Tuberculosis A15.0; A15.9

In 1882 Robert Koch discovered the tuberculosis bacterium. The species name M. tuberculosis was introduced in 1896 by Lehmann and Neumann. In 1908 A. Calmette and C. Guérin succeeded in breeding a strain of M. bovis by passages in culture media.

A classical infectious disease occurring worldwide, which must be reported by name (notifiable: TB disease in need of treatment and death, refusal of treatment and discontinuation of treatment) in which the lungs, intrathoracic lymph nodes, bronchi and pleura are most frequently affected. Tuberculosis of the urogenital tract, peripheral lymph nodes, bones, joints and skin is not uncommon.

Mycobacterium tuberculosis complex. This includes the following species:

• M. tuberculosis (99%; human as reservoir).
• M. bovis (bovine tuberculosis)
• M. africanum (human as reservoir, see Mycobacteria).

Note: Other mycobacteria cause tuberculosis-like diseases (see, e.g., non-tuberculous (atypical) mycobacterioses).

A distinction is made between:

I. Latent tuberculous infection, which occurs as an initial infection with successful containment of the pathogens. This is to be assumed if a positive tuberculin skin test or a positive interferon-γ test is available, but no radiological or clinical organ findings can be detected. 90-95% of initial infections go unnoticed and leave only a positive tuberculin skin test or a latent or dormant infection.

II. primary tuberculosis as initial or initial infection. Mostly pulmonary focus of infection. Other manifestations of primary tuberculosis are ...

1. Hilus lymph node tuberculosis
2. pleurisy tuberculosis
3. meningitis tuberculosa
4. Miliary tuberculosis
5. Cheesy pneumonia
6. Landouzy-Sepsis

III. post-primary tuberculosis: organ tuberculosis after infection or as primary tuberculosis with latency up to decades. It can occur at any age. About 80% of pulmonary tuberculoses (e.g. cheesy bronchopneumonia which can change into a melting ulcerous-cheesy bronchopneumonia with the formation of caverns) occur as postprimary organ tuberculoses; furthermore, about 20% of postprimary tuberculoses occur as extrapulmonary tuberculoses: e.g.E.g. extrathoracic lymph nodes (lymphonodular hilar tuberculosis), pleura (pleuritis tuberculosa), urogenital tract, bones/joints, less frequently than postprimary tuberculosis of the skin, digestive tract, meninges (meningitis tuberculosa in the context of miliary tuberculosis) and the CNS. Threatening complications with a poor immunological initial situation are sepsis Landouzy and miliary tuberculosis. In the case of cavern formation, there is a high risk of scattering to the surroundings, lung bleeding, mycotic aneurysm, spontaneous pneumothorax, respiratory insufficiency, cor pulmonale, amyloidosis, etc.

It is estimated that 1/3 of humanity is infected with tuberculosis. Approximately 15% of the infected persons are affected by active tuberculosis. About 95% of the cases of disease and death affect developing countries. This is due to the general nutritional status and the high HIV infection.

The average incidence in Germany is 5.4/100,000 inhabitants/year, in Western Europe 10/100,000 inhabitants/year, in Eastern Europe 40>200/100,000 inhabitants/year. It is at different levels. It is significantly higher among various risk groups (HIV-infected persons, immunosuppressions, drug addicts, malnourished persons, migrants from high-risk countries). TB is the most frequent cause of death in AIDS patients. Multidrug-resistant tuberculosis (MDR = multidrug-resistant tuberculosis = resistance to at least INH+RMP) tuberculosis is becoming an increasing problem (the number of infected people worldwide is estimated at 50 million). Countries with a high burden of MDR tuberculosis are (according to WHO, as of 2013: Ethiopia, Armenia, Azerbaijan, Bangladesh, Bulgaria, Belarus, China, Congo, Estonia, Georgia, India, Indonesia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Myanmar, Nigeria, Pakistan, Philippines, Russia, South Africa, Tajikistan, Ukraine, Uzbekistan, Vietnam).

Cutaneous tuberculosis, for example, affects about 1.0-1.5% of all extrapulmonary tuberculosis infections.

Multi-resistant tuberculosis is causing increasing therapeutic problems.

Transmission most frequently by droplet infection (M. tuberculosis can hover in the air for several hours, which increases the possibility of spread), respiratory tract are the most important entry points. Rarely via the digestive tract or, in case of injured skin, via skin contact with infected material. The development of an infection depends on a genetic disposition, on the amount of inhaled bacteria, as well as on the general defence system. There is an increased risk in the case of long-term therapeutic (e.g. anti-TNF-alpha antibodies) and infectious (e.g. AIDS) immunosuppression, in diabetes mellitus, alcoholism, silicosis, Hodgkin's/non-Hodgkin's lymphomas.

Medical history: Tuberculosis cases in the vicinity; tuberculosis in the patient's own history, nationality, immune depression in question.

Clinic: Depending on the organ involvement, clinical (general complaints such as subfebrile temperatures, weight loss, night sweats, general weakness and other organ typical complaints) or radiological findings.

Pathogen detection: Microscopic (Ziehl-Neelsen staining) or cultural pathogen detection (only culture and animal experiments are reliable - see below mycobacteria).

Culture: Multiple culture with resistogram: Positive culture proves active tuberculosis, but a negative culture does not exclude it. Results on a solid medium usually take 3-4 weeks, possibly up to 12 weeks. Result of liquid culture (e.g. BATEC - method) takes only 1-2 weeks.

Nucleic acid amplification techniques (NAT): e.g. PCR takes 1-2 days; must be confirmed by control analysis from 2nd sample. Tuberculosis is positive for 1 year.

Serology: The interferon-gamma test (e.g. Quantiferon-TB-Gold test) has become established as the serological detection method. This is a highly sensitive immunological test for tuberculosis screening, in which the tuberculosis-specific antigens ESAT-6 (early secretory antigen target-6), CFP-10 (culture filtrate protein 10) and TB 7.7(p4) are used. These only occur in M. tuberculosis and M. bovis.

Skin tests: Tuberculin skin test (see there): In Germany, this is usually only used on children.

This depends on the respective organ infestation. With bacteriological pathogen detection, the diagnosis is clear. S. exemplarily under skin tuberculosis.

1. Koch R (1882) The etiology of tuberculosis. Berlin clinical weekly 19: 221-230
2. Koch R (1884) The etiology of tuberculosis. Announcements from the Imperial Health Office 2: 1-88
3. Mann D eet al (2019) Cutaneous tuberculosis in Rio de Janeiro, Brazil: description of a series of 75cases
   . Int J Dermatol doi: 10.1111/ijd.14617.
4. Peters F et al (2016) Germ or no germ: Challenges in the diagnosis of mycobacterial skin infections. J Dtsch Dermatol Ges 14:1227-1236