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Lepra of the eye: general information
Medical expert of the article
Last reviewed: 12.07.2025
[ Causes of Leprosy
The causative agent of human leprosy is Mycobacterium leprae (M. leprae hominis, M. Hanseni), described in 1874 by G. Hansen, and belongs to the genus Mycobacterium.
The morphology of the leprosy pathogen has been studied on fixed preparations using light and electron microscopes. The typical form of mycobacteria leprosy is straight or slightly curved rods with rounded ends, 1 to 4-7 μm long and 0.2-0.5 μm wide. Granular, branched and other forms of the pathogen are also observed. They are immobile, do not form spores or capsules, are acid- and alcohol-resistant, gram-negative, and stain red according to Ziehl-Neelsen. They are located intra- and extracellularly, tend to group together, located parallel to each other ("cigarette packs"). They can be in the form of spherical clusters (globi), 10-100 μm in diameter, sometimes about 200 μm. In terms of morphology, tinctorial and antigenic properties, the human leprosy pathogen is very similar to mycobacterium tuberculosis.
Immunity in leprosy
Most healthy people develop relative natural immunity to leprosy mycobacteria, which is characterized by a fairly high intensity. The state of the macroorganism's immunological reactivity to the leprosy pathogen is determined mainly by cellular immunity reactions. The intradermal lepromin test is most often used for this purpose. Positive results of this test indicate a pronounced ability of the organism to develop a response to the introduction of leprosy mycobacteria, i.e. a high degree of natural immunity. A negative response indicates suppression of cellular immunity reactions, in other words, the absence of natural immunity.
Symptoms of Leprosy
The incubation period for leprosy is long: on average 3-7 years, in some cases from 1 year to 15-20 years or more. In the initial period of the disease, subfebrile body temperature, malaise, drowsiness, loss of appetite and weight loss, arthralgia, neuralgia, paresthesia of the extremities, rhinitis and frequent nosebleeds may be observed. Then clinical signs of one of the forms of the disease appear.
In the lepromatous type of leprosy, skin lesions are extremely varied: spots, infiltrates, nodes. At the onset of the disease, symmetrically located erythematous and erythematous-pigmented spots with a smooth, shiny surface appear on the skin of the face, extensor surfaces of the forearms, shins and buttocks. Their size is small, the color is initially red, then yellowish-brown (copper, rusty shade), the boundaries are unclear.
Symptoms of leprosy of the organ of vision
Before the widespread use of sulfone drugs, damage to the organ of vision in leprosy occurred in a large percentage of cases: 77.4%. Such a high frequency of eye damage was not observed in any other infectious disease. At present, due to the success of therapy and prevention of leprosy, disease of the organ of vision is observed much less frequently: according to U. Ticho, J. Sira (1970) - in 6.3%, A. Patel and J. Khatri (1973) - in 25.6% of cases. However, among untreated patients, specific inflammation of the eye and its accessory organs, according to observations of A. Patel, J. Khatri (1973), is 74.4%.
The visual organ in patients with leprosy is involved in the pathological process only several years after the onset of the disease. Inflammation of the eyes and their accessory organs is observed in all types of leprosy, most often in lepromatous leprosy. In this case, changes in the accessory organs of the eye (eyebrows, eyelids, muscles of the eyeball, lacrimal apparatus, conjunctiva), fibrous, vascular and retinal membranes of the eyeball and optic nerve are detected.
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Classification of leprosy
According to the classification adopted at the VI International Congress on Leprosy in Madrid in 1953, the following forms of leprosy are distinguished: lepromatous, tuberculoid, undifferentiated and borderline (dimorphic). The first two types of leprosy are recognized as polar.
The lepromatous type is the most severe form of the disease, highly contagious, and difficult to treat. The skin, mucous membranes, lymph nodes, visceral organs, eyes, and peripheral nerves are affected. A typical skin lesion is a diffuse and limited infiltrate (lepromatous infiltration and leproma). Bacteriological examination of scrapings from skin lesions and the nasal mucosa reveals a huge amount of the pathogen. The intracutaneous lepromin test is negative. Histological examination of the lesions reveals a lepromatous granuloma, the main cellular elements of which are Virchow's leprosy cells - macrophages with "foamy" cytoplasm containing leprosy mycobacteria.
Diagnostics of leprosy of the organ of vision
Leprosy is diagnosed only in the presence of clinical signs of the disease. As stated above, clinical symptoms of damage to the organ of vision in patients with leprosy are detected only many years after the onset of the disease. Consequently, the basis for establishing the leprosy etiology of eye disease is primarily the clinical manifestations of the disease, expressed mainly in a variety of dermatological and neurological symptoms and characterized by a chronic course with periodic exacerbations.
The diagnosis is established using data from epidemiological, radiological, functional and laboratory studies.
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Treatment and prevention of leprosy of the organ of vision
In the treatment of leprosy damage to the organ of vision, the main thing is to carry out general specific therapy.
The total duration of treatment for patients with lepromatous and borderline leprosy is 5-10 years, and for tuberculoid and undifferentiated leprosy it is at least 3-5 years. In some cases, treatment for patients with lepromatous leprosy continues throughout their lives. Initially, treatment is carried out in a leprosarium. After the clinical signs of leprosy activity disappear, and there are multiple negative results of bacterioscopic and histological examinations of various areas of the skin and the mucous membrane of the nasal septum, the patient is transferred to outpatient treatment in a leprosarium or a dermatovenerologic dispensary at the place of residence. Treatment is carried out according to the leprologist's prescription. Upon completion of outpatient treatment, the patient remains under dispensary observation throughout his or her life. All patients discharged for outpatient treatment receive specialized care (including ophthalmological care) in general medical institutions.
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