Conditions Tuberculosis

Tuberculosis is an infectious disease that was formerly known as consumption. Today, the abbreviation TB or Tbc is often used. Tuberculosis typically affects the lungs. But other organs can also be affected. The infection is caused by tuberculosis bacteria that can be transmitted through the air in tiny droplets when a person speaks, sneezes, coughs, or sings. 

It is estimated that around one quarter of the world’s population is infected with the tuberculosis pathogen. Most people’s immune systems can successfully fight off the bacteria or trap them in a protective wall so they can’t spread. If an infection does not lead to tuberculosis, it is referred to as a latent tuberculosis infection (LTBI). With LTBI, there are no symptoms and it is not contagious. However, in this way, the bacteria can survive in the body in a dormant state for years. The disease breaks out at some point in only 5 to 10 percent of infected individuals. 

Tuberculosis can start with general symptoms such as loss of weight, slightly raised body temperature, night sweats and coughing. 

The treatment of tuberculosis is a lengthy process. Tuberculosis bacteria are very resistant and are present in various stages of growth. Therefore, various medications are used simultaneously during treatment.

Information about tuberculosis that is easy for laypersons to understand is also provided by the Deutsche Zentralkomitee zur Bekämpfung der Tuberkulose (German Central Committee for the Fight against Tuberculosis).

The lungs are most commonly affected, but sometimes other organs are impacted too. The initial infection generally proceeds without symptoms. 

Following infection, the course of the disease can vary: 

Latent tuberculosis infection (LTBI) without symptoms

Bacteria walled off by the immune system can survive in the body for years without causing symptoms. This is known as a latent tuberculosis infection (LTBI). If the body’s immune system weakens, the disease can break out. In the case of an LTBI, it is unfortunately impossible to distinguish whether the bacteria were completely killed off by the body’s immune system after infection, or if living (and dormant) tuberculosis bacteria are still present in the body. 

Onset of disease: active tuberculosis requiring treatment

If a tuberculosis infection does develop into the active disease, it usually breaks out within the first 1 to 2 years. However, it can also appear decades later. 

The lungs are affected in over 70 percent of those with the infection who show symptoms. In addition, the lymph nodes, pleura, kidneys, and urinary tract may be affected, as well as (in rare cases) bones, the meninges, or other organs. 

The disease usually starts with a mild fever, weakness, unexplained weight loss and night sweats. If the lungs are affected, a persistent cough typically occurs, occasionally accompanied by chest pain and shortness of breath. You might also cough up phlegm. In rare cases, the phlegm may be bloody. 

Other possible general symptoms are:

• poor general health
• loss of appetite
• fatigue

It is estimated that in about a quarter of those affected, the symptoms are very mild or entirely absent.

If the immune system is already weakened, the first symptoms usually appear within 2 years of infection. This most commonly affects small children and untreated individuals infected with HIV. Even if your body safely locked the bacteria away in the past, a drop in your immune system can cause these “sleeping” bacteria to wake up and make you sick.

In rare cases, small foci of infection can spread throughout the body, for instance when the immune system is severely weakened. The pathogens can also trigger blood poisoning (sepsis).

Tuberculosis is an infection with bacteria that is transmitted from one person to another.

Tuberculosis bacteria

Tuberculosis is triggered by rod-shaped bacteria from the Mycobacteria family. The most common pathogen to trigger the infection is Mycobacterium tuberculosis, which was discovered by Robert Koch.

Routes of transmission

You can become infected with tuberculosis if you have contact with people who have active tuberculosis. In cases of active tuberculosis, the pathogens are released by infected individuals in tiny droplets (aerosols) within exhaled air. This happens primarily when someone sneezes and coughs. In this way, they can infect other people through the air. This is usually possible when prolonged contact occurs in enclosed spaces. 

When tuberculosis affects organs other than the lungs, the bacteria generally remain inside the body, so transmission is not possible.

In rare cases, pregnant women with untreated tuberculosis can infect their unborn baby during pregnancy or at the time of birth. However, transmission most frequently occurs through close contact between mother and newborn after birth. Infection via breast milk, however, is not possible.

How is a patient’s contagiousness tested?

The more bacteria someone with active pulmonary tuberculosis coughs up, the more contagious this person is. A person’s contagiousness is determined by examining a sample of coughed-up mucus under a microscope. If bacteria are visible in it, this indicates a high level of contagiousness. A person is less contagious if the bacteria can only be detected through a laboratory culture or molecular biological testing. This is often the case with children under 10 years of age. In addition, children are less contagious than adults because their cough strength is weaker.

There are certain groups of people and patients who are particularly at risk of developing active tuberculosis requiring treatment following an infection.

For example:

• close contacts of individuals with active tuberculosis
• infants and small children
• people with a weakened immune system, for example due to HIV
• patients receiving medication that suppresses the immune system, for example due to rheumatism or following a transplant
• people from countries where tuberculosis is common
• alcohol or drug addicts
• homeless people
• people with malnutrition
• patients with silicosis, a lung condition caused by dust-containing silica and often occurring in the construction and ceramics industries

Tuberculosis is very common all over the world. It can spread easily, especially in areas where large numbers of people are infected with HIV. Their immune deficiency puts them at an increased risk of contracting the disease. In addition, treatment in these areas is often inadequate and the tuberculosis bacteria are increasingly resistant to the medications (antibiotics) used.

Prevalence worldwide

An estimated quarter of the world’s population carries the pathogen. However, most people do not develop any symptoms as a result, because their immune system keeps the pathogens under control. The disease breaks out in approximately 10 million people per year, and approximately 1.5 million die of tuberculosis every year. This makes tuberculosis the most common fatal bacterial infectious disease worldwide among adolescents and adults. It is one of the most common causes of death in people infected with HIV. Around 87 percent of all people with a new infection live in Southeast Asia, Africa, and the Western Pacific Region.

Prevalence in Europe

Europe accounts for around 2 percent of all new cases of tuberculosis worldwide, with significant regional differences. For instance, in Western European countries and the Balkan states (excluding Kosovo), fewer than 15 people per 100,000 inhabitants fall ill annually.

In most European countries, the numbers have been falling continuously for many years. In Eastern Europe and Central Asia, the situation is made more difficult by increasing regional drug resistance – that is to say the insensitivity of the tuberculosis bacteria to antibiotics.

Prevalence in Germany

In Germany, approximately 4,500 cases of tuberculosis are reported to the Robert Koch Institut annually. Accordingly, there are approximately 5 cases per 100,000 inhabitants.

People who are born in countries where tuberculosis is still very common are most affected. As about 70 percent of tuberculosis cases are cases of open (and contagious) pulmonary tuberculosis, the occurrence of TB infections is monitored by the local health authorities.

People with healthy immune systems

Only some of those infected actually develop tuberculosis that needs treatment. The figure is around 5 to 10 percent for adults and adolescents with a normal immune system.

The risk of disease is at its highest in the first two years after infection.

People with impaired immune systems

People with a weakened immune system, in particular, can develop tuberculosis soon after infection. In these people, the bacteria can spread more easily to other organs via the lymphatic pathways and/or the bloodstream. Complications can include disease affecting the meninges or the brain. In addition, if their immune system is weakened – for example due to taking certain medications – people can still develop tuberculosis decades after the initial infection (known as reactivation).

Infants and young children

Infants and young children are particularly at risk of infection and of becoming ill because their immune systems are not yet fully developed.

A vaccine against tuberculosis (the BCG vaccine) has been available worldwide for many decades. However, in Germany, this has not been recommended by the Standing Committee on Vaccination (STIKO) at the Robert Koch Institute since 1998. There are several reasons for this:

• The vaccination protects against severe forms of the disease such as meningitis or sepsis, but not against infection with or developing tuberculosis.
• The vaccination is therefore only useful for small children in regions with a high infection risk.
• In Germany, the risk of infection is low.
• As it is a life-long vaccine, there is an increased risk of side effects.

In many countries, especially where the risk of infection is high, the BCG vaccination is still administered immediately after birth. In some countries, vaccination is required if the person wants to stay there for an extended period. This should be discussed in detail with a family doctor.

Tests are done both at the beginning and during treatment to monitor its success. Typically, mucus from the lungs that has been coughed up or suctioned out is examined. Depending on which organs are affected, the pathogens can also be detected in gastric juice, urine, cerebrospinal fluid or other fluid and tissue samples.

If there are enough bacteria in the sample, they can be detected directly under a microscope. Smaller quantities of bacteria can be detected by propagating them in a bacterial culture or by examining the sample for bacterial DNA. In addition, tests are carried out to determine whether the bacteria are resistant to tuberculosis medications.

In addition to pathogen detection, the diagnostic workup always includes a chest X-ray. This way doctors can determine whether there are indications of pulmonary tuberculosis, which could potentially be contagious. An X-ray can also be used to assess whether the treatment for pulmonary tuberculosis is progressing successfully. To be able to assess changes in the lungs more precisely, a computed tomography scan – a type of cross-sectional X-ray – may also be performed in some cases. 

If at least 6 to 8 weeks have passed since exposure, an infection with tuberculosis bacteria can also be detected using a blood test. For children under the age of 5, a skin test is usually performed. To do this, components of killed bacteria are injected under the skin, and the subsequent reaction is evaluated. For older children and adults, a blood test is usually performed.

Successfully treating tuberculosis requires following a few special guidelines. The metabolism of tuberculosis bacteria can sometimes be very sluggish, or they may be in a resting state. With these bacteria, it takes longer for the medications to be absorbed and take effect. In addition, the immune system partially contains the bacteria, building up layers of tissue around them in the process. This makes it more difficult for the medications to reach their target site. Some tuberculosis bacteria are also resistant to several antibiotics.

Medication

A tuberculosis infection is always treated with several drugs at the same time. The mechanisms of action of the various medications target the different metabolic states of the bacteria. This allows both resting and active bacteria to be fought at the same time. In addition, there are always a few pathogens against which individual medications are ineffective. By combining multiple medications, the likelihood that the treatment is effective against all tuberculosis bacteria is increased. 

Standard treatment for tuberculosis involves four active agents administered simultaneously:

• Isoniazide
• Rifampicin
• Ethambutol
• Pyrazinamide

There are also medications that are used in the event of resistance or intolerances.

Standard treatment

Usually, children and adults receive a combination of medications for a total of at least six months. This combination is made up of four of the aforementioned antibiotics for two months, and then two of them for four months. The treatment can lead to various side effects, including skin rashes, vision problems and impaired liver function. Patients who respond to treatment are usually no longer contagious within a few weeks.

Problem: resistance to medication

Continuous monitoring of the course of therapy is very important. This way, it is possible to quickly detect if the person concerned is not tolerating the medication or if the pathogen has become resistant to the medication. In some cases, a different medication is used, and the treatment may be extended. If there is unfavorable drug resistance, treatment with alternative medications can last up to 18 months.

Multiresistant tuberculosis, where there is simultaneous resistance to the two main medications isoniazide and rifampicin, is particularly significant. There are also tuberculosis bacteria that are resistant to other medications.

The number of cases of resistant tuberculosis bacteria has remained stable at a low level in Germany in recent years. However, they may be higher for people born outside of Germany. The highest proportion of multiresistant tuberculosis is found in people with the disease from countries of the former Soviet Union.

Supporting treatment

It is important to support those affected during treatment rather than excluding them. Family and friends play an important role in this. Contact is usually possible provided that a suitable full face mask is worn. Digital applications such as apps or websites can also be used to support treatment. Some of these apps can also help patients take the medication they need on a daily basis. 

Stopping treatment prematurely can lead to a relapse or to other tuberculosis bacteria becoming resistant to drugs. 

An app providing information in over 40 languages is available on the Explain TB website.

Practical information for patients undergoing tuberculosis therapy is provided by the German Central Committee against Tuberculosis (Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose).

Every case of tuberculosis requiring treatment must be reported to the local health authority. Those with active tuberculosis are initially isolated in a hospital for as long as they are contagious. If no tuberculosis bacteria are detectable in the coughed-up mucus, patients can generally continue to be treated at home. Contacts of infected individuals are also examined and, if infection is confirmed, may receive preventive treatment.

People who have or are suspected of having a contagious tuberculosis infection are not permitted to work in community facilities such as pre-schools, schools or hospitals. Their treating physician, together with the public health authority, will determine when they will be permitted to do so. Before this can happen, the infection should no longer be contagious and the treatment must be well tolerated.

You can find answers to frequently asked questions (FAQs) on the website of the Deutsche Zentralkomitees zur Bekämpfung der Tuberkulose (German Central Committee for the Control of Tuberculosis).