Events

Live GP web chat with tuberculosis specialists

We understand that after our GP study afternoons, there may still be unanswered questions or questions that need further explanation. We will be hosting a follow-up web chat about tuberculosis (TB) following our GP study afternoon on 2 June.

Join us at 11.30 on the 15 June, when we will pose questions to Professor Onn Min Kon, consultant respiratory physician and chief of service for the TB service at our Trust.

The chat will be public, so please be sure you do not include any information that could be used to identify patients in your questions. Enter your email address below to receive a reminder before the start of the web chat. 

Professor Onn Min Kon
11:36 Hi everyone, Prof Kon is now here to answer questions. We'll address a number of issues that were discussed at our last event for GPs as well as any other questions that come up. Let's get started!
Comment From Guest
What are the most unusual presentations of TB?

Professor Onn Min Kon
Half of all active cases are now extrapulmonary and these will include spinal, abdominal, CNS (ie TB meningitis) cases in addition to the more clinically obvious lymphadenopathy (neck nodes are the commonest site).

Comment From Guest
What do we have to look out for in primary care?

Professor Onn Min Kon
In any individual with any potential risk factors (i.e. young immigrant from high incidence country/ immunosuppressed (e.g. HIV/ renal failure/ on biologic or disease modifying therapy) consider TB if unexplained weight loss/ non resolving cough/ night sweats/ haemoptysis. Also consider extrapulmonary manifestations such as back pain/ abdominal pain/ headaches should there be atypical features.

Comment From Guest
Once a patient has been diagnosed, what do we need to do at the GP practice?

Professor Onn Min Kon
Generally once the patient has been diagnosed and is being looked after by the TB clinic, there will be no specific requirements as all prescriptions are free and supplied by the units. The active cases are also all case managed so the TB nurses so they are reviewed every month. The TB teams will liaise with you if there are specific issues that will need primary care input around identifying tracing or if there are issues of non-attendance as you may have more information than is evident.

Comment From Guest
What effects has TB screening had in NWL? Has there been a reduction of cases?

Professor Onn Min Kon
It is too early to know about the effect of the National Strategy or locally but published information from a pilot study in Westminster with 4 surgeries was very successful in identifying latent cases but also brought up a few active cases. This pilot was also the basis of some of the cost-effectiveness that has directly informed the national strategy. Initial experience from the Newham pilot sites has also shown very impressive rates of case detection.

Comment From Guest
I would like to be more about the latent TB screening.

Professor Onn Min Kon
This is now being rolled out so that an interferon gamma release assay (a single visit blood test rather than the traditional mantoux tuberculin skin test) is performed in primary care with an initial questionnaire in eligible new entrants to the UK - the current scheme has the following criteria: aged 18-35 years/ arrived in the UK within the last 5 years from any country with a local incidence of > 150 per 100,000 or sub Saharan Africa (born or spent > 6 months in the high incidence country)

Comment From Guest
How close are we to a TB vaccination in the UK?

Professor Onn Min Kon
  The current BCG is not sufficiently effective and there are significant issues with the supply of the 100 year old vaccine. There are several new vaccines being evaluated internationally but these are not likely to be available for some years.

Comment From Guest
Is NWL a high risk area for TB? Why?

Professor Onn Min Kon
This is likely to be related to the mix of ethnicities in NWL (as it is in NEL) as the highest rates of TB are in those from people born aboard from high incidence countries (e.g. Indian subcontinent/ Sub-Saharan Africa/ China/ South East Asia) but even those of specific ethnicities but UK-born still have a slightly higher risk. It should be stressed that anyone can have active tuberculosis and so a specific country of birth or ethnicity should not put you off a diagnosis of active TB should there be suspicious signs or symptoms.

Comment From Guest
What if a patient’s TB test is indeterminate?

Professor Onn Min Kon
In terms of the national scheme, the test should be repeated (and will be performed free of cost by the diagnostic provider). If it is indeterminate again, then the patient should be seen in their local TB clinic.

Comment From Guest
Who are the largest group affected by an increase in TB?

Professor Onn Min Kon
This can affect anyone in London as TB can be transmitted from active lung cases through respiratory particles (i.e. coughing) but as TB has higher rates in some ethnic groups and people born in other high incidence countries, those communities have a higher burden of TB.

There are also concerns about specific vulnerable groups such as the homeless, drug-users, alcoholics and those with a prior prison history as the evidence appears to very high rates of TB and also show ongoing transmission.

Comment From Gp
Do we need to treat children with TB symptoms any differently than adults? Are there unique investigations or treatments for children?

Professor Onn Min Kon
Children with a contact history of TB or with symptoms of TB need to be investigated urgently. One of the most serious forms of TB can be TB meningitis which can affect the young as a manifestation of primary TB. Investigations for children are more limited given that is harder to get respiratory and also other samples from the young. The use of gastric and induced sputum samples are therefore more commonly used in children. In addition the imaging tests we use in adults such as CT scan are generally avoided in the young given the radiation dose and so plain chest X-rays are generally the initial limit of radiology which can be non specific.

The treatment of TB is similar for children but with age and weight specific dosing and so must be supervised by a specialist paediatrician.

Comment From Anon
What can people do to reduce their chances of contracting TB?

Professor Onn Min Kon
There is some evidence that a low vitamin D may be a risk factor for developing active TB - in this setting although there are no specific data showing that supplementation can protect an individual, it is important to ensure you have a healthy diet.

The immune system is key in protection and so if you are on drugs (e.g. steroids/ immune modulators/ chemotherapy) or have a condition that affects the immune system (like kidney failure) it is important to ask your doctor whether you should be screened for latent (dormant) TB to allow for preventative treatment.

It is important to not be in close contact with persons with infectious lung TB - generally most are rendered non infectious by 2 weeks treatment. Patients with newly diagnosed active lung TB are advised about self-isolation and told when it is safe for them to then de-isolate. TB can only be caught by inhalation of respiratory particles and hence does not to apply to cases without lung TB. For instance it cannot be caught by using utensils/ toilet seats etc.

Professor Onn Min Kon
At our last GP event, several GPs were unable to stay for the discussion about screening, so here's some background information you might find useful:

If the Interferon gamma release assay is positive, then this is consistent with the individual having dormant (‘latent’) TB – this is a state where the TB bacteria are contained somewhere in the body after having being infected at some stage. They will be asymptomatic and a chest X-ray may be completely normal. They will have a lifetime risk of developing active TB of about 10-15% over their lifetime and so the screening aim is to identify these individuals and to be able to offer preventative TB treatment so they never develop the active form of TB.

Prior to the blood tests being available, a tuberculin skin test was used traditionally (such as the mantoux or heaf test) to identify patients with dormant TB but this can be affected by the BCG vaccine which will cause a ‘false’ positive and is hence less specific.

Comment From Guest 
What are the most common tests for TB?

Professor Onn Min Kon
This depends on whether you are trying to diagnose a case of active or latent (dormant) TB.

For active TB in the lung we would always get a chest X-ray and sputum samples initially. In some cases we also go on to a skin test and blood tests. There may need to be additional tests such as a CT scan/ ultrasound/ MRI dependent on the site of the disease.

For latent TB we would normally also get a chest -X-ray and the interferon gamma release assay blood test. At Imperial we also offer a mantoux skin test routinely. In children, a skin test is used for those aged less than 5 as the performance of the blood tests is still uncertain.

Comment From Guest
How does the incidence of TB in London compare to the rest of the U.K.?

Professor Onn Min Kon
London has the highest rates but this is also commonly found in other cities with a higher ethnic mix (e.g. Birmingham/ Leeds). For instance London's incidence is 30.1 per 100,000 but England as a whole is only about 11 per 100,000. It should be stressed there is also a lot of variation in rates even between different boroughs and sectors of London.

Professor Onn Min Kon
The TB team at Imperial have specific referral forms and an e-mail that can be used to make any referrals that fall outside the new primary care screening plan or if there are any queries that need to be addressed. Our email address is ichc-tr.tbserviceimperial@nhs.net and you can find more information about referrals on our website.

Professor Onn Min Kon
That's all the time we have for today. If you'd like more information, you can refer to slides from our recent GP events, which are available on our website: https://www.imperial.nhs.uk...

Professor Onn Min Kon
Thanks everyone!