Tuberculosis (TB) is a bacterial infection resulting from a complication of pneumonia. It is often regarded as a form of pneumonia.
It is also considered to be a multisystem disease because other than the lungs, which are the most commonly affected organs, tuberculosis can affect any other part of the body except the teeth, nails and hair.
It is common in the developing countries due to HIV, poverty, wars and malnutrition among many other factors.
It has recently declined in occurrence though it is still a major source of concern on global health.
The causative agent of tuberculosis is an aerobic bacterium known as Mycobacterium tuberculosis. Because it is aerobic, this organism survives best in a place richly supplied with oxygen, like the lungs. It is found in various strains but M.tuberculosis hominis, M.tuberculosis bovis and M.tuberculosis africanum are the most common. The reservoir of M.bovis is cattle whereas the reservoir of M.africanum is human.
Other strains include: M.microti, M.pinnipedii and M.canetti.
The transmission of M.tuberculosis occurs via:
When the organism is inhaled, it reaches the alveoli of the lungs and initiates a cell-mediated immune response. The organism is phagocytosed by microphages and together, they form a complex which is hardened through the process of calcification.
Tuberculosis can be classified according to the time of infection whether first time or second time. They are as indicated below:
Tuberculosis can also be classified on the basis of its site of infection and this includes:
There are a number of factors that put you at an increased risk of contracting tuberculosis. They include:
What are the signs and symptoms do tuberculosis?
Once in the human body, the disease can spread through routes such as:
Active tuberculosis infection can be detected through various labaratory investigations such as:
Chest X-ray, complete blood count and histopathology are also done to confirm and determine the type of TB.
Latent infection is diagnosed through:
All forms of tuberculosis are usually treated for 6 months except tuberculosis of Milliary tuberculosis and tuberculosis of bone and joint which is treated for 12 months. Treatment is done in two phases.
The first phase is the intensive phase where rifampicin, isoniazid, pyrazineamide and ethambutol are combined for the treatment of tuberculosis. It is usually done for 2 months and is designed to rapidly decrease the overall number of tuberculisis bacteria in the body.
The second phase is the continuation phase where only two of the drugs, rifampicin and isoniazid are continued. It takes place for the next 4 months and is aimed at clearing the remaining bacteria.
For the milliary tuberculosis and tuberculosis of bone and joint, the continuation phase takes 10 months.
Resistant strains have, however, emerged and in this case second-line drugs anti-bacterial drugs should be considered. These include flouroquinolones, macrolide, amikacin, cycloserine, capreomycin and kanamycin.
Non-compliant patients should be directly observed to ensure that they take the right drugs at the right amounts and at the right time.
Any person having an active tuberculosis and is not treated is infectious and can transmit the disease to another person. But once the person has commenced on drugs, he/she no longer becomes infectious.
Prevention measures for TB may include the following:
The outcomes of tuberculosis are good with treatment and bad without treatment. Twenty-five percent of those who do not get treated usually die in the first year. Known cases of tuberculosis should therefore be treated with adequate therapy.
Sometimes back, in some countries, infected people who failed to adhere to the TB drug regimen used to be imprisoned until they finished taking the drugs. Nowadays, this has been abolished because it has been seen as a violation of the human rights.
Tuberculosis is a public health concern. Any hospital which registers a case of tuberculosis is expected to report to the ministry of health for record keeping.