Tuberculosis is abbreviated as TB. It is a chronic infectious disease caused by a bacterium called Mycobacterium. This infection usually occurs by coming in contact with someone who has already been exposed to it.
An infectious aerosol droplet of 0.5 to 5.0 µm in size is released when an infected person coughs, sings or talks. About 40 thousand drops come out from a sneeze, every single drop of them can spread infection.
Tuberculosis is a serious disease, if it is not treated in time, then it can also cause death.
According to a report by W.H.O, a total of 1.5 million people died of TB in the year 2020.
TB is the 13th leading cause of death worldwide and the second leading infectious disease after COVID-19.
Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs. It can be treated and this disease can be prevented.
TB mainly affects the heart and its upper organs but gradually starts taking its effect on the whole body.
Types of Tuberculosis
1. Pulmonary Tuberculosis
This is the most common type of tuberculosis in which the lungs are affected. The cells in the lungs are damaged by bacteria causing inflammation and cheese-like pus.
Symptoms of pulmonary TB include cough, difficulty in breathing, blood-stained sputum, fever, and weight loss. It is usually spread through the air (airborne transmission) when a person infected with TB coughs or sneezes. Poor nutritional status or a weakened immune system are risk factors for developing pulmonary tuberculosis.
2. Extrapulmonary Tuberculosis
TB infection that occurs anywhere in the body outside the lungs is known as extrapulmonary tuberculosis. Based on its location, it is further classified as:
- Tuberculous lymphadenitis
It is the second most common form of TB, which usually affects children. This is the most common extrapulmonary (outside the lung/respiratory system) form of TB. It usually affects the lymph nodes of the neck and chest causing them to enlarge and sometimes appear as a swelling on the skin, or felt under the skin. These lumps are painless and gradually pus starts forming in them. This abscess can protrude out of the skin.
- Tuberculosis Meningitis
It is more common in developing countries. Malnourished children are at risk of getting this infection. The bacteria, upon entering the body, affect the covering of the brain (meninges), causing their inflammation known as meningitis. The infection presents with symptoms such as headache, vomiting, neck stiffness, loss of appetite, and weight loss. If not diagnosed on time or treated appropriately, the infection can result in death.
- Intestinal Tuberculosis
It is the most common form of gastrointestinal TB. When bacteria accidentally enter the gastrointestinal tract, they block off at the junction of the small and large intestine (ileocecal junction) and narrow the intestinal tract. It causes symptoms such as severe abdominal cramps, vomiting, fever, loss of appetite, and weight loss.
- Pott’s Spine
This is another common type of extrapulmonary TB, which affects the bones of the spine. The infection begins at the intervertebral discs and gradually progresses to the ligaments and the bones around them. It causes chronic back pain, kyphosis (loss of position of the spine), abscess (pus) formation, and compression of the spinal cord.
- Renal TB
This is a rare type of TB where bacteria accumulate in the kidneys, causing inflammation of the kidney cells. The infection usually causes burning or painful urination, hematuria (passing of blood in the urine), pyuria (passing of pus cells in the urine), and increased frequency of urination. It rarely causes fever and weight loss.
Stages of Tuberculosis (TB)
Tuberculosis has mainly three stages – the latency stage/dormancy, followed by active TB where the disease spreads to the lungs or any other organ and then, if untreated or in immunocompromised patients, widespread TB i.e. miliary TB could happen.
- Latent Tuberculosis
Most people in developing countries are infected with TB or have TB bacteria in their bodies, but they do not develop an obvious disease and show no signs or symptoms of illness. Also, the results of various blood tests or chest X-rays are normal in such individuals. The only manifestation they have is the response to the tuberculin test (Mantoux test) or the interferon-gamma release assay (IGRA). These individuals are at risk of developing an apparent disease if their immune system is compromised or if they contract an infection that can affect their immune system (such as HIV infection).
- Active Tuberculosis
Active TB means that TB bacteria are multiplying rapidly and invading body parts. The most common organs affected are the lungs and others less common are lymph nodes, bones, brain among others. Active TB causes typical symptoms such as cough, blood-stained sputum, difficulty breathing, weight loss, weakness, and fever.
- Miliary Tuberculosis
This is a rare condition in which the disease is highly active. TB bacteria enter the bloodstream and spread throughout the body, forming small nodules and affecting many organs. It is the most dangerous and deadly form of TB.
Symptoms of Tuberculosis (TB)
Worldwide, most people are exposed to Mycobacterium tuberculosis and many of them harbor this bacterium. An inactive or latent disease rarely causes any symptoms, however, it may only show a positive reaction to the tuberculin skin test (Mantoux test). It is unpredictable how long this latency period will persist, or whether it will develop into active disease.
In Inactive disease, a variety of symptoms can be observed that help determine the severity of the disease. Usually, the lungs are involved and show signs and symptoms of TB.
Symptoms in different types of TB are:
- A chronic cough (cough lasting more than 3 weeks)
- Hemoptysis (blood-stained sputum)
- shortness of breath
- Fever (initially low-grade and eventually, high-grade)
- night sweats
- weight loss
- loss of appetite
TB bacteria are known to affect other organs such as lymph nodes, bones, brain (meninges), intestines, and even kidneys; When the disease affects organs other than the lungs, it is known as extrapulmonary tuberculosis.
Symptoms of extrapulmonary tuberculosis include:
- TB lymphadenitis
- Persistent swelling of lymph nodes
- pus or abscess formation in lymph nodes
- Colic (severe pain in the abdominal area)
- Weight loss
- tour (fits)
- chronic back pain
- abscess formation
- Kyphosis – abnormal forward curvature of the spine
- Hematuria (blood in the urine)
- Pyuria (pus in the urine)
- Dysuria (painful or difficult urination)
In some immunocompromised (those with weakened immune systems) or drug-resistant people, the bacteria enter the bloodstream and spread throughout the body, causing miliary tuberculosis.
Symptoms of miliary TB include:
- Night sweats.
- Anorexia (loss of appetite)
- Weight loss
- A dry cough
- Enlarged lymph nodes
Miliary TB is fatal if not treated properly or on time.
Tuberculosis (TB) Causes and Risks
TB is caused by a bacteria called Mycobacterium tuberculosis, also known as Koch bacteria. It spreads from person to person through tiny droplets that travel through the air. These droplets are released when a person with active TB coughs, sneezes, spit, or talks. It is easy enough to contract TB bacteria, but it is not that easy to develop an infection. It usually causes illness when you are in close contact with a person with active TB for a long time. If the immune system is active and efficient, it usually does not allow the disease to develop, but immunocompromised patients have a much higher risk of developing TB. Latent tuberculosis is not contagious, but when active, a person with it can spread the disease.
Anyone can get a mycobacterial infection and develop TB, however, some factors can increase a person’s chances of developing the disease. These risk factors include:
1. The poor or weakened immune system
A healthy immune system is known to fight off mycobacterium and can prevent disease but the risk increases manifold if resistance is low.
Factors responsible for weakening the immune system are:
- HIV infection.
- Uncontrolled diabetes.
- Severe kidney disease.
- Steroids or immunosuppressant drugs.
- Old age
2. Geographic Region
Some countries/regions have more tuberculosis cases per year. Living in or traveling to these countries/regions may increase your risk of developing the disease. These countries and continents/regions include:
- Africa Asia
- Eastern Europe
- Caribbean islands
- Latin America
3. Socioeconomic Status
Socioeconomic status is an important factor in the development of TB, as it also defines the standard of living, nutritional status, and availability of medicines. Poor socioeconomic status has a huge impact on the development of TB, as it can lead to inability to afford drugs, poor nutritional status, exposure to extreme environmental conditions, low immune status, and ultimately higher exposure to TB bacteria could be the reason.
4. Substance Abuse
Alcohol or drug use can damage and weaken the immune system, increasing the risk of developing TB.
Prevention of Tuberculosis (TB)
TB prevention has many aspects, from cough etiquette to vaccination with very high success rates. Here are some preventive measures:
1. General Precautions
Avoid contact with TB patients or use a face mask when in contact with a person with TB. Use a handkerchief or cover the nose and mouth if someone is coughing nearby, as this prevents the entry of germs and infection.
2. Cough Etiquette
Keep a tissue or cover your mouth and nose while coughing or sneezing to avoid spreading germs.
3. Medicine for latent infection
If the test comes out positive for latent infection, it is best to start TB medicine immediately under the guidance of your doctor. Staying at home, ventilate the room, and following cough etiquette can help prevent the spread of TB bacteria.
4. For people with HIV infection
It is important to maintain a good nutritional status. Have regular CD4 cell counts, as well as take anti-retroviral therapy for HIV infection.
5. For Frequent Travelers
Traveling to endemic areas (where TB infections regularly occur) can expose you to TB bacteria. Therefore, it is better to avoid living in such areas in an overcrowded or closed environment. Routine evaluation for Mycobacterium is another effective method of detecting TB infection at an early stage or during the latency period.
The BCG (Bacille Calmette-Guerin) vaccine is commonly used against TB. In endemic countries, it is given at birth, while in developed countries, where the incidence of TB is low, it is given to babies after they are tested for the tuberculin skin test; If the test result is negative, they are vaccinated with BCG. The BCG vaccine contains a bovine of Mycobacterium (a bacterial strain that causes TB in cows) and is a live-diluted (attenuated) vaccine. The vaccine is known to have a success rate.
Tuberculosis (TB) Diagnosis
In most cases, a careful clinical history and a thorough physical examination of the patient give an idea of diagnosing tuberculosis. Nevertheless, for confirmation, certain tests are used, which help determine the severity of the infection and guide the planning of a therapeutic approach.
1. Physical examination
A complete medical history with a complete examination of the chest or airways suggests the presence of an abnormal breathing sound. Other symptoms that may be present include increased body temperature, pallor (due to anemia), and sometimes low oxygen saturation levels. In the case of extrapulmonary TB, other symptoms may also occur, such as a stiff neck and enlarged lymph nodes.
2. Blood Test
The tuberculin skin test or Mantoux test helps diagnose TB, but it can be falsely positive in patients who have either previously been exposed to TB bacteria or who have been vaccinated with BCG. Other tests include:
- Quantiferon TB Gold
- T-spot test
These tests evaluate the immune response to TB bacteria and a positive test indicates infection with Mycobacterium tuberculosis. Sputum test In addition to blood tests, sputum or mucus that comes from coughing is evaluated for TB bacteria.
3. Sputum test
Not only helps in confirming the presence of Mycobacterium but also helps in selecting the right and effective drugs that can be used to treat this infection. A sputum test is more important if the person is suffering from drug-resistant TB.
Usually, a chest X-ray helps confirm the diagnosis. However, sometimes a CT scan of the chest is also used to diagnose tuberculosis.
5. Biopsy or FNAC (fine needle aspiration cytology)
In some cases, as in extra-pulmonary TB, a small needle is inserted into an enlarged lymph node or spinal cord (meninges) to obtain a sample, which is then tested for the presence of TB bacteria. Positive reports confirm extrapulmonary tuberculosis.
Tuberculosis (TB) Treatment
Tuberculosis is the most studied disease and a wide variety of drugs are available for its treatment. These drugs are classified as bactericidal (drugs that kill bacteria) and bacteriostatic drugs (inhibiting the growth of bacteria so that our immune cells can kill them). The drug selection, dosage, and duration of treatment are determined by the type of infection and the severity of the infection.
1. Latent Infection
It is usually treated with a single drug, taken for six months.
2. Active TB infection
Typically, combination therapy is used to treat pulmonary TB and treatment lasts six to nine months.
3. Extrapulmonary Tuberculosis
It is considered a relatively severe form of the disease and multiple combinations are used for the initial 6-9 months, followed by a short course of a single drug for the next three months.
4. Drug Resistance Infection
In a drug-resistant infection, the bacteria develop certain mechanisms to counteract the effects of the drugs and become resistant to them. Thus, susceptibility testing is first done to find out which drugs can be used to kill the bacteria and that drug is given as a combination therapy with other drugs and the type of resistance. That is, given based on multi-drug resistance (MDR). – TB) or extreme drug resistance (XDR-TB), the duration of therapy and therapy is fixed, which ranges from 18 months to 3 years.
Commonly used drugs to treat TB include:
In the case of a drug-resistant TB, injectable drugs are used, such as fluoroquinolones and amikacin, kanamycin, or capreomycin (fluoroquinolones and amikacin, kanamycin, or capreomycin). These medicines are given in combination with oral medications. Since the treatment of TB lasts longer and the drugs used have relatively higher drug potency; These drugs are known to have serious side effects. Most of these are toxic to the liver.
If you experience any of the following symptoms, it is important to notify your doctor immediately:
- Persistent nausea and Vomiting
- Yellowing of the Skin (jaundice)
- Loss of Appetite
- Persistent Fever
Tuberculosis has a significant impact on a person’s normal lifestyle, as the treatment of TB is complex as well as lengthy. The best way to live with it is to stick to treatment and get regular follow-ups with your doctor. Sometimes, one may need the help of a psychologist, as there are possibilities of developing mental illnesses, such as hopelessness, anxiety, stress, depression, or even denial.
Proper nutrition and positive coping strategies are vital to combating TB. Apart from these, some other lifestyle modifications include:
It is better to stay at home during the active phase of the disease as the infection can spread to others. Even at home, follow coughing etiquette such as covering the mouth when coughing or sneezing, collecting sputum in a disposable bag or tissue, and throwing it on the collection. After a few weeks of treatment, once you are no longer contagious, you can resume your normal activities.
2. Personal Hygiene
Personal hygiene plays an important role in preventing the spread of disease. These measures include keeping the room ventilated, using a mask to cover the nose and mouth, and regularly cleaning personal items, among others.
3. Proper Treatment
Getting enough rest and following the medication schedule are the major factors. If you stop taking medicines or change the dosage of medicines, there is a possibility of developing drug resistance, which is difficult to treat and may require longer therapy. Drug overuse can also cause problems because most of these drugs are toxic to the liver.
4. Routine Follow-up and Evaluation of Blood Parameters
Apart from taking medicines regularly, it is important to visit your doctor regularly for check-ups and since these medicines have some harmful effects on the liver, so can blood parameters like complete blood count (CBC), creatinine, and liver function test (LFT). ) have been estimated and evaluated to confirm that these drugs are not causing any side effects.
5. Nutritional Status
It is equally important to maintain a good nutritional status or positive nitrogen balance and to accelerate recovery and reduce the recovery phase. A good diet rich in protein and carbohydrates forms the foundation for healthy weight gain, which is important to compensate for the weight loss that occurs during the transition.
TB Prognosis And Complications
Prognosis of Disease
Tuberculosis is a treatable infection. If diagnosed early enough with effective therapy, it can be completely cured. However, if treatment is abandoned or inadequate, it can result in drug resistance (MDR – Multiple Drug Resistance and XDR – Extreme Drug Resistance). In cases of drug resistance, therapy is prolonged; It is 18 months for MDR and 36 months for XDR. Whereas MDR has a relatively better prognosis than XDR.
In addition to drug resistance, some factors adversely affect prognosis, including:
- Chronic Kidney Disease
- HIV infection
- COPD (a type of chronic lung disease)
- Drinking Alcohol
If left untreated or poorly treated, tuberculosis can be fatal. Mycobacterium can enter the bloodstream and travel anywhere in the body and infect any organ or organ system. Some of the commonly seen complications include:
1. Drug Resistance
It is the most common complication seen in people with poor socioeconomic status and poor adherence to medication schedules. It occurs as a result of inadequate or incomplete treatment. This can result in MDR (Multiple Drug Resistance) or XDR (Extreme Drug Resistance). MDR has a better prognosis, but XDR is always fatal.
2. Spinal Cord Damage
TB bacteria can enter the bones of the spinal cord and affect the spinal column causing back pain, stiffness, sciatica, and sometimes a cold abscess.
3. Joint Pain
Rarely, these bacteria can affect the joints, causing tuberculous arthritis, which most commonly affects the hips and knees.
It is one of the most common complications seen in young children in which bacteria reach the brain and meninges. It can cause symptoms such as headache, vomiting, stiff neck, and sometimes confusion or brain damage. It can also be fatal.
In very rare cases, mycobacterium can affect the covering of the heart (pericardium) and cause inflammation. This can cause fluid to build up around the heart and reduce its pumping efficiency. Then again, it can also be life-threatening.
6. Miliary TB
Miliary TB is a rare condition in which TB bacteria enter the bloodstream and infect multiple organs at the same time, resulting in a fatal condition. If treatment is delayed, it always leads to death.