Leprosy is a systemic infectious process with a chronic course caused by Mycobacterium leprosy and accompanied by epidermal, visceral manifestations, as well as signs of damage to the nervous system. There are 4 clinical forms: lepromatous, tuberculoid, undifferentiated and borderline. Typical signs are skin manifestations (erythematous pigment spots, nodules, tubercles), polyneuritis, severe deformation and disfigurement of the face, limbs, etc. The diagnosis is facilitated by conducting a lepromin test, bacterioscopy and pathohistological examination of a biopsy from the affected foci. Treatment is carried out for a long time, repeated courses of anti-leprosy drugs.
A30 Leprosy [Hansen’s disease]
Leprosy (Hansen’s disease) is a low–contagious infection that leads to generalized granulomatous damage to the integumentary tissues, peripheral nerves, in severe cases – the musculoskeletal system, eyes and internal organs. Disease is considered one of the oldest diseases of mankind, for many centuries inspired ominous horror. In the Middle Ages, “lepers” were declared “dead alive”, were ostracized or isolated for life in specialized hospitals – leprosariums. Today, the attitude towards the disease has changed significantly, however, despite the availability of specific treatment, the problem of the incidence remains relevant for a number of countries in Asia, Africa, Latin America. According to various data, from 3 to 12-15 million people in the world are sick with leprosy; more than 500-800 thousand new cases of the disease are diagnosed annually.
The discovery of the causative agent – Mycobacterium leprae, belongs to the Norwegian physician A. Hansen (1874). Mycobacterium leprosy is a gram-positive rod-shaped bacterium 1-7 microns long and 0.2-0.5 microns in diameter, in its morphology and properties close to Mycobacterium tuberculosis. Hansen’s bacillus is an obligate intracellular parasite that affects tissue macrophages and has a pronounced tropism to the skin and nervous tissue.
The sources of leprosy infection are sick people who secrete pathogens with nasal mucus, saliva, breast milk, seminal fluid, urine, fecal matter, separated ulcerated leprom skin. Also, the natural reservoirs of infection can be animals – armadillos and monkeys. Infection with Mycobacterium leprosy occurs mainly by airborne droplets, less often – with damage to the skin or bites of blood-sucking insects. Cases of infection during tattooing are described.
Disease is considered a low-contagious disease; infection is usually preceded by regular and prolonged contact with the patient. Healthy people have a high natural resistance to leprosy. To a greater extent, children are susceptible to leprosy infection, as well as people suffering from chronic intercurrent diseases, alcoholism, drug addiction. The reliable duration of the incubation period has not been established; according to various authors, it can range from 2-3 months to 20 or more years (on average 3-7 years).
According to the generally accepted classification, there are 4 main clinical types of leprosy: lepromatous, tuberculoid, undifferentiated and borderline (dimorphic). Undifferentiated leprosy is considered an early manifestation of the disease, from which two polar clinical and immunological variants develop in the future – lepromatous or tuberculoid. The most malignant type – lepromatous leprosy is characterized by the presence of large amounts of mycobacteria in the body and the negative nature of the lepromin test. With a relatively favorable, tuberculoid type of leprosy, on the contrary, there is a small amount of the pathogen and a positive lepromin reaction.
During each of the variants of leprosy, stationary, progressive, regressive and residual stages are noted. The first two stages are characterized by leprosy reactions – exacerbation of the foci of the disease, despite the therapy.
The most unfavorable clinical variant of this disease, occurring with generalized lesions of the skin, mucous membranes, eyes, peripheral nerves, lymph nodes, internal organs. The skin syndrome is characterized by the presence of symmetrical erythematous spots on the face, hands, forearms, shins, buttocks. At first they have a red color, a rounded or oval shape, a smooth shiny surface, but over time they acquire a brown-rusty color. Months and even years later, the skin in the area of these rashes thickens, and the elements themselves turn into infiltrates and tubercles (lepromes).
In the area of infiltrates, the skin has a bluish-brown color, increased greasiness, enlarged pores. Sweating in the affected skin areas first decreases, then stops completely. There is a loss of eyebrows, eyelashes, beard, mustache. Diffuse infiltrative changes lead to deepening of natural wrinkles and folds of the skin of the face, thickening of the nose, brow and zygomatic arches, violation of facial expressions, which causes the face of the patient with leprosy to disfigure and take a ferocious appearance (“lion’s face”). Already in the early stages, lepromes are formed in infiltrative foci – painless tubercles ranging in size from 1-2 mm to 2-3 cm, located hypodermally or dermally.
Areas of skin peeling, telangiectasia can be detected on the smooth glossy surface of leprom. In the absence of treatment, the leprosy ulcerates; the healing of ulcers occurs for a long time with the formation of a keloid scar. The skin of the armpits, elbow, popliteal, inguinal areas, scalp is not affected.
With lepromatous leprosy, the eyes are often involved in the pathological process with the development of conjunctivitis, episcleritis, keratitis, iridocyclitis. Typical is the interest of the mucous membrane of the oral cavity, larynx, tongue, the red border of the lips and especially the nasal mucosa. In the latter case, nosebleeds, rhinitis occur; in the future, infiltration and leprosy. With the development of leprom in the area of the cartilaginous septum of the nose, its perforation may occur and a deformation of the nose may occur. The defeat of the larynx and trachea in the lepromatous type of leprosy leads to a violation of the voice up to aphonia, stenosis of the glottis. Visceral lesions are represented by chronic hepatitis, prostatitis, urethritis, orchitis and orchiepididymitis, nephritis. Involvement in a specific process of the peripheral nervous system proceeds according to the type of symmetrical polyneuritis. With leprosy, sensitivity disorders, trophic and motor disorders develop (paresis of facial muscles, contractures, trophic ulcers, mutations, atrophy of sweat and sebaceous glands).
The course of lepromatous leprosy is characterized by periodic exacerbations (lepromatous reactions), during which there is an increase and ulceration of leprom, the formation of new elements, fever, polylymphadenitis occurs.
The tuberculoid type proceeds more benign with damage to the skin and peripheral nerves. Dermatological signs are characterized by the appearance of hypochromic or erythematous spots with clear contours on the skin of the face, trunk, upper extremities. Flat dense papules of a reddish-purple hue appear on the periphery of the spots, resembling red lichen planus. Merging with each other, papules form plaques of a ring-shaped configuration (shaped tuberculoid), in the center of which a site of depigmentation and atrophy appears. In the affected areas of the skin, the functions of sweat and sebaceous glands decrease, dryness and hyperkeratosis develop, and downy hair loss occurs. With tuberculoid leprosy, nails are often affected, which become dull gray, thickened, deformed, brittle.
Due to the lesion of peripheral nerves, disease is accompanied by a violation of temperature, tactile and pain sensitivity. The defeat of the facial, radial and peroneal nerves is more common: they thicken, become painful and palpate well. The consequence of pathological changes in peripheral nerves are paresis and paralysis, muscle atrophy, trophic ulcers of the feet, contractures (“claw-like brush”, “seal foot”). In advanced cases, resorption of the phalanges and shortening (mutation) of the hands and feet may occur. Internal organs with tuberculoid leprosy, as a rule, are not affected.
Undifferentiated and borderline
With an undifferentiated type, there are no typical dermatological manifestations. At the same time, asymmetric areas of hypo- or hyperpigmentation occur on the skin of patients with this form of leprosy, accompanied by a decrease in skin sensitivity and anhidrosis. Nerve damage proceeds according to the type of polyneuritis with paralysis, deformity and trophic ulceration of the extremities.
Cutaneous manifestations of borderline form are represented by asymmetric pigment spots, individual nodes or protruding plaques of a stagnant red color. Usually rashes are localized on the lower extremities. Neurological manifestations include asymmetric neuritis. In the future, undifferentiated and borderline leprosy can transform into both lepromatous and tuberculoid forms.
Leprosy is not such a forgotten disease, and doctors of various specialties are likely to encounter it in clinical practice: infectious diseases, dermatologists, neurologists, etc. Therefore, caution should be exercised and the leprosy process should be excluded in patients with long-term non-regressing skin rashes (erythema, age spots, papules, infiltrates, tubercles, nodes), violation of various types of sensitivity in certain areas of the skin, thickening of nerve trunks and other typical manifestations. A more accurate diagnosis allows bacterioscopic detection of Mycobacterium leprosy in scrapings of the nasal mucosa and affected skin areas, histological preparations of leprosy tubercles and lymph nodes.
The results of the reaction to lepromin make it possible to differentiate the type of leprosy. Thus, the tuberculoid form of leprosy gives a sharply positive lepromin test; the lepromatous form is negative. In undifferentiated leprosy, the reaction to the lepromatous antigen is weakly positive or negative; in borderline leprosy, it is negative. Functional tests with nicotinic acid, histamine, mustard plaster, and the Minor test have less specificity.
Leprosy should be differentiated from a number of diseases of the skin and peripheral nervous system. Among the dermatological manifestations, rashes in the tertiary period of syphilis, multiform exudative erythema, toxicoderma, tuberculosis and sarcoidosis of the skin, lichen planus, leishmaniasis, nodular erythema, etc. have similarities with leprosy. From the lesions of the nervous system, it is necessary to exclude syringomyelia, neuritis of traumatic genesis, Charcot-Marie-Tut neural amyotrophy, etc.
Currently, leprosy is a curable disease. With common skin manifestations, positive microscopy results or relapses of leprosy, patients are hospitalized in special anti-leprosy institutions. In other cases, patients receive outpatient therapy at their place of residence.
Treatment of leprosy is carried out for a long time and comprehensively, by a course method. At the same time, 2-3 anti-leprosy agents are prescribed, the main of which are preparations of the sulfone series (diaminodiphenylsulfone, sulfametrol, etc.). In order to avoid the development of drug resistance, drugs and their combination are changed every 2 courses of treatment. The duration of the course of specific treatment of leprosy is several years. Antibiotics (rifampicin, ofloxacin), immunocorrectors, vitamins, adaptogens, hepatoprotectors, iron preparations are also used. In order to increase the immunoreactivity of patients with leprosy, vaccination is indicated.
To prevent disability from the very beginning of treatment, patients with leprosy are prescribed massage, exercise therapy, mechanotherapy, physiotherapy, wearing orthopedic aids. Psychotherapy, professional reorientation, employment, overcoming leprophobia in society are important components of comprehensive rehabilitation.
Prognosis and prevention
The prognosis depends on the clinical form of pathology and the timing of the start of therapy. Early diagnosis and initiation of treatment (within a year from the moment of the development of leprosy symptoms) allow to avoid disabling consequences. In the case of later detection of leprosy, sensitivity disorders, paresis, disfiguring deformities persist. In the absence of treatment, the death of patients can occur from leprosy cachexia, asphyxia, amyloidosis, intercurrent diseases.
Disease prevention system provides for mandatory registration and registration of patients, hospitalization of newly identified patients, dispensary monitoring of family members and contact persons. General preventive measures are aimed at improving the conditions and quality of life, strengthening immunity. Persons are not allowed to work in the food and communal spheres, children’s and medical institutions; they cannot change their country of residence.