Swansea University Project
First Edition
Understanding Chronic Pain
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Preface
This booklet has been written by three Swansea University medical students as part of a 201617 final year project in Developing Professional Practice. The authors are: Danielle Monteil Nicholas Newton Mared Thomas The content was reviewed by: Dr James Greville, Lecturer in Psychology, Aberystwyth University Dr Sajida Javaid, Spasticity and Chronic Pain Consultant, Neath Port Talbot Hospital All design and illustrations courtesy of Judit Imre, Graphic Designer, UWTSD, www.juditimredesign.net. Printing costs covered by a grant awarded from St David’s Medical Foundation and a monetary donation from Wesleyan. A Welsh-language version of this document is currently in production. If you would prefer to read this booklet in Welsh, please email danielle.monteil@gmail.com.
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Swansea University Project
Understanding Chronic Pain
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Meet Hywel
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Where does pain come from?
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Chapter 01
An introduction to chronic pain 10 What is chronic pain?
Why do we feel pain?
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Why does chronic pain happen?
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18 Why are my test results normal?
Phantom limb syndrome
Why do I feel different types of pain?
Chapter 2Â
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Investigating and controlling chronic pain
Targeting inflammation 23
Three ways of targeting pain
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Morphine: tolerance, dependence & withdrawal
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Targeting nociception
28 Targeting perception
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38 Hywel’s treatment plan 4
Targeting Pain Summary
Chapter 03
Good news Chronic pain and neuroplasticity
More than medicine
Managing chronic pain: mind, body and mood
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Staying balanced
Body: Do more and feel better
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Mind: Addressing your feelings and understanding your pain
Moving forward
Glossary: New words and how to say them
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Chapter 1: An introduction to chronic pain
Meet Hywel Hywel is an expert patient who lives with chronic pain. Although living with chronic pain can be challenging, Hywel has found that understanding his pain and the treatments for it help him to cope with it better. You might find the same. Let us share his story with you.
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Where does pain come from? Hywel’s pain was in his lower back. Well, sort of... The truth is, although Hywel felt pain in his back, the pain was never really there. The pain Hywel felt in his back was really coming from his brain. This is true of all pain, no matter how it feels and no matter how long you’ve had it. It might seem confusing but understanding a bit about the way pain is produced in your body might help make things clearer. Find out more at the next lightbulb station.
Using this booklet: While you are reading Hywel’s story you may come across the following signs. Here’s a list of what they are and what they mean: This symbol means there’s more information about the science of what happens in chronic pain at the next lightbulb station. These are the purple pages with a pink lightbulb symbol. Look out for them if you would like more information. If you don’t want to know more, don’t worry. You won’t need to read these parts to understand Hywel’s story or to benefit from this booklet. Tip: You may find it useful to read Hywel’s story first and then come back to the lightbulb symbols at the end. Some of the words used in this booklet might be new to you. If you’d like to check what these words mean or how to say them, you can refer to the Glossary of New Words at the back of this booklet. Only words with this symbol next to them are listed in the Glossary.
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The nervous system Together your brain, spinal cord and nerves are called your nervous system. This can be divided into two different parts:
Your Central nervous system This is your brain and spinal cord. Messages that travel from your brain to your peripheral nervous system move down your spinal cord. These might be things you need to think about, for example moving your arms and legs. But there are many other messages that travel from your brain down your spinal cord that you aren’t usually aware of such as your heartbeat and breathing. Other messages that travel down your spinal cord can help to dampen down or increase the amount of sensation messages that come from your peripheral nervous system.
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Your brain controls every part of your body. It is constantly working - sending messages down your spinal cord to your peripheral nervous system and receiving information as well.
Your Peripheral nervous system This is all of the other nerves inside your body.
Messages that travel from nerves in your peripheral nervous system to your brain move up your spinal cord. These messages are usually about sensations and the environment around you.
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Why do we feel pain? When Hywel’s back problems first started he was no stranger to pain. He’d sprained both his ankles and broken many bones playing rugby in the past. Once, he’d even scalded his skin with a kettle full of boiling hot water. He remembered feeling a lot of pain each time he was injured but this pain went away completely once he’d healed. Even though his injuries hurt at the time, Hywel knew pain happened for a good reason - because his body was damaged. It made him rest until his body was healed well enough to work properly again. In this case, his pain was useful. It was a symptom of his problem but not the problem itself. Hywel learned that this sort of pain is called acute pain. Acute pain is pain that has an obvious cause for it, like a broken bone or a burn on your skin. In this case, your damaged tissue releases lots of chemical messengers called neurotransmitters . These neurotransmitters switch on the nerves that detect painful stimuli in your tissues. As your tissue heals it releases fewer neurotransmitters and so the pain eases. Find out more about how pain is produced in your body at the next lightbulb station.
What is chronic pain? Hywel’s back pain was different from anything he’d ever had before. It was there all the time and he was sure it was getting worse. Frustrated, he went to his doctor for help. His doctor examined him and did a lot of tests. He even had a scan of his back. But none of the tests showed that anything was wrong. You can read more about this in Chapter 2: Investigating and treating chronic pain. Eventually Hywel was told that the reason his back hurt was because he had chronic pain. Chronic pain is useless pain. It is not a signal that something is wrong in your body.
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Chapter 1 : An introduction to chronic pain
Chronic pain happens when you keep feeling pain after your injury has healed or when you feel pain even without any injury happening at all. Hywel felt low and hopeless. The pain was now affecting his mood, making it harder for him to do things he used to enjoy doing. He stopped working and going out with his friends. Since the test results were all normal, he was sure his doctor and everyone else thought he was making it all up. He felt angry and depressed.
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Let’s look at the way pain happens (step by step)
STEP 4: If the message first started in nociceptors in your left arm, the part of your brain that receives sensation messages from this arm will be switched on. This is how your brain knows your left arm hurts. You will only feel pain when your brain processes the nociceptive signal.
STEP 2: When your tissues are damaged, they release chemical messengers called neurotransmitters. These switch your nociceptor on, allowing it to carry the message to your spinal cord in the form of an electrical impulse. The painful stimulus has now been converted into a nociceptive signal.
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Chapter 1 : An introduction to chronic pain
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STEP 3: The nociceptive signal is passed on to your spinal cord and sent up to your brain in the form of another electrical impulse. Some messages that travel down your spinal cord can help to dampen down or increase these signals.
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STEP 1:
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Special nerves that detect painful stimuli are called nociceptors. They branch out into your tissues like a tree. Having lots of branches means that a single nociceptor can detect painful stimuli from a large area of tissue.
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Why does chronic pain happen? If nothing was wrong with his back, why did it hurt so much? This was something Hywel asked himself over and over again. He became determined to find out the answer. This was the start of his journey - a journey towards understanding more about chronic pain and his brain. The first thing Hywel learned was that his brain, spinal cord and nerves are always changing. They are constantly being moulded and remodelled according to the messages they receive. This is how your nervous system learns. It’s called neuroplasticity . Being able to ride a bike is a very good example of everyday neuroplasticity. Hywel remembered the first time he tried to ride a bike; he fell off straight away. After a few tries he was getting better but needed to concentrate hard. Eventually, after lots of practice he was able to ride his bike without thinking about it. This happened because he had made all of the nerve pathways he needed very strong by repeating them over and over again in his practice.
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Chapter 1 : An introduction to chronic pain
Learning to ride a bike is an example of helpful neuroplasticity. Chronic pain on the other hand is not. In chronic pain, the pain pathways become so strong that the brain learns to feel pain all or most of the time. This is an unfortunate result of having a nervous system that learns by repetition. Chronic pain happens because of changes to nerve pathways that carry and deal with pain pathways inside your nervous system. These changes may take place in your central nervous system (brain and spinal cord) as well as the nerves in your tissues (peripheral nervous system). When you are injured the nerves inside your damaged tissues are also affected; they may themselves be damaged. This causes them to get switched on very easily and send nociceptive signals to your brain. Nociceptive signals are messages that start in nociceptors and get sent to your brain. Remember, nociceptors are special nerves inside your tissues that detect painful stimuli. Your brain receives these messages and understands them to mean that you are in pain. If your tissues are damaged they release lots of neurotransmitters (chemical messengers) that can also switch your nociceptors on. And, there’s some evidence that feeling anxious or depressed can make your brain more likely to receive nociceptive signals even if you haven’t been injured. This is probably to do with the fact that many neurotransmitters involved in pain also play an important role in anxiety and depression. Neuroplasticity causes nociceptive signals to keep getting sent to your brain if you have chronic pain. Stop to read the next lightbulb station if you’d like to know more about how this happens. Although neuroplasticity builds strong pain pathways into your brain there are ways you can try to reverse this process. We will talk more about these in Chapter 3: Managing chronic pain - mind, body & mood.
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How does neuroplasticity cause chronic pain? The processes that allow your nociceptors to be more easily switched on lead to peripheral sensitisation . It’s called this because nociceptors in your peripheral nervous system have become more sensitive to detecting painful stimuli. Peripheral sensitisation can be useful. It’s the reason why having a hot shower is painful on sunburned skin. But for unknown reasons peripheral sensitisation does not stop if you have chronic pain. It causes you to feel high levels of pain and means that things feel painful when they shouldn’t. Once a nociceptor has been switched on, it can communicate with its neighbours. These may be very close to the damaged tissue but not part of it. This is called cross-talk. It increases the number of nociceptive signals sent to your central nervous system (brain and spinal cord), telling it that a large amount of pain is coming from a large area of your peripheral nervous system. Your central nervous system relies on messages it gets from your peripheral nervous system to tell it what is going on inside your body and in the outside world. It believes everything your peripheral nervous system tells it, even if these messages aren’t true. In chronic pain your central nervous system is constantly receiving nociceptive signals because of peripheral sensitisation and cross-talk. Your spinal cord responds by making it easier for these nociceptive signals to go up to the brain, even if there isn’t a reason for them anymore. This process is called wind-up. Your brain responds to high levels of nociceptive messages in a similar way. It dedicates more of its cells to receiving them and so is constantly telling you that your body is in pain. Like riding a bike, the repeated nociceptive signals make the pain pathways very strong. In effect, your brain becomes trained to feel pain.
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Chapter 1 : An introduction to chronic pain
Phantom limb syndrome When Hywel first learned about neuroplasticity, he didn’t believe it. He was sure his back pain had nothing to do with his nerves or his brain but then he met Abdul in the waiting room of his GP surgery. Abdul was an amputee. He’d lost his left arm in a factory accident and now had Phantom Limb Syndrome. This is a common condition in people who have had one or more of their limbs removed. Even though the limb isn’t attached to their body anymore, they can still feel sensations coming from it. This can be any sensation but pain is very common.
Abdul explained that his pain had also been caused by neuroplasticity. Now that his limb had been amputated all of the nerves
that used to receive sensation messages from it needed to be put to a different use. It was like having a spare shelf in his wardrobe. In the past he used this shelf to store his tennis racket but recently he’d given it away. Rather than leaving the shelf empty whilst keeping the rest of the wardrobe full, he’d rearranged everything so that he could use the space more effectively. In the same way, the area of Abdul’s brain that used to get sensation messages from his left arm was now accepting messages from nerves in other parts of his body. But because his brain was still programmed to think these messages came from his left arm, it told him the sensations were coming from his missing arm. It might seem very strange but neuroscientists have been able to show that this happens by studying the brains of amputees in research centres.
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Why do I feel different types of pain?
Abdul and Hywel became friends. Hywel found it helpful to talk to someone who understood what he was going through. Abdul knew a lot about chronic pain because he’d been living with it for many years. He also knew several other people who had this condition. One of these was Maria. Maria had Complex Regional Pain Syndrome. This caused her to have persistent pain in her lower leg, which started after she’d twisted her ankle whilst running. To look at, her leg was red and swollen. It was also very tender to touch. Maria explained that these were signs of inflammation . Inflammation is normal in recent injuries but should go away when your tissue heals. For reasons that aren’t very well understood, inflammation and pain do not settle if you have Complex Regional Pain Syndrome. They may even spread across the whole affected limb. This is probably to do with abnormal communications that develop between nerves and blood vessels when your damaged tissue is healing. Maria felt different types of pain all the time. Mostly, her leg felt as though it was on fire - a burning kind of pain. But there was also always a background ache that throbbed. This was worse when her leg was very swollen. Maria explained that the different kinds of pain she felt were because of what caused them. For example, the aching, throbbing pain she felt was because of inflammation in her tissues. But her burning pain was due to damaged nerves. This is neuropathic pain . She said she found it difficult to explain how her pain felt to other people because it could be so different. Hywel understood this completely.
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Chapter 1 : An introduction to chronic pain
Hywel thought about his pain after talking to Maria. He remembered that if he bent forward he could feel an intense shooting pain that seemed to move down his leg. This made it difficult for him to pinpoint the pain and work out where exactly it came from. Other times it was hot and burning, almost like a red-hot poker inside him. This was his neuropathic pain. It happened because of irritation and damage to the nerves in his lower back. The dull ache he felt the rest of the time was likely due to inflammation in the tissues around that area. However, because neuroplasticity caused his nerves to become sensitised to detecting painful stimuli, a very low level of inflammation in his back could cause his brain to tell him he was in quite a lot of pain.
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Chapter 2:
Investigating and controlling chronic pain Why are my test results normal? Blood tests When Hywel’s pain didn’t go away, his doctor sent him for some blood tests. This was to look for signs of inflammation that might be causing his pain. The blood tests doctors use to measure inflammation in your blood are called CRP and ESR. These might go up if you have inflammation in your body but they don’t say where the inflammation is coming from. Hywel’s doctor explained that these tests can be very useful in helping to diagnose some diseases but they are often completely normal if you have chronic pain.
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Hywel’s blood tests were normal. This is because his pain was not caused by high levels of inflammation in his lower back or anywhere else in his body. It was caused by the abnormal passage of electrical impulses along nerves to his brain. This cannot be measured using blood tests.
Scans Hywel’s doctor thought it would be a good idea to send him for a scan of his back, just to make sure they weren’t missing anything. Hywel had a CT scan but the type of scan a person has depends on different factors including what your doctor thinks the problem might be. CT stands for Computed Tomography. A CT scan uses X-rays to create an image of the structures within the part of your body that it looks at. It’s very quick to do but involves a high dose of radiation so doctors have to weigh up the advantages of having a scan against the risks of radiation exposure.
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There are other types of scans, which do not use radiation such as MRI. This stands for Magnetic Resonance Imaging. It uses magnets and not X-rays to map out structures within your body. It is safer and sometimes gives more detail than CT but it can take several hours and you will need to stay very still for the whole time to get the best quality image. Many people do not like having an MRI because there is not very much space inside the MRI machine. This makes them feel claustrophobic. On the day of his CT scan Hywel got to the hospital early. The scan itself was very quick, but it had to be read by a radiologist before the results were ready. A radiologist is a doctor who is trained to look at and interpret scans. The radiologist would write a report of his findings and send this letter to Hywel’s doctor. The following month Hywel returned to his doctor to get his results. His pain had been getting worse and he was certain the CT report would have an explanation. So when his doctor explained that his CT scan did not show any physical problems, Hywel felt disappointed and frustrated again. His doctor explained that this is common in chronic pain because scans can’t give any information about the way nerves communicate inside your body.
Three ways to control pain Hywel’s doctor wanted to help him get his pain under control as best as possible. She explained that there are three main ways to treat pain with medical therapy.
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Targeting inflammation Targeting nociception Targeting perception
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Targeting inflammation Inflammation in your tissues switches nociceptors on. Remember, nociceptors are special nerves that detect painful stimuli in your tissues. They send nociceptive signals up your spinal cord to your brain. Your brain understands these signals as pain. Medicines that block inflammation can help stop the nociceptive signal from starting in the first place. These are anti-inflammatory medicines, like aspirin and ibuprofen. Aspirin has been used for hundreds of years to help treat pain and fevers. It stops chemicals that cause inflammation from being released. Other medicines called non-steroidal antiinflammatory drugs (NSAIDs) like ibuprofen and naproxen also treat pain in this way. Aspirin and NSAIDs can irritate the lining of your stomach and cause ulcers. If you need to take these medicines regularly your doctor may prescribe other medicines, which reduce the amount of acid in your stomach. This helps to reduce your risk of developing an ulcer.
Targeting nociception There are many different ways of reducing the number of nociceptive signals that get to your brain but not all of these methods are suitable for everyone. Some methods may work better for your pain than others. Talk to your pain doctor about which treatments might be right for you.
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Oral Medicines Some medicines work directly on your nociceptors. These are gabapentin and pregabalin, which were first used to prevent seizures in patients with epilepsy. These medicines are very useful for treating neuropathic pain. Remember, this is pain that’s caused by damage to the nerve itself. Like a key fitting into a lock, gabapentin and pregabalin fit into specific locks on the surface of your nociceptors, switching them off. Damaged nociceptors have more locks on their surface because of peripheral sensitisation. This is the process by which your peripheral nervous system is made very sensitive to receiving nociceptive signals. It means that gabapentin and pregabalin are more active against damaged nociceptors than normal ones because of the greater number of locks on their surface. Read more about peripheral sensitisation and chronic pain in Chapter 1: An introduction to chronic pain.
Injected Medicines Your pain doctor may suggest injecting an anaesthetic into the area of your body that is causing your pain. This can be done in different places, for example directly around the problem nerve or into the area around your spinal cord. Anaesthetic medicines work by stopping the electrical impulse from traveling along your nerves. Again, like keys fitting into specific locks these medicines fit into tiny openings along the surface of your nociceptor. If these openings are blocked by an anaesthetic medicine, the electrical signal cannot pass through as easily so fewer nociceptive signals get through.
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Two anaesthetic medications that are commonly used to treat pain are called lidocaine and bupivicaine. These are the same medicines you might be given to numb your mouth before having dental work done at the dentist.
Electrical Therapy Some treatments use electricity to help control chronic pain. These work by sending electrical impulses to your brain. The main electrical treatments available for chronic pain are called Transcutaneous Electrical Nerve Stimulation (TENS) and Spinal Cord Stimulation (SCS). In TENS, the electrical current is delivered through pads that are stuck to your skin. There is not yet a lot evidence to say how well these machines work and what sort of pain they work best for but you may want to try it because it is safe and inexpensive. The main drawback is that TENS only works when you are using it. On the other hand SCS uses electrodes that are implanted into your body. It may be useful if you have complex regional pain syndrome or if your pain comes from a particular nerve. But SCS is not suitable for treating all every typw of pain. If you would like to try electrical therapy for pain, talk to your pain doctor about which options might be right for you. Read more about how it works at the next lightbulb station.
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Rub it better
Gate control theory and electrical treatments for pain If you were to accidentally bang your thumb with a hammer the first thing you might do is grab it tightly and rub it better. This works because of the gate control theory of pain. Rubbing your thumb switches on nerves that carry information about pressure, not nociception to your brain. Since only so many signals can move up your spinal cord to your brain at a time, sending lots of non-nociceptive signals stops some of the nociceptive ones from getting through. In this way your spinal cord is overwhelmed by the new signals and reduces the number of nociceptive signals it carries to your brain. Gate control theory explains why rubbing an injury makes it feel better. The nerves that carry sensation information to your brain control a cell in your spinal cord in the middle of this pathway. Think of this cell as a pain gate. Normally, the gate is shut but when a nociceptive signal arrives it opens the gate and your brain understands this signal as pain. Importantly, the gate can be shut if other sensation signals are sent up your spinal cord. But this only works as long as that signal is being produced. Gate control theory means that rubbing your thumb when you hit it with a hammer only works for as long as you rub it. It also explains why TENS only relieves pain while you’re using it. Gate control theory is why some people find TENS machines, massage and heat packs helpful when they are in pain. It’s also the reason why rubbing a nettle sting with a dock leaf can make it sting less.
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Brain
Rubbing signal stops nociceptive pain signals
Gate is closed as other sensation signals are sent up to the brain Pain gate
rubbing signal pain
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Targeting perception There are several medicines that help to reduce the amount of pain you feel by working directly on your spinal cord and brain.
Paracetamol
Paracetamol is a very safe and effective medicine for pain when taken at the right dose. It does not irritate the lining of your stomach the way NSAIDs and aspirin do. It might surprise you to learn that the way paracetamol relieves pain is still not completely understood. It seems to act on your brain to prevent it telling you that you’re in pain but it can also reduce inflammation in your tissues. Because paracetamol works on your brain, it reduces the dose you need to take of other medicines that also work in this way. Paracetamol works best for chronic pain when it is taken regularly but taking more than the recommended amount can damage your liver, which is very dangerous. Paracetamol may be included in pain medicines that you have bought without a prescription so it’s important to check what’s in any other medicines you’re taking. This is to make sure you don’t have too much paracetamol by mistake.
Anti-neuropathic pain medicines There are some medicines that reduce your brain’s ability to understand the nociceptive signals sent to it from damaged nociceptors. These include medicines called amitriptyline and duloxetine. They are particularly good at treating neuropathic pain. Remember, this is pain that’s caused by damage to your nerves themselves. Anti-neuropathic pain medicines work by increasing the levels of noradrenaline and serotonin in your spinal cord. These are neurotransmitters that help to dampen down the activity of your nociceptors and reduce the number of nociceptive signals that get to your brain. Noradrenaline and serotonin are the same brain chemicals that are low in depression. It was found out by accident that some medicines used to treat
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Chapter 2: Investigating and controlling chronic pain
depression can also help to relieve neuropathic pain . But the dose for treating pain is often much lower than the dose needed to treat depression so being prescribed these medicines does not mean that your doctor is treating you for depression.
Morphine and similar medicines Morphine is a very strong painkiller. It belongs to a group of medicines called opioids . These medicines are excellent at treating acute pain but they have lots of side effects, which we will talk about later. They work like keys fitting into specific chemical receptors (which can be thought of as locks) on the nerves that carry nociceptive signals. The same locks can also be found throughout the rest of the body so the effects of opioids are not specific to treating pain. Read more about opioids at the next lightbulb station.
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More about opioids How opioids work Opioids have a similar structure to enkephalins . Enkephalins are brain chemicals (neurotransmitters) that have positive effects on your mood. They are produced naturally by your central nervous system and are your brain’s way of relieving pain and making you feel better without medicine. Enkephalins belong to a special group of neurotransmitters called endorphins . These will be discussed more in Chapter 3: Managing chronic pain: mind, body and mood. Because opioids have a similar chemical structure to enkephalins, they are like two different keys that can both open the same lock. There are many of these locks throughout your nervous system and the rest of your body. All nociceptors have these particular locks on their surfaces. When an opioid key fits into one of these locks it causes a series of chemical changes to happen. This switches your nociceptor off and makes it less likely to start sending a nociceptive signal to your brain. The location of these locks and how easily a medicine gets to them determines its side effects.
NATURAL ENDORPHIN
NERVE CELL
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Chapter 2: Investigating and controlling chronic pain
OPIOID
Side effects Even though opioids are very good at reducing pain they cause many side effects because there are enkephalin locks throughout your whole body. For example, morphine may cause you to feel intensely happy when it fits into enkephalin locks in a part of your brain called the ventral tegmental area. But because it can also fit into locks in a part of your nervous system called the area postrema it can make you feel or be sick. Other common side effects of morphine include changes to the way your gut works and changes to your breathing. For example, morphine fits into enkephalin locks in your gut, slowing it down and causing constipation. Because it also fits into enkephalin locks in your lungs it can stop you from coughing and slow down your breathing, which is potentially dangerous. Long-term use of opioids can cause many other unpleasant side effects. Some men might develop breasts if they take these medicines for a long time. It can also weaken your immune system and confusingly, high levels of opioids can actually increase the amount of pain you feel. Talk to your doctor if you have any concerns or if you notice any of these changes. Some opioids are not as strong as morphine and do not have as many side effects, for example codeine. Codeine can be used alongside other medicines such as paracetamol to reduce the amount of opioid that you need. A mixture of codeine and paracetamol is called co-codamol. Like some anti-neuropathic pain medicines, some opioids also increase levels of serotonin in your spinal cord. This helps to dampen down the number of nociceptive signals that get to your brain. Medicines like tramadol and tapentadol (Palexia) work in this way.
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Morphine: tolerance, dependence & withdrawal One day Maria rang Hywel with concerns about her pain treatment. She explained that her doctor wanted to stop prescribing morphine to treat her pain. He was planning to lower the dose gradually over several months. But Maria felt that she needed a high dose of morphine to control her pain. She didn’t know what to do. Since Maria had been taking morphine for such a long time, she had built up tolerance towards it. Tolerance means that each time you take a medicine it has less effect. Read more about what causes tolerance at the next lightbulb station. Maria was on a very high dose of morphine to relieve her pain. Her doctor was concerned because this increased her risk of developing serious side effects, like suppressing her immune system or even increasing the amount of pain she felt. He also believed that Maria had become dependent on morphine and that she didn’t need as much of it as she said she did for her pain. Dependence means that you feel you have no choice but to take a drug. It might be physical or psychological. Read more about dependence at the next lightbulb station.
If you have become dependent on your medicine in any way, talk to your doctor or nurse. There are lots of ways they can help.
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What causes tolerance? Opioids are like keys that fit into specific locks on the surface of nociceptors. This causes a series of chemical changes to happen, blocking nociceptive signals and reducing pain. Tolerance happens when you take an opioid regularly for a long time. The number of locks on the nociceptor surface decreases, and the remaining locks may become blocked by other chemicals. These changes make it difficult for opioids to find the locks they need to fit in to work. Ultimately, you will need more and more opioids to get the same effect. Although opioids are very good at relieving pain in the short-term, the need for higher doses increases the risk of serious side effects. This makes them problematic for dealing with pain in the long term.
Psychological and physical dependence There are two main types of dependence – psychological and physical. Psychological dependence can be thought of as cravings. Cravings happen because the medicine has pleasant effects so you want to repeat the experience of taking it. They can be triggered by anything that you associate with the medicine, including sights and smells. Some people use painkillers to treat emotional pain as well as the physical pain they feel. Because of this they crave the medicine when they feel low but this is dangerous and is only effective in the short-term. There are other more effective ways of addressing any emotional pain you feel. Read about these in Chapter 3: Managing chronic pain: mind body and mood. Physical dependence is to do with the physical effects you might experience if you stop taking a medicine. It tends to last a shorter time than psychological dependence. These physical effects are often called withdrawal symptoms and can happen when you stop taking many medicines, including opioids and sleeping tablets.
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Even though Maria disagreed, her doctor was right. She had become dependent on morphine. If she tried to stop taking it she would feel very unwell. Her heart would race and she’d become very sweaty and anxious. These were withdrawal symptoms. They happened because Maria had become physically dependent on morphine. Hywel was relieved that Maria’s doctor had noticed these changes in her and decided to address them. To find out more about withdrawal and what causes it, read the lightbulb station. Maria’s pain improved soon after her doctor reduced her next dose of morphine. This came as an unexpected but pleasant surprise as she’d been worrying about it for weeks. Her doctor explained that her pain improved because she’d developed a strange side effect of morphine called opioidinduced hyperalgesia. This is when increasing the dose of morphine you’re having actually increases the amount of pain you feel. Reducing the dose seems to make the pain better. It isn’t clear why exactly this happens but you’re most at risk if you are taking a high dose of an opioid for a long time. Opioid-induced hyperalgesia makes it difficult for doctors to decide whether or not your pain is getting worse because you’re having this side effect or if it’s because you’ve become tolerant to your painkiller. The way to tell is by reducing the dose of morphine you’re having. If your pain gets worse then you have become tolerant to your morphine and you need a high dose to get any pain relief. But if your pain improves when you are having a lower dose of morphine, you have probably developed opioid-induced hyperalgesia. There are other symptoms of opioid-induced hyperalgesia like seizures, agitation, pain that moves around or jerking of your arms and legs. But these are not very specific and may happen for lots of other reasons. Talk to your doctor if you have any questions about this or if you would like to know more about the side effects of morphine.
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Chapter 2: Investigating and controlling chronic pain
What is withdrawal and what causes it? If you continue to have a medicine like morphine regularly and often, your nociceptors and other nerves eventually become less sensitive to its effects. One reason for this is that they start to produce high levels of a specific neurotransmitter called noradrenaline to make up for the effects of the morphine. You may have heard of noradrenaline as the “fight or flight” brain chemical. This is because it’s the neurotransmitter your body releases when you’re scared, angry or stressed. If you stop taking morphine, at first your nociceptors (and other nerves) will still be over-producing noradrenaline. High levels of noradrenaline without the dampening down effect of morphine leads to withdrawal symptoms like sweating, a racing heart, anxiety and muscle cramps.
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Targeting pain - summary
Targeting perception • Paracetamol • Anti-neuropathic pain medicines • Opiates
1 : An and introduction to chronic pain Investigating controlling 36 Chapter 2: Chapter
Targeting nociception • Anti-seizure medicines • Local anaesthetic • Electrical therapy
Targeting inflammation • • • •
Aspirin Ibruprofen Naproxen Paracetamol
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Hywel’s treatment plan Hywel was surprised to learn how many ways of treating pain there are. But when he left his first pain appointment having only been prescribed regular paracetamol and ibuprofen, he felt angry and disappointed. He could easily have gone to the pharmacy and bought these medicines himself without visiting a doctor at all. What a waste of time, he thought. When Hywel returned to his doctor the following month, he explained his frustrations. His doctor explained the importance of using the safest medicines first and then building up to stronger painkillers if needed. This is because the strongest painkillers doctors can prescribe are opioids, which have lots of side effects. She explained that even though she was completely committed to treating Hywel’s pain, she wanted to make sure she treated him safely and appropriately. This is also why she’d given him medicine to protect his stomach against the harmful effects of ibuprofen. Hywel felt reassured and agreed that they should work together to manage his pain from that point onwards. Hywel’s back pain was relieved a little by daily paracetamol and ibuprofen but the burning pain down his leg continued. His doctor decided to prescribe amitriptyline because these symptoms were probably caused by damage to his nerves. Although amitriptyline is used to treat depression, it is very good at treating pain caused by damaged nerves. Together the regular paracetamol, ibuprofen and amitriptyline helped Hywel’s pain a lot but he still struggled with his pain when doing household chores. His doctor suggested switching his daily paracetamol to co-codamol. This is a mixture of codeine and paracetamol. But Hywel didn’t want to do this. He had been given codeine in the past for a broken bone and it made him feel very nauseous and constipated. He also worried that he would become addicted to painkillers because of what he’d seen with Maria. His doctor understood completely. She said that it was important to always tailor pain treatment to individual circumstances. She explained that there are many other treatments other than opioids. These include things like electrical therapy and anaesthetic injections around the nerves that were causing him pain.
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Chapter 2: Investigating and controlling chronic pain
Hywel decided to try electrical therapy first. He found that TENS was very effective at treating his pain but it only worked when he was using it, which he found impractical. His doctor also suggested trying an anaesthetic injection into the nerves around his lower back. This helped him at first but became less effective over time. Becoming increasingly fed up, Hywel decided to look into other ways he could reduce his pain. His doctor mentioned that there were many things he could change in his lifestyle that might help. You can read more about this in Chapter 3: Managing chronic pain: mind, body and mood.
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Chapter 3:
Managing chronic pain: mind, body and mood
Good news In this section we will discuss things that you can do to help yourself. Your pain, like Hywel’s, probably affects most areas of your life. The good news is that the more areas of your life pain affects, the more ways there are for you to combat it.
It’s important to remember that treating chronic pain in one way is unlikely to be as effective as approaching it from multiple angles.
40 Chapter 3: Managing chronic pain: mind, body and mood.
Chronic pain and neuroplasticity Imagine you’ve gone for a walk and you want to cross an overgrown field to get to a pond. You decide to go straight down the middle and tread a path through all the weeds. If you don’t go back to the pond after that first time the weeds will grow back and the field will look the same as it always did. But if you take that same walk every day, gradually you’ll make a more permanent path. If other people start using your path, it gets wider and less likely to go back to how it used to be. Soon enough everyone else is walking up and down your path to cross the field. Forming a well-established path is the same as what’s happened to pain pathways in your body. Because your pain pathways have been used so much they have gradually become very clear, well-established routes. Remember, this happens because of neuroplasticity - the ability of your nervous system to be moulded and re-modelled, like plastic. This happens over time. At the beginning, you might not have even really noticed the changes but as the pain pathways grew stronger your pain may have become more and more of a problem. Chronic pain pathways are the bad side of neuroplasticity. But logically, if your brain can create new, unhelpful paths it’s also able to create new helpful paths as well. Whilst it’s true that your brain can change, it’s also a creature of habit so changing it might not be easy. It may have taken several years to build and strengthen all of the pathways causing your pain so reversing this won’t happen overnight. Imagine trying to stop all of those people using your path several years later. It would be very difficult.
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More than medicine Taking medicine for chronic pain is like building a fence right at the beginning of that pathway you made in the overgrown field. It might stop some people from using the path but others will jump over the fence and keep using it. Even though the fence is useful, it doesn’t get rid of this path completely. In the same way, pain medicines treat some of your symptoms but not your disease. Medical therapy may still be an important part of your treatment if it reduces your symptoms enough for you to focus on activities that build new, more helpful nerve pathways. Let’s talk about ways you can do this by focusing on your mind, body and mood.
MIND
IDEAL PAIN MANAGEMENT MOOD
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BODY
Body: Do more and feel better
When Hywel’s doctor first told him that exercise would help his pain he almost walked out of the consultation room. How on earth was he supposed to exercise when getting out of bed in the morning was painful? And if moving around just a little hurt as much as it did, then how could moving around more make him better? It seemed like a ridiculous suggestion. Really, his doctor should have been clearer. She should have said that she wanted him to increase his activity levels gently, not run a marathon. You see - before he developed chronic pain Hywel was very fit and active. He used to be able to play an entire rugby match without any problems. So when his doctor said “exercise”, he naturally assumed that this was what she meant. Because Hywel was nowhere near as fit as he used to be, climbing a flight of stairs now made his heart rate go up as though he’d just run the length of two rugby pitches. He needed to accept that the amount of activity his body now considered to be exercise had changed quite a lot. Hywel’s doctor referred him for physiotherapy because she wanted him to make his body stronger. She explained that if he didn’t use his muscles, they would weaken and reduce in size. This could reinforce unhelpful nerve pathways and make his pain worse. By keeping his body active he also could start rebuilding normal and non-painful pathways in his nervous system and also release endorphins. Those are the “feel-good” brain chemicals (neurotransmitters) that we talked about in Chapter 2: Investigating and treating chronic pain. Endorphins make us happy, feel more energetic and even act as totally natural painkillers. Unlike opioids, you cannot get addicted to endorphins because your body has a quick and effective way of regulating the levels. Meditation and controlled-breathing exercises such as Yoga, Pilates and Tai-Chi encourage your nervous system to release endorphins. Other relaxation activities such as acupuncture and massage also do this.
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Hywel was ready to increase his activity levels but his doctor warned him to take things slowly. She explained that many patients with chronic pain find that they have a few days when they can cope with their pain followed by a few days when it’s unbearable. On the good days they often do too much and then have extreme pain afterwards because they’ve overdone it. The message here is that in order to make chronic pain better it’s important to increase your activity levels gradually. The best way to manage this is by doing exactly the same amount of activity every day. This might mean forcing yourself to stay active on the bad days and stop yourself from doing too much on the good days. It is a slow process but gradually you will build up your strength. There are other things you can do to try to keep your body strong. These include eating well, staying a healthy weight and stopping smoking if you smoke. If you’d like advice about this ask your doctor who will be happy to help.
Staying balanced Hywel was very good at doing the exercises his physiotherapist suggested but he was still neglecting a lot of everyday activities he used to do before he had pain, like household chores and going out to see his friends. Sitting at home all day not doing anything in particular gave him lots of time to think about his pain, reinforcing the negative pain pathways. His pain got worse and he started to feel even lower. Hywel’s doctor was not surprised to hear his pain got worse when he told her what he’d been up to. She said that a balanced lifestyle was a really important part of managing chronic pain and that she wanted him to keep doing as many everyday activities as he could. This would help to make him feel normal and help take his mind off the pain. She was especially concerned that the activities Hywel had stopped doing were the things he used to enjoy, like going to the cinema with his friends, as well as things that made him feel useful, like going to work. She wanted him to continue doing these things as well as the exercises his physiotherapist suggested.
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Chapter 3: Managing chronic pain: mind, body and mood.
Ignoring these areas of his life would be more harmful for him in the long run. You might find it helpful to make a list of things you’ve stopped doing since your pain started and think about how good these things made you feel. And when you’re ready, start introducing them back into your life. You might have to adapt the things you did slightly or do them for a shorter time at first. However, reintroducing these activities gradually and doing a little every day can help you rebuild positive non-painful nerve pathways. If you need more advice about how much physical activity you should do, talk to your pain doctor or physiotherapist.
FRIENDS PHYSIOTHERAPY FEELING LOW
CINEMA WORK EXERCISE
Mind: Addressing your feelings and understanding your pain Your pain is unique to you. No one else will ever know what it feels like for you or what it’s like to live with. Because of this, you are the best person to make it better. But to improve your pain you need to understand it, accept it and find out what makes it better or worse. Educating yourself about your pain and building ways of coping with it physically and psychologically are the most important ways you can improve your outlook.
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Your brain has changed with your pain and so have you. In fact, if you think about it you’ll realise that quite a few things in your life have changed since you started having chronic pain. For one, you probably used to sleep better. Maybe you did more with your day and weren’t as stressed out. Perhaps you went out more and had better relationships with your friends and family. Maybe you felt happier. When Hywel first started having pain, his sleep got worse and worse. He found it difficult to get comfortable in bed at night because of the pain. Sometimes it would wake him up. He was tired all the time. His pain and tiredness made it difficult for him to do as much as he used to. Sometimes he couldn’t even do his own washing or manage to have a bath. He stopped going out with friends. It seemed like he never had fun anymore. He felt low and his pain got worse and worse. This might sound familiar to you. In this situation you can see that Hywel’s mood and motivations changed as his pain pathways became stronger. This is very common in people who have chronic pain but it’s a vicious spiral downwards. It happens because mood, sleep and stress all play a huge role in the amount of pain you feel. In particular, feeling low, stressed and tired can make your pain worse. This is because depression and chronic pain share similar neurotransmitters. They also share similar nerve pathways in your brain and spinal cord. Negative thoughts and feelings can lower your threshold for pain and make you feel pain even when you shouldn’t. Treating your mood is therefore really important if you want to build new, helpful pathways in your nervous system. There are lots of ways to help improve your mood if you have chronic pain. Read about these next.
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Chapter 3: Managing chronic pain: mind, body and mood.
STRESS - LOW
MOOD - PAIN
TIREDNESS - FR
USTRATION
BECOMING WIT
HDRAWN
POOR SLE
EP - MORE
PAIN
Cognitive-behavioural therapy (CBT) You might find it useful to attend cognitive behavioural therapy (CBT) sessions. This is a talking therapy that can help you manage your problems better by changing the way you think and behave. It is based on the theory that your thoughts, feelings, physical sensations and actions are all interconnected. CBT doesn’t get rid of your problems but it can teach you to deal with them in a healthier way. In this way, improving your mood and mental health can help you to build healthier nerve pathways in your body. CBT is available on the NHS but you may have to wait a while to be seen. Talk to your doctor if you would like to know more.
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Mindfulness-based stress reduction (MBSR) Mindfulness is a form of mind-body therapy. It teaches you to live in the present, paying particular attention to your body and the world around you at any given moment. Mindfulness uses special breathing exercises, yoga and meditation to help you do this. These activities encourage your brain and spinal cord to release endorphins. Remember, these are the “feel-good” brain chemicals that help to relieve pain and lift your mood. New research shows that practiing mindfulness for a long time can affect how your brain works and even change its physical structure. Mindfulness will soon be available on the NHS although there are courses you can attend sooner if you are willing to pay a fee. Find out more at: www.bemindful.co.uk
Counselling Feelings like stress, anxiety and depression can make pain worse. These feelings may have caused your pain or may have been caused by your pain but the order is not so important if you have chronic pain. What’s important is that you address these feelings head on so that you can start rebuilding healthier non-painful nerve pathways. Counselling can often involve talking to a trained counsellor about your life with special attention to areas that are emotionally painful and which cause you to have negative feelings. Counselling aims to help you understand your thoughts and feelings better and help you find solutions to your problems. There are many different types of counselling available on the NHS. Talk to your doctor if you think counselling might be useful to you.
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Reading treatment The NHS offers specific books on prescription to help you cope with a range of feelings, including anxiety, depression and stress. Reading can give you ideas about how to deal with your feelings as well as practical matters such as getting better sleep or dealing with relationship problems. You might find them helpful on their own or while you are waiting for another treatment. You can access these books electronically or by borrowing them from your local library. Ask your doctor if you would like to know more.
Anti-depressant medicines Many people say that anti-depressant medicines help improve their mood when they are feeling low. They work by increasing the levels of serotonin and noradrenaline in your brain and spinal cord. These are brain chemicals that are thought to be low in people who have depression. Because some anti-depressants are used to treat neuropathic pain, you may already be on a low dose of one of these medicines for pain. But remember the dose needed to treat pain is much lower than the dose you would be on for depression. Talk to your doctor if you have any questions about taking antidepressants.
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Moving Forward Hywel still has chronic pain but he’s coping with it better these days. Each day is a new day and he takes his pain day by day. Some days it’s better and some days it’s worse. But overall, it’s gradually getting better. Hywel continues to take his pain medicine daily. He also uses his TENS machine more days than not. Even though these treatments don’t make his pain stop completely, he understands his pain now and knows that he needs some medical therapy to ease his symptoms. This allows him to focus on other aspects of his life and not only his pain. He stays healthy by eating well and staying as active as he can. He’s even stopped smoking, which was very hard but he’s proud of this achievement. And although Hywel doesn’t play rugby anymore, he’s found that doing gentle yoga exercises and walking his dog every day are just the right amount of activity for him at the moment. Hywel still meets with Abdul and Maria regularly. He also goes to the cinema with friends at least once a month. This was his counsellor’s suggestion and he’s glad he took this advice. Social activities have been really important for keeping his spirits up and helping him stay positive. He also does regular breathing exercises and has recently started practising mindfulness. This helps to quieten his mind and helps him manage his emotions and pain better. Hywel feels positive about the future, even though he knows there is a possibility he may always live with some pain. He hopes that by sharing his journey with you, he has answered some questions you may have had about your pain and inspired you to build new, helpful pathways in your nervous system. If you need any further information or support, talk to your pain doctor about ways you can change your lifestyle to improve your pain. Good luck and all the best from Hywel, Abdul and Maria.
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Glossary: New words and how to say them Many of the words used in this booklet might be completely new to you so we’ve included this section to help you understand what they mean and how to say them. A Anaesthetic [an-es -thet-ik] This is a medicine that blocks all sensations, including pain. C Claustrophobic [clos-tro-fo-bik] This means feeing afraid of small spaces. E Endorphin [en-door-fin] This is a special type of “feel good� brain chemical that is produced naturally in our bodies. Endorphins can act as natural painkillers. They are a type of enkephalin. Enkephalin [en-kef-ah-lin] This is a specific type of brain chemical that is produced naturally in our bodies. Enkephalins have positive effects on mood. I Inflammation [in-fla-may-shun] This is the release of chemical messengers in damaged tissues that causes pain, swelling, redness and heat in the affected area. N Neurotransmitter [new-ro-trans-mit-ter] This is a brain chemical that allows nerves to send messages and communicate with each other. Because of this neurotransmitters are often called chemical messengers. Endorphins and enkephalins are all types of neurotransmitters.
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Chapter 3: Managing chronic pain: mind, body and mood.
Neuropathic [new-ro-path-ik] This means diseased nerve. Neuropathic pain is pain that comes from a damaged nerve. Neuroplasticity [new-ro-plas-tis-it-ee] This is the ability of the nervous system to rearrange itself according to the messages it receives. It’s how the nervous system learns. Nociceptor [no-see-sep-tor] This is a nerve in the peripheral nervous system that detects painful stimuli. Noradrenaline [nor-ah-dren-ah-lin] A type of neurotransmitter (brain chemical) that is low in depression. It is also known as the “fight or flight� chemical. O Opioid [o-pee-oid] This is a type of medicine that has a similar structure to enkephalins and so can mimic enkephalin effects in the body. Although they are very good at relieving pain, opioid medicines have lots of side effects. P Peripheral Sensitisation [pur-if-ah-rul ; sen-si-tie-zay-shun] This is when the nerves in your tissues (peripheral nervous system) detect painful stimuli too easily. S Serotonin [seh-ro-toe-nin] A type of neurotransmitter (brain chemical) that is low in depression.
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Understanding Chronic Pain - Summary
Chapter 1 It may seem strange but having chronic pain does not mean that your body is damaged. Chronic pain comes from your brain. It is caused by changes in the nerves that communicate about pain inside your body. Because of this, chronic pain is not easy for other people to see and it cannot be diagnosed with blood tests or scans.
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Chapter 2 Doctors treat pain by targeting the entire pain pathway. They may aim to treat your pain in three different ways: reducing inflammation in your tissues, stopping the nerve signals that tell your brain about pain and lastly, by changing your brain’s perception of these signals. To do this your healthcare team will use a mixture of medicines and therapies. If you have any concerns about your treatment, talk to your doctor or nurse specialist about them.
Chapter 3 Good news! The more parts of your life that pain affects, the more ways there are for you to treat it. Importantly, having a healthy body and mind are just as useful for improving your pain as medicine. Simple ways you can do this include gentle breathing exercises and meditation as well as keeping to a healthy weight and stopping smoking if you smoke.
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More Information & Support Living life well www.wales.nhs.uk/sitesplus/863/page/47545 The Living Life Well Programme offers a range of services and courses to help reduce stress and improve your mental wellbeing. ACTivate your life www.swansea.gov.uk/article/22453/ACTivate-your-life A four-week taught course based on Acceptance and Commitment Therapy. Available in Swansea. NHS Live Well - Living With Pain www.nhs.uk/Livewell/Pain/Pages/Painhome.aspx Self-help tips, where to find help and a pain forum Pain Concern www.painconcern.org.uk Helpline: 0300 123 0789 This website features podcasts, a forum and a helpline all devoted to helping you understand and manage your chronic pain. The Pain Toolkit www.paintoolkit.org A collection of pain management tools and strategies developed by someone living with chronic pain.
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Action on Pain www.action-on-pain.co.uk Helpline: 0345 603 1593 A registered charity run by volunteers who are affected by chronic pain. Pain Association Scotland www.painassociation.com A charity that offers advice on self-management and a tool to track your progress. Scottish Intercollegiate Guidelines Network (SIGN) www.sign.ac.uk Tel: 0131 623 4720 SIGN has produced a booklet for patients and carers called “Managing chronic pain�. You can find this on their website or contact them by telephone to get a print copy. British Pain Society www.britishpainsociety.org The British Pain Society has produced information for patients and healthcare professionals about chronic pain. Partners Against Pain www.partnersagainstpain.com A website for people with pain and their partners.
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Thank you for reading this booklet. We hope you have found the information in it useful. If you would like to help us with our research, please complete the feedback form that came with your booklet and post it back to the chronic pain team in the self-addressed envelope we gave you. Please note that you will need to add a stamp to the envelope yourself. If you’d prefer to give us your feedback online instead, please visit the website written at the top of the feedback form. We will use your feedback to help us write our report and improve this resource for patients like you in the future. Thank you for your time - we really appreciate it. Nick, Maz and Dani Swansea Medical Students 2013-17
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