About Pain

Most of us have experience of everyday pain including headaches, pain from minor injuries and muscular pain for example following exercise. These pains are self-limiting and often do not need treatment. All pain is affected by current mood, past experience of pain and concerns about the cause of the pain. Worries and distress about the impact of the pain and what the implications are for the future will worsen the experience of pain. Also, unpleasant thoughts, feelings and memories (even if those are unrelated to pain) can influence how we perceive pain. Anxiety, depression, post-traumatic stress disorder, and previous emotional trauma or other mental health diagnoses, are likely to worsen the experience of pain and make it more difficult to treat.

Pain is usually described as acute (short term) or chronic (long term - usually more than three months). Acute pain is usually related to an obvious injury such as dental disease, fracture or operation. Chronic pain sometimes begins with an acute injury but the pain does not resolve as expected; often it is not clear how a chronic pain has started. Common types of chronic pain include low back pain, pain related to arthritis and pain related to injury to a nerve or other part of the nervous system (neuropathic pain). Both types of pain can range from mild or severe with the difference being the duration of symptoms. Chronic pain is usually not a sign of on-going tissue damage but may relate to changes in the peripheral and central nervous system that occur over time so that the pain signalling becomes self-sustaining over a prolonged period. However, it is always important to make a thorough assessment for potential on-going tissue damage as a cause for long-term pain. Cancer pain is usually described separately and may be short or long lasting. The pain can relate to the cancer itself or the cancer treatment. Additionally, patients with cancer may experience acute or chronic pain unrelated to their cancer.

Although the pain categories may overlap some generalisations can be made about approaches to treatments and the effectiveness of treatment.

Acute pain can be severe but usually resolves over a short period of time (days or weeks). Treatments usually only need to be given for a short time while healing of the injury begins. Acute pain is often straightforward to treat with a range of analgesics and other interventions depending on the pain severity. Opioids are useful for treating acute pain and usually only need to be given for a period of a few days. The dose of analgesia should be reduced as healing occurs.

Chronic pain can cause low mood, irritability, poor sleep and mobility impairment. Unlike acute pain, chronic pain is difficult to treat with most types of treatment helping less than a third of patients. Most treatments aim to help the patients self-manage their pain and improve function in a number of domains. Different treatments work for different patients. Medicines generally and opioids in particular are often not very effective for chronic pain. Other non-drug treatments may be used such as stimulating techniques (TENS machine), acupuncture, advice about activity and increasing physical fitness, and psychological therapies such as Cognitive Behavioural Therapy and meditation techniques such as mindfulness. Helping a patient understand about chronic pain is important and in particular helping him or her understand that physical activity does not usually cause further tissue damage and is therefore safe. It is important that patients with chronic pain understand that treatments tend not to be very effective and that the aim is to support them in functioning as well as possible.

Neuropathic pain is a type of chronic pain associated with injury to nerves or the nervous system. Types and causes of neuropathic pain include:

  • lumbar radiculopathy following disc prolapse
  • nerve injury following spinal surgery
  • pain after infection such as shingles or HIV/AIDS
  • pain associated with diabetes
  • pain after amputation (phantom limb pain or stump pain)
  • pain associated with multiple sclerosis or stroke.

Neuropathic pain is usually severe and intrusive. Medications may be used to treat neuropathic pain but are usually not very effective and work for only a small proportion of patients. Patients may not benefit from the first drug tried so they may need to be given a number of drugs in an attempt to optimise symptoms.

Cancer pain is usually associated with an obvious source of tissue damage and may be acute or chronic. Neuropathic pain occurs in relation to cancer diagnoses and treatments (such as radiotherapy). Because cancer pain treatment, particularly at the end of life, is often for a short duration, it is usually more successful than chronic pain treatment. Patients who recover from cancer or who survive a long time with cancer may have pain that is more difficult to treat.