What is Tuberculosis?
Tuberculosis or TB is an infection which is caused by a type of bacteria called Mycobacterium tuberculosis. This disease can affect the lungs as well as other organs of the body such as those in the central nervous system, lymphatic system, and circulatory system. After infection, the bacteria multiply in the lings creating cavitary lesions and creating pneumonia. During this time, the person may have chest pain and cough which may bring about blood. In addition, lymph nodes near the heart and lungs become enlarged. As the bacteria try to spread to other parts of the body they are interrupted by the body’s immune system. The body's immune system causes the formation of scar tissue or fibrosis around the bacterium, which helps fight the infection and prevents it from spreading within the body and to other people. If bacteria penetrate through the tissue, the infection becomes active which leads to the development of pneumonia and damage to kidneys, bones, and the meninges that line the spinal cord and brain.
Tuberculosis is classified as either latent or active. Latent TB means that the bacteria are inactive but present in the body; during this stage the patient has no symptoms and is not contagious. Active TB on the other hand means that bacteria are active inside the body and are making the patient ill. This stage is contagious.
Tuberculosis is an infection caused by the Mycobacterium tuberculosis, a bacterium that is spread from person to person through the air. Once Mycobacterium tuberculosis enters the body, three things may happen to it. Either the bacterium is destroyed because the body has a strong immune system or the bacterium enters the body and remains as latent TB infection in which the patient has no symptoms and cannot transmit it to other people; or the patient becomes ill with TB.
Tuberculosis may bring about a lot of signs and symptoms such as unexplained weight loss, fatigue, shortness of breath, fever, night sweats, chills and loss of appetite. Lung symptoms may include coughing that lasts for 3 or more weeks, coughing up blood, chest pain, painful breathing and pain when coughing.
Tuberculosis is often diagnosed by a blood or skin test, a sputum test, and a chest X-ray. One simple skin test to diagnose tuberculosis is the Mantoux test. In this test, a small amount of purified protein derivative (PPD) tuberculin is injected into the forearm. After 48 to 72 hours, a doctor or nurse looks for a reaction at the injection site; a hard, raised red bump usually indicates a positive test for TB. Other tests include the IGRAs (interferon-gamma release assays) which measure how the patient’s immune system reacts to Mycobacterium tuberculosis.
Those who are at high risk for acquiring tuberculosis include individuals who live with others who have active TB infections, poor or homeless people, young children, nursing home residents, alcoholics and intravenous drug users, anybody who suffers from malnutrition and patients with HIV/AIDS or other immune system problems.
New Test for Tuberculosis Can Detect Latent Infection
A recent discovery is a screening process for tuberculosis (TB) infections in Canadian prisons which can eliminate false positives. This screening process are interferon-gamma release assays (IGRA) that will detect a pre-existing TB infection, or latent TB, that might not present itself for many years, or until the body becomes weakened by another source. The IGRA test was developed in the last 10-15 years and diagnoses a latent TB infection. The body’s immune system is provoked with a small amount of protein from the TB virus and if the body has previously been infected then a reaction will occur and the patient’s blood will test positive for TB. This eliminates the disadvantages of PPD testing.
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