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BRITISH BROADCASTING CORPORATION
RADIO SCIENCE UNIT
CASE NOTES Programme no. 6 - Poisons
RADIO 4
TX DATE: TUESDAY 2ND SEPTEMBER 2008 2100-2130
PRESENTER: MARK PORTER
CONTRIBUTORS: SIMON THOMAS
ANDY BROWN
SHIRLEY THOMAS
PRODUCER: HELEN SHARP
NOT CHECKED AS BROADCAST
ACTUALITY
National Poison Service...
PORTER
If you, or a member of your family, have the misfortune to be poisoned - either accidentally or deliberately - then the National Poisons Information Service is where the healthcare professionals looking after you will turn for advice on how to treat you. It's made up of a network of four centres across the UK - at Birmingham, Cardiff, Edinburgh and Newcastle - and it's to the latter that I have come for today's programme.
As well as providing telephone advice, the unit at Newcastle also has an inpatient facility for treating people who have been poisoned. And it hosts the National Teratology Information Service which advises on, and collates data about, the toxicity of drugs and chemicals in pregnancy.
Dr Simon Thomas heads up the team.
THOMAS
I'm Dr Simon Thomas, I'm a consultant physician and clinical pharmacologist here in Newcastle. We're in the Royal Victoria Infirmary, this is our emergency assessment unit and this is where patients with poisoning would be brought if they need to come into hospital and be admitted.
PORTER
And what sort of problems will they have - how have they been poisoned?
THOMAS
The most common type of poisoning we see is drug overdose and this is an adult unit, so for them the most common type of poisoning is drug overdose, intentional type drug overdose in the context of self harm. But we also see people with poisoning associated with drugs of misuse, which is very common, and we may see people with other types of poisoning - exposure to household or occupational chemicals, environmental poisons, although that's much less common.
PORTER
On a national scale how big a problem is poisoning, whether accidental or otherwise, how many people will die a year from being poisoned?
THOMAS
Well there's probably a few thousand deaths per year in the UK from poisoning. In terms of its public health impact there's probably more than a hundred thousand admissions to hospitals each year because of poisoning. It's one of the more common reasons for presentation to an A&E department or for medical admission to hospital. The great majority of these patients are not seriously poisoned but they need to stay in hospital overnight until they've recovered from acute toxic effects and sometimes, if it's an intentional overdose, they may also need some input from psychiatric services also.
PORTER
And the most common poisons would be?
THOMAS
Well by far the most common poison that we see is paracetamol. About 40% of all drug overdoses in the UK involve paracetamol. After that, and less commonly, drugs like non-steroidal anti-inflammatory drugs, which are increasingly sold as analgesics over the counter ...
PORTER
Ibuprofen.
THOMAS
Exactly. Drug used in psychiatry like tranquillisers, antidepressants, occasionally drugs used for treating schizophrenia we will see and then less commonly other sorts of prescription medication. And of course alcohol is very commonly involved in drug overdose as well.
PORTER
A scenario familiar to Andy Brown who, 20 years ago, ended up in the Poisons Unit at Birmingham after mixing alcohol with a massive dose of paracetamol. In the lead up to the overdose his mental health had deteriorated to such an extent that he had been detained under the Mental Health Act. But once he started to improve, things took another turn for the worse after he was discharged to supported housing as part of his move back into the community.
BROWN
I just felt I didn't have any control over my life at that point. My previous life had sort of disappeared - you know jobs and relationships and things - that had all gone. I'd been in hospital which was a new experience for me. And then suddenly I was sharing a house and just, you know, just felt there was - I didn't have any control over it and you know couldn't express myself, didn't have any freedom to do anything, no future, very empty. So I made a plan to kill myself basically. It was quite an easy thing to do to plan it because in those days we didn't have the internet to get all the information and I'm afraid paracetamol overdose was the thing that popped into most people's minds at the time. So I picked a date when the house was going to be empty one evening, a few weeks in the future, and of course in those days paracetamol came in quite large containers, I think - was it 200 that you could get in one go and no questions asked. So I got a few of those and planned it all and get a few cans of cheap bitter from the Kwik Save. And then one Monday night while Peak Practice was on took as many as I could until eventually I felt rather poorly and dashed to the toilet.
PORTER
Paracetamol is the most common type of overdose in the UK, accounting for more than 20,000 hospital admissions every year. Most involve much smaller quantities of tablets than Andy Brown took but that doesn't make them any less lethal. Simon Thomas:
THOMAS
Well partly it's the easy availability of paracetamol tablets, they're available on general sales lists, so in many outlets you can buy them. We have a culture in this country of using paracetamol as our number one analgesic ...
PORTER
So there's some in every home.
THOMAS
It's cheap and cheerful, everybody has some, there's widespread availability to it. And so at that moment when you feel that you might like to take too many tablets that's what's easily available to you.
PORTER
Have the recent restrictions - because as most people know if you go and try and buy some paracetamol you're limited in the number you can buy - has that made a difference to the number of cases that you're seeing?
THOMAS
Well it's been disappointing, as you say the legislation to restrict paracetamol and in fact aspirin pack sizes came in, I think it was, 1998 and we did initially see a reduction in very serious poisoning with paracetamol. But data that's been published more recently suggests that that may have been a somewhat short term effect and certainly paracetamol poisoning is still a very common problem. We haven't seen a dramatic reduction in the numbers of presentations and it's still our number one problem.
BROWN
I felt very, very nauseous, you know the taste, if nothing else, but I just felt that I had to be sick, you know that feeling. And was violently and painfully sick everywhere. It was a nasty chalky bitter retching vomit all over the place. And so essentially I then tidied it up and went to my bedroom and lay down and thought oh well I won't be here tomorrow.
PORTER
Is it a treatable problem?
THOMAS
Certainly it's treatable. If patients come in early enough we may be able to limit the absorption of the paracetamol into their bloodstream. We use a substance called activated charcoal, which is effectively very fine grains of charcoal that patients can swallow, drugs like paracetamol become stuck on the charcoal and stay inside the gut rather than being absorbed into the body and so they don't present toxic problems. And if patients come within an hour or so of swallowing toxins that treatment may be effective. If it's not effective and they absorb significant amounts of paracetamol into their blood we have an excellent antidote for paracetamol poisoning and if we can start the antidote sufficiently early after the episode of overdose then it's very likely to be completely effective and to prevent any of the serious longer term harms of paracetamol overdose.
PORTER
And by sufficiently early, how soon would that need to be given?
THOMAS
Well we're very keen to try and get the antidote in within about eight hours of the overdose. After that the antidote becomes progressively less effective but it may have some effect at any time.
PORTER
And what sort of dosage would you start to consider giving someone an antidote?
THOMAS
Well we generally decide on whether people need antidotes on the basis of what the levels of paracetamol are in the blood. So we would measure that and use that, together with the time, to make some sort of judgement. In terms of the amount of tablets that people might take, certainly anybody who was to take as many as a box, say 16 tablets, we would be concerned about and we would want to go through this process, probably fewer tablets than that in fact.
BROWN
I'm not sure how much I slept that night but I certainly woke up the next morning and still felt rather ill and over the next few days I continued to be sick - well retching - because I couldn't keep any food down and hardly any water. By the Friday of course I'd been to bed, woken up, two or three times and so I was rapidly coming to the conclusion that I wasn't just going to die, I was either going to get better but that didn't seem to be happening or I was going to get more ill and more ill and feel bad and of course I couldn't hide it anymore from the - from the staff and the other residents because it was obvious that I was - that there was something more serious wrong than just a dicky tummy. And so I reluctantly said that okay I'll go along to the GP who I remember asked me why are your eyes so bloodshot and I said to him I think it must be something to do with the 200 paracetamol I took on Monday. And so he organised an ambulance and I was whizzed in to A&E at the Walsgrave Hospital in Coventry.
PORTER
Obviously if somebody reports immediately they've taken an overdose you can either give them the activated charcoal or the antidote but what happens if somebody wasn't to report soon enough and maybe come in a day or two later, what's the natural history of paracetamol poisoning?
THOMAS
Well without treatment serious paracetamol poisoning results in damage to the liver, this damage comes on over a period of days after the overdose, so we might see signs developing after 24 hours but coming to a peak maybe after three days. Shorter time if the poisoning is more severe. This means that there's a delay between a person taking the tablets and actually developing serious clinical effects.
PORTER
So they can feel fine initially, so maybe they regret the overdose or they feel fine so they don't bother seeking help.
THOMAS
Yes it's unfortunate but it does happen that people sometimes, for example, in the evening might take paracetamol maybe with some alcohol, fall asleep and then feel okay the next day and not do anything about it and only present when they start to develop features of the paracetamol induced liver damage.
PORTER
Which can be irreversible?
THOMAS
Well by that stage it can be irreversible and patients can certainly die from damage to the liver or require treatment in a liver unit, maybe liver transplantation - paracetamol poisoning's one of the commonest reasons for that.
PORTER
You talked about specific antidote for paracetamol, do most poisons have some form of antidote that you hold that you give?
THOMAS
Well in fact it's true that only a minority of poisons that we treat would have a specific antidote. Paracetamol's one, another antidote that we use very commonly is something called Nixolone which we use for overdoses of morphine or morphine like drugs, including heroin for example and intravenous heroin can sometimes cause very severe toxic effects in drug users and it's a very common cause of death in that group and it can be reversed very dramatically by administration of this antidote if it can be provided quickly enough.
PORTER
But you don't have antidotes for most of the things that you're dealing with so it's general supportive measures?
THOMAS
That's right.
PORTER
And that would be done where - in your special ward? So say somebody came into the unit here and they needed longer care you'd be moving them to your own ward?
THOMAS
Our patients - the ones that we look after in the toxicology service - we look after within this environment, within either this unit here, the admissions unit, or just next door in our admissions ward. Patients who require specialist care might need to go to one of our intensive care units or to the high dependency unit where they would be looked after principally by the specialists in that area but we would give our input as needed on a regular basis. Sometimes patients might need to go to the renal unit, for example, if they needed dialysis because that method can be effective for removing some poisons and reducing the duration of toxicity.
PORTER
Andy, might have been hoping that after taking the combination of paracetamol and beer he would fall asleep never to wake again. What he didn't envisage was lying prostrate in an accident and emergency department with eyes, that he describes, as looking like bulging bags of blood.
BROWN
My memories of A&E were of - I think they must have given me some sort of drug or something but I remember throwing up very, very, very violently and throwing up what looked like chunks of tar but were - I'm guessing - congealed blood. And that was one of the nastiest experiences I've ever had, that felt - that made me feel like I either was dying or I really wanted to die there and then because that was such a horrible experience. And then the next day or the day after I was rushed in the back of an ambulance at high speed to Dudley Road Hospital in Birmingham where they've got a poisons unit because they wanted to - or needed to put me on a haemo filtration machine. As I understand it because my liver and especially my kidneys were basically failing at that point lots of poisons were building up in my body that needed to be filtered otherwise I would just slowly poison myself to death that way. And then it was into the intensive therapy unit after that, I was the only conscious person on that ward, but they gave me a nice radio and I could listen to Radio 4 24 hours a day and that was lovely and peaceful. So that gave me a little bit of time to chill out actually.
PORTER
Andy's memory of what happened next is hazy but his mother said afterwards that the family had been told he probably wouldn't pull through.
BROWN
As far as I recall from being admitted to A&E to being discharged from Birmingham was probably about three weeks, something like that. Before I was discharged my consultant at Birmingham - and they were doing regular blood tests to check my pre-apnin levels, or some such thing, which is one of those poisons I believe that builds up when you've got liver and kidney failure and he told me that he was surprised that my levels seemed to be okay and that my organs seemed to have started working again. His words to me were that he thought that I would end up on a transplant list or at least be on dialysis long term and he was very surprised that I was in a state where he could just discharge me back into psychiatric services needing no particular treatment, apart from just a follow up to check that everything was going okay.
PORTER
Andy Brown.
Back at Newcastle, caring for patients like Andy is just part of the role of Simon Thomas's team.
ACTUALITY
... and how old is he? Okay. And what's happened to him?
PORTER
Across the road from the hospital is a call centre staffed by a multidisciplinary team made up of nurses, medical scientists and pharmacists. It's one of four such centres in the NHS that provide advice and information to healthcare professionals looking after someone who has been poisoned. Much of the information comes from Toxbase - a vast, constantly updated database on the diagnosis and management of poisonings. And a database that can now be accessed direct via the internet - albeit currently only by healthcare professionals.
Well over in the corner is Vince who's sitting at a console with Toxbase, now you're going to talk me through Toxbase Vince, so I mean it's an internet site basically.
VINCE
Yes, it's an internet site which is accessible to all healthcare professionals in the UK. It's reasonably easy to use in that you've got a search box at the top of the site and then if you have someone come in - if someone who's eaten a yew berry, so you can put in yew ... just an example of plant, product search ...
PORTER
Here it comes, that's quite useful, the first thing it shows is a picture actually, so presumably if somebody's describing something in an accident and emergency department they can confirm what they're looking at.
VINCE
Or you can show someone the picture, is this what you mean and then it brings down - they all have the same common format, it'll have the common name which is the yew....
PORTER
An evergreen tree which rarely grows taller than 20 feet, yes.
VINCE
It has a Latin name at the top, what the toxic constitute is...
PORTER
So that's the bit that's going to do you the harm.
VINCE
Yeah and it gives you a brief sort of synopsis of the toxicity. And then I suppose what yourself would be looking at, more interest, is actual features - what you're going to see.
PORTER
Yeah, no I can see a couple of things I've picked out already, I mean all parts of the plant are toxic with the exception of the fleshy red part of the berry, so a lot of people would probably think the berries are the poisonous bit, it's not it's the rest of it.
VINCE
It's the rest of it.
PORTER
And then it tells you what it does - so ingestion of fleshy part of the berry alone just nausea and vomiting but the other parts - quite a lot of side effects.
VINCE
It takes you through the various things that it can cause. The advice would vary, say for the management, if only the red fleshy part of the berry has been eaten we'd advise a small glass of milk or water and keep...
PORTER
Right through to giving some pretty significant drugs at the end there.
VINCE
Yes right through to sort of...
PORTER
IV fluids, dopamine, yeah intensive care stuff.
At the moment Toxbase can only accessed online by medical professionals, who are increasingly bypassing the telephone service to view the information it contains directly. So might the general public be able to do the same one day? Simon Thomas again.
THOMAS
I think that would be a very good development and certainly one which myself and many of our colleagues would be keen to support. I think the problem at the moment is that the database isn't really constructed in an appropriate way for the general public, it's full of technical information but we would certainly be interested in developing a public access part of our website in the future.
ACTUALITY
Hello.
Hi. I want to go to the general hospital, A&E please.
PORTER
Time to meet some of the staff who deal with poisonings at the front line of the NHS, so it was into a cab and off to the A&E Department at Newcastle General Hospital.
ACTUALITY
Thank you very much, thank you.
SHIRLEY THOMAS
I am Shirley Thomas, I'm the lead nurse for paediatrics in A&E but work in the department as a paediatric emergency nurse practitioner. And we see children from 0 to 16 who come to the department in this paediatric area here.
PORTER
Yes it's obviously paediatric because it's got cartoons all over the walls. What sort of proportion of your workload do children make up generally?
SHIRLEY THOMAS
Around about 25% of the total number of patients who come through the department are children.
PORTER
And is poisoning a large part of that workload?
SHIRLEY THOMAS
It's a significant amount, it's not a huge amount but we certainly see about three or four accidental poisonings a week. On top of that we do obviously see deliberate overdoses as well.
PORTER
And are some children more prone to it than others, I'm thinking of age groups here and perhaps the inquisitive toddler getting his or her hands into things they shouldn't do?
SHIRLEY THOMAS
Yeah certainly the inquisitive toddler does make a significant amount of that workload and then you sort of progress to children who are a little bit older who maybe are being a bit more adventurous in say auntie or grandma's house, helping themselves to pills and things that are lying around because they look a little bit like sweets, progressing on to sort of the teenager who may take a deliberate overdose.
PORTER
And are pills the main problem or are household items like bleach and things, presumably they present a hazard as well?
SHIRLEY THOMAS
They're quite a common presentation as well - children who come across household products and decide to have a bit of a taste or a bit of a spray of those.
PORTER
Do you have a sort of top five of likely culprits that you see coming in here?
SHIRLEY THOMAS
Paracetamol, Calpol's the top favourite because it tastes so good and most houses with children have Calpol in them, so we get a lot of children who have taken some Calpol. Things like Domestos ...
PORTER
Things that are kept under the kitchen sink.
SHIRLEY THOMAS
Under the kitchen sink - bio tabs, are quite a common one.
PORTER
But presumably when a child takes something like that, I mean they ingest something like Domestos, they don't think a lot because it's not very nice to swallow whereas a tablet they could swallow a few of those without you even knowing. I suppose the big concern with parents is you wouldn't really know whether they'd been at the pills or not whereas if they drunk some bleach they're likely to make a big fuss about it.
SHIRLEY THOMAS
Yeah, I mean I suppose if they've drank bleach they're obviously going to smell of bleach and they tend to have split bleach on them as well. Tablets, obviously for younger children are more difficult to chew so you tend to get a lot of residue still in their mouth or they're trying to spit it out by the time mum and dad's found them. But it's quite common that children are brought in and the possibility is that they've ingested tablets but they don't know how many were in the packet to begin with.
PORTER
I suppose that's your big challenge because you don't know either, do you, so how do you go about finding out how much a child has taken?
SHIRLEY THOMAS
Well I mean say they had a bubble pack of paracetamol and there was six missing and you just have to go with the worst possible scenario that they have taken six, I mean that's probably most unlikely but we tend to just treat on the worst possible scenario.
PORTER
And then presumably you can do blood tests and things to analyse how much - if there's any signs of them in the blood.
SHIRLEY THOMAS
That's right, yeah.
PORTER
And how would you manage a child who'd taken a drug overdose? Let's say it was paracetamol here what would be your first priority?
SHIRLEY THOMAS
I mean the first thing we do is try and ascertain obviously how much they've taken and then we'd see how the child is - do a baseline observation, certainly do a weight because the problems with ingestion is very closely related to the weight of the child versus how much they've possibly have taken. And then with that information we'd go to Toxbase, access Toxbase get the information from there about sort of how much is safe and when we need to start worrying about treatment.
PORTER
What about emptying the stomach - the child's stomach - making them sick?
SHIRLEY THOMAS
We don't do that anymore.
PORTER
So that's something you would say to parents that if they suspect that their child ingested something take them to A&E don't do that?
SHIRLEY THOMAS
Yeah, we don't do that at all now.
PORTER
And why is that?
SHIRLEY THOMAS
I suppose the difficulty is there's a possibility of aspiration if they're trying to make the child sick.
PORTER
That's inhaling the vomit into the lungs.
SHIRLEY THOMAS
Yeah, yeah so we don't do that anymore.
PORTER
And if it's a nasty substance and it's done some damage on the way back you don't want it to do more damage on the way out either.
SHIRLEY THOMAS
Exactly, some of them can be corrosive on the way back, yeah.
PORTER
And what do parents tend to do when they're concerned that their child might have ingested something they shouldn't have, do they ring you or do they bring the child in here?
SHIRLEY THOMAS
They tend to come in here or they access NHS Direct who invariably advise them to come down to A&E to be checked over, which is the right thing to do.
PORTER
Presumably the vast majority of children that you see here make a complete recovery and go home but what sort of parting advice do you give to their parents because you must see a lot of people with the same sort of story - they've been at my pills, they've been under the kitchen sink?
SHIRLEY THOMAS
Yeah, I mean certainly we talk to them about the safe storage of medicines and household products - chemicals and things. Also that we advise them that the health visitor or the school nurse will have been informed that they've attended A&E and they may well reinforce what we've already said to them.
PORTER
Back at the Newcastle arm of the National Poisons Information Service, team member Vince, who is a parent himself, is all too aware of the hazards after dispensing advice to so many others.
VINCE
One of the most common calls we get is mum or dad's given the child the 5 mls of Calpol, a normal dose, put the bottle down to do something else, baby's got hold of it and thought I'll drink the rest of that and it's something I like to try and avoid at home, make sure, yes, you put the top back on and you put the bottle back in the cupboard and it's out of the way. Yes, I've gone round putting catches on cupboard doors so they can't get at the bleach and the washing powder. And just finished a course where we were looking at sort of prevention of poisoning and the various strategies and so the advice of never taking tablets in front of children because they will emulate what they see you do, so if they see you taking tablets and then they come across them yes they will take them, so at least try. Which is again a common call we get especially with ageing population, especially this time of year when you've got people visiting grandparents, school summer holidays, things are in handbags, children go through handbags, so dose set boxes which have to be easy for people to open because as you get older then it's harder to open pill packets but then if children get hold of them yes they can take what's in them. So it's sort of just keep your handbags out of reach as well because if people are on medication it's something that can happen.
PORTER
Simon Thomas's unit at Newcastle also hosts the National Teratology Information service which offers specific advice and information on the toxic effects of drugs and chemicals in pregnancy.
THOMAS
Takes inquiries about all aspects of drug and chemical exposures during pregnancy, including overdose.
PORTER
Presumably the lion's share of that is people taking prescribed medicines and being concerned, is it, rather than accidental or intentional poisoning?
THOMAS
That's right. It's just simply therapeutic uses of drugs in one context or another. So women may be prescribed medication and they then become pregnant and well wish to have information about what the potential implications of that treatment are on their own baby. They may be prescribed things in pregnancy and health professionals who are prescribing to them may want to know what the most appropriate drugs are to use for particular circumstances. So that's a very common part of our workload. We also get inquiries when women have had children who have got malformations, whether medications or substances that they've been exposed to in their pregnancy could have been relevant or responsible.
PORTER
Looking for a cause.
THOMAS
Yes indeed.
PORTER
And you're using a database there presumably as well, you're looking back through publications to see if there's any evidence of previous problems?
THOMAS
Yes we do that, we certainly look at the world literature in these areas. We have our own ...
PORTER
Because these drugs aren't tested on pregnant women are they by the drug companies?
THOMAS
No, it's obviously extremely difficult to do the type of testing that we would need to provide the information that we're looking for, for ethical reasons. So there's often a dearth of information on the effects of drugs and particularly chemicals in human pregnancy. There may be information about what the effects are from animal studies but they don't necessarily reflect what's going to happen in humans. So in terms of the information that we have available to us there is the world literature of course, we also collect outcome data from pregnancies that we've been informed about. So if you, as a GP, were to contact us about a woman who had been prescribed a medication during pregnancy to seek our advice we would provide our advice and then at the end of the pregnancy we would come back to you and ask you what the outcome of that pregnancy was and in that way we collect data, gradually over a period of years we collect more experience about use of particular drugs in pregnancy and in this way we build a database and we now have outcomes of more than 10,000 pregnancies logged in this way. And that helps us to provide more information to the next inquiry down the line.
PORTER
And are you sharing that database with organisations like yourself in other countries?
THOMAS
Yes there are information centres like ours in the UK in other countries around the world, there is a European network of teratology information services and if we need larger data sets, and we often do, combining with their data is very useful.
PORTER
Dr Simon Thomas talking to me in Newcastle. Although neither the teratology or Poisons Information Service can be accessed by the public you can obtain some of the information they contain via NHS Direct or NHS 24, if you live in Scotland. Over a quarter of the calls to the Newcastle team come in via these organisations.
That's it for this week. Next week's programme is all about hair - from the causes of generalised thinning in women to the steps hospitals now take to prevent hair loss during chemotherapy.
ENDS
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