Tuberculosis: Infection, symptoms, therapy
Tuberculosis is a serious infectious disease caused by bacteria. The pathogens are usually transmitted by droplets in the air we breathe, which are inhaled. Therefore, tuberculosis usually affects the lungs first. However, it can also affect other organs such as the intestines or bones. Read here what tuberculosis is, how to get infected, how to recognise it and what treatment options are available.
Tuberculosis short overview
- Description: Notifiable bacterial infectious disease. Affects mainly the lungs, but also bones, intestines and other organs
- Infection: Mostly by droplet infection via the lungs, but also via the digestive tract or skin injuries. Only one in ten infected people develop symptoms
- Symptoms: Fever, cough, night sweats, weight loss, exhaustion, in later stages bloody sputum
- Especially vulnerable: People with weak immune systems, e.g. HIV patients, people taking immunosuppressive drugs, homeless, malnourished, children, addicted patients
- Diagnosis: antibody test on the skin, blood tests, X-rays, direct detection of bacteria
- Treatment: Special antibiotics, difficult treatment for resistant bacterial strains
- Prognosis: Otherwise healthy patients have good chances of recovery if the disease is detected early.
Tuberculosis is caused by rod-shaped bacteria, so-called mycobacteria. It mainly affects the lungs, but can also affect other organs.
Tuberculosis is much more common in other regions, especially in Africa, Southeast Asia and the West Pacific. People who have close contact with patients with infectious tuberculosis are also at risk. As well as HIV-infected persons and persons with a weak immune system. Other risk factors are drug addiction, homelessness and poverty.
Tuberculosis can be treated with different combinations of drugs. On average, you should expect six months for a standard therapy. However, if complications arise, such as resistant bacterial strains, a therapy can take much longer. The decisive factor for success is timely treatment and regular intake of the medication, even if it is for a longer period of time.
In most cases, the body is able to successfully fight the pathogens or render them harmless by encapsulation. Only in about ten percent of cases does tuberculosis actually break out. Symptoms are then fever, fatigue, night sweats and weight loss. Later also bloody cough and shortness of breath.
In the past, the disease was also known as consumption, because without effective treatment, the sufferers physically deteriorate very quickly.
The lungs are most frequently affected by tuberculosis. After infestation with the tuberculosis bacteria, a nodular focus of inflammation forms and lymph glands swell.
Tuberculosis – how to become infected
For a long time, tuberculosis was considered almost extinct in the western industrialised countries. In recent years, the disease has become more frequent again due to the immigration of sick people, for example from Eastern European countries.
How do the bacteria enter the body?
Tuberculosis is transmitted via different routes:
Infection via the air we breathe: By far the largest proportion of patients become infected when infectious microdroplets enter the lungs with the air we breathe. The bacteria are sneezed or coughed out by patients with so-called open tuberculosis. Open tuberculosis means that the focus of infection in the lungs is not encapsulated, but open to the bronchial tubes.
Infection via the digestive tract: The bacteria can also enter the body via the digestive tract. The pathogen causing bovine tuberculosis, Mycobacterium bovis, can be transmitted to humans, for example through raw milk from diseased cows.
Infection via the skin: Another transmission route is through skin lesions through which the tuberculosis pathogen enters the body.
How contagious is tuberculosis?
Tuberculosis is not very contagious compared to other infectious diseases such as influenza. Only one in ten infected persons actually breaks out of the disease. Whether one falls ill oneself after contact with an infected person depends mainly on two factors:
- how much of the pathogen the patient has excreted
- how powerful the own immune system is
The incubation period for tuberculosis can last from weeks to months.
Which signs of tuberculosis there are and which symptoms a tuberculosis patient suffers from depends on the stage of the disease and the organs affected.
After a tuberculosis infection, patients often have no complaints. In most cases, the body manages to keep the bacteria in check. Then there are no symptoms of tuberculosis. This condition is known as latent tuberculosis.
In people with good body defence, the defence cells around the centres of inflammation form a kind of capsule. Nodular structures, so-called granulomas or tubercles, develop. The pathogens can still be active in these tubercules, but do not cause any damage in the body. Later, the tubercle will increasingly scar and calcify. They can often be seen on X-rays even years later. Doctors refer to this form of the disease as closed tuberculosis.
In about five to ten percent of patients, the body’s immune system is unable to successfully encapsulate the pathogen. Then centres of inflammation form in the lungs and the nearby lymph nodes. These increase in size. This condition is known as primary tuberculosis. However, the process progresses only slowly: this stage usually begins within two years of infection.
Often the patients do not even notice this form of tuberculosis. However, various complaints can also occur such as:
- night sweats
- Loss of appetite
- Weight loss
If the infection spreads in the body, cavities, so-called caverns, form in the lung tissue. They are filled with dead cells and active tuberculosis bacteria (necrosis, cheese-making). If these cavities break through to the bronchial tubes, one speaks of open tuberculosis.
Then typical tuberculosis symptoms appear: The patient coughs up mucus, which can also be bloody. The pathogens then often reach the air we breathe in large numbers. Patients with open tuberculosis are highly infectious.
Pulmonary tuberculosis begins with a small inflammatory focus in the lungs. In the growing herds, cells die and the pathogen can spread further.
Tuberculosis pathogens can persist in the body for a long time without causing symptoms. However, the disease can also break out for the first time or again many years after the initial infection. Then one speaks of a post-primary tuberculosis.
In about 80 percent of the cases it affects the lungs. Sometimes, however, the pathogens also spread through the bloodstream. The smallest inflammations in other organs, so-called “minimal lesions”, develop.
Mostly the pleura, lymph nodes, bones and joints are affected. But also the digestive tract, skin and sexual organs can be affected.
Tuberculosis outside the lung tissue
Although they are usually located in the lungs, tuberculosis pathogens can infect organs and tissues throughout the body. Very different symptoms occur.
Lung root: Where the bronchial tubes enter the lungs (pulmonary root, pulmonary hilus), there are a particularly large number of lymph nodes. If they are attacked by tuberculosis bacteria, they swell and compress the adjacent airways.
The lung tissue behind it is cut off from the air supply and collapses. If the area of the lung that is no longer ventilated is large, the patient suffers noticeably from shortness of breath.
Costal pleura: In the case of tuberculosis of the pleura (pleuritis tuberculosa), those affected usually have pain when breathing. In a “wet” pleurisy, fluid accumulates around the lungs, which can compress the lungs so much that breathing becomes difficult.
Miliary tuberculosis: Miliary tuberculosis is a TB infection that affects not only the lungs but also the meninges, liver, spleen, kidneys and eyes. In the process, small granule-sized centres of inflammation form, distributed throughout the entire organ. They are reminiscent of millet grains, Latin milium. In Germany, this form is rare, but more often affects children or people with a weakened immune system. This special form (1-2% of cases) mainly affects people with weak immune systems. Numerous small centres of infection form in the lungs, brain and other organs.
The tuberculosis symptoms are then unspecific. This means that they can also occur with many other diseases and are not typical of tuberculosis. These include fever, headaches, a stiff neck and impaired vision.
Intestinal tuberculosis: Patients become infected with intestinal tuberculosis mainly through the consumption of infected raw cow’s milk.
In addition to flu-like symptoms, there are complaints reminiscent of a chronic inflammatory bowel disease: diarrhoea, abdominal pain and weight loss. Often there is also blood in the stool. As the disease progresses, peritonitis or a dangerous intestinal obstruction may occur.
Skin tuberculosis: An infection of the skin with tuberculosis pathogens can manifest itself in different ways. The most common areal, reddish-brown skin changes. These are often hardened and clearly palpable. However, the patient is not in pain. Doctors also refer to this clinical picture as Lupus vulgaris.
Tuberculosis of the urinary tract: If the urinary tract is affected by tuberculosis, inflamed nodules form in the kidneys, ureters and bladder, which can scar and calcify.
Those affected suffer from pain when passing water and in the flanks. You may find blood or pus in the urine. The nodules can also close the urinary tract, so that urine is retained. The urinary organs can suffer permanent damage as a result.
Tuberculosis of the reproductive organs: In women, tuberculosis infection of the reproductive organs usually migrates from the fallopian tubes into the uterus. Afterwards, menstruation often stops and the woman can become infertile.
In men the epididymis can be infected by tuberculosis bacteria. These swell painfully and are reddened. The disease can lead to infertility.
Bone and joint tuberculosis (Spondylitis tuberculosa): Bone and joint TB manifests itself in swelling and pain in the joints, but especially in the thoracic and lumbar spine. The patients feel very ill.
If the inflammatory process of this tuberculosis continues untreated, abscesses form. There are nervous failures with paralysis in the affected areas. A hunchback often forms. In extreme cases, the spine bends backwards. These severe TB symptoms have become very rare thanks to good treatment options.
Tuberculosis: Causes and risk factors
At over 95 percent, Mycobacterium tuberculosis is the most common human tuberculosis pathogen. The disease mainly breaks out in people with weakened immune systems. These include:
- HIV infected, AIDS patients
- chronically ill people (e.g. diabetics)
- Patients in whom the immune system is suppressed by medication (e.g. after a transplant)
- Drug addicts, smokers and alcoholics
- older humans
- Diabetics and patients with kidney weakness
- Infants and children under four years of age
Migrants coming from countries with poor health care are comparatively more likely to suffer from tuberculosis. The risk of infection is also particularly high in the confinement of refugee accommodation. Tuberculosis is also more widespread among prisoners than in the rest of the population.
In both groups, the medical side therefore pays particular attention to the possible spread of TB.
Tuberculosis: Diagnosis and examination
The signs of TBc are only slightly characteristic (unspecific). In about 15 percent of the cases no symptoms occur at all. The infection is therefore usually discovered by chance, for example during a check-up at the family doctor or specialist for internal medicine.
Medical history (anamnesis)
If TB is suspected, the doctor will ask the patient about any symptoms that may occur, for example:
- Do you have a slight fever?
- Do you sweat a lot at night?
- Have you lost much weight recently?
Other circumstances that make tuberculosis more likely to occur
- previous tuberculosis infection. In this case, tuberculosis bacteria slumbering in the body may have been reactivated.
- known cases of TB in the immediate vicinity, i.e. among relatives and acquaintances or at work (especially in the medical field)
- Travelling to countries with a higher spread of tuberculosis
- Pre-existing conditions or drugs that weaken the immune system and thus promote tuberculosis infection
Since tuberculosis usually occurs in the lungs, the doctor examines them by listening and tapping. Signs of consumption can also be found in other parts of the body, such as skin changes or headaches over the lateral ribs or kidneys.
If a doctor suspects a tuberculosis infection, he has a number of further examination options at his disposal which can confirm this suspicion.
Tuberculosis: Test procedure
There are special tests that help to make a diagnosis of tuberculosis.
Tuberculin skin test (THT): In the Mendel-Mantoux tuberculin test, the doctor injects a small amount of protein of the pathogen (tuberculin) under the skin of the patient. Since the immune system of infected persons usually forms special antibodies against the pathogens after a few weeks, tuberculosis infected persons develop a reddened hardening at the injection site.
However, the test does not provide evidence for or against an infection. If it occurs too early after infection, or if the immune system is weakened, it does not (yet) produce enough antibodies. The tuberculosis skin test turns out negative despite the infection.
IGRA (Interferon Gamma Release Assay): This test examines the blood of patients. If a person is infected with tuberculosis, special defence cells produce interferon gamma, which can be detected during this examination.
The test is more accurate than the skin test. However, at the moment, doctors primarily use it in addition to the tuberculin skin test (THT). If both the skin test and the IGRA test are negative, consumption is very unlikely.
Direct pathogen detection
If, for example, the X-ray image shows shadows in the lung tissue and the TB tests are positive, the tuberculosis bacteria must be detected directly. Sputum, gastric juice, urine, monthly blood and cerebral fluid are examined. In some cases, doctors also take tissue samples from the lungs or lymph nodes (biopsies).
This involves immediate investigation of whether the strain in question is resistant to certain antibiotics. However, direct pathogen detection is costly and time-consuming. It may take up to twelve weeks before results are available.
You can read more about the different test procedures in the article Tuberculosis Test.
An X-ray of the chest can reveal possible centres of inflammation. In primary tuberculosis, these appear as round shadows. If the hilus lymph nodes are infected, the shadow resembles a chimney. With miliary TB, on the other hand, the doctor can detect many small dots.
The picture also shows fluid accumulations, for example in case of an infestation of the pleura. If a fresh TB infection is suspected, a new intake is made after three months at the earliest. This allows the course of tuberculosis to be assessed.
CT (computer tomography)
If nothing or only little can be seen on an X-ray, the doctor arranges for a CT. In this way, tuberculosis foci can also be detected, which are hidden by the collarbone, for example. CT images are also helpful for inflammations elsewhere in the body (extrapulmonary tuberculosis).
Through a comprehensive examination of the blood, the doctor checks values whose changes indicate the disease of a particular organ. In addition, certain blood values such as CRP and white blood cells may be elevated, which indicate inflammation in the body.
Thanks to antibiotics, tuberculosis is curable today. Especially in immunocompromised people, the disease can still be severe.
An active tuberculosis must always be treated. Speak for an active TB:
- Cavity (cavern) in the airways caused by illness
- Focus of inflammation (visible as a shadow in the lungs)
- Enlargement of an old (already known) hearth with reactivated Tbc
- Pathogen detection
Inpatient treatment and quarantine
Particular caution is required with open tuberculosis. Patients are usually admitted to the hospital as inpatients and isolated. If an effective tuberculosis therapy has been initiated, the isolation can usually be lifted after three weeks. Afterwards, the person concerned can also receive further care at home (outpatient).
Tuberculosis is mainly treated with antibiotics, which have proved particularly effective in treating the disease. They are called antituberculotics. At the beginning of the therapy, four drugs are prescribed simultaneously for the first two months as standard:
- alternatively: Streptomycin
Two antituberculotics, usually rifampicin and isoniazid, are then given for another four months. For example, if the patient has a disease such as HIV that weakens the immune system, or if he or she suffers relapses, the duration of treatment is extended.
The therapy of a complicated tuberculosis can also take longer than one year. Since the drugs can have side effects, regular medical checks of important blood values and organ functions are carried out. The doctor pays particular attention to the liver, kidneys and eyes.
If the meninges, pericardium, peritoneum or adrenal glands of tuberculosis patients are inflamed, doctors initially administer corticosteroids additionally. This is intended to throttle an excessive inflammatory process.
In the case of open pulmonary tuberculosis, the doctor also administers cough-relieving medication. This also protects the environment, as the patient spreads fewer pathogens in the air.
In some cases, the drug therapy for tuberculosis is insufficient or not effective at all. This is the case for example with very large centres of inflammation. But surgery can also be useful for bacterial strains that are resistant to drugs. Surgeons try to remove the tuberculous centres of inflammation.
Anyone suffering from tuberculosis should avoid anything that could worsen the course of the disease. This includes the consumption of alcohol and tobacco products. In addition to tuberculosis, doctors also treat other diseases that could make tuberculosis worse.
Tuberculosis: Course of disease and prognosis
If a patient is treated correctly and in time, tuberculosis is usually curable. However, there are some factors that make the treatment of consumption difficult.
If the patient suffers from chronic diseases or has a weakened immune system, the chances of curing tuberculosis decrease. In severe cases, this can lead to lung bleeding, lung collapse or blood poisoning with severe organ damage.
Particularly dangerous is also the rapid death of the inflamed lung areas, the so-called “galloping consumption”. In this case, the lung tissue becomes yellowish and crumbly, which is why experts call this process cheese formation. If the dead material liquefies (melting), the Tbc stove can scatter.
Tbc bacteria that have become resistant to tuberculosis drugs pose a particular problem. In Germany, approximately twelve percent of tuberculosis cases are currently caused by pathogens in which at least one anti-tuberculosis drug fails.
In about two percent of cases, the bacteria are even resistant to several drugs. Experts then speak of multi-resistance. With this complicated TB, doctors then have to resort to reserve funds. The treatment takes one and a half to two years.
Lack of adherence to therapy
It is crucial for the success of the therapy that the patient takes the prescribed medication regularly and permanently, even though the side effects can be unpleasant. Otherwise, the pathogens are not killed sufficiently and resistances develop more quickly. Because of the long duration of treatment and the side effects of some drugs, some patients do not adhere to their treatment plan.
It is particularly important to recognize and treat infected patients in time. Especially when you come into contact with a patient with open tuberculosis, you are immediately isolated. Only when three independent samples of the ejection are free from pathogens, the isolation is lifted.
After unprotected contact with an infected person, preventive treatment with the antituberculotic isoniazid is also advisable. This prophylaxis usually lasts three to six months if the TB skin tests have turned out negative. If their test result is positive, nine months of preventive treatment is given.
These measures are particularly important for immunocompromised persons, children and persons travelling to high risk areas in the foreseeable future.
Hygiene measures in contact with infected persons
In contact with patients with open tuberculosis, strict hygiene measures are important. The contact persons/caregivers should wear gloves, smocks and a nose-mouth protection.
Obligation to notify
Every patient who falls ill with tuberculosis and needs treatment is reported to the public health department. Personal data is registered and stored there. This is intended to detect and prevent the spread of the disease at an early stage.
In the vaccination against tuberculosis, an attenuated mycobacterial strain is injected into the skin.
The vaccination also does not provide reliable protection. After all, children in risk areas in particular benefit from this: In the case of tuberculosis infection, they fall ill less severely.
In some countries vaccination is therefore still recommended. You can read more about this topic in the article Tuberculosis – Vaccination.