Tuberculosis
Tuberculosis or TB is a potentially severe contagious condition that involves your lungs commonly among other organs getting infected by a type of bacteria known as Mycobacterium tuberculosis.
Alternative Names of Tuberculosis
Phthisis, Tabes, Schachepheth, White plague, or Consumptions.
Associated Anatomy of TB
Lungs (primarily affected organ), lymph nodes, pleura, liver, brain, spine, joints, kidneys, etc.
Types of Tuberculosis
You may not necessarily get sick if TB bacteria infect you. Accordingly, the types of TB are:
Latent TB Infection (LTBI): In LTBI, although you have germs in your body, your immune system protects you, and you are asymptomatic.
Active TB Disease: In active TB, the germs multiply, leading to symptoms in your body.
Drug-Resistant TB: A TB infection wherein Category I medications don't work against the TB bacteria is known as drug resistant TB.
Tuberculosis Causes
A bacteria called Mycobacterium tuberculosis infects a person's lungs and spreads from one person to another via tiny droplets diffused into the air when the infected person sneezes, coughs, speaks. You are likely to get TB if you contact a person who has it or if you have immunocompromised conditions like HIV.
Tuberculosis Symptoms
The most common symptoms of active lung TB are:
Cough that lasts for a duration longer than three weeks
Fever
Weight loss
Loss of appetite
Blood in the cough
Weakness
Chest pains
Chills
Night sweats
Back pain (due to spine TB)
Blood in the urine (due to kidney TB)
Tuberculosis Stages
Three stages characterise TB infection:
Stage I - Exposure: When a person is exposed to a person having TB (negative skin test and normal X-ray).
Stage II - Latent TB Infection: A person doesn't actually have symptoms, despite having bacteria in their body (positive skin test but negative x-ray).
Stage III - TB Disease: An individual shows all signs and symptoms with positive skin and chest x-ray.
Tuberculosis Diagnosis
Typical Tests
To diagnose TB, a doctor will first conduct a physical exam to look for inflamed lymph nodes or patches in lungs. A blood test may also be required, wherein TB proteins are added to your blood sample to check your immune response, for countries with low prevalence of TB. In addition, sputum or acid-fast bacillus (AFB) tests are used to identify TB bacteria in your system.
Differential Diagnosis of Tuberculosis
The common differential diagnosis of TB includes:
Bacterial pneumonia
Bronchogenic carcinoma
Brucellosis
Hodgkin lymphoma
Sarcoidosis
Mycoplasmal pneumonia
Blastomycosis
Tularemia
Actinomycosis
Tuberculous lymphadenitis
Skeletal tuberculosis
Tuberculosis peritonitis
Tuberculosis Treatment
Latent TB treatment involves medications (either alone or in a combination of isoniazid, rifapentine, or rifampin) to prevent TB from becoming an active disease. You may be on these medications for around nine months.
Active TB is curable and can be treated with the standard six-month course of four antimicrobial drugs (ethambutol, isoniazid, pyrazinamide, and rifampin) combined under the guidance of a health practitioner.
Drug-resistant TB requires one or several other medicines to be taken for a longer duration, around twenty four months.
Risk Associated with Tuberculosis
Your chances of acquiring TB infection increase if:
Your family member, friend, or colleague has active TB.
If you live in places where TB is prevalent.
If you travel to areas where TB is relatively common (Russia, Latin America, Asia, or Africa).
You live in or work in a hospital, prison, or people with HIV.
If you have a weakened immune system.
If you have HIV or AIDS, kidney disease, or diabetes.
If you are on medications for organ transplant or undergoing chemotherapy.
You are a smoker.
Possible Complications of Tuberculosis
Severe TB is associated with complications like lung and joint damage. It also involves infection in your spinal cord, bones, brain, lymph nodes, liver, or kidney. Additionally, patients may experience back pain and stiffness. Fluid collection and inflammation of the tissues near your heart may lead to cardiac tamponade. Infections and inflammation near the brain may cause meningitis. In conditions like HIV, which weaken your immune system, your body cannot control TB bacteria, thereby deteriorating your condition. Untreated TB can be fatal.
Tuberculosis Prevention
You may be able to help prevent the spread of TB by taking these precautions:
Taking all medicines meticulously, despite having a latent infection.
Limiting your contact with people if you have TB.
Use a surgical mask while sneezing or coughing.
Avoid travelling to areas where TB is more prevalent.
Get kids vaccinated with the BCG vaccine.
Epidemiology of TB
TB stands as the 13th leading cause of death and the 2nd leading infectious killer among the infectious diseases. In the year 2020, up to 1.5 million people lost their lives due to TB (including 2,14,000 people with HIV).
Around ten million people get infected with TB every year; affected people comprise about 5.6 million men, approximately 3.3 million women, and nearly 1.1 million children.
TB is commonly found in countries of India, China, the Philippines, Pakistan, Nigeria, Indonesia, Bangladesh, and South Africa.
The good news is the incidence of TB is decreasing by about 2% per year, and the cumulative reduction between 2015 and 2020 is by 11%.
Expected Prognosis of TB
TB is categorised as a curable disease. Once diagnosed, TB can be cured with a practical, adequate, and appropriate treatment plan. The prognosis of TB depends on several things like your overall health, the severity of infection, and how diligently you follow doctors' directions on treatment. However, the prognosis may be poor for senior citizens or people with serious medical conditions.
Natural Progression of TB
The progression of TB from the state of infection to the fully-developed illness involves overcoming your immune system's defences against TB bacteria. As these bacteria start to multiply, they target your immune system, causing active TB. The bacteria can further spread via blood from the lungs to the kidney, spine, or brain, eventually damaging the other tissues and organs of the body.
Pathophysiology of TB
The TB bacteria settle and multiply in the lung's alveoli. Alveolar macrophages destroy the majority of the bacteria. However, some may multiply intracellularly and are released when the macrophages die. Although TB in the lungs is infectious, TB allied with other body parts is usually not infectious.
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