TUBERCULOSIS ( TB )
What is Tuberculosis?
Tuberculosis or TB is an infection caused by a bacteria called as Mycobacterium Tuberculosis.
How does Tuberculosis occur ?
TB is prevalent in areas with low socio-economic status and is predisposed due to overcrowding, poverty, poor ventilation, unhygienic living conditions and close contact with patients having tuberculosis. The most common way of acquiring the infection is by droplet or through air. The germs of TB enter the respiratory tract (breathing passages) into the lungs and after a period of 4 to 8 weeks develop a focus in the lungs. This focus is known as primary focus. The infection spreads to the adjacent gland (lymph node) and the primary focus with involvement of adjacent gland is called as Primary Complex. Untreated, the disease then spreads to other organs of the body through blood leading to TB of various organ such as brain (TB meningitis), other glands (TB lymphadenopathy) and even spread to other areas of the lungs.
In Western and developed countries primary TB occurs in teenage period whereas in developing countries, infection may occur much earlier.
Does every person exposed to the TB bacteria get the infection ?
Infection with TB bacteria varies from person to person. In some individuals exposed to TB germ, no infection may occur. Some individuals may develop the infection but the bodyís immunity may take care of it and there may be no disease. Some individuals may develop infection and form primary complex but again may be self-contained and there may be no progression. It is called as silent primary infection. Here the TB germs may remain dormant and become active when the personís immunity decreases. In patients with lower immunity, the disease may progress and cause symptoms and problems.
In adults, who had developed primary complex in childhood and with lowering of immunity, there may be reactivation of dormant bacteria that can lead to TB of lungs forming a cavity in the lungs and is called as secondary or Reactivation Tuberculosis.
What are the symptoms of TB ?
Patients with silent primary infection have no symptoms. They are incidentally detected on a tuberculin test. Patients with progressive disease present with fever which is especially more at nights, cough, pneumonia (which does not resolve with antibiotics), pain in chest, poor appetite, loss of weight, weakness and fatigue.
In patients with TB of the lymph nodes (glands), there may be enlargement of the glands leading to swellings in neck or cough if involving glands in the lungs.
In patients with TB of the intestine, there may be diarrhea or constipation, pain in abdomen and malabsorption additionally.
TB of the brain may present with fever, headache, vomiting, loss of appetite, fits (seizures) and even coma. Accumulation of water in brain cavity (hydrocephalus) can also occur.
Rarely TB may affect bones and joints. Involvement of spine may lead to paralysis.
Can TB be prevented ?
BCG vaccine has been used for prevention of severe forms of TB. BCG does not prevent infection with the TB bacteria but it reduces the progression of the disease and hence TB of other organs is less common in patients vaccinated with BCG.
How is the diagnosis of TB made ?
Tuberculin test is a skin test where an injection of modified TB vaccine is injected in a minute dose in the skin. The test is then read after 48 hours. A positive test suggests that the person had an infection by TB which may be silent primary disease or may be due to progressive disease.
However, a negative test does not exclude TB. In 25-50% of children with TB, the test may be negative.
Others laboratory tests such as X-ray of the chest is necessary. The TB bacterium can be isolated from sputum or other body fluids. Most important in children is to find the adult source of TB in the family as TB in children is usually due to inhalation of the germs from an adult infected patient.
What is the treatment of Tuberculosis ?
Tuberculosis is a chronic disease and requires effective treatment to prevent complications. There are certain antituberculous drugs ( ATT / AKT ) that are used in treatment of TB such as Streptomycin, Isoniazid, Rifampicin, Pyrazinamide and Ethambutol. All these drugs are required for a prolonged period of time for the treatment to be effective. These drugs have side effects involving liver, ear, eyes and kidney and hence monitoring for these side effects is essential. The duration of treatment varies from 6-12 months depending on the type and severity of TB.
If any adult family member has TB, is treatment for TB required in the child?
Children less than 5 years who have malnutrition and are in close contact with an adult who has open TB ( the adult coughs out the TB bacteria and has a cavity in the lungs ) need to be given Anti-TB drugs for 4-6 months. The objective is to prevent tuberculous infection and its progression.
What if the standard drugs for TB failed to control the infection ?
Drug-resistant TB is fairly rare. However in a few instances the standard drugs may not work and other alternate drugs such as PAS, Kanamycin, Ofloxacin, ethionamide may be required depending on whether the TB bacterium is sensitive to the drugs. Here the duration of treatment would be even more extensive.
Last created on 1-5-2006
Last updated on 18-11-2006