Tuberculosis is a chronic infection caused by Mycobacterium tuberculosis complex bacteria. When affected by tuberculous mycobacteria, respiratory organs most often suffer, in addition, tuberculosis of bones and joints, genitourinary organs, eyes, peripheral lymph nodes occurs. Diagnosis consists in conducting a tuberculin test, X-ray examination of the lungs, detection of mycobacterium tuberculosis in sputum, flushing from the bronchi, separation of skin elements, additional instrumental examination of tuberculosis-affected organs. Treatment is a complex and long-term systemic antibiotic therapy. According to the indications, surgical treatment is performed.
Disease is a chronic infection caused by Mycobacterium tuberculosis complex bacteria. When affected by tuberculous mycobacteria, respiratory organs most often suffer, in addition, tuberculosis of bones and joints, genitourinary organs, eyes, peripheral lymph nodes occurs. Most often, infection occurs by airborne droplets, less often by contact or alimentary.
Characteristics of the pathogen
Mycobacterium tuberculosis complex is a group of bacterial species capable of causing tuberculosis in humans. The most common pathogen is Mycobacterium tuberculosis (obsolete. – Koch’s wand), is a gram-positive acid-resistant sticks of the actinomycete family, the genus of mycobacteria. In rare cases, disease is caused by other representatives of this genus. Endotoxins and exotoxins are not isolated.
Mycobacteria are extremely resistant to environmental influences, persist outside the body for a long time, but die under the influence of direct sunlight and ultraviolet radiation. They can form low-virulent L-forms that contribute to the formation of specific immunity in the presence of the body without the development of the disease.
Mechanism of infection
The reservoir of infection and the source are sick people (most often infection occurs through contact with patients with pulmonary form in an open form – when bacteria are excreted with sputum). At the same time, the respiratory path of infection is realized (inhalation of air with scattered bacteria). A patient with an active release of mycobacteria and a pronounced cough is able to infect more than a dozen people within a year.
Infection from carriers with scant bacterial excretion and a closed form is possible only with close constant contacts. Sometimes there is an alimentary infection (bacteria enter the digestive tract) or by contact (through damage to the skin). The source of infection can be sick cattle, poultry. Disease is transmitted with milk, eggs, when animal feces enter water sources. It is not always the ingestion of tuberculosis bacteria into the body that causes the development of infection. Tuberculosis is a disease often associated with unfavorable living conditions, decreased immunity, and protective properties of the body.
During disease, there are primary and secondary stages. Primary form develops in the zone of introduction of the pathogen and is characterized by high sensitivity of tissues to it. In the first days after infection, the immune system is activated, producing specific antibodies to destroy the pathogen. Most often, in the lungs and intra–thoracic lymph nodes, and in the alimentary or contact pathway of infection – and in the gastrointestinal tract and skin, a focus of inflammation is formed. At the same time, bacteria can disperse with the flow of blood and lymph through the body and form primary foci in other organs (kidneys, bones, joints).
Soon the primary focus heals, and the body acquires a strong anti-tuberculosis immunity. However, with a decrease in immune properties (in adolescence or old age, with a weakening of the body, immunodeficiency syndrome, hormone therapy, diabetes mellitus, etc.), infection in the foci becomes more active and secondary form develops.
Tuberculosis is distinguished into primary and secondary. Primary, in turn, can be dolocal (tuberculosis intoxication in children and adolescents) and localized (primary tuberculosis complex, which is a focus at the site of infection, and tuberculosis of the intra-thoracic lymph nodes).
Secondary tuberculosis differs in localization into pulmonary and non-pulmonary forms. Pulmonary form, depending on the prevalence and degree of lesion, can be miliary, disseminated, focal, infiltrative, cavernous, fibrous-cavernous, cirrhotic. Caseous pneumonia and tuberculosis are also isolated. Tuberculous pleurisy, pleural empyema and sarcoidosis were isolated as separate forms.
Disease of the brain and spinal cord and meninges, tuberculosis of the intestine, peritoneum, mesenteric lymph nodes, bones, joints, kidneys, genitals, mammary glands, skin and subcutaneous tissue, eyes are found outside the lungs. Sometimes there is a lesion of other organs. In the development of tuberculosis, there are phases of infiltration, decay, seeding, resorption, compaction, scarring and calcification. In relation to the isolation of bacteria, there is an open form (with the isolation of bacteria, MBT-positive) and a closed form (without isolation, MBT-negative).
Due to the multiplicity of clinical forms, pathology can manifest itself in a wide variety of symptom complexes. The course of the disease is chronic, usually begins gradually (it can be asymptomatic for a long time). Over time, symptoms of general intoxication appear – hyperthermia, tachycardia, weakness, decreased performance, loss of appetite and weight loss, sweating. With the progression of infection and its spread through the body, intoxication can be quite intense. Patients lose significantly in body weight, facial features become sharper, a painful blush appears. The body temperature does not rise above subfebrile figures, but it lasts for a long time. Fever occurs only in the case of a massive lesion.
- Pulmonary form is usually accompanied by a cough (initially dry), which worsens at night and in the morning. The existence of persistent cough for more than three weeks is an alarming symptom, and in such cases it is necessary to consult a doctor. With the progression of the disease, hemoptysis may appear. Pulmonary tuberculosis can be complicated by a life–threatening condition – pulmonary bleeding.
Tuberculosis of other organs and systems happens much less often and is detected, as a rule, after the exclusion of other pathologies.
- Meninges and brain. It develops gradually over 1-2 weeks, most often in children and people with immunodeficiency, in patients with diabetes mellitus. Initially, in addition to the symptoms of intoxication, sleep disorders and headaches appear, vomiting joins from the second week of the disease, the headache becomes intense and persistent. By the end of the first week, meningeal symptoms (rigidity of the occipital muscles, symptoms of Kernig and Brudzinsky), neurological disorders are noted.
- Tuberculosis of the digestive tract is characterized by a combination of general intoxication with stool disorders (constipation, alternating with diarrhea), symptoms of dyspepsia, abdominal pain, sometimes bloody impurities in the stool. Intestinal tuberculosis can contribute to the development of obstruction.
- Bones, joints and spine. With tuberculosis of the joints, symptoms of arthritis are noted (pain in the affected joints, limited mobility), With bone damage, their soreness is noted, a tendency to fractures.
- Genitourinary system. With the localization of the focus of infection in the kidneys, patients note the symptoms of nephritis, back pain, the appearance of blood in the urine is possible. It is quite rare that tuberculosis of the urinary tract can develop, in this case, dysuria (violation of the urination process), soreness during urination will be the manifestations. Tuberculosis of the genitals (genital form) may be the cause of infertility.
- Tuberculosis of the skin is characterized by the appearance of dense nodules under the skin, with the progression of increasing and opening on the skin with the release of white curd masses.
Pulmonary tuberculosis can be complicated by hemoptysis and pulmonary hemorrhage, atelectasis, pneumothorax and cardiopulmonary insufficiency. In addition, tuberculosis can contribute to the occurrence of fistulas (bronchial and thoracic, other localization in extrapulmonary forms), amyloidosis of organs, renal failure.
Diagnosis of pulmonary tuberculosis
Since tuberculosis is often asymptomatic at first, preventive examinations play a significant role in its diagnosis. In the diagnosis of pulmonary tuberculosis are used:
- Screening methods. Adults annually need to perform fluorography of the chest organs, children – a Mantoux test (a method of tuberculin diagnostics that reveals the degree of infection of the body with tuberculosis bacillus and tissue reactivity). As an alternative to the tuberculin test and the diaskin test, laboratory methods have been proposed to detect latent and active tubinfection: T-SPOT test and quantiferon test.
- Topical radiation diagnostics. The main method of diagnosis of tuberculosis is lung x-ray. At the same time, it is possible to detect foci of infection, both in the lungs and in other organs and tissues. If necessary, CT of the lungs is performed.
- Research of biological environments. To determine the pathogen, sputum is seeded, bronchial and gastric lavage waters are separated from skin formations. If it is impossible to sow a bacterium from biological materials, we can talk about an ICD-negative form.
- Biopsy. In some cases, bronchoscopy with biopsy, lymph node biopsy is performed to clarify the diagnosis.
Diagnosis of extrapulmonary tuberculosis
The data of laboratory tests are non-specific and indicates inflammation, intoxication, sometimes (proteinuria, blood in the feces) may indicate the localization of the focus. However, a comprehensive study of the state of the body in tuberculosis is important when choosing treatment tactics.
If an extrapulmonary form is suspected, it is often resorted to a more in–depth than Mantoux tuberculin diagnosis – the Koch test. Diagnosis of tuberculous meningitis or encephalitis is often carried out by neurologists. The patient is examined using rheoencephalography, EEG, CT or MRI of the brain. To isolate the pathogen from the cerebrospinal fluid, a lumbar puncture is performed.
With the development of this disease of the digestive organs, a consultation of a gastroenterologist, ultrasound of the abdominal cavity, a coprogram is necessary. Tuberculosis of the musculoskeletal system requires appropriate X-ray examinations, CT of the spine, arthroscopy of the affected joint. Additional methods of examination for tuberculosis of the genitourinary system include ultrasound of the kidneys and bladder. Patients with suspected tuberculosis of the skin need to consult a dermatologist.
Treatment of tuberculosis is aimed at healing foci and eliminating symptoms. Neglected tuberculosis responds to treatment noticeably worse than timely detected, even more severe course (destructive forms). Treatment takes a year or more, is complex (combines methods of drug therapy, physiotherapy). Initially, treatment is carried out in a tuberculosis dispensary until the release of microorganisms stops. After that, patients are discharged to continue outpatient treatment. Patients who have undergone tuberculosis therapy are recommended to be treated in specialized sanatoriums and dispensaries.
Surgical treatment is indicated in cases where conservative therapy is not sufficient to achieve a cure (cavernous form of pulmonary form, various complications). The most common surgical technique for the treatment is partial resection of the lung with excision of the affected segments. Surgical collapse therapy is also used. Patients suffering are prescribed a special high-calorie diet (table No. 11), rich in easily digestible protein, vitamins C and group B.
Bed rest is prescribed only for patients with a high degree of lung destruction, severe hemoptysis. In other cases, walking, physical therapy, and active physical activity are recommended for patients.
Currently, in most cases, with timely detection and compliance with the necessary therapeutic measures, the prognosis is favorable – tuberculosis foci heal and clinical signs subside, which can be considered a clinical recovery. After treatment, scars, areas of fibrosis, encapsulated foci containing bacteria in a dormant state may remain at the site of localization of foci. If the condition of the body worsens, a recurrence of the disease is possible, therefore, patients after clinical cure are registered with a phthisiologist and undergo regular examination. After the transfer and cure of tuberculosis, the tuberculin test remains positive.
In the absence of treatment or non-compliance with recommendations, tuberculosis mortality reaches 50% of cases. In addition, the prognosis worsens in the elderly, HIV-infected and people with diabetes.
Preventive measures carried out by specialized anti-tuberculosis medical institutions together with general medical institutions include preventive examinations of citizens (mandatory annual fluorography), identification of patients suffering from open forms of tuberculosis, their isolation, examination of contact persons, specific prevention of tuberculosis.
Specific prophylaxis (vaccination) is aimed at the formation of anti-tuberculosis immunity, includes the introduction of BCG vaccine or preventive chemicals. In people vaccinated with BCG, tuberculosis occurs in milder, benign forms, easier to treat. Immunity is usually formed 2 months after vaccination and fades after 5-7 years. Chemoprophylaxis measures are used among persons with an increased risk of infection: persons who have come into contact with tuberculosis patients with a negative tuberculin test (primary chemoprophylaxis) and infected persons (secondary).