The NICE guideline on TB should raise awareness of the disease in primary care, explains Dr Peter Saul
The new NICE guideline on tuberculosis (TB), published last month,1 acknowledges that this condition has begun to re-emerge as a public health problem in the UK.
Many GPs are unfamiliar with the risk factors and modes of presentation of TB, and are confused about policies concerning prevention, screening and treatment, since in most areas of the country we see few TB patients. For example, TB notifications in my area are 6.1 per 100,000 patients – less than one-fifth of those seen in London.
Although much of the document is directed at public health professionals and specialist TB clinicians the quick reference guide is easier to work through and has some important messages for GPs and community-based staff.
In the section on diagnosis of active respiratory TB, GPs are reminded of the need to order chest X-rays and obtain multiple sputum samples for TB microscopy. Positive findings warrant referral to a specialist.
If non-respiratory TB is suspected, the nature of the investigations required also means it is necessary to refer.
The new interferon-gamma immunological test is described in the guideline. This is a blood test which is reported to be more sensitive and specific than the Mantoux test. NICE recommends its use to back up positive skin testing, but so far it is not widely available.
Preventing TB in vulnerable individuals and detecting latent TB, a condition where an individual has dormant TB bacteria but no clinical infection, are prominent in the guideline. Policies to identify and screen individuals at high risk are recommended and are of interest to public health staff writing national and local policy.
But there are important practical lessons for GPs too. The concept of 'high incidence countries' and 'high incidence PCOs' is introduced. These are areas where TB incidence is more than 40 cases per 100,000 of the population per year. The Health Protection Agency's website lists PCTs and overseas countries with a high incidence of the disease.2
Practices based in high incidence PCOs will need to consider policies to ensure all new patients, including babies, have been offered screening and/or BCG immunisation if appropriate.
A checklist from the local PCO based on this guideline would be useful. It could include local contacts for support and advice, as well as agreed procedures for identifying groups who should be offered screening or BCG vaccination.
All GPs should take note of the need to assess new patients who have come to the UK from high incidence countries (e.g. countries in sub-Saharan Africa, Portugal, Singapore). This will be particularly important for those practising in university towns with high numbers of overseas students and in areas with communities from such countries. People arriving in the UK should have been offered TB screening by Port Health Services, but in my experience take-up is patchy and further review by the GP is essential.
The guideline also indicates a need for awareness of the risks of TB in vulnerable populations such as the homeless and those with certain chronic illnesses.
Much of the therapy for TB should be community-based, and while this will be specialist led, the primary care team will have a supporting role.
The challenge for local health communities is to take this guideline and use it to develop local policies in which GPs can play an informed and valuable part.
- NICE clinical guideline 33.Tuberculosis: Clinical diagnosis and management of tuberculosis and measures for its prevention and control. London: NICE, 2006