Chronic pain

What is the problem?

Chronic pain is not a simple physical problem. Apart from poor general physical health and disability, depression, unemployment and family stress may be present. Many of these factors interact and the whole picture needs to be be considered. The impact of chronic pain on patients' lives varies from minor restrictions to complete loss of independence.

How we feel pain is a complicated process. Intensity of pain does not always appear to fit in with the degree of injury or physical problem. It is affected by a number of factors and mechanisms, and there may be an overlap in the recognised categories of pain type. Pain medicines (analgesics) can be effective for pain relief, but they fail in the majority of patients. The focus should be on improving quality of life, and non-pharmacological options. Excessive prescribing of medicines has the potential to do more harm than good.

How common is chronic pain?

In the UK we have no accurate figures for how many people have chronic pain. It seems to be common though, affecting perhaps one in two or one in three of the population. It is not known what proportion of people with chronic pain either need or want treatment.

Chronic primary pain is thought to affect between 1 in 100 and 6 in 100 people in England.

What is chronic primary pain?

Chronic widespread pain of the condition called fibromyalgia, complex regional pain syndrome, chronic primary headache and orofacial pain, chronic primary visceral pain and chronic primary musculoskeletal pain are all examples of chronic primary pain. Sometimes what doctors call these conditions may change over time. This can be confusing but usually happens because of advances in our understanding of these diseases and how they affect people.

The mechanisms underlying chronic primary pain are only partially understood and the definitions are fairly new. All forms of pain can cause distress and disability, but these features are particularly prominent in chronic primary pain.

What is chronic secondary pain?

This is pain caused by a medical condition. Joint or low back pain from osteoarthritis, or nerve pain after shingles are common examples of secondary pain.

There are dedicated leaflets to many chronic conditions and their recommended options for managing pain are contained within them.

The rest of this leaflet will deal with the assessment and management of chronic primary pain.

What about neuropathic pain?

Neuropathic pain is caused by a problem with one or more nerves themselves. The function of the nerve is affected in the way that it sends pain messages to the brain. Neuropathic pain is often described as burning, stabbing, shooting or aching, or like an electric shock.

Neuropathic pain is less likely to be helped by traditional painkillers. Antidepressant or antiepileptic medicines may help by an action that is separate to their action on depression and epilepsy.

Causes of neuropathic pain include:

• Trigeminal neuralgia.

• Pain following shingles (postherpetic neuralgia).

• Diabetic neuropathy - a nerve disorder that develops in some people with diabetes.

• Phantom limb pain following surgical removal (amputation) of a limb.

• Multiple sclerosis.

• Pain following chemotherapy.

• HIV infection.

• Alcohol dependency.

• Cancer.

• Atypical facial pain.

• Various other uncommon nerve disorders.

Read the separate leaflet called Neuropathic Pain for more information.

How will my pain be assessed?

Your healthcare professional will ask you to describe how your pain affects your life, and how it affects your family, friends and carers. It is also important to discuss how aspects of your life can affect your pain. Things to consider include:

• Your lifestyle and day-to-day activities, including work (occupational performance and any dissatisfaction at work) and sleep disturbance.

• Your physical and psychological well-being.

• Any stressful life events, including previous or current physical or emotional trauma.

• Any current or past history of substance misuse.

• Your social interactions and relationships, including your ability to self-care, influence of family on pain behaviour, and family overprotection.

• Any difficulties with housing, income and other social concerns.

This discussion might also involve you talking about what you believe causes your pain; what you expect might happen in the future regarding your pain, and your understanding of how possible treatments might help.

In addition, a thorough medical assessment will include:

• A complete pain history assessing each individual pain (for site, character, intensity, onset, triggers, duration, intensity, worsening and relieving factors, night pain, and possible causes). Any other symptoms and your past medical history.

• A complete physical examination.

• Looking through your previous investigations and their results.

• Discussing your previous and current treatments - how you responded to them and any side-effects.

This full assessment will obviously take some time. Several appointments may be required or your doctor may arrange a longer appointment to deal specifically with this.

What investigations might I need to assess my pain?

Decisions about searching for any injury or disease that may be causing the pain are matters for careful consideration and they need discussion. Sometimes the anxiety of waiting for an investigation appointment, going through the investigation and then waiting for the results may itself be harmful. It can be hard to hear normal or negative test results when you are in pain and are searching for an answer.

A great deal of care and skill is often required to avoid unnecessary and inappropriate investigations and referrals, which may only serve to increase your (or your family's) underlying anxiety. A balance must be struck between ensuring that important and/or treatable conditions are excluded whilst in some cases avoiding an endless quest for a physical diagnosis.

What strategies help a person cope with chronic pain?

It is very important that all those supporting the individual with pain recognise and openly acknowledge that living with pain can be extremely distressing. Patients need to be involved in making decisions about their care at all stages. To help with this your doctor will need to talk about the normal course of pain. This can be hard to predict but can follow these patterns:

• It may be that over time your pain will have better and worse spells and it may not always be possible to work out why this has happened.

• It may also happen that your pain may not get better and may worsen over time.

• Even if the pain is unchanged your quality of life might improve.

Having a care and support plan can be very helpful. This might include options for managing the pain as well as managing the effects of the pain on your life, such as stopping you attending school or work.

Separate leaflets on specific individual pain syndromes - such as Fibromyalgia - may be helpful.

The best approach is likely to involve nurses, pharmacists, physiotherapists, psychological therapists, counsellors and occupational therapists. It may also include liaison with social services, employers and benefits agencies.

Self-management should be encouraged and supported from an early stage of a pain condition and as part of a long-term management strategy. Education about the condition and support from others also managing their (similar) conditions can be beneficial.

The treatment should not just be focused on pain relief but also at changing behaviours and improving function. The goals of treatment must be realistic and should be focused on restoration of normal function (minimal disability), better quality of life, reduction of use of medication and prevention of relapse of chronic symptoms.

Referral to a specialist pain management service should be considered when non-specialist management is failing, chronic pain is poorly controlled, there is significant distress, and/or where specific specialised intervention or assessment is considered.

Non-medicine strategies

National Institute for Health and Care Excellence (NICE) Guidelines April 2021 recommend physical activity and exercise programmes for chronic pain. Evidence from 23 studies show that exercise reduces pain and improves quality of life for people with chronic primary pain. The benefit does not depend on the type of exercise and can be long-lasting. Most of the research looked at women with fibromyalgia or people with chronic neck pain.

NICE also suggests acceptance and commitment therapy (ACT) or cognitive behavioural therapy (CBT) for pain for people aged 16 years and over with chronic primary pain. ACT improves quality of life and sleep, and reduces pain and psychological distress. This evidence was from a fairly small number of studies but there was not enough evidence to support a preference for ACT over CBT or CBT over ACT. CBT for pain improves quality of life but there is no evidence of consistent improvement in other areas such as pain or sleep.

NICE also suggests a single course of acupuncture (or dry needling) delivered in a community setting. 27 studies showed that acupuncture reduced pain and improved quality of life for up to three months when compared with usual care or with 'sham' (pretend) acupuncture. There was not enough evidence to determine any longer-term benefits.

Note: there is no evidence of benefit from transcutaneous electrical nerve stimulation (TENS), ultrasound or interferential therapy for chronic primary pain and NICE says these should not be recommended. Laser therapy and transcranial magnetic stimulation (TMS) both showed a benefit for patient-reported pain. Laser therapy also demonstrated improvements in quality of life in larger studies. However, the laser therapy used in the studies varied widely, particularly in terms of wavelength, power and the time the laser was applied to each painful area. The evidence for TMS was from seven studies, and although benefits were seen in pain reduction, there were no benefits in any other outcome. The evidence at more than three months' follow up was limited for both treatments and cost-effectiveness is difficult to assess.

Medicines for chronic primary pain

Antidepressants

Medicines such as amitriptyline, citalopram, duloxetine, fluoxetine, paroxetine or sertraline can be used in people aged 18 years and over to manage chronic primary pain. You should understand the possible benefits and harms of these medicines before starting them. These medicines may help with quality of life, pain, sleep and psychological distress, even in the absence of a diagnosis of depression.

In April 2021, this was an 'off-label' use of these antidepressants. This means the medicine is being used for a reason that is outside the usual reasons for prescribing it. There are clinical situations when the use of medicines outside the terms of the licence may be judged by the doctor to be in the best interest of the patient on the basis of available evidence. Such practice is particularly common in certain areas of medicine. Using these medicines for young people aged 16-17 years needs careful consideration and your local GP may ask a specialist for advice.

Antiepileptic medicines

Antiepileptic drugs (including gabapentin and pregabalin) should not be used for chronic primary pain. The exception is if they are offered as part of a clinical trial for complex regional pain syndrome. If you are already taking these medicines your doctor may need to discuss your use of them with you. There is little evidence that these medicines help chronic primary pain but if you think they help you, your doctor will agree a shared plan for continuing safely. If you decide to reduce or stop them, your doctor can advise how to do this safely to minimise withdrawal effects.

Cannabis-based medicines

NICE did not find any evidence on the effectiveness of cannabis-based products for chronic primary pain. Some evidence suggested that the treatment could cause problems in the short term. However, this was limited evidence from a small study. More research would be useful for future practice.

Opioid medicines

In recent years there has been a significant increase in in the UK in prescribing of opioids (such as tramadol and morphine) for chronic, non-cancer pain. There is no good-quality evidence to support the use of opioids in this situation. There is no evidence that opioid medicines help chronic primary pain, and long-term use (more than six months) has an increased risk of dependence. Based on their experience, the doctors writing the guideline for NICE agreed that even short-term use of opioids could be harmful for a chronic condition. The evidence of long‑term harm, along with lack of evidence on effectiveness of opioids, persuaded the committee to recommend against starting opioid treatment for people with chronic primary pain.

An increasing awareness of rising rates of opioid prescriptions and, in some cases, related deaths has prompted clinicians around the world to be more careful when using these medicines in chronic pain. Patients need to be made aware of the risks of medicine treatments, and of the alternatives available.

Non-opioid analgesics

These are used in the treatment of secondary pain conditions and there are in-text links to dedicated information about these conditions. They are not used for chronic primary pain.

• Non-steroidal anti-inflammatory drugs (NSAIDs) may be considered in the treatment of patients with chronic nonspecific low back pain. However, there is potential gastroenterological and cardiological adverse effects and your individual risk needs to be assessed.

• Paracetamol may be considered alone or in combination with NSAIDs in the management of pain in patients with hip or knee osteoarthritis in addition to non-pharmacological treatments.

• Topical NSAIDs should be considered in the treatment of patients with chronic pain from musculoskeletal conditions, particularly for patients who cannot tolerate oral NSAIDs.

• Topical capsaicin patches may be considered in specialist pain clinics for the treatment of patients with peripheral neuropathic pain when first-line pharmacological therapies have been ineffective or not tolerated.

• Topical lidocaine should be considered for the treatment of patients with postherpetic neuralgia if first-line pharmacological therapies have been ineffective.

Outlook and complications of chronic pain

Chronic pain has a negative effect on physical health, daily activity, psychological health, employment and economic well-being. It can result in:

• Prolonged physical suffering.

• Depression.

• Increased risk of suicidal thoughts and attempted suicide.

• Sleep disturbance.

• Marital or family problems.

• Negative effects on work, and loss of employment.

• Disability.

• Adverse medical reactions from long-term therapy, including side-effects, interactions, drug dependence and misuse.

It can be difficult to predict how the pain will be over time and to balance a positive outlook with acceptance and realism. Considerable improvement is possible with suitable support and management.