Tuberculosis

   Tuberculosis - an infectious disease caused by Mycobacterium tuberculosis and characterized by the development of cell allergies, specific granulomas in various organs and tissues and polymorphic clinical picture.

   Tuberculosis has been known since ancient times and still is a major health and social problem. Every year, the world's 8,000,000 people become ill, and 3,000,000 - are dying of tuberculosis. The value of a pandemic is so great that in 1993 the WHO declared TB an issue of "great danger." In recent years, the world has increased the incidence of tuberculosis.
The main reasons for increasing the incidence of: reducing the standard of living of the population, which caused the deterioration of the quality of food, increased migration from epidemiologically disadvantaged areas, reducing the scope and quality of the set of control activities and the emergence of resistant strains of a specific therapy. To alleviate the problem, WHO has identified as key components of the program to combat the disease active case detection and immunization against tuberculosis. 

Aetiology

    Tuberculosis in humans are caused by mycobacteria: in 92% of cases - Mycobacterium tuberculosis, in other cases - M. bovis (kind that causes TB in cattle and humans). M. tuberculosis - still thin sticks, aerobic. Acid resistance to staining them requires a special technique (Ziehl-Nielsen). Pathogen can multiply in macrophages and extracellularly. The sticks are stable in the environment: in the pages of the books are stored 3-4 months in the street dust - 10 days in the water - up to a year in a frozen state - for decades. When UV and boiling die within a few minutes. Grow slowly on classical culture media - the appearance of the first colonies celebrate after 4-8 weeks. 

Epidemiology

    TB sick people of all ages - from newborns to the elderly. Sources of infection: a sick man, meat and dairy products from animals infected with tuberculosis. Modes of transmission: most - airborne, at least - alimentary; also possible transplacental route of infection (from a pregnant woman to the fetus). Factors transmission - prolonged contact with MbT bad social conditions, starvation, immunosuppression. Infectivity is low, largely depends on the host's defenses. Seasonality and frequency of morbidity are not typical.

   Although tuberculosis is not considered to be vysokokontagioznym disease, 25-50% of people in close contact with smear, infected. Each patient-bacilli can infect 10-15 people. It should be remembered that get TB - not to get sick. Clinical forms of tuberculosis develops in 5-15% of cases, other forms of contaminated non-sterile immunity.

   Almost 90% of the cases can not identify the source of infection, suggesting that there is a significant reservoir of TB infection in the population. The risk of developing the disease is higher the younger the child during the period of infection. 

Patogenz

    The pathogenesis consists of three main stages: infection, the development of the primary lesion in any organ, disease progression with the appearance of new symptoms.

   Penetration of mycobacteria in the primary site gives rise to a process of interaction between macro-and micro-organism. One part of the pathogens remains a place of introduction, the other part is released from macrophages in regional lymph nodes. The primary focus, lymphangitis and regional lymphadenitis form the primary tuberculosis complex. Phagocytic reactions are incomplete, so in primary Mycobacterium tuberculosis complex multiply and, occasionally getting into the blood and lymph vessels, spread throughout the body. Primary bacteremia does not manifest clinically. After 4-8 weeks of developing sensitization, becoming positive tuberculin skin test (turn). Formed "sterile" immunity. Most children and adults developing protective responses inhibit the infectious agent in the area of ​​primary affect, the latter gradually fibrosing and calcify. Otherwise mycobacteria may spread from the primary tumor to the surrounding tissues or blood flow in distant organs, causing them progressive morphological changes. A manifestation of this process in the early stages of becoming paraspetsificheskie, allergic and toxic-allergic reactions corresponding to the term "early tuberculous intoxication."

   Feature of TB infection - long-term (over many years, sometimes for life) preservation of a viable pathogen in the primary focus, lymph nodes, foci of dissemination. The weakening of the body, decreased immunity in infectious (measles, viral hepatitis, HIV) infection and other diseases lead to the activation seems to be completely "healed" lesions. 

Classification

    According to the existing classification of 1973, adopted by the VIII All-Union Congress of TB specialists, allocate 3 of the main clinical forms of tuberculosis.

• Group I. Tuberculous intoxication in children and adolescents.

• Group II. Pulmonary tuberculosis (primary tuberculosis complex, tuberculosis of intrathoracic lymph nodes, disseminated tuberculosis, focal pulmonary tuberculosis, and other forms).

• Group III. Tuberculosis of other organs and systems (eg, tuberculosis of the meninges and central nervous system, bone and joint TB, tuberculosis, urinary and reproductive organs, intestinal tuberculosis, and other forms).

The clinical picture

    Clinical presentation depends on the location of tuberculosis mycobacteria implementation, the phase of the pathological process, presence of complications. The disease develops slowly and can last for a long time, sometimes for decades.

   In children and adolescents often identify primary disease that occurs during infection with 
Mycobacterium tuberculosis previously uninfected body. Among all forms of primary tuberculosis prevails tuberculosis of intrathoracic lymph nodes, rarely diagnosed tubercular intoxication, primary tuberculosis complex, pleurisy, etc. Most of tuberculosis in the lungs of children (85.3% in local forms of tuberculosis). Extrapulmonary result from hematogenous dissemination of infection from the primary tumor. Dominated by symptoms of intoxication, signs of local inflammation are less pronounced. Characteristic of the state of hypersensitivity, manifested paraspetsificheskimi reactions. The younger the child is sick, the higher the likelihood of severe local and generalized forms of tuberculosis. Below are the most frequent or severe clinical forms of tuberculosis in children. 

Tuberculous intoxication in children and adolescents

    This is the most common form of the disease. Usually develops during the preschool and early school age. There are low-grade fever, irritability, fatigue, sleep disturbances, appetite. On examination can reveal pale skin, weight loss, soft tissue turgor, mikropoliadeniyu. In this form of TB sometimes occur following paraspetsificheskie manifestation.

• Erythema nodosum - violet-purple maloboleznennye nodes 1-5 cm in diameter on the legs, hips, shoulders.

• Phlyctenular keratoconjunctivitis - inflammation of the conjunctiva and cornea to produce conflict.

• Reactive arthritis (synovitis), etc.

   For the diagnosis of tuberculous intoxication important discovery bend tuberculin tests - for the first time identified a positive Mantoux test or increase the size of induration of 6 mm or more as compared to the previous reaction. The instrumental study of the internal organs of a specific lesion can not be identified.

Outcomes. Infectious process may occur in waves over the years with a possible cure itself after the formation of immunity or transfer to local form. 

Primary tuberculosis complex

    Asymptomatic (before the development of complications), and can only be detected by X-ray study. In such cases reveal plot shaded in a light, enlarged lymph nodes of the root and linking them to "track", formed by the shadow of the vessels and bronchi. 

Complications. Pneumonia, pleural involvement in subpleural localization of the center. 

Outcomes. With a favorable course is calcification of lymph nodes and caseous focus in the lung complications of possible development of hematogenous dissemination, atelectasis, lymphogenous dissemination and education cavity. 

Tuberculosis bronhadenit

    Tuberculosis of intrathoracic lymph nodes (TB bronhadenit) - the most common local form of primary tuberculosis in children. Swollen lymph nodes leads to compression of the tracheobronchial tree. When a diffuse hyperplasia of the lymph nodes in patients with symptoms only appear tuberculosis intoxication. In marked bronhadenite developing quite typical clinical manifestations: bitonal, Whooping cough, hoarseness, chronic or acute signs of intoxication. Due to the increase of mediastinal lymph nodes may develop local changes: the expansion of the subcutaneous venous network in the skin breast enlargement surface of the capillary network in Zone C (symptom Frank), shortening of the percussion sound over the area mediastinum. Auscultation picture is poor. To confirm the diagnosis is carried out x-ray, and bronchoscopy. 

Complications. Violation of bronchial patency, bronchial tuberculosis, pleurisy. 

Outcomes. With a favorable course is calcification of lymph nodes, possible complications in the development of hematogenous dissemination, atelectasis, lymphogenous dissemination and education cavity.