The management of chronic pain depends on reaching a diagnosis as to the cause of the pain by a detailed history, examination and the appropriate use of investigations. A treatment plan has several components:
1 Psychological. The appreciation of pain is always subjective. A hronic pain may profoundly influence apatient’s life-style. Depression is almost universally associated with chronic benign pain, whereas overall only 15-20% of cancer patients are clinically depressed. Antidepressant drugs and modification of life style have
a place in treatment.
2 Analgesics. Analgesic drugs should be prescribed according to the analgesic ladder (see p. 376). Inadequate analgesia following optimal use of a drug from one group indicates the need for prescription from the group one step higher. The prescription should be for regular doses with extra ‘as required’ doses for breakthrough pain. Medication should be given orally except in cases of gastrointestinal dysfunction or if the patient is comatose. The effect of any prescription should be reviewed regularly at a time interval suited to the severity of the pain.
3 Co-analgesics. Co-analgesics are drugs which have a primary indication other than pain but in some conditions are effective either alone or when added to conventional analgesics. Examples are the non-steroidal anti-inflammatory drugs used in bone pain; tricyclic antidepressants and anticonvulsants used in deafferentation pain . Calcium channel blockers (nifedipine) can improve sympathetically mediated pain. Muscle relaxants, antibiotics and steroids by injection are analgesic when used in specific situations. 4 Stimulation. Acupuncture, ultrasound, massage, transcutaneous. electrical nerve stimulation (TENS) and spinal cord stimulation all achieve analgesia by an effect on large myelinated nerve fibres.
5 Nerve blocks. Pain pathways can be blocked either temporarily by local anaesthetic or permanently using chemicals such as phenol or radiofrequency
(a) Somatic system blocks:
(i) Peripheral-nerve and plexus blocks.
(ii) Central-epidurals and spinals.
(b) Sympathetic blocks:
(i) Central-epidurals and spinals.
(ii) Peripheral-sympathetic ganglia and nerve endings.
6 Ablative neurosurgical techniques, e.g. dorsal rhizotomy, sympathectomy, cordotomy, should only be performed when physical and pharmacological therapies have failed. These may be carried out percutaneously or by open procedure.
Chronic and recurrent pain is disabling and distressing to the patient. Multidisciplinary pain relief clinics are often helpful in providing specific and supportive therapy but the management of pain should be part of the skills of all doctors.