What is Chronic Fatigue Syndrome?

with Dr. Esther Crawley, Bristol University

Kat - Let's start by just really going back to basics, what exactly do we mean by chronic fatigue syndrome? What is this disorder?

Esther - Well, patients with chronic fatigue syndrome are first of all very disabled by very significant and difficult fatigue, and then they usually have a variety of other symptoms. So, one of the most common symptoms for example is headaches which are very difficult and often constant. They often have muscle and joint aches and pains. I mainly see children and teenagers and they often start off by feeling very, very sick, particularly first thing in the morning and dizzy, and sore throats and swollen lymph nodes are also some of the symptoms. One of the problems with this illness is it comes and goes and it affects people differently in different days. It can cycle by days or by weeks, or by months. It's a very, very difficult and disabling condition.

Kat - Who normally gets this disorder because I remember when it sort of rose to prominence, a couple of decades ago, people referred to it as "yuppie flu", but I understand that's not actually really the sort of people that it affects?

Esther - Well, it can affect everybody. It tends to be more common in women. In fact, it tends to be more common in those of lower socio-economic class, so more deprived families. And there's reasonable evidence now that it's also, certainly in this country, it's more common in ethnic minorities. And you can look for this condition everywhere and every country that you look for it, you're going to find it, and the poorer the country, the more common it seems to be. So, in fact, it's quite the reverse of yuppie flu. It's an illness of social deprivation not of wealth. It's just the yuppies, the rich people are more likely to be successful in seeking healthcare.

Kat - And what sort of healthcare is available? There's no medical treatment. What sort of treatments or interventions might be available for it at the moment?

Esther - Well, there are no magic pills for it at the moment. There are some medications that help with pain and there are some medications that some patients find helpful with sleep. But mainly, treatment focuses on improving quality of sleep and improving activity and exercise in a very, very gentle way to get patients back to doing the things they want to do.

Kat - What's actually causing CFS? What makes someone develop this disorder?

Esther - We don't know the cause is and I think it's really important to start at the beginning of your programme by saying it's quite likely that it's not just one illness. Certainly, all the research in adults have shown that there's probably between 3 and 5 different types of illness that present with different groups of symptoms. So it may well be that fatigue and the symptoms I described might be the sort of end pathway. In children, we've also described between 3 and 4 different types of illness.

And so, what do we know about it? Well, we know that in many people, it's triggered off by an infection and some research has shown that it's the severity of the initial infection, rather than the actual type of infection, that's important.

But we also see a similar problem with fatigue after other types of insults. So for example, we're quite interested in what happens to patients after they have treatment for cancer. Also, we quite often see it in other illnesses. So, if you get very, very ill with diabetes for example, quite a lot of children after that develop a very similar looking illness.

So, I think that you need a big hit, but also, there's good evidence to show that in both children and adults, people are what we call 'genetically vulnerable'. So you're probably born with genes that make you vulnerable to fatigue and then you need an environmental insult to set it all off.

Kat - What kind of evidence do you have that there may be a genetic component to this?

Esther - There's different types of studies and the most convincing are twin studies. Interestingly, it looks like children are more genetically vulnerable than adults. So, if you're monozygotic twins, if you're identical twins and one of you gets it, you're much more likely that the other one will get it than if you're dizygotic, where you're only going to share half the DNA.

Kat - So basically, if you develop it as a child, it's more likely that it had a stronger genetic component to it.

Esther - Yes, so you only needed 1 or 2 viruses and then you set the whole thing off whereas as an adult, it looks like probably, you need to have the genes and then you need other things. So for example, we know that in adults, if you're depressed in your 40s, you're more likely to get it in your 50s, and that just doesn't seem to be true in children. So in adults, you need a variety of things together at the same time as well as the infection to set the whole thing off.

Kat - What do you think is going on with the infection? You talked about someone having an infection. It doesn't matter what's infected them. Do we have any clues about what's going on in the immune system?

Esther - Well, there are a lot of studies that have looked at the immune system and it's quite difficult to interpret exactly what's going on. I mean, clearly people with chronic fatigue syndrome, when you look at the immune system, it seems to be very different to controls. It's difficult to interpret because there are also lots of other differences going on. So for example, they're more sedentary, so they're not doing as much exercise as healthy controls. I mean, we believe the way forward is by doing very, very large studies, looking at the genetic material from thousands and thousands of patients. Of course you need very large studies because there are different types of illness and looking at blood in a large number of patients, but also, we're using longitudinal cohorts so, looking at DNA and blood, and also other factors before people get ill, to try and work out what the causes are. And also, what we call the maintenance factor, so what keeps you sick.

Kat - So if you think you can understand some of the pointers that might be causing it or indicating that it's about to happen, do you think you could help prevent people developing CFS in the first place?

Esther - Well I mean, I think that's why we're looking at it and also, we don't have any medical treatments. So, understanding more about the causes might help us develop that. But I think there's other things that you can do as well, so we're quite interested in what's called early intervention studies. So, if you - for example in children - if you can identify children as they start to become unwell with this illness, then what teenagers tell us is, if they get the right advice very early on, they believe they could stop it becoming a long-term illness. So I think there's definitely a role for looking at early intervention studies in both teenagers and there's also studies in Bristol going on in adults, seeing if you can prevent it becoming a long time problem.

Kat - What sort of interventions are you talking about in these cases?

Esther - Well, the teenagers tell us that the most useful thing that they wish they'd known right at the beginning is advice about sleep. So, what happens when you get chronic fatigue syndrome is you feel very, very awful and very, very tired, and instinctively, when you feel tired, you lengthen your sleep. And so, a lot of teenagers end up sleeping for between 12 and 20 hours. The problem with lengthening the time that you're asleep is that the quality of your sleep deteriorates, so you feel more tired, and so you lengthen it again, and that reduces the quality.

You also end up with change in your wake up time and changing your wake up time changes the cortisol that's released in the brain. So cortisol is a type of steroid and for those of us without chronic fatigue syndrome, we usually get a cortisol hit in the morning and that helps us feel awake.

If you're constantly changing your wake up time, then we think that that's one of the reasons why it ends up being quite flat in teenagers with chronic fatigue syndrome. So we give quite simple advice about keeping your sleep at night very short and making sure you always wake up at the same time. Teenagers often find that it really makes a big difference to them and what they say is that they wish they'd had that advice very early on because their view is that it prevent them getting as sick as they get.

Kat - It sounds absolutely fascinating with a disease that's extremely complex. So, that's Esther Crawley from the University of Bristol. Thank you.