Tuberculosis is an infectious bacterial disease which is transmitted via drops in the air. The disease primarily affects the lungs; however, it can also affect other organs. In earlier times, tuberculosis was known worldwide under the name of consumption. With the development of antibiotics and a vaccine, tuberculosis has declined significantly in the Western world. Nowadays, the disease is gaining ground again. The reasons for this are global migration and the development of antibiotic resistance.

Tuberculosis at a glance

Tuberculosis (TB for short) is an infectious disease caused by bacteria from the mycobacteria family. Until Robert Koch discovered Mycobacterium tuberculosis in 1905, tuberculosis, then known as consumption, was a widespread and feared disease.

In the first half of the 19th century alone, more than 20% of those suffering from tuberculosis died from it. It was only with the development of a vaccine, improved living conditions and the introduction of antibiotic combination therapy that the spread of this infectious disease declined sharply in the Western world.

Despite advances in medicine, new medications, examinations and treatments, tuberculosis has never been completely eradicated worldwide. In recent years, the number of tuberculosis cases has risen again. The resurgence of the illness can be attributed to the spread of certain drug-resistant strains of tuberculosis. Global migration also contributes to the rise in tuberculosis cases. 

 

Types of tuberculosis

Primary tuberculosis

In primary tuberculosis, a primary complex develops from the initial infection, i.e. a local, tuberculous inflammation area affecting regional lymph nodes. In most cases, these areas of inflammation are slowly enclosed by the immune system, resulting in small, nodule-shaped structures known as tubercles.

Pulmonary tuberculosis (tuberculosis of the lungs)

Most people associate tuberculosis with the lung disease pulmonary tuberculosis because around 70% of tuberculosis patients are affected by it. However, tuberculosis comes in many forms, which can be distinguished from one another depending on the stage and course of the disease. A distinction is made between pulmonary tuberculosis and extrapulmonary tuberculosis (tuberculosis outside the lungs). 

Extrapulmonary tuberculosis

Extrapulmonary tuberculosis refers to tuberculosis that causes symptoms outside the lungs. Although tuberculosis usually affects the lungs, there are many different forms of extrapulmonary tuberculosis worldwide that can occur alone or in combination with pulmonary tuberculosis.

Extrapulmonary forms of tuberculosis include:

  • Bone and joint tuberculosis
  • Lymph node tuberculosis
  • Genitourinary tuberculosis
  • Central nervous system tuberculosis
  • Abdominal tuberculosis

Latent tuberculosis (latent tuberculosis infection)

Nine out of 10 people infected with tuberculosis remain latent for their entire life, meaning they do not show any symptoms of tuberculosis. Only a weakening of the immune system can lead to latent tuberculosis becoming active.

When the disease breaks out, the latent tuberculosis becomes active tuberculosis: bacteria multiply, symptoms occur and the disease can be transmitted to other people.

Latent tuberculosis (latent tuberculosis infection) is therefore the most common form of the illness in patients with a healthy immune system. Latent tuberculosis can break out months or even years later. 

Incidence and age

While in Europe, primarily adults and more rarely children are affected by tuberculosis, in countries with a high rate of TB, it’s often children who fall ill. Asian and South African countries are most affected by tuberculosis. According to the FOPH, most tuberculosis cases in Switzerland occur in people who come from countries with a high incidence of tuberculosis.

In Switzerland alone, around 550 cases occur every year. The fact that a previous tuberculosis infection does not lead to immunity is particularly serious: tuberculosis infection can occur repeatedly, with young children and people with a weakened immune system being particularly at risk. 

Causes of tuberculosis

Tuberculosis is caused by bacteria from the mycobacteria family. Although most of the 160 different mycobacteria are harmless to humans, certain species, such as the mycobacterium M. tuberculosis, can lead to tuberculosis.

Transmission of the pathogen occurs almost exclusively via the air. When coughing or talking to a person with respiratory tuberculosis, tiny bronchial droplets are released. If inhaled, they can cause an infection. The higher the number of bacteria inhaled, the more likely an infection.

Important: only 5–10% of those infected develop active tuberculosis during their lifetime. In other words, not every infection automatically leads to an active illness.

If TB bacteria enter a person’s body, the immune system can fight them in different ways.

If the immune system fails to successfully fight the TB bacteria, tuberculosis can occur. 

Symptoms

If the tuberculosis sites have a direct connection to the bronchi, this is called ‘open tuberculosis’. If tuberculosis bacteria can be detected in the sputum, the illness can be transmitted from the person infected to others, leading to a risk of infection.

Symptoms of primary tuberculosis

In many cases, primary tuberculosis does not cause any symptoms. However, if tuberculosis symptoms do occur, they are often non-specific, meaning that they are frequently attributed to other diseases, such as the flu. The symptoms include:

  • Poor general condition
  • Weakness
  • Tiredness
  • Heavy sweating (especially at night)
  • Impaired performance
  • Mild fever
  • Loss of appetite
  • Unintentional weight loss

Symptoms of pulmonary tuberculosis (tuberculosis of the lungs)

Tuberculosis usually progresses slowly, and the severity of possible symptoms is initially mild. Pulmonary tuberculosis also causes only a few symptoms at the beginning of the infectious disease. As the illness progresses, the typical symptoms occur, which are also common to many other lung diseases. These include:

Note: any cough that lasts longer than three weeks should be examined by a doctor. Coughing with no known cause or bloody sputum requires medical clarification.

Symptoms of extrapulmonary tuberculosis (tuberculosis outside the lungs)

As with pulmonary tuberculosis, the symptoms of extrapulmonary tuberculosis develop gradually and are non-specific at the onset of the illness, making diagnosis difficult. Different symptoms can occur depending on the organ affected. Organ-related symptoms can indicate which form of tuberculosis is present. The following symptoms may occur, among others:

  • For skin and lymph node tuberculosis: thickening, nodules and other skin changes
  • For intestinal tuberculosis: gastrointestinal problems
  • For tuberculous meningitis: nausea, vomiting, stiff neck
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Diagnosis

When it comes to diagnosis, pneumology faces difficulties in certain cases: it is challenging to diagnose tuberculosis at the onset of the disease because the symptoms of tuberculosis are only mild and very similar to those of other illnesses.

Various clarifications and examinations are carried out to diagnose tuberculosis. It begins with a medical history, i.e. the patient is asked targeted questions regarding their medical background. The targeted questions aim to determine the causes of their complaints and to establish a basis for diagnosis and treatment.

In some cases, depending on the form of tuberculosis, a bronchoscopy with a tissue sample may be necessary. Additionally, X-ray images and blood tests can be used for diagnosis.

To make a definite diagnosis, the TB pathogens must be detected with a laboratory test. Laboratory tests require saliva samples, urine samples, blood samples or other body fluids or tissues, such as skin samples. Particularly in the case of latent tuberculosis, a positive tuberculosis test is usually the only reliable evidence, as latent tuberculosis does not cause any symptoms.

Tuberculosis treatment

Tuberculosis is an infectious disease with reporting obligations. If a person’s immune system is weakened or the tuberculosis goes undetected for too long, the course is not favourable. Without treatment, the illness can even be fatal. If, on the other hand, it is diagnosed early and treated for a sufficient amount of time, the chances of recovering from tuberculosis without lasting damage are good.

Tuberculosis is usually treated with antibiotics. The drug therapy lasts at least six months, and the treatment success is reviewed at regular intervals. Those affected are isolated at the start of treatment until they are no longer contagious. Patients who have been undergoing treatment for tuberculosis for at least two weeks are considered to be no longer contagious.

If medication is insufficient for the treatment, surgical intervention is required. Surgery is considered when parts of the lung are permanently destroyed, when cavities (larger hollow spaces in the lung tissue) have formed that do not shrink, or if tuberculosis sites cause complications in other organs. In each of these cases, a specialised medical team will decide whether or not surgery is appropriate.

Latent tuberculosis treatment

If tuberculosis is latent, it does not cause symptoms and is not contagious. However, the risk of tuberculosis reactivation can be reduced by preventive drug therapy. The treatment aim is to eliminate the bacteria remaining in the body.

Prevention

Protection against tuberculosis infection is possible by consistently avoiding contact with people suffering from it. However, this is difficult to implement, in particular because tuberculosis symptoms are rarely recognised as such in everyday life.

Another way to protect yourself against tuberculosis is to get a vaccination against it. In Switzerland, however, this is now only recommended in exceptional cases, such as before emigrating to a country with high rates of tuberculosis or for newborns and babies younger than 12 months who have a high risk of infection due to their country of origin having a high incidence of tuberculosis.

Questions about tuberculosis

Is tuberculosis dangerous?

Yes, if left untreated and in particularly severe cases, tuberculosis can be fatal. Tuberculosis is still the most lethal bacterial infectious disease.

Is tuberculosis curable?

Yes, tuberculosis is curable. With targeted antibiotic treatment, the bacteria that cause the illness can be completely eliminated. In most cases, active treatment over several weeks is necessary.

What does the skin look like with tuberculosis?

Tuberculosis typically affects the lungs. In rare cases, some form of extrapulmonary tuberculosis can also cause skin changes – for example, small nodules may appear on the skin.

Can you have tuberculosis without noticing it?

Yes, many people carry the pathogen Mycobacterium tuberculosis without showing any symptoms. Around a quarter of the world’s population is infected with tuberculosis bacteria in their lifetime. However, not everyone suffers from the disease. In 90–95% of all those infected, the infection remains latent for life, i.e. without tuberculosis symptoms. In such cases, only a weakened immune system leads to the outbreak of the disease.

Is there a tuberculosis vaccination in Switzerland?

In Switzerland, vaccination against tuberculosis is no longer routinely carried out. It is only administered in select cases for people with increased risk.

Can tuberculosis cure itself?

No, tuberculosis does not usually cure itself. Without treatment, the illness can become chronic, affect other organs and even lead to death. Medical diagnosis and treatment are therefore essential.

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