Specimens are termed “smear-positive” if AAFB are demonstrated by staining techniques.

Although molecular tests have improved the diagnosis of the disease, microscopy and culture remain the gold standard. Tuberculosis (TB) is a disease that has been present in the human race for thousands of years. Patients should be reviewed at least every month, but may need to be seen three times per week if directly observed therapy is indicated. Tuberculosis is caused by bacteria of the Mycobacterium tuberculosis complex. All patients should have a chest X-ray. The tests are specific, and are 95 per cent sensitive in smear-positive patients, but have low sensitivity in smear-negative patients. Mycobacteria isolated from culture are further identified by microscopic appearance, growth characteristics and biochemical tests. Department of Health. TB rates in the indigenous UK population have continued to decline, and in 2005 the schools programme was stopped. Sensitivity testing can also be done using the rapid culture systems. The tuberculin skin test (Heaf or Mantoux) is used as a screening test for tuberculous infection or disease, and to aid diagnosis by assessing the local skin reaction to an intradermal injection of mycobacterial antigens. Frieden TR, Sterling TR, Munsiff SS, Watt CJ, Dye C. Tuberculosis. In the UK, screening of new immigrants from countries with a TB incidence greater than 40 per 100,000 population is recommended in order to identify infected people, particularly children, who might require chemoprophylaxis, or non-infected persons who might require BCG vaccination. For example, TB of the spine may cause back pain; TB of the kidney may cause blood Paraspinal cold abscesses may develop from spread of the infection, and weakness or paralysis of the lower extremities may occur. The risk of death in HIV infected people with active TB is three to seven times higher than in those without HIV infection. Following exposure to TB, individuals with HIV are at a greater risk of active disease with a more rapid progression.9 The risk of reactivation is much higher in patients with HIV, at 10 per cent per year.

Macrophages and T-lymphocytes are fundamentally important to the immune response to TB. A blood test has recently been developed which measures interferon-g released from T cells in response to stimulation with mycobacterial antigens. Pulmonary cavities may become super-infected with other organisms, such as Aspergillus spp or non-tuberculous mycobacteria.

Isoniazid (INH) Rifampin (RIF) Pyrazinamide (PZA) Ethambutol (EMB) The current World Health Organization recommendations are that all new patients with tuberculosis, irrespective of site or severity of disease, and in the absence of evidence of drug resistance, should receive a 6-month course of therapy, … You will be re-directed back to this page where you will have the ability to comment. The highest rates are seen in black Africans, although the largest numbers of cases occur in people of Indian, Bangladeshi and Pakistani origin. Up to 10 per cent of  TB cases are diagnosed by contact tracing, and disease occurs in about 1 per cent of contacts.12 The risk of infection is determined by how infectious the source case is and the duration and level of exposure. For more information please take a look at our terms and conditions. Lymphadenitis usually affects the cervical and supraclavicular areas; involvement of other nodes suggests more widespread disease. Alveolar macrophages have special receptors which can recognise foreign material, such as mycobacterial lipoproteins. Subscribe to our free alerts. Mycobacteria Tuberculosis Non sporing, Non-capsulated. The incidence of TB is high among homeless people, and transmission can occur in hostels or other temporary accommodation. Treatment includes anti-tuberculous drugs with good CNS penetration and corticosteroids. Daley CL, Small PM, Schecter GF, Schoolnik GK, McAdam RA, Jacobs WR et al. Invasive procedures such as liver biopsy or mediastinoscopy may occasionally be necessary to obtain tissue samples. The remaining 10 per cent develop progressive primary tuberculosis. Mycobacterium africanum is a rare pathogen causing TB in Africa. Cookies are small text files stored on the device you are using to access this website. He cultivated the bacteria and succeeded in infecting animals with TB using isolated cultures. Immune reconstitution inflammatory syndrome may occur in individuals with advanced HIV infection and active or latent TB on starting anti-retroviral therapy. These patients do not require further isolation, unless other patients on the ward are immunocompromised, in which case three negative sputum smears should be obtained before stopping isolation. The Lancet Infectious Diseases 2004;4: 761–6.

Other specimens should be stained using the Ziehl-Neelson method — mycobacteria are seen as pink rods against a blue or green background. Some parts of the site may not work properly if you choose not to accept cookies. 13, p73 | After two weeks of a treatment regimen including rifampicin and isoniazid, patients with smear-positive tuberculosis with no risk factors for MDR-TB are usually non-infectious, even though bacilli might still be seen in sputum smears. In settings where other patients may be infected with HIV or otherwise immunocompromised, suspected or confirmed cases of pulmonary tuberculosis should be considered potentially infectious on every admission, and should be admitted to a single room on a separate ward or a negative-pressure ventilation room on the same ward. Mycobacterium bovis is the pathogen responsible for bovine tuberculosis, a cause of human TB that was common before milk was pasteurised, but is now rare. However, TB affecting the central nervous system continues to have a poor prognosis, with a mortality rate of 20 per cent in children under five years, and 60 per cent in adults over 50 years of age.6.