Chronic Pain

Chronic Pain what is it?

Chronic pain affects up to half the population, so it is important if not well understand this medical condition.

Although many definitions are used, chronic pain is usually defined as pain lasting beyond 3 months. It is pain that remains after the original insult, indicating an ongoing causative process.

The latest International Classification of Diseases (ICD-11 in 2017) definition recognises that there are 7 categories of chronic pain:

7 categories of chronic pain:

–Primary which is more than 3 months of pain in 1 or more area without explanation

–Cancer

–Post-traumatic from either direct injury or surgery

–Neuropathic

–Head or orofacial occurring on more than ½ the day in 3 months

– Visceral arising from internal organs

–Musculoskeletal from bones, joints or muscles

Where does it come from?

1.Chronic pain can arise from inappropriate peripheral pain receptor/nerve firing, spinal cord modulation or brain perception activation.

Chronic pain is typically caused by surgery, cancer, infections, and arthritis. Persisting backache and headache are also common forms of chronic. Fibromyalgia is a particular condition characterised by widespread chronic.

There are two ways in which this is generated – nociceptive and neuropathic.

2.Nociceptive pain arises from the activation of pain sensors by tissue damage. This can be superficial e.g. from an injury to the skin, or deep from either visceral cells e.g. colon cancer or somatic cells e.g. ligaments in arthritis.

3.Neuropathic pain arises from malfunction or damage to the nervous system itself – either the peripheral nervous system e.g. shingles or the central nervous system.

While pain in response to an initial insult or injury is normal, the continuation of pain without the original cause is not. Pain is converted from acute to chronic through changes leading to a reduction of the pain threshold and an increase in activation of pain-recognising brain centres.

Some theories suggest certain personality types are prone to chronic pain as it is associated with anxiety, insomnia and depression. However, increasing evidence suggests the opposite is true and chronic pain causes those states.

The change process is very much real. Chronic pain has been shown to affect the structure of brains on MRI (magnetic resonance imaging) scans and their function in EEG (electro encephalogram) recordings.

How can it be treated?

The difficulty with chronic pain is that since it exists without a continuing identifiable cause, treatment is without a specific target. Chronic pain is currently treated through a combination of options that include any of the following:

–Non-opioid medications work well for neuropathic pain. Beyond simple painkillers such as paracetamol and ibuprofen, commonly used ones include tricyclic antidepressants (TCA’s), serotonin-norepinephrine reuptake inhibitors (SNRI’s) and anticonvulsants. Where legal, cannabis has also been used for this type of pain.

–Opioid medication such as codeine and morphine work well for nociceptive chronic pain

–Medical interventions ranging from local anaesthetic nerve blocks to trigger point injections to transcutaneous electrical nerve stimulation (TENS.)

–Psychological interventions ranging from CBT to mindfulness to acceptance and commitment therapy

–Physiological interventions such as graded exercise and physiotherapy

–Surgery can also be used albeit rarely e.g. to decompress nerves

–Alternative therapies ranging from acupuncture to hypnosis

Encouraged by recent research, there has been a shift towards self-management as a better way to manage chronic pain. In this, the patient is empowered through being given more decision-making control of their treatment options which leads them to cope better with this undoubtedly serious and difficult situation.