Tuberculosis is an infectious disease that primarily affects the lung, but can cause disease in almost any organ.

Article by Nicola Davis

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Tuberculosis is an infectious disease that primarily affects the lung, but can cause disease in almost any organ. The sites most commonly affected after the lung include the lymph nodes, kidneys, brain, spine and gastrointestinal system.

Tuberculosis is present in every part of the world. Countries which currently have a high prevalence of tuberculosis include Bangladesh, China, the Democratic Republic of the Congo, India, Indonesia, Nigeria, Pakistan and the Philippines (World Health Organization, 2022).

The UK is a low-prevalence area; in 2021, approximately 76% of the 4425 cases of tuberculosis in the UK occurred among people born outside of the UK (UK Health Security Agency, 2023). Social factors such as homelessness, asylum seeker status, drug and alcohol dependency and imprisonment have also been associated with an increased risk of tuberculosis infection (UK Health Security Agency, 2023).

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One or more of the below symptoms are usually present in patients with pulmonary tuberculosis:

  • persistent cough
  • chest pain
  • haemoptysis (coughing up blood)
  • weight loss
  • fever and drenching night sweats
  • lethargy

In extrapulmonary tuberculosis, symptoms depend on the affected organ, which can make diagnosis challenging. After the lung, the lymph nodes are the second most affected site, so tuberculosis should be considered as a possible cause of any lymph node swelling, particularly in the neck, in an individual who was born in or has visited an area of high tuberculosis prevalence. Weight loss, fever and night sweats may also be present in people with extrapulmonary tuberculosis.

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Mycobacterium tuberculosis complex is a subset of approximately 100 mycobacteria that cause tuberculosis infection. Other mycobacteria cause opportunistic infections in people who are immunocompromised, and are classed as non-tuberculosis mycobacteria or atypical mycobacteria. These are non-infectious but are treated with similar antibiotic therapies to M. tuberculosis.

M. tuberculosis are transmitted via droplet transmission when an infectious individual (index case) coughs or sneezes. The bacteria are then inhaled into the lung of the newly exposed individual. Prolonged close contact is generally required for transmission to occur, such as sharing living and sleeping accommodation. Tuberculosis affecting other organs cannot be transmitted in this way.

Initial (primary) tuberculosis infection can either:

  • Resolve spontaneously – the bacteria are destroyed by the alveolar macrophages and the individual does not become ill and is not infectious
  • Remain latent – the host has no symptoms and is not infectious, but the tuberculosis bacteria remain

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For patients with suspected active pulmonary tuberculosis, three early morning sputum samples should be sent for laboratory testing for tuberculosis microscopy, culture and sensitivities (National Institute for Health and Care Excellence, 2019). Gastric lavage or induced sputum samples are often used for infants and young people. The samples will be observed under the microscope (sputum smear) and preliminary results can be available within 24 hours. Individuals who are sputum smear positive (when mycobacteria can be seen under the microscope) pose a higher risk of transmission.

Rapid molecular testing is now able to detect the presence of tuberculosis bacteria and give an indication as to whether any drug resistance is likely. Full culture, species identification and antibiotic sensitivities can take some weeks to process, as mycobacteria are particularly slow growing. Hospital inpatients with suspected pulmonary tuberculosis should be isolated in a single side room while definitive results are awaited.

For individuals

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Front-line healthcare workers should ensure prompt referral for symptomatic individuals who have visited a high-prevalence country or deemed to be at high risk of tuberculosis disease to the local tuberculosis specialist team. Tuberculosis is a notifiable disease under UK public health regulations and all suspected cases of active disease are reported to the UK Health Security Agency.

Local tuberculosis teams include specialist consultants, nurses and case workers who work together to diagnose, treat, monitor and support individuals through their long course of treatment. Tuberculosis screening is also offered to close contacts of all individuals diagnosed with pulmonary tuberculosis. Social contacts (including most workplace contacts) are only screened on a risk-assessment basis. Local tuberculosis teams work with the UK Health Security Agency to manage incidents of infectious pulmonary tuberculosis in schools, prisons and inpatient facilities, or when clusters of cases are identified in the community. Whole-genome sequencing technology can now identify

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For fully drug-sensitive tuberculosis disease, a minimum 6-month treatment of quadruple therapy is needed. Repeated X-rays and/or computed tomography scans can be used to monitor resolution of the disease.

The four front-line antibiotics commonly used in the UK are:

  • rifampicin
  • isoniazid
  • ethambutol
  • pyrazinamide

Dosages are prescribed according to weight, and treatment often involves taking a large number of tablets daily. Liquid medications are available for children. The medication must be taken on an empty stomach to ensure absorption. After 2 weeks of taking the antibiotics effectively, individuals can be considered non-infectious.

There are a number of side effects and interactions associated with these antibiotics, including:

  • Gastrointestinal disturbance – nausea, vomiting, diarrhoea and bloating are quite common, these often subside after the first weeks of treatment
  • Liver toxicity – liver function blood tests are monitored, particularly if the individual has underlying liver disease and/or drug and alcohol dependency
  • Loss of sensation

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NMC proficiencies

Nursing and Midwifery Council: standards of proficiency for registered nurses

Part 1: Procedures for assessing people’s needs for person-centred care

2.9 Collect and observe sputum, urine and stool and vomit specimens, undertaking routine analysis and interpreting findings

Part 2: Procedures for the planning, provision and management of person-centred nursing care

9.1 Observe, assess and respond rapidly to potential infection risks using best practice guidelines

11.1 Carry out initial and continued assessments of people receiving care and their ability to self-administer their own medications

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Heymann D. Control of communicable diseases manual. 21st ed. Washington DC: American Public Health Association Press: 2022

National Institute for Health and Clinical Excellence. Tuberculosis. 2019. https://www.nice.org.uk/guidance/ng33/resources/tuberculosis-pdf-1837390683589 (accessed 21 November 2023)

Rodrigues LC, Diwan VK and Wheeler JG. Protective effect of BCG against tuberculous meningitis and military tuberculosis: a meta-analysis. Int J Epidemiol. 1993;22(6):1154–8. https://doi.org/10.1093/ije/22.6.1154 

UK Health Security Agency. Tuberculosis. 2018. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/731848/_Greenbook_chapter_32_Tuberculosis_.pdf (accessed 21 November 2023)

UK Health Security Agency. Tuberculosis in England, 2022 report (data up to end of 2021). 2023. https://www.gov.uk/government/publications/tuberculosis-in-england-2022-report-data-up-to-end-of-2021 (accessed 21 November 2023)

World Health Organization. Treatment of tuberculosis guidelines. 4th edn. Geneva; World Health Organization: 2010

World Health Organization. Global tuberculosis report 2022. https://www.who.int/teams/global-tuberculosis-programme/tb-reports/global-tuberculosis-report-2022/ (accessed 21 November 2023)

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