Pain

• Causes of pain
• History and examination
• Tests for pain
• Pain management

Causes of pain

Pain is an unpleasant sensory and emotional experience common to many different conditions. It can be caused by damage to tissues, or by damage to nerve cells and pathways. For more information about the mechanisms and different types of pain, see the anatomy and physiology of pain. Most diseases are associated with some degree of pain.
For more specific information about pain in different areas of the body, see:

• Abdominal pain
• Cancer pain
• Chest pain
• Joint pain
• Headache

History and examination

If you visit your health practitioner complaining of pain, he or she will ask a number of questions about the quality and location of the pain. This may help to identify the cause of pain. Questions may include:

• Site: The exact location of the pain should be determined. In many cases, pointing to the site of worst pain is helpful. Is the pain well or poorly localised?
• Radiation: Any radiation of pain (e.g. pain which is felt mostly in one place, but which “goes through” to another) may be characteristic of certain diseases.
• Onset and offset: Did the pain develop acutely? Is it continuously present or intermittent? Was the onset of pain associated with any identifiable event, such as the onset of back pain while lifting something heavy?
• Quality: Descriptions such as sharp, dull, stabbing, cramp-like (colicky) or burning may help to characterise the pain as being directly due to tissue damage, or due to nerve damage (known as neuropathic pain).
• Severity: This may be recorded on a scale of one to ten, where ten is the worst pain possible. It is also important to discuss whether the pain interferes with sleep or normal daily activities.
• Aggravating and relieving factors: Do certain positions make the pain better or worse? Has any pain-relieving medication been tried, and was it effective?
• Associated symptoms: Including nausea and vomiting, muscle weakness etc.

Your health practitioner will then need to examine you. The type of examination will depend on the location and type of pain.

Tests for pain

The tests performed will depend on the location and type of pain. They may include blood tests such as full blood picture or imaging tests such as x-ray, CT, ultrasound or MRI. Patients with chronic pain may be asked to complete specialised pain questionnaires such as the Pain Disability Index or McGill Pain Questionnaire. These are designed to assess the level of pain and the degree to which pain impairs functional abilities.

Pain management

Pain management is a complex subject. Depending on the cause, type and location of pain, a different treatment strategy will be needed. Some pain will be self-limiting (meaning it will go away by itself), and need pain-relief medications only temporarily or not at all; whereas chronic pain may last years, be resistant to most of the normal pain treatment options, and require a more holistic (whole-person) approach. Management of chronic pain is best managed with a multidisciplinary approach. Some of the different methods that may be used are discussed below.

Analgesics

The World Health Organisation (WHO) groups analgesics for the management of severe, chronic pain into three groups:

1. Non-opioid drugs: Simple analgesics, including paracetamol, aspirin and non-steroidal antiinflammatory drugs
2. Weak opioid drugs: Include codeine and dextropropoxyphene
3. Strong opioid drugs: Include fentanyl (Durogesic), morphine (Kapanol), methadone and buprenorphine

One or more of these agents may be required to achieve pain control. The approach should be individualised according to patient requirements.

Co-analgesics

Co-analgesic medications are those which are not specifically designed to relieve pain, but which can help improve pain either alone or in combination with other medications. They are often particularly useful in the management of neuropathic pain. Examples of some co-analgesic drugs include:

• Tricyclic antidepressants: Such as amitriptyline (Endep)
• Anticonvulsants and antiarrhythmics: Such as phenytoin, carbamazepine, gabapentin and lignocaine
• Calcium channel blockers: Such as nifedipine (Adalat)
• Steroids

Psychological and social aspects

Depression is a common problem in patients with chronic pain. It is a serious condition which requires treatment. Managing depression appropriately can also improve perception of pain.

Behavioural approaches

Behavioural approaches include relaxation techniques, hypnotic techniques, biofeedback and cognitive-behavioural therapy. They have all been shown to reduce pain intensity and improve long-term functioning in patients with chronic pain. These methods should generally be used as part of an integrated multidisciplinary approach.

Stimulation techniques

Medical acupuncture, ice and heat, ultrasound, massage, transcutaneous electrical nerve stimulation (TENS) and spinal cord stimulation devices all utilise the gating mechanism of pain modulation to relieve pain (see spinal cord stimulation for more information).

Nerve blocks

A variety of nerve blocks techniques including epidural and spinal analgesia can be used for pain which is not responding to other treatments.

Children

For information about the management of pain in children, see paediatric pain management.

References

1. Ashburn MA, Staats PS. Management of chronic pain. Lancet. 1999;353(9167):1865-9. [Abstract]
2. Braunwald E, Fauci AS, Kasper DL, et al. Harrison’s Principles of Internal Medicine (16th edition). New York: McGraw-Hill Publishing; 2005.
3. Jones JB. Pathophysiology of acute pain: Implications for clinical management. Emerg Med (Fremantle). 2001;13(3):288-92. [Abstract]
4. Kumar P, Clark M (eds). Clinical Medicine (6th edition). Edinburgh: WB Saunders Company; 2005.
5. Murtagh J. General Practice (3rd edition). New York: McGraw-Hill; 2003.
6. Talley NJ, O’Connor S. Clinical Examination: A Systematic Guide to Physical Diagnosis (4th edition). Eastgardens, NSW: MacLennan & Petty; 2001.