Tuberculosis (TB) is an infectious disease that, although it can affect any organ in the body, usually affects the lung. It can grow when bacteria spread in the air through droplets. TB may be fatal but is preventable and treatable in many cases.
TB, or “consumption,” has, in the past, been a significant cause of death worldwide. Following improvements in living conditions and antibiotic growth, the prevalence of TB in developed countries fell dramatically.
Figures however started to grow again in the 1980s. The World Health Organization (WHO) describes it as a “epidemic,” reporting that it is one of the top 10 causes of death worldwide and “the leading cause of death from a single infectious agent.”
WHO reports that nearly 10 million people worldwide developed tuberculosis and 1.5 million died from the disease in 2018, including 251,000 people who also had HIV.
Most of the affected people had been in Asia. Yet in many other countries, including the United States, TB remains a matter of concern.
According to the Centers for Disease Control and Prevention (CDC) doctors reported 9,025 cases of TB in the United States the same year.
Antibiotic resistance is currently causing renewed concern among experts regarding TB. Some disease strains do not respond to the most suitable treatment options. TB is difficult to handle in this situation.
What is tuberculosis?
After inhaling the bacteria Mycobacterium tuberculosis (M. tuberculosis), a person can contract tB.
The disease is the most infectious when TB enters the lungs, but a person typically only gets sick after close contact with someone who has this type of TB.
TB infection (latent TB)
A person may have bacteria of TB in his or her body and never develop symptoms. The immune system will absorb the bacteria in most cases, so that they do not replicate and cause disease. A person may have an infection of TB but not an active disease in that case.
Doctors call it latent TB. An individual may never have symptoms and may not be aware they have the infection. There is also no chance of another person transmitting a latent infection. An individual with latent TB still needs care though.
The CDC reports that latent TB has reached as many as 13 million people in the US.
TB disease (active TB)
It is likely that the body can not contain TB bacteria. It becomes more likely when the immune system is weakened because of disease or the use of other medications.
When this occurs, the bacteria can replicate and cause symptoms, leading to active TB. The infection will spread to people with active TB.
TB is involved in 5-10 percent of people with the infection without medical intervention. According to the CDC, the progression happens in about 50 percent of these people within 2–5 years of having the infection.
The risk of developing active TB is higher in:
- anyone with a weakened immune system
- anyone who first developed the infection in the past 2–5 years
- older adults and young children
- people who use injected recreational drugs
- people who have not received appropriate treatment for TB in the past
Early warning signs
A person should see a doctor if they experience:
- a persistent cough, lasting at least 3 weeks
- phlegm, which may have blood in it, when they cough
- a loss of appetite and weight
- a general feeling of fatigue and being unwell
- swelling in the neck
- a fever
- night sweats
- chest pain
Symptoms
Latent TB: No signs will occur in a person with latent TB, and no harm will occur on an X-ray in his chest. A blood test or skin prick test, however, may mean they have an infection with TB.
Active TB: A person with TB disease may experience cough that causes phlegm, exhaustion, fever, chills, and weight loss and appetite. Over time, symptoms usually intensify but they may also go away and return spontaneously.
Beyond the lungs
TB usually affects the lungs, while symptoms can occur elsewhere in the body. This is more common in people suffering from weakened immune systems.
TB can cause:
- persistently swollen lymph nodes, or “swollen glands”
- abdominal pain
- joint or bone pain
- confusion
- a persistent headache
- seizures
Diagnosis
A person with latent tuberculosis may have no symptoms, but tests can show the infection. People will request a check for TB if they do:
- have spent time with a person who has or is at risk of TB
- have spent time in a country with high rates of TB
- work in an environment where TB may be present
A doctor will ask about any symptoms and the medical history of the person. They will also conduct a physical exam, which includes listening to the lungs and testing for lymph node swelling.
Two tests can show whether TB bacteria are present:
- the TB skin test
- the TB blood test
These can not however show whether tuberculosis is active or latent. The doctor may prescribe a sputum test and an X-ray in the chest to check for the active TB disease.
All with TB requires treatment, no matter whether the infection is active or latent.
Treatment
With early detection and appropriate antibiotics, TB is treatable.
The right type of antibiotic and length of treatment will depend on:
- the person’s age and overall health
- whether they have latent or active TB
- the location of the infection
- whether the strain of TB is drug resistant
Treatment for latent TB can be vary. It can mean taking an antibiotic for 12 weeks once a week, or for 9 months every day.
Treatment for active TB can require 6–9 months of taking many drugs. If a person has a drug-resistant TB strain, the treatment is more complicated.
Completing the full course of care is important, even if the symptoms go away. If a person stops taking their medication early, some bacteria may live and become antibiotic resistant. In this scenario, the person can go on to develop drug-resistant TB.
A doctor can also prescribe corticosteroids depending on the parts of the body which cause TB.
Causes
M. Bacteria causing tuberculosis cause TB. If a person with pulmonary TB coughs, sneezes, spits, laughs or speaks, they will disperse into droplets through the air.
The infection can only be transmitted by individuals with active TB. However, most people with the disease can no longer spread the bacteria after having at least 2 weeks of effective care.
Prevention
Ways of preventing TB from infecting others include:
- getting a diagnosis and treatment early
- staying away from other people until there is no longer a risk of infection
- wearing a mask, covering the mouth, and ventilating rooms
TB vaccination
Children in certain countries receive an anti-TB injection — the bacillus Calmette–Guérin (BCG) vaccine — as part of a regular immunization program.
However, for most people, US experts do not recommend BCG inoculation unless they have a high risk of TB. Many of the reasons include a low national risk of infection, and a high probability that the vaccine will conflict with any potential skin tests for TB.
Risk factors
Active TB is most likely to occur in people with weakened immune systems. The following are some issues which may weaken the immune system.
HIV
Doctors find TB to be an opportunistic infection for people living with HIV. That means a person with HIV is at a higher risk of developing TB and experiencing more serious symptoms than a person with a healthy immune system.
TB treatment in a person with HIV may be difficult but a doctor may create a comprehensive treatment plan that addresses both issues.
Smoking
Tobacco use and second-hand smoke increase the risk of TB might develop. Such factors also make the condition more difficult to treat, and more likely to return after therapy.
Quitting smoking and avoiding smoking can reduce the risk of developing TB.
Other conditions
Additional health problems that weaken the immune system and can increase the risk of developing TB include:
- low body weight
- substance abuse disorders
- diabetes
- silicosis
- severe kidney disease
- head and neck cancer
Other medical procedures, such as an organ transplant, also impede the immune system’s functioning.
Also, spending time in a country where TB is common may increase the risk of it developing. Using this WHO tool to get information on the prevalence of TB in different countries.
Complications
TB can get fatal without treatment.
If it spreads across the body, the infection can cause, among other problems, problems with the cardiovascular system and metabolic function.
TB may also cause sepsis, a life-threatening type of infection.
Outlook
An active TB infection is contagious, and potentially life-threatening, if a person is not treated properly. Most cases are treatable, however, particularly if identified early by doctors.
Anyone with a potential risk of developing TB or signs of the disease should see a doctor at the earliest opportunity.
