Tuberculosis: Causes, Symptoms, Diagnosis

Tuberculosis: Causes, Symptoms, Diagnosis

Tuberculosis is a serious disease that can be fatal if left untreated. However, it is a treatable disease. Early diagnosis and treatment are Tuberculosis is one of the most common infectious diseases. It is estimated that more than 10 million people worldwide are infected with tuberculosis each year, and more than 1 million people die from it each year.

Tuberculosis is a leading cause of death worldwide, accounting for 1.8 million deaths each year. Of all new tuberculosis cases reported in 2021, 86% occurred in 30 countries with the highest incidence. Two-thirds of cases are concentrated in eight countries, with India leading the way, followed by China, Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh, and South Africa. Nevertheless, it is estimated that diagnosis and treatment of tuberculosis have saved 66 million lives between 2000 and 2021.

Treatment in Switzerland is performed at the highest level using cutting-edge methods in conditions comparable to living in a five-star hotel.


Tuberculosis is an infectious disease caused by bacteria.

The active development of the disease in people infected with Koch's bacillus depends on many factors (genetic, immunological, nutritional, social). It is estimated that 5-15% of infected people will develop tuberculosis with symptoms during their lifetime. The bacillus can remain in the body in a "dormant" state for years. People with weakened immunity have a higher risk of developing active tuberculosis. The HIV virus and Koch's bacillus actually form a dangerous association, because the system deficiencies caused by HIV infection contribute to the progression of tuberculosis. Without treatment, tuberculosis leads to death in almost all AIDS patients.

The bacteria mainly affect the lungs. When the affected person speaks, sneezes, or coughs, they release droplets containing microbes that other people can inhale with the air. But not everyone who comes into contact with the bacteria gets sick. The body's own defense forces fight off pathogens and often neutralize them. Sometimes the bacteria remain dormant in the body for many years. If the immune system is weakened, the bacteria can spread throughout the body, including to the lymph nodes, bones, urinary tract, or meninges.

Symptoms of tuberculosis

Tuberculosis is a cunning disease. In most patients, the symptoms are mild, and in many cases the disease is diagnosed too late. In particular, extrapulmonary tuberculosis, which is now very rare, is often difficult to diagnose. A person should see a doctor if they have any of the following symptoms:

  • Persistent cough lasting at least 3 weeks
  • Sputum with blood when coughing
  • Loss of appetite and weight
  • General feeling of fatigue and malaise
  • Swelling on the neck
  • Fever
  • Increased sweating at night
  • Chest pain

Diagnosis of tuberculosis - smear

The doctor suspects the disease based on the symptoms of the disease or the result of a chest X-ray. Additional tests are always necessary to confirm the disease. A definite diagnosis of tuberculosis can only be made on the basis of the presence of mycobacteria in the test material by smear or sowing. In special cases, the diagnosis (understood as a decision to start treatment) is made despite the lack of bacteriological confirmation of tuberculosis.

In patients with suspected pulmonary tuberculosis, the main material for research is sputum. When coughing up sputum for research, make sure that it is really bronchial fluid, not saliva.

Diagnosis of tuberculosis - chest X-ray

This is the main test for determining the presence of tuberculosis lesions in the lungs and assessing their severity.

Lesions suspected of tuberculosis etiology have a characteristic appearance on a chest X-ray. Unfortunately, they are not completely specific for this disease, so their detection requires additional research.

A chest X-ray is a basic study in the radiological diagnosis of pulmonary tuberculosis, the result of which often guides further treatment. In rare cases, computed tomography of the chest organs is required, most often in a high-frequency algorithm, which allows for accurate visualization of the lung parenchyma.

Diagnosis of tuberculosis - tuberculin test

This diagnosis consists in injecting a standard amount of highly purified filterate of a tuberculosis culture into the skin of the forearm. The drug is injected intradermally, so the injection is painless. The body of a person who has previously come into contact with mycobacteria (that is, infected or vaccinated with BCG) reacts with an immune response to the antigens of mycobacteria. There is erythema on the skin at the injection site, and a thickening is felt under the fingers. In people with a high immune response, small blisters may form on the skin. The size of the reaction does not exceed 2-3 cm. The indication is based on measuring the diameter of the infiltrate, which you can feel on the skin, and is performed approximately 48-72 hours after administration.


The test is safe andessential for a successful outcome. The test is safe and has no contraindications. Even the strongest reaction eventually goes away without leaving any marks on the skin. A positive result indicates:


  • Mycobacterial infection or active tuberculosis (does not differentiate between previous infection and active disease)
  • BCG vaccination (and successfully elicit an immune response to this vaccine). If most people in a given population have been vaccinated with BCG, this reduces the diagnostic utility of the test.
  • Contact with nontuberculous mycobacteria (these are bacteria that are common in the environment and very rarely cause diseases called mycobacterial infections).

Unfortunately, a large percentage (up to 40%) of people infected with mycobacteria have a negative tuberculin test. The most common causes of this are factors that weaken or modify the body's immune system, such as some viral infections (e.g., smallpox, measles, mumps, especially HIV infection), chronic diseases (e.g., diabetes, kidney failure), medications (e.g., corticosteroids), poor nutrition, and many other factors. Because of these factors, a negative tuberculin test result does not in any way exclude infection with mycobacteria. The test can be safely repeated many times. If the size of the induration increases by 10 mm over 12 months, this indicates recent mycobacterial infection

Based on the above, we understand how important it is to undergo diagnostics in a timely manner when a number of symptoms are detected that may indicate tuberculosis Diagnostics in Switzerland provides for the use of all the latest technologies in the world.


How is tuberculosis transmitted?

Mycobacterium tuberculosis is transmitted by airborne micro-droplets from a person with tuberculosis, in particular, when coughing, talking, singing, or sneezing.

Tuberculosis is less contagious than diseases such as the flu or measles: transmission usually requires prolonged close contact (in an enclosed space), for example, when living in the same room with an infectious person or when traveling together in a car. This also depends on the degree of contagiousness of the sick person, as well as the duration of contact (usually several hours of contact are required).


Thus, not all people who have come into contact with a tuberculosis patient will be systematically infected or, moreover, sick. However, young children and people with weakened immune systems are especially vulnerable.