Overview & Different Type of Tuberculosis

Tuberculosis (TB) is caused by a bacteria known as Mycobacterium tuberculosis. Although TB bacteria mainly infect the lungs, they can also infect other organs of the body, including the kidneys, spinal cord, and brain. The TB disease could be life-threatening if it is not treated properly. TB bacteria can be transferred from one individual to another through the air.

These bacteria can enter the air when an individual with the TB disease communicates with the other person or coughs in the environment without covering their mouth. People nearby can inhale these bacteria and develop the TB disease. The bacteria can enter the lungs and start to develop there after they are inhaled. These bacteria can then travel to the kidneys, spine, and brain through the bloodstream. The TB infection seen in the throat or lungs might be contagious. This means that the bacteria may transmit to other people. In the other organs of the body, such as the kidneys or spine, TB is typically not contagious.

Those who have the TB disease will spread it to the people they interact with frequently such as close family members and friends as well as colleagues and classmates.

What Are the Different Types of TB?

Active TB

Active TB is a multiorgan disease caused by the primary infection or recurrence of latent TB (an asymptomatic condition). Active TB develops when your immune system fails to fight the Mycobacterium tuberculosis (MTB) infection. It is a disease in which the TB bacteria rapidly infect many organs and advance throughout the body.
Cough, phlegm, chest discomfort, weakness, loss of weight, chills, fever, and sweating at night are some of the typical signs of active TB. A person with active TB can spread it to others by coughing up germs into the air. If you are diagnosed with the active TB disease, you should give your doctor a detailed history of everyone you have interacted with in the past since they may need to undergo TB testing because these people may have become contagious and can spread TB to anybody with whom they interact or engage in any activities.

Latent TB

Many individuals with latent tuberculosis do not develop the TB disease. The TB bacteria remain latent in these individuals for several years without leading to the condition. However, in some people, particularly those with a weak immune system, the bacteria become active, grow, and develop active tuberculosis. If your immune system fails to fight off the infection, the bacteria may spread throughout the body, including the lungs, which could cause symptoms to appear weeks or months after the disease turns into active tuberculosis. Age, malnutrition, smoking, drinking, and drug use are other factors that can cause latent TB to develop into active TB.

Individuals with latent tuberculosis don’t feel sick and exhibit no signs or symptoms of this condition. They get infected with tuberculosis bacteria but don’t suffer from the TB disease. The sole means of confirming the tuberculosis infection in a latent TB case is a positive result from a tuberculin skin test. Individuals with latent tuberculosis are not contagious and cannot spread the disease to others.

Pulmonary TB

Pulmonary tuberculosis is a condition that results when Mycobacterium tuberculosis bacteria attack the lungs first and then spread to the other organs. Coughing up mucus and blood, suffering from a persistent fever, sweating at night, losing weight unexpectedly, and chest discomfort are common symptoms of pulmonary TB. Other signs of pulmonary TB, like fatigue, may also develop. After a thorough examination of all your symptoms, your doctor should be able to advise you if you should get a TB test.

As pulmonary TB is transmissible through the air, you can acquire M. tuberculosis bacteria by inhaling air that has been exhaled in the environment by a person who has the disease. The air exhaled can be from sneezing, laughing, coughing, or singing. Germs can survive in the environment for several hours, so even if the infected person is not there, you can breathe the germs and get infected. However, in most cases, acquiring pulmonary TB requires prolonged contact with an infected person.

Liver TB

Liver TB develops when TB infects the liver. It is also called hepatic TB. Liver tuberculosis is rare, accounting for less than 1% of all tuberculous diseases. It is rare because mycobacterial growth is inhibited by reduced oxygen levels in the tissues of the liver. The condition can develop at any age, but it is more frequently seen in young people than in adults.

Hepatic tuberculosis can develop as a localised primary infection or as a result of the spread of a pulmonary disease, which is known as miliary hepatic tuberculosis. When the TB bacteria are inhaled, they pass through the gastrointestinal (GI) mucosal layer (innermost layer of the GI wall) and enter the liver through the portal vein (a blood vessel that transports blood from the intestines, pancreas, spleen, and gallbladder into the liver). Sometimes, small tubercles appear in the liver as the disease spreads across the hepatic artery.

Genitourinary TB

Genitourinary tuberculosis is the 2nd most prevalent type of extrapulmonary tuberculosis. It can infect any area of the genital or urinary system, but the kidneys are the most commonly affected organs. It commonly spreads to the region of the lungs through blood vessels or lymph nodes. People with this kind of TB frequently develop tuberculous ulcers on their genitals or inside the genital tract. Some other symptoms of genitourinary tuberculosis include swelling of testicles, unpleasant urination, reduced or obstructed urine flow, pelvic discomfort, back pain, reduced sperm volume, and infertility.

Extrapulmonary TB

Patients with disseminated tuberculosis (a condition in which mycobacteria spreads from the lungs to other parts of the body) may experience extrapulmonary TB either alone or in conjunction with pulmonary TB. About 15% to 20% of all tuberculosis cases are immunocompetent patients (patients with normal immune response), and in HIV-positive people, over 50% of this infection is caused by extrapulmonary tuberculosis (EPTB). Every part of the body can be infected with extrapulmonary TB, with lymph nodes and pleural effusion being the most frequent sites of infections. The diagnosis is frequently delayed because EPTB has an unusual clinical presentation and obtaining tissue samples for diagnosis can be challenging. The availability of computed tomography scans, magnetic resonance imaging (MRI), laparoscopy, and endoscopy has greatly aided in the anatomical identification of EPTB. Standard antituberculosis medication therapy typically has positive results for the condition.

Skeletal TB

Skeletal TB, also known as bone TB, is a type of tuberculosis that develops from your lymph nodes or your lungs to the bones. All the bones in your body, particularly your spine and joints, are prone to developing skeletal TB. Although skeletal TB is uncommon, it is currently on the rise in several nations that have a high prevalence of AIDS transmission. Skeletal TB doesn’t initially exhibit any symptoms, but with time, it can result in general active tuberculosis leading to symptoms such as intense back pain, stiffness, inflammation, abscess formation, and skeletal abnormalities.

The most common indication of skeletal TB is back pain; nearby muscles start to become inflamed, and the patient may experience spasms when the infection spreads to the spinal column. Severe back stiffness may result from this. The condition of the spine could deteriorate, and the spinal cord may start getting affected by tuberculosis if it is left untreated. Paralysis may result in very rare conditions. Weakness, fatigue, and fever are additional common symptoms that are linked to skeletal TB symptoms.

Miliary TB

Miliary tuberculosis is a serious type of tuberculosis caused by an excessive number of bacteria travelling through the bloodstream and spreading inside the body.
Miliary tuberculosis gets its name from the numerous microscopic spots that grow in the lungs, which are the size of millet (the tiny spherical seeds found in bird food). Miliary TB can damage one or more organs, or it might spread throughout the body. It primarily infects the lungs, bone marrow, and liver but it can infect any organ in the body, which includes the tissues surrounding the brain and the spinal cord (meninges) as well as the two-layered membrane that surrounds the heart (pericardium). Miliary tuberculosis is most common in children under the age of four years, individuals with weak immune systems, and senior citizens.

Brain TB

Brain tuberculosis typically affects the meninges (membranes surrounding the brain). Infected meninges cause a serious type of tuberculosis known as TB meningitis. Brain tuberculosis can also cause tuberculomas, tiny tumours seen in the brain. Although brain TB can occur in children and adults of all ages, specific medical conditions may expose a person to TB meningitis. In children, these conditions include underweight or malnourishment, ailments that cause weakened immune systems, such as HIV/AIDS and hyperglycaemia (diabetes), and even the age of below 2 years.

People with brain TB experience varying degrees of headache accompanied by a disturbed state of mind. The patients’ confused state and unpredictable behaviour, which differs from their usual behaviour, can typically be noticed by family members. TB meningitis symptoms gradually develop over a duration of 1 to 3 weeks. If the infection is left untreated for a long period, patients can go into a coma, which can make it highly challenging for them to recover.