Tuberculosis used to be a dreaded disease, which was practically incurable even in the first half of the 20th century. The theme of tuberculosis is commonly present in the books of Erich Maria Remarque, the famous French author. Today, the tuberculosis is much less feared thanks to the invention of antibiotics and vaccination.
Tuberculosis is an infectious disease caused by bacterium known as Mycobacterium tuberculosis or Koch's bacillus (named after its discoverer). The bacterium has some special attributes. It multiplies slowly and it is very resistant to staining by the microbiological dyes. In addition, it is quite resistant to our immune system, which is the main problem.
The bacteria most often enter our body via the airways when coughed up from lungs of s sick person. However, this transmission is typical for a long-term close contact with the infected. In the lungs, the bacteria invade a small area known as the primary infection and local pulmonary lymph node. The primary infection and the affected lymph node is referred to as the “primary complex”
Much rarely, the bacteria can enter the body through the intestinal wall, which usually happened when drinking milk from cows infected by tuberculosis. In the intestine, the situation is similar to the lungs and the primary infected area of intestinal wall and a local lymph node form the so-called primary complex.
What could happen then? There are three main possible ways:
1st The immune system is sufficient in handling the infection. The bacteria are either totally destroyed or at least, the infection is stopped from further spreading. However, when the infection has not been completely destroyed, it can further spread later during the life, when the immune system of the individual gets weakened.
2nd In individuals with weakened immune system, the bacteria can rapidly spread throughout the body causing quick death.
3rd This is probably the most well-known form, which is described in books and movies. In this case, the immune system is strong enough to prevent the bacterial spread throughout the body, but not strong enough to completely stop the bacterial multiplication. The bacteria slowly and locally spread through the lungs battling with our immune system. The immune system is paradoxically the source of the problem as the tissues of the patient (i.e. lung tissue) is destroyed by the aggressive immune response. However, when the immune system gets exhausted, the infection may progress into rapid spread (see 2nd) and kill the patient.
The first symptoms of tuberculosis are very discreet. The most people complain about fatigue, chronically elevated body temperature, night sweats, weight loss and general malaise. The affection of lungs may result in cough and blood expectoration. The coughing up blood occurs when a pulmonary blood vessel is eroded by the pathological process.
The mentioned clinical signs may be generally warning, but they are not typical just for the tuberculosis. The lung affection can be found by chest X-ray or by computed tomography. The bacteria can be directly confirmed from a sample of sputum, but the cultivation in microbiological laboratory lasts a long time.
The prevention is possible by a vaccination. We use special strains of mycobacteria that are injected under the skin. These weakened bacteria cause local skin infection, but it quickly heals by a scar and the produced antibodies protect us against the dangerous strains of mycobacteria. However, the protection is not sure at 100%.
When the diagnosis is proven, the affected person must be treated by a combination of special antibiotics and chemotherapeutic. The treatment lasts for several months and requires cooperation of the patient. The therapy must be performed dutifully as the inadequately treated infection may cause occurrence of bacterial resistance to the antibiotics. Before the invention of antibiotics, the only effective method used to be an indirect support of the immune system of the patient including adequate nutrition, clean air and regular sunbathing.