Tuberculosis (TBC)Tuberculosis (TBC for short) is an infectious disease caused by certain bacteria from the group of mycobacteria (Mycobacterium tuberculosis). Usually the lungs are affected, but in principle all organs can be affected by tuberculosis. Read more about the symptoms, causes, treatment and prevention of tuberculosis.
Since the beginning of the industrial age, tuberculosis has been one of the great epidemics in human history. Due to the improved living conditions including the improved treatment possibilities, tuberculosis has been greatly reduced in Central Europe in the last century.
The incidence of tuberculosis has increased significantly in Germany since 2012. For the year 2018, the Robert Koch Institute registered 5.429 cases of tuberculosis. This corresponds to an incidence of 6.5 diseases per 100.000 inhabitants. Men are affected about twice as often as women. In 75 percent of cases, TB remains confined to stages I and II, according to the Lung Information Service (see symptoms).
Tuberculosis often progresses insidiously with general symptoms such as increased temperature, loss of appetite, night sweats and weight loss. Dry cough with sputum. Shortness of breath is another symptom of tuberculosis. Tuberculosis classically progresses in two stages.
Stage I of tuberculosis
Stage I of tuberculosis is also known as the primary or early stage. After infection, the pathogens migrate to the lungs. Leading there to small inflammations. Immune cells of the blood enclose these inflammatory foci, small "nodules" are formed – so-called tubercles. Because this inflammatory process is self-contained, no pathogens can escape to the outside world. Therefore the patients are not contagious. Physicians refer to this phase as closed tuberculosis. Most patients have no symptoms at this stage.
If the foci of inflammation cannot be encapsulated, those affected feel generally sickly and cough frequently. Night sweats, loss of appetite, mild fever and fatigue are also typical symptoms. Sometimes there are also severe courses with severe weight loss, bloody cough and pronounced anemia. The further course of tuberculosis depends on the pathogen. Depends on the immune status of the affected person. With an intact immune system, the disease comes to a halt. This gives the organism a certain immunity against further infections. However, reproductive TB bacteria are dormant in these foci. In the past, the primary infection was usually contracted in childhood, but today it is more likely to be contracted in adolescence or adulthood.
Stage II of tuberculosis
In more than 10 percent of people infected with tuberculosis bacteria, the inflammatory foci in the lungs break out at a later stage. Doctors call this phase reactivation phase, post-primary tuberculosis or also secondary tuberculosis. The pathogens destroy the lung tie. The destroyed lung tie breaks into the respiratory tract and is coughed up. So the sputum contains TB bacteria, the patients are highly contagious. Doctors therefore speak of open tuberculosis.
Typical symptoms in stage II of tuberculosis are:
– cough lasting for weeks – coughing up yellow-green, mucous sputum – chest pain, shortness of breath – pronounced exhaustion, weakness and fatigue – slight fever during the day, night sweats at night.
Tuberculosis outside the lungs
If stage II progresses untreated, tuberculosis bacteria enter the bloodstream and infect other organs. Then a variety of symptoms are possible. Examples are abdominal pain in intestinal tuberculosis, chest pain in pulmonary tuberculosis, joint swelling in bone tuberculosis, and ulcerated, non-healing skin lesions in cutaneous tuberculosis. Severe headache, vomiting, fever, pronounced neck stiffness and clouding of consciousness are symptoms of tuberculous meningitis.
A particularly severe form of tuberculosis is miliary tuberculosis. It occurs mainly in immunocompromised persons. In this form, the TB bacteria flood the lymphatic and blood systems, spreading throughout the body. The consequences are high, long-lasting fever and severe feeling of illness. If left untreated, miliary tuberculosis leads to sepsis, which results in coma and is fatal.
Tuberculosis is transmitted by mycobacteria, usually by Mycobacterium tuberculosis, less frequently by Mycobacterium bovis or Mycobacterium africanum.
Transmission of TB bacteria
TB bacteria enter the body primarily through inhalation of droplets infected with TB bacteria (droplet infection). This is done, for example, by coughing, sneezing or talking to people with overt tuberculosis. Other routes, such as via the milk (in the case of bovine tuberculosis), via the skin or from the expectant mother to the child, are much rarer. The main source of infection is the diseased person.
Whether and how severely one falls ill with tuberculosis depends on the number and strength of the pathogens and on the individual's immune system. In fact, only about 3 percent of infected persons contract the disease. Particularly at risk are infants and young children, the elderly, and people with serious illnesses such as cancer or AIDS.
Multi-drug resistant tuberculosis (MDR-TB)
Multidrug-resistant tuberculosis (MDR-TB) has been spreading for a few years, especially in China, India, Russia and countries of the former Soviet Union. According to the World Health Organization (WHO), the number of cases of MDR tuberculosis worldwide is about 490.000 (2016). The Robert Koch Institute recently reported 104 infections with multi-resistant tuberculosis bacteria in Germany.
On the one hand, X-rays of the lungs (or other organs) are used to diagnose tuberculosis. On the other hand, attempts are being made to detect the pathogen, the TB bacteria, directly in test material such as sputum, gastric juice or nerve fluid, or to cultivate them on tie cultures. Since TB bacteria grow very slowly, a result is only obtained in 2 to 3 weeks. Therefore, the use of a modern method is recommended, in which the genetic material of the TB bacteria is detected. This test, the so-called polymerase chain reaction, takes about 6 days, but is not always successful.
In the tuberculin test (z.B. Tine test), tuberculosis particles are injected under the skin. Within 2 to 3 days there is a positive skin reaction with redness and swelling in patients, but also in vaccinated persons and in healthy persons with healed primary tuberculosis. However, even a negative tuberculin test does not rule out the possibility of tuberculosis.
Immunological test procedures such as the interferon test support the diagnosis of tuberculosis. In this test, immune cells from the blood are mixed with antigens from mycobacteria in a test tube. If the immune cells have already had contact with the tuberculosis pathogens, they produce more of the messenger substance γ-interferon.
Very effective special antibiotics are used to treat tuberculosis. Cough suppressants, such as codeine, are often given in combination with these tests. Cortisone preparations such as dexamethasone or prednisolone are used to relieve inflammation.
The treatment of tuberculosis requires some patience and strict adherence to therapy. Medications such as isoniazid, rifampicin, ethambutol and pyrazinamide must be taken for a period of 6 to 9 months. Then the treatment of tuberculosis is successful in almost all cases.
After successful therapy, those affected must attend medical follow-up examinations for at least two years.
Currently, there is no effective tuberculosis vaccination in Germany. The BCG vaccination is not recommended because of its limited effectiveness. The risk of vaccination complications since 1998 no longer recommended. Therefore, the most important measure is to detect and treat tuberculosis as early as possible.
It is even better to avoid infection. If you come into contact with tuberculosis patients, you should therefore attach great importance to hygiene. This includes – especially in the case of open tuberculosis – gloves. A mouth guard as well as regular hand disinfection.
Earlier serial X-ray examinations of the lungs and repeated tuberculin tests for the early detection of tuberculosis are also no longer performed in Germany.
A healthy immune system does not offer guaranteed protection against tuberculosis, but it does reduce the risk of contracting the disease. A varied and fresh low-fat diet, plenty of exercise in the fresh air, avoidance of nicotine and, at most, moderate consumption of alcohol promote the immune system.