Tuberculosis (TB)

                      Tuberculosis or TB, is an infectious bacterial disease caused by Mycobacterium tuberculosis, which most commonly affects the lungs. It is transmitted from person to person via droplets from the throat and lungs of people with the active respiratory disease. Mycobacterium tuberculosis, was described on March 24, 1882 by Robert Koch. He received the Nobel Prize in physiology or medicine for this discovery in 1905. If left untreated, more than 50% will die in a few years time. It causes about 2-3 million deaths per year out of 9-10 million cases and is especially prevalent in undeveloped, tropical countries.

Risk Factors 
1. HIV-positive or AIDS patients
2. People undergoing treatment for autoimmune diseases
3. Close contact
4. Bronchial asthma
5. COPD
6. Cancer patients
7. Organ transplant recipients
8. People with kidney disease

Symptoms and Signs
The symptoms of tuberculosis range from no symptoms (latent tuberculosis) to symptoms of active disease. In fact, you may not even be aware that you have a latent TB infection until it's revealed through a skin test, perhaps during a routine checkup.
If you have active TB disease, you may have these symptoms :
- Overall sensation of feeling unwell
- Cough, possibly with bloody mucus
- Fatigue
- Chest pain
- Shortness of breath (SOB)
- Weight loss
- Slight fever
- Night sweats
- Pain in the chest
- Hemoptysis (Coughing Up Blood)
- Weight Loss
- Anorexia

Diagnosis
1. Clinical symptoms
2. Sputum test : Sputum smears and cultures should be done for acid-fast bacilli if the patient is producing sputum.
3. Chest X-ray : A chest X-ray is essential in all cases of suspected pulmonary tuberculosis. The classical X-ray picture of post-primary tuberculosis is of bilateral, posterior apical, cavitation-forming, caseous lesions.
4. Mantoux test : The Mantoux test should be done in all cases of suspected tuberculosis, although the results must be interpreted carefully. Purified protein derivative (PPD) tuberculin, a precipitate of non-species-specific molecules obtained from filtrates of sterilized, concentrated cultures, is injected intradermally (into the skin) and read 48 to 72 hours later. A patient who has been exposed to the bacteria is expected to mount an immune response in the skin containing the bacterial proteins. An induration (hardened spot of skin) of more than 10mm to 10 Mantoux units is considered a positive result, indicating TB infection. A negative test does not exclude active tuberculosis, especially if the test was done within six to eight weeks of acquiring the infection, if the infection is overwhelming, or if the patient is immunocompromised.
5. Blood test

Related articles :

- World Tuberculosis Day Themes (2000 to 2014)

- Mantoux Test (Tuberculin Skin Test)

- Hemoptysis (Coughing Up Blood)

Treatment
The current accepted first-line therapy is a combination of the drugs rifampicin, isoniazid (INH), pyrizinamide, and ethambutol. Supplemental pyridoxine (vitamin B6) is often given with these drugs. After two months, the number of drugs is reduced. A typical treatment for a standard (i.e. non-drug resistant) strain of TB is 2HRZE / 4HR (= two months of INH, Rifampin, Pyrazinmid and Ethambutol followed by four months of Rifampin and INH). The number of relapses is about 2-3% this way. Medication can be given two or three times per week (different/higher dosages) with the same results as daily therapy.

The World Health Organization (WHO) currently recommends DOTS or Directly Observed Treatment, Short-course. The mainstay of this is the DOT or Directly Observed Treatment portion which involves health care workers directly monitoring tuberculosis patients actually swallowing their anti-tuberculous therapy for at least the first two months of treatment. Treatment with properly implemented DOTS has a success rate exceeding 95% and prevents the emergence of further multi-drug resistant strains of tuberculosis.

Prevention
BCG immunization gives the receiver between 50% to 80% resistance to TB. In tropical areas where the incidence of atypical mycobacteria is high (exposure to non-TB mycobacteria gives some protection against TB), the effectiveness of BCGs is much lower than in areas where mycobacteria are much less prevalent. Infected people have a 10% chance to get active TB. Usually INH-prophylaxis is advised to people with positive mantoux (skin) tests. After taking six months of INH, the chance to get active TB is lowered to about 3%.

Before a BCG vaccination is given, a Heaf test (see Mantoux test) is often performed to determine whether a subject is already immune to TB. A Heaf test is also commonly used to determine whether someone already has TB, but the BCG vaccine is not effective in people who are suffering from the disease at the time of vaccination. In the United Kingdom, children aged 10-14 are typically immunized during school.