva and involvement of the cornea in the trachomatous process. Aggravating factors in the development of trachoma are the layering of bacterial or viral conjunctivitis, purulent keratitis, dacryoadenitis, dacryocystitis, canaliculitis, decreased immune reactivity, the presence of other diseases (tuberculosis, scrofulosis, worm infestation, malaria, etc.). In the case of secondary infection, trachoma is often complicated by corneal ulcer, iridocyclitis, hypopion, perforation, endo- and panophthalmitis.
The outcome of the recurrent course of trachoma is scarring of the conjunctiva in the area of transitional folds, characterized by the formation of adhesions between the inner surface of the eyelid and the eyeball. This leads to a shortening of the conjunctival arches or their complete disappearance (simblefaron). Scarring of cartilage in trachoma causes the development of eyelid inversion, trichiasis, drooping of the upper eyelid. Scarring processes in the lacrimal gland are accompanied by a decrease in lacrimation and drying of the conjunctival and corneal surfaces (dry eye syndrome). Taken together, all these changes cause a decrease in vision, and clouding and scarring of the cornea can cause partial or complete loss of vision.
Preliminary recognition of trachoma is based on clinical and diagnostic signs. During the external examination of the eyes, the ophthalmologist focuses on the presence of deep infiltration of tissues, follicles, changes in the limb and cornea, scars.
Confirmation of the diagnosis of trachoma is carried out by cytological examination of scraping from the conjunctiva: when specific cytoplasmic inclusions are detected in epithelial cells – Provacek–Halberstedter bodies, the diagnosis is beyond doubt. Among the methods of laboratory diagnosis of trachoma, ELISA (detection of specific antibodies to chlamydia in blood serum), RIF (detection of chlamydia antigens in epithelial cells), PCR scraping, culture method (bacteriological examination of a smear from the conjunctiva) are used.
For a more detailed study of lesions of the conjunctiva, cornea and lacrimal tracts, biomicroscopy of the eye, fluorescein instillation test, color tear-nasal test is performed. In the future, to assess the severity of complications of trachoma, it may be necessary to check visual acuity, diaphanoscopy of the eye and its appendages, and other studies.
Topical trachoma therapy is carried out by instillation of solutions and placing antibiotics and sulfonamides in the conjunctival sac (drops and ointments with tetracycline, erythromycin, oletetrin, doxycycline, sodium sulfapyridazine, etc.). In severe forms of trachoma, tetracycline antibiotics are prescribed orally. The complex therapy of trachoma includes courses of interferon and interferon inducers, immunomodulators.
Mechanical methods of trachoma treatment include expression (extrusion) of follicles using special tweezers under local anesthesia. The expression of follicles is a small surgical manipulation, which should be carried out taking into account the requirements of asepsis and antiseptics. It allows you to shorten the treatment of trachoma and achieve faster and more gentle scarring of the mucosa. Repeated squeezing of the follicles, if necessary, is carried out every 12-15 days under the guise of drug therapy. In some cases, repeated diathermocoagulation of multiple infiltrates is resorted to.
With the consequences, surgical treatment is resorted to, which depends on the nature of the complications. Elimination of trichiasis is carried out by thorough mechanical epilation of eyelashes, using electrolysis or cryosurgery. When trichiasis is combined with the deformation of the eyelids, a plastic correction of the eyelid inversion is performed. With persistent trichiasis, a flap of the lip mucosa is transplanted into the edge of the eyelids, which allows you to remove incorrectly growing eyelashes from the eyeball.
In xerophthalmia, the parotid duct of the salivary gland is implanted into the arch of the conjunctival cavity to moisten the surface of the eye. Chronic purulent dacryocystitis requires dacryocystorinostomy.
Prognosis and prevention
Timely treatment of trachoma is the main condition for a favorable prognosis. About 80% of patients recover within 2-3 months. At the fourth stage of trachoma, relapses are possible even after 5-20 years. Complicated and recurrent course of trachoma leads to intense opacity of the cornea and a significant decrease in vision, up to blindness.
Measures for the prevention of trachoma include timely localization of epidemic foci, detection of sporadic cases, regular medical examination of patients, hygiene.