TB
Tuberculosis
By law Tuberculosis disease is a Notifiable Disease. Early notification to Public Health ensures that the infection control and preventative measures are taken as soon as possible.
Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis. Once a person has been infected the bacterium can persist for a long time if treatment is not given. TB is preventable and curable.
When somebody becomes infected, (by breathing in the bacteria) the TB bacilli multiply in the small air sacs of the lungs. A small number enter the bloodstream and spread throughout the body. Depending on the infected person's immune system, the infection can remain latent (dormant), or it can develop into active TB disease quite quickly. A small proportion of people who get infected are able to kill off the infection naturally. About 5 to 10% of people who have latent TB infection will develop the disease at some time in their lives, but the risk is greatest in the first year or two after infection.
Active TB disease usually occurs in the lungs (pulmonary or respiratory TB), but it can also occur in other parts of the body. This is known as non-respiratory (outside the lungs) TB when the bacteria are carried to other parts of the body where they multiply and cause disease. Around 40% of all TB is non-respiratory and the person with this type of disease is referred to as having ‘closed TB’. This means that they are not able to pass on the disease to other people as the bacteria are not in the lungs and cannot be expelled into the air.
TB control
Case Finding
This means that people can present with symptoms to the doctor. In addition Public Health in conjunction with the Primary Health Care team especially the GP service actively search for cases of TB disease or latent TB infection and screen individuals at high risk of exposure to TB.
- Screening contacts of the person diagnosed
- to find out if possible who has caused the infection in the person with symptoms
- who may have acquired the infection from that person.
- Screening of people who are more likely to have been exposed to TB disease (migrants).
The symptoms of TB usually develop slowly. The following history taking by the GP would help him to consider TB as a possible cause for a person’s illness:
- Symptoms
- Ethnic background
- Recent arrival from a country where there are more than 40 cases of TB per 1000 population
- Travel history
- Previous contact with someone with TB disease
- BCG vaccination history
Symptoms of respiratory TB disease - the TB patient may not experience all of these symptoms
- Cough - we recommend a person to consult their GP if a cough lasts for over 3 weeks
- Weight loss
- Malaise/lethargy – feeling unwell
- Night sweats
- Haemoptysis – coughing up blood
- Fever which peaks in the evening
- Difficulty breathing when the disease has been present for a long time undiagnosed
Symptoms of non-respiratory TB disease:
- Weight loss
- Malaise/lethargy – feeling unwell
- Night sweats
- Pain or swelling at the site of the disease, for example lymph glands, spine, bladder etc
- Fever which peaks in the evening
Diagnosis is made by chest X-ray and other radiological tests, sputum testing, urine testing and blood testing.
Treatment of cases
A person with TB disease is usually treated with anti-tuberculosis therapy for a total of 6 months. The TB case is commenced on an initial phase of treatment which lasts 2 months and involves 4 anti-TB drugs to be taken daily. These drugs can cause specific side effects which are monitored closely. After completion of the initial phase the person enters the continuation phase of therapy lasting a further 4 months and involves taking 2 drugs only.
This treatment time may need to be extended in the following situations:
- if the mycobacterium is found to be resistant to any of the drugs – other drugs are introduced whose effectiveness is not known
- the disease is TB meningitis
- if the person has a severe reaction to one or more of the drugs the concoction of drug therapies has to be changed to include some whose effectiveness is not known, hence the extended therapy time.
It is extremely important that the patient takes the therapy exactly as prescribed to prevent them from developing resistance to those drugs. Support is given throughout by the Health Protection Nurse. In some cases a Directly Observed Therapy service can be employed to give extra support to the patient on a daily basis.
Treatment of latent TB infection
People, who through screening have been found to have infection but not disease, are treated in the absence of symptoms. This is TB in a dormant or hidden stage. A small number of Mycobacterium tuberculosis bacteria are present. These bacteria are not dead and can be killed by a shortened course of anti-TB therapy. The important thing to remember is that the person with latent TB infection is not infectious to anyone. The therapy is usually 2 drugs for 3 months. Alternatively one drug could be given for 6 months.
BCG the BCG policy since 2005 targets groups at highest risk of exposure to TB disease.
For further information and advice about Tuberculosis please contact Public Health on +44 1624 642615 or +44 1624 642657.
