Leprosy is a chronic infectious disease caused by Mycobacterium leprae, which mainly invades the skin and peripheral nerves. Cases with low resistance may involve deep tissues and internal organs in the middle and late stage. Leprosy rarely leads to death, but it can lead to physical disability and deformity, making patients lose their labor force.
Etiology examination forum
The pathogen of the disease is Mycobacterium leprae (hereinafter referred to as Mycobacterium leprae), which is generally short and rod-shaped or slightly curved, with a length of about 2 ~ 6 microns and a width of about 0.2 ~ 0.6 microns. There are no flagella, spores or capsules, and occasionally one or both ends are as thick as drumsticks or dumbbells, and bacteria often gather in bundles or balls. The treated bacteria can be short rod-shaped, double spherical, rosary or granular. Acid-fast staining was red and Gram staining was positive. The strain contains catechol oxidase, which is helpful for its identification. Phenolglycolipid-1(PGL- 1) was once identified as the first specific antigen of leprosy. Antibody PGL- 1 can be detected in the sera of most patients with multi-bacterial leprosy, and its titer is directly proportional to the amount of bacteria. However, in recent years, it has been reported that PGL- 1 also exists in Nocardia.
The basic biological research of Leprosy Bacillus (including its metabolic process and chemical structure) has been hindered by its inability to culture in vitro. It has been proved that Leprosy can only multiply in several animals and cause diseases, among which armadillos are the most noteworthy. Armadillo maculata is an animal that has recently provided a large number of leprosy bacilli for research purposes and vaccine production. Foot pad inoculation of other immune normal mice is the basic means to evaluate the anti-leprosy activity of drugs and study the drug resistance of leprosy bacteria, and it is also an important method to evaluate the protective effect of vaccines. The application of immunocompromised animals, that is, thymectomy, X-ray irradiation of mice, mice and thymectomy newborn rats, is the most sensitive method to detect the existence of live bacteria in chemotherapy patients at present. In recent 10 years, the experimental infection of Leprosy Bacillus on three kinds of monkeys (black-haired monkey, African green monkey and rhesus monkey) and chimpanzees was reported.
Through the experimental study of foot pad inoculation in rats, we have a further understanding of the viability of Leprosy Bacillus. The first generation of leprosy needs 12 ~ 13 days, which can explain the chronic process and long incubation period of leprosy. The experiment shows that there is Leprosy Bacillus in nasal secretions of leprosy patients, and it can still survive for 2 ~ 9 days after the secretions are naturally dried in vitro. Leprosy bacilli can survive for 3 ~ 4 weeks at 0℃, can be inactivated after boiling for 8 minutes, and can lose their fecundity after 2 ~ 3 hours of direct sunlight in summer.
Type a description
With the development of clinic, bacteriology, pathology and modern immunology, the classification of leprosy is constantly improving and perfecting. At present, there are two classification methods: multi-bacteria type, few-bacteria type and five-level classification (Ridley-Jopling classification). Madrid classification (that is, two types and two categories) is no longer used. In view of the fact that our country has been using Madrid classification for a long time, we can refer to the data classified in the past according to the original classification, but it is not suitable to apply the five-level classification. If it needs to be summarized together with the new classification method, it can only be applied according to the multi-bacterial type and the few-bacterial type.
According to the five-level classification, its clinical characteristics are described as follows.
(1) Patients with tuberculoid leprosy (TT) have strong immunity, local tissues have strong immunopathological reactions, and the damage is often confined to peripheral nerves and skin. Common basal lesions are red or dark red spots, which are round or map-like. The main lesion in some cases is erythema or mild pigmentation. Some edges have small papules. This kind of skin lesions is characterized by a small number, usually only one or two pieces, clear edges, dry and hairless surface, sometimes scales, and early and obvious local sensory disturbance. Peripheral nerve invasion is less, only 1 ~ 2 nerves, nerve dysfunction appears early and seriously, nerve trunk is thick and obvious, and it is hard. The bacterial test was negative. The late reaction of leprosy test is mostly strong positive.
(2) Borderline leprosy (BT) has erythema and plaque. Its basic characteristics are like tuberculous leprosy, but the damage tendency is frequent, widely distributed, but asymmetrical; There are often small satellite-like injuries around large injuries; The edge of some skin lesions is not clear; Some patches may have a "blank area" in the middle, but their inner and outer edges are clear. Peripheral nerve injury is similar to tuberculosis, but it is more common. Mucosa, lymph nodes, eyes and internal organs are less and less involved. The bacterial test was negative or positive (1 ~ 2+). Late reaction of leprosy test (+-■), a few may be negative.
(3) The basic lesions of leprosy-like (BB) in the middle boundary are pleomorphic and polychromatic (red, orange-red, orange-yellow, reddish-brown, yellow-brown, etc. ). You can see the characteristic inverted disc damage, target damage and satellite damage. Some people can have bipolar skin lesions at the same time. The damage varies in size and quantity, and is widely distributed but asymmetrical. Nerve injury is common, but asymmetrical. Its roughness and dysfunction are between tuberculoid type and tumor type, showing uniformity, roughness and softness. Eyebrows are intact or asymmetrical and sparse. Mucosa, lymph nodes and internal organs will be damaged. The bacterial test was positive (2 ~ 4+), with many bacteria balls, and the late reaction of leprosy test was negative.
(4) Lesions of borderline neoplastic leprosy (BL) include macula, plaque, nodule and diffuse infiltration. Most of them are neoplastic leprosy, which is widely distributed and not completely symmetrical, and a few lesions can be seen at the edge. Some diffuse infiltration can be seen in the central blank area. Some skin lesions have superficial sensory disturbance, which appears later and lighter. The nerve trunk is slightly thick, uniform and soft, multiple but asymmetrical, and the deformity appears late and lightly. Eyebrows and hair can fall off sparsely, but asymmetrically. Congestion and swelling of nasal mucosa occur earlier, and symptoms such as lymph nodes, testicles and organs often appear in patients in the middle and late stage. Bacterial test was positive (4 ~ 6+). Leprosy is negative in the late stage.
(5) Leprosy early tumor-like lesions (LL) are mostly patchy, reddish or light in color, with blurred edges, small and numerous figures and symmetrical distribution. There is no obvious sensory disturbance and sweating, but there are itching, ant walking and other sensory abnormalities. If the course of disease is long, there may be a sense of warmth and slow pain. These injuries are easily delayed in diagnosis and treatment.
In addition to macula, diffuse infiltration and nodules can also appear in the medium-term tumor type, with unclear edge, bright and juicy surface and wide distribution, and mild superficial sensory impairment in some areas.
The diffuse infiltration of advanced tumor leprosy is more obvious and develops to a deeper level, and most of the skin on the body surface has infiltration. Diffuse thickening of facial skin, deepening of frontotemporal dermatoglyphics, hypertrophy of nose and lips, and hypertrophy of earlobe. Extensive and deep infiltration of limbs and trunk, with obvious sensory disturbance and sweating.
The early involvement of nerve damage is not obvious, and the nerve is not bulky. In the middle and late stage, extensive and symmetrical nerve trunks can appear, which are thick, uniform and soft. Can lead to serious deformity.
Early eyebrows are symmetrical and sparse. As the disease progresses, eyebrows and eyelashes can fall off. Hair can also gradually fall off.
Mucosal damage occurs early and obviously, and lymph nodes, testicles, eyeballs, internal organs and other injuries often occur in the middle and late stages.
Bacterial test was positive (5 ~ 6+). Leprosy is negative in the late stage.
(6) Uncertain leprosy (1) Early leprosy, with a few macules, mostly light spots and a few light erythema, with different degrees of superficial sensory impairment and clear or unclear edges. Peripheral nerves are less involved. Bacterial test is negative or rare (1+). The late reaction of leprosy test is mostly positive, and a few can be negative.
For the implementation of combined chemotherapy, patients are divided into multi-bacterial type and less-bacterial type from clinical and therapeutic aspects, but this is not an attempt to establish another classification method. Its relationship with other types is described as follows.