To date, tuberculosis of the lymph nodes is considered one of the most common forms of extrapulmonary tuberculosis (extrapulmonary tuberculosis), which can develop as a result of primary tuberculosis infection.
A localization of pathological lesions in the tissues of lymph nodes - granulomatous inflammation - is explained by lymphogenesis
And the spread of this infection in the body.
Since the lymph nodes (nodus lymphaticus) are the peripheral part of the branched lymphatic system, the definition of tuberculosis of peripheral lymph nodes, tuberculous peripheral lymphadenopathy is used; also can be called "peripheral tuberculous lymphadenitis." Although the nature of the defeat of lymphoid tissue with lymphadenitis has a different pathogenesis and course, and the disease itself, in accordance with ICD-10, refers to infections of the skin and subcutaneous tissue (L04). While all forms of tuberculosis - and tuberculosis of the lymph nodes - are included in the class of infectious diseases (A15-A19).
Statistics, presented in the latest WHO Global Tuberculosis Report, allow to assess the state of the epidemic of this infection. In 2015, there were 10.4 million new cases of tuberculosis worldwide. Of these, 56% (5.9 million) are men; 34% (3.5 million) are women and 10% (1 million) are children. HIV-positive people accounted for 11% (1.2 million) of detected cases of tuberculosis.
The number of deaths in 2015 is estimated at 1.4 million, which is 22% less than in 2000.
The tuberculosis of lymph nodes, as the main form of extrapulmonary tuberculosis, accounts for up to 5% of cases in European countries, about 10% in North America; in the endemic countries of the Indochina Peninsula and South Africa, this figure is 15-20% of all cases of tuberculosis (more than half are AIDS patients).
In HIV-infected cases, extrapulmonary tuberculosis develops in 68% of cases, and 45-60% of them are tuberculosis of peripheral lymph nodes of different localization.
Causes of the tuberculosis of lymph nodes
The causes of tuberculosis of the lymph nodes are the penetration into the body of mycobacterium tuberculosis (Mycobacterium tuberculosis) or Koch sticks, which belongs to the class of actinobacteria (Actinobacteria).
How is tuberculosis of lymph nodes transmitted? This bacterium, unable to move independently, but withstands both heat, frost, and lack of moisture, is most often transmitted from a sick person to a healthy person by coughing or sneezing, and this way of infection - airborne (aerogenic) - is the main one. Once in the lungs, the bacteria settle on the epithelium of the lower respiratory tract, and then they are absorbed by the alveolar macrophages (phagocytic cells) of the lung tissue. When macrophages can not cope with the digestion of bacteria, a pulmonary form of the disease develops, in which there may also be tuberculosis of the peripheral lymph nodes, as the pathogen of infection through the intercellular fluid enters the lymph and settles in the lymphoid tissue of the lymph nodes that serve as a lymphatic fluid filter.
Also phthisiatricians believe that it is possible to catch tuberculosis through food (for which M. Tuberculosis has got), for example, tuberculosis of the mesenteric lymph nodes can develop from the use of unpasteurized milk.
In addition, the infection is transmitted by contact, or it can be obtained in the womb of the mother, who is the carrier of this bacterium.
The main risk factors are associated with immune suppression accompanying diseases such as gastric ulcer and diabetes mellitus, and also with a decrease in body defenses due to alcoholism and drug addiction, the use of immunosuppressant drugs, and of course in AIDS patients.
Tuberculosis of the peripheral lymph nodes is the primary tuberculosis, since the lymph nodes are the first conductors of migration of immune cells to the introduction of Mycobacterium tuberculosis.
Studying the pathogenesis of lesions of lymph nodes with mycobacteria of tuberculosis, the researchers found that the macrophages of the stroma of the lymph nodes in the process of chemotaxis absorb Koch's rods, moving them into their cytoplasm (with part of their own plasma membrane).
After that, phagosomes are formed in the lymphoid tissue (with absorbed mycobacteria), and of them - after fusion with lysosomes (which contain digesting enzymes-peroxides) - phagolysomes are formed.
However, compared to most pathogens, M. Tuberculosis has unique virulence factors: they show increased resistance to phagocytosis, that is, the destructive effect of lysosomal enzymes-due to the peculiarities of the cell membrane (containing lipid components), as well as the complex of alpha-, methoxy-, and keto-mycolic acids.
In addition, M. Tuberculosis: has the UreC gene, which prevents the increase in acidity in phagosomes; blocks the molecules of endosomal autoantigens; It produces isotuberculozinol (isoTb), which prevents phagos maturation.
Moreover, tuberculosis bacteria not only persist within phagolysosomes, but also continue to multiply by replication, feeding on cholesterol, which is part of cell membranes. Thus, due to their immunomodulating effect, tuberculosis bacteria maintain their viability, which leads to the development of latent tuberculosis infection.
On the other hand, activation of the cytokines (T-lymphocytes) and monocytes involved in the immune response promotes the formation of phagocytic-type granulomas that are formed from sedentary histiocytes (transformed macrophages). And granulotomatous lesions of lymph nodes (often with caseous necrosis) are the main pathogenetic factor of tuberculosis of peripheral lymph nodes.
By the way, relapse of tuberculosis of lymph nodes is most often associated with the activation of the so-called L-forms of tuberculous mycobacteria that appear under the action of antibacterial drugs (used in the treatment of all forms of tuberculosis) and are able to exist for a long time in the cells of the body.
Symptoms of the tuberculosis of lymph nodes
According to clinical observations, the symptoms of lymph node tuberculosis do not appear immediately, since the disease is slowly progressing (from 3 weeks to 8 months).
The first signs of tuberculosis of the cervical lymph nodes are non-specific and are manifested by their painless swelling and some condensation. The affected node becomes well marked (reaches a size of 1-3 cm), elastic and mobile, but does not cause painful sensations when pressed. However, at the examination in 10-35% of patients morbidity is noted. In 85% of cases, the lesion is unilateral.
Over time, the clinical picture is complemented by the pallor of the skin; fever and chills; hyperhidrosis (severe sweating); deterioration of appetite and weight loss; malaise and fatigue. As the lesion progresses (with caseous necrosis), the skin in the lymph node becomes yellow or brownish. Blood tests show accelerated ESR, increased levels of lymphocytes and plasma proteins, a slight decrease in hemoglobin.
With tuberculosis of the intrathoracic lymph nodes, symptoms caused by intoxication predominate (weakness, poor appetite, sweating in the dream, fever), and complaints of chest pain and coughing appear at the pressure of enlarged lymph nodes on the bronchi. In children, phthisiatricians notice an expansion of the peripheral venous network on the anterior wall of the chest (the Vidergoffer symptom indicates a compression of the unpaired vein); soreness by pressing on III-VI) thoracic vertebrae (speaks about obvious inflammatory changes in the region of the posterior mediastinum).
In addition to fever, night sweats and weakness, the symptoms of tuberculozalymphatic nodes of intraperitoneal (mesenteric) are indicated as nausea, vomiting, abdominal pain (lower right), abdominal distention, constipation, or diarrhea. According to specialists, clinically acute tuberculosis of the mesenteric lymph nodes manifests itself as acute appendicitis or acute gastroenteritis.
Among the signs of tuberculosis of intra-abdominal lymph nodes are also noted fever, weight loss, pain when touching the affected lymph node. And since the node is constantly increasing, it can grow into nearby structures with the formation of adhesions.
In the development of tuberculous peripheral lymphadenopathy, four stages are noted.
The first stage begins with the moment of the M. Tuberculosis subsidence of the lymph node capsule before the formation of a granulotomatous focus in the lymphoid tissue. As the granuloma grows, it occupies a significant part of the fibrous capsule of the node, which leads to an increase in the node and a pathological change in the structure of its tissues. This stage is called proliferative.
In the second stage, the capsule walls of the granuloma become thicker (due to the dystrophic transformation of the extracellular matrix proteins into the hyaline), and in its center a necrosis zone is formed. The curious appearance of the mass of dead cells caused the name of this stage of tuberculosis of lymph nodes - caseous; at this stage, the pathological process may be accompanied by calcification of necrotic masses in the granuloma.
During the 3rd, abscessed stage, myomalacia (softening) of the contents of the granuloma occurs, turning it into a kind of pus (doctors call it a "cold abscess"). And the fourth stage is marked with superficially located large granulomas that break through the thinning skin, and then the pus exits through the fistula, and in its place a wound is formed.
In clinical phthisiology, the types of tuberculosis of lymph nodes are distinguished by their location.
Tuberculosis of the cervical lymph nodes can affect the anterior and posterior submandibular, bovine and jugular lymph nodes, Virchov's nodes (in the supraclavicular fossa), paratracheal lymph nodes (on the front surface of the neck).
Tuberculosis of the intrathoracic lymph nodes - parietal and visceral - extends to nodes localized in the lungs and along the bronchi (bronchopulmonary) and at the junction of the trachea and bronchi (tracheobronchial). This includes a group of lymph nodes of the posterior mediastinum (located near the thoracic aorta), and the mediastinal lymph nodes along the esophagus. Specialists note a more frequent lesion of M. Tuberculosis bronchopulmonary basal lymph nodes. And although the infection does not spread directly to the lung tissue, they undergo significant changes due to the formation of infiltrates. The diagnosis can be referred to as tubercular bronchoadenitis.
This localization of extrapulmonary tuberculosis infection accounts for up to two thirds of all cases, and if tuberculosis of lymph nodes in children develops, then 95% is a given type of disease. More information in the article - Tuberculosis of the intrathoracic lymph nodes in children
Tuberculosis of intra-abdominal lymph nodes (intra-abdominal tuberculous lymphadenitis) includes tuberculosis of mesenteric lymph nodes (intraperitoneal or mesenteric, often ileocecal lymph nodes) and tuberculosis of retroperitoneal nodes located in the spleen, portal and inferior vena cava, etc. The so-called mesenteric lymphadenopathy (or tuberculous mesenteric lymphadenitis) in most cases occurs with tuberculous lesions of the stomach or small intestine (that is, it is a secondary form); its prevalence does not exceed 0.05% and is mostly detected in childhood and adolescence.
Complications and consequences
As the main consequences and complications of tuberculosis of the intrathoracic lymph nodes are marked pathological changes in lung tissue. The most common complications are endobronchitis (sometimes with obturation and atelectasis of the segment or lobe of the lung, which leads to respiratory failure) and inter-partic pleurisy. There is also a threat of perforation of the caseous node and the release of its contents into the lumens of the bronchial tree, which is fraught with secondary infection of the pericardial lymph nodes.
With tuberculosis of intra-abdominal lymph nodes complication can be the formation of ulcers, intestinal obstruction or partial obstruction of the intestine, varicose veins, ascites, tuberculous peritonitis, etc.
Diagnostics of the tuberculosis of lymph nodes
To date, the diagnosis of tuberculosis of lymph nodes, in addition to anamnesis and examination, includes blood tests: clinical and biochemical (including the level of T-lymphocytes).
Instrumental diagnosis is radiography, ultrasound, CT, and in some cases, MRI. An excisional biopsy of the inflamed lymph node is used for the subsequent histomorphological examination of its contents. With deeply located diseased lymph nodes, the selection method can be an endoscopic ultrasound with a biopsy.
Tuberculous lesions of the mesenteric lymph nodes, even with radiographic examination, are very similar to stones in the kidney or gallbladder, and urine or cholangiography is often required. And with particularly large granulomatous lesions of the lymph nodes in the mesentery (up to 8-10 cm in diameter), laparotomy may be required.
Given the high virulence of M. Tuberculosis, the role of differential diagnosis of this disease can not be overestimated. For example, lymphadenitis of the neck (lymphadenitis) caused by atypical mycobacteria (Mycobacterium scrofulaceum) and other pathogens (Streptococcus pyogenes, Staphylococcus aureu, etc.) should be excluded.
Differential diagnosis of tuberculosis, localized in the hilar lymph nodes, is intended to distinguish it from the lymph node hyperplasia, Hodgkin's disease, lymphatic leukemia, lung manifestation of cancer, metastasis of carcinoma, and tumors of the thymus gland cysts or bronchi, teratoma, sarcoidosis et al.
Tuberculosis of the intra-abdominal lymph nodes can mimic a number of other disorders in the abdominal region, such as pancreatic cancer, node metastases, and lymphoma. Physicians can not easily distinguish between mesenteric mesenteric tuberculosis and chronic appendicitis, a cancerous tumor of ileocecal lymph nodes, and Burkitt's lymphoma.
Tuberculosis of lymph nodes of intra-abdominal localization can look like a cyst or a malignant neoplasm of the pancreas, which creates serious diagnostic problems.
It should be noted immediately that the treatment of tuberculosis of lymph nodes can be medicated or surgical. The doctors claim that no compresses for tuberculosis of the lymph nodes help, and they recommend taking vitamins (they will be of use to them).
A first-line anti-tuberculosis drugs that are used in combination therapy for this disease include the following drugs:
Isoniazid (Izonizid, Tubazid, Dinakrin, Pyrazidin, Eutisone, etc. Trade names) - is administered in / m or / in, and tablets (100, 200 and 300 mg) are taken orally at the rate of 5-15 mg per kilogram of body weight per day (for three meals a day). The duration of treatment is determined by the doctor. There may be side effects in the form of headache, nausea and vomiting, hives, insomnia, worsening of the liver, soreness along the peripheral nerves and paresthesia. These drugs are not prescribed for epilepsy, problems with the liver and thyroid gland, atherosclerosis, bronchial asthma, skin autoimmune diseases.
Antibiotic Rifampicin (Rifampin, Riphoral, Ripamizin Benemecin, Tubocin) is prescribed for 450 mg once a day (one hour before a meal). Side effects include dyspepsia, impaired pancreatic and liver function, and a decrease in leukocytes in the blood. And the list of contraindications includes pathologies of the kidneys, pregnancy and early childhood.
Antituberculous drug Sodium para-aminosalicylate (PASK sodium salt) in the form of a powder for the preparation of a solution, as a rule, take two packets per day (not more than 12 g), dissolving the powder in warm water (half a cup for a single dose). This drug is contraindicated in cases of inflammation of the kidneys, hepatitis and cirrhosis of the liver, ulcerative gastrointestinal diseases (it is undesirable to take with problems with the thyroid gland); and its side effects include loss of appetite, nausea and vomiting, abdominal pain, bronchospasm, joint pain.
Calcium benzamidosalicylate (Bepask) is used in the same way in powder or tabletted.
Surgical treatment of tuberculosis of lymph nodes assumes the removal of the contents of granulotomatous formation in the lymph node after its opening - in the subsequent disinfection and (if necessary) drainage.
Western phthisiatricians use such a surgical method as excision of tuberculous lymph nodes, but only in exceptional cases and in accessible places. Also, the affected nodes on the neck can be removed either by repeated aspiration, or by curettage (scraping).
However, experience has shown that excision should be considered as an adjunct to antibiotic therapy. For example, the removal of the BTE from the mycobacterium tuberculosis often recurs the tuberculosis of the lymph nodes, and also causes the spread of the infection to other organs. In addition, when cervical lymph nodes are removed, there is a risk of damage to the facial nerve
So the most effective treatment is considered traditional antibiotic treatment - within two to three months.
Tuberculosis is curable if the diagnosis is made early enough and appropriate treatment is started. So, with adequate therapy, tuberculosis of the cervical lymph nodes gives almost 98% clinical remission.
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