Managing motor neurone disease

First this week, we were devastated to learn of the passing of rugby legend Rob Burrow, who has just died from motor neurone disease.

But, winding back a bit, nobody had expected Rob Burrow to make it as a professional rugby league player. He stood at 5 '5'' and, more often than not, happened to be the smallest player on the pitch. But he defied his size and used his brilliant rugby brain - and majestic pace - to outthink and outpace his much larger opponents…

Rob Burrow - I went in the room and he told me and I had a bit of a shock and, maybe it's the athlete in us all, we don't want to lie down and just take it. I'm taking it as a challenge. I don't intend to lie down. I want to get stuck into it, a bit like my career.

John - MND stands for motor neurone disease and it describes a condition where the motor nerves, the nerves that connect your brain to the muscles that you move, die off. They die off prematurely. When those motor nerves malfunction or die, the muscles that they connect to become weak and so you can no longer move the muscles that you want to move on a daily basis. That could be muscles of your tongue or the muscles of your arms or legs or hands. All your voluntary muscles can be affected and ultimately it can affect your breathing muscles, which are also under voluntary control.

Chris - Who tends to be affected and at what age?

John - It occurs more commonly in men than women, but it definitely occurs in both sexes. It occurs in all areas of the world. It tends to be more commonly seen in people who are older, and it can also occur in people where there's a family history of the disease. That's the thing we've learned recently quite a lot about.

Chris - Let's build on that then. What do we understand about the mechanism of the disease? What's actually happening to make those nerve cells die off? And how does that then translate into the syndrome we see for the patients?

John - I suppose that's where we still are struggling a bit. We see individuals in whom the disease has already started and we could look at tests and those individuals and know that those motor nerves aren't working very well and some of them have died off. To understand more fully what sets off the process, I think we need to do a lot more work. We know that the nerves that we're talking about are incredibly sensitive to minor changes. If you imagine what a motor nerve does: it's often about a metre in length, it goes from your brain all the way down to the bottom of your spinal cord, and it has to control your muscles over the course of a life of 70, 80, 90 years. It's probably lots of little things that just push it toward becoming damaged that lead to motor immune disease. Age, being a bloke, maybe having some genetic factor, but also environmental factors that we don't fully understand.

Chris - How might a person tell that there's something wrong? What would they notice that this might be coming on?

John - It usually presents with weakness, which often starts asymmetrically: it starts in one part of the body, one side of the body. It might be a weak foot or a weak hand or weak speech. For example, somebody's speech might become slurred and that progressively gets worse over a number of months. In contrast to a stroke, for example, which comes on suddenly and often slightly improves over time. The history, the trajectory of this gradually worsening disease is over months where patients become weak and or wasted with their muscles, without any numbness or tingling. It's very much a muscle disease as opposed to a sensation disease.

Chris - Most of the people who present with this are older people, but there are notable exceptions who are younger people. Stephen Hawking from Cambridge, classically, we know about him very well. He was very young when he developed something that resembled motor neurone disease. And poor old Rob Burrow who's died, he's very young indeed as well. What do we think's going on there? Is this a different disease in these younger people or are they just prone to develop it at a younger age for some reason?

John - I'm sure they are prone to develop it for some reason. I suppose my view over the years is that I've thought of MND not really as a single disease. It's a combination of many different diseases that ultimately end up with those motor nerves dying prematurely. We now can split the disease up into different genetic forms where there's a faulty gene which caused the disease in one family but not another family. Then, there are the additional factors, the environmental factors, and other ones we don't fully understand. People have thought about environmental factors such as toxins in the environment and, particularly with cases in young sporting people, whether or not exercise or head injuries that we get with repeated head trauma for rugby or football may play a role in damaging the motor nerves and just pushing them more toward damage than repair, leading to them dying prematurely.

Chris - So is there a generally accepted association then between people who are taking a lot of severe exercise, pushing their body very hard, and having a higher risk of developing this? Or is it that those sorts of people tend to be notable characters and it makes a huge impact on their career so they tend to get talked about a bit like Lou Gehrig, for example, the famous baseball player.

John - I think the jury's out on that one. I mean, you're absolutely right, those young, relatively famous people who develop the disease are people that we all think about and they get lots of press. Rob Burrow and his colleagues have done huge amounts to raise the profile of MND. I'm uncertain. I think the evidence is still uncertain as to whether or not exercise per se damages motor nerves, or whether the head injuries damage motor nerves, or whether they are just genetically predetermined to get the disease at an earlier stage. We have a lot more work to do. What I wouldn't want to do is to give the impression that exercise is bad for people, because we know that exercise is generally very good, either psychologically good for us or good for our heart, good for our blood pressure. Exercise has many positive sides to it. I think it'd be wrong to blame exercise per se for MND at this stage.

Chris - And when you see people who've already got this in your clinic, what can you do for them? What's the prognosis and how do we aim to support people with this? How long is this going to go on for them?

John - It's the question I'm often asked: what's the prognosis? How long have I got doctor? And actually it's very difficult to know that. The disease is hugely variable. Yes, you can read the literature which says that a certain amount of people will be dead in a certain period of time, but I think in an individual it's quite difficult to extrapolate what's going to happen to that individual. It may be involving their other frailties, how old they are, what other medical problems they have, where the diseases first affected them. For example, if it's affecting their speech, their swallow, their breathing muscles early, then that's clearly something which is more worrying to me as a medic than if it affects an arm or a leg. I suppose we try to individualise our care, so we listen to the individuals that we are seeing, we try to understand where they're coming from, explain the disease in terms that they can understand, and then see how we can help. So if, for example, they have a problem with their speech, well what can we do to maximise their understanding, the clarity of their speech? If it's swallow, can we do something to help improve their swallow? Do they need a gastrostomy tube to help overcome a difficulty with swallowing if they have breathing muscle weakness? We have a clear intervention called non-invasive ventilation which we know both prolongs life and maintains quality of life. We can also start people on medication, so although we have no cure for the disease, we do have a tablet called riluzole, which is licensed, which we know is a benefit. Although it provides a relatively small amount of benefit, we feel that most patients do benefit from this drug with minimal side effects. We can also talk to them about the counselling, the support they need, or what support they and their family need to keep as independent for as long as possible. There's a lot we can do in the clinic, although at the present time we don't yet have a cure, I'm afraid to say.