Nice | Tuberculosis (TB)

This is an updated guideline from NICE on managing tuberculosis. I guess the relevance will be largely related to where you work. There isn't any really big change here, but there are lots of things that I wasn't aware of, so I will do a general summary of the guideline. There is a lot more detail in the guideline itself to refer to if needed - I have just given a broad-brush overview.

Definitions

There are a lot of definitions in this guideline that you need to understand for it to make any sense.

High Incidence Countries - any country with an incidence of tuberculosis over 40 per 100,000 per year. A list of high incidence countries can be found on the government's website.

UK Incidence - a list of incidence across all UK counties can also be found on the government's website.

Mantoux testing - where PPD tuberculin is injected into the forearm and a reaction suggests previous exposure. Prior BCG vaccination can cause a false positive result. It can't distinguish between latent and active TB.

Interferon-gamma release assay - where blood is mixed with antigens and controls. If they have had previoustuberculosis exposure, they will react. Prior BCG vaccination does not cause a false positive. It can't distinguish between latent and active TB.

Close Contacts

  • Household contacts (e.g. share room / kitchen / bathroom / sitting room)
  • Frequent visitors to the house
  • Partners
  • Coworkers may be, but are normally classed as social contacts

Social Contacts - contacts who are not in frequent, prolonged or intense contact.

New Entrants - when considering at risk groups, also include people who have had a prolonged stay (>1m) in a high risk country.

High risk groups - anyone at higher risk of having or contacting TB. This includes close contacts, new entrants from high incidence countries, immunocompromised people and 'under-served' people (eg homeless, vulnerable migrants, substance misuse and prisons).

How do you diagnose active TB?

  • CXR
  • Sputum samples x 3 for microscopy (AFB) and culture (NB there is a NAAT test now available and this should be done for HIV patients).

How do you diagnose latent tuberculosis?

Generally you start with a Mantoux test. If this is inconclusive or positive, you may go on to do an interferon-gamma release assay. If that is positive, they need testing for active TB as above. If that testing is negative, then they are said to have latent TB.

Who do you test for latent tuberculosis?

New Entrant from high incidence country - Mantoux testing. It is worth being aware that new entrants who require a visa to stay, have to prove testing or vaccination for TB. Bear in mind that HIV could also be present, so assess for the risk of this too. It could alter your decision over whether to offer BCG vaccination.

Close contact adults and children over 2 yrs old of people with pulmonary or laryngeal TB - start with Mantoux testing.

Close contact children < 2 yrs -  if the index case was 'smear negative' then refer

Close contact neonate (< 4w old) - if  the index patient is 'smear positive' and hasn't had at least 2/52 of treatment, they need assessment for active TB AND also need to start treatment. They then have a Mantoux test after 6/52 to decide on whether further treatment is needed.

Close contact child 4w to 2 yrs - if the index patient is 'smear positive' and has not had at least 2/52 of treatment, they need assessment for active TB and to start treatment and should have a Mantoux test.

Immunocompromised patients (risk assessment should be done to see if further testing is needed - eg are they from a high incidence country etc).

Severely immunocompromised patients - offer both Mantoux testing and interferon-gamma release assay.

New NHS employees - we probably won't have to do this, but basically they all need assessing and to have Mantoux testing if there is no documentation of vaccination or a BCG scar.

NHS employees exposed - who have had contact with groups of patients where TB is prevalent, should have interferon-gamma release assay.

Who should be receiving the BCG vaccination?

Adults over 16 should be assessed for whether they need BCG vaccination on first registering in GP and when accessing antenatal services.  Remember to assess for the risk of HIV too.

Children > 4w should be opportunistically assessed for risk.

Neonates (< 4w) - should be vaccinated in hospital if at higher risk, but check at 6/52. If there is a high incidence in the local area, all babies may be vaccinated. Higher risk includes children who are:

  • born in a high incidence area.
  • have 1 or more parent or grandparent born in a high incidence country.
  • have a family history of TB in the last 5 years.

Children 4w - 5 yrs - offer BCG if they should have had it as a neonate. Do not do a Mantoux first, unless they have had a stay of > 1m in a high incidence country.

Children 6 - 15 - offer BCG if they should have had it as a neonate. Do a Mantoux test first.

New Entrants - Offer Mantoux testing OR interferon-gamma release assay then BCG if they are

  • from a high incidence country AND
  • are unvaccinated (no proof of vaccination or no scar) AND
  • are younger than 16 OR
  • are < 35 if they are from sub-Saharan Africa or a country with a TB incidence of 500 per 100,000 or more.

Healthcare workers - if they are unvaccinated (or have no scar), offer Mantoux testing or interferon-gamma release assay then, if negative, offer BCG.

Contacts of TB if Mantoux or interferon-gamma release assay negative - offer BCG if:

  • index case has laryngeal or pulmonary TB.
  • they are not previously vaccinated AND
  • are < 35 OR
  • are any age if they are a healthcare worker or laboratory worker who has had contact with patients or materials.

Other at risk groups - Offer Mantoux testing or interferon-gamma release assay. If negative offer BCG if they are 35 and under and are:

  • veterinary staff or abattoir workers with animals known to be infected (eg simians).
  • prison staff working directly with prisoners,
  • staff in care homes for older people.
  • staff in hostels for the homeless, refugees and asylum seekers.
  • going to live or work among local people for 3m or more in a high incidence country.

Louise Hudman

I'm a freelance GP locum in Winchester & Southampton.

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2 Responses

  1. Ken Garrett
    Thanks Louise, very helpful.
  2. Sara Chambers
    Great clarity. Thanks Louise.

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