Chronic pain is pain that persists beyond the expected time of healing. The time course for the development of chronic pain is variable, and arbitrary time classifications (e.g. longer than 6 months) are often inaccurate. The ongoing pain becomes a significant disease process, rather than being a symptom. The transition to chronic pain is marked by changes in both physiological and psychological responses.
The neuroendocrine stress response is typically exhausted in chronic pain states, and catecholamine-induced changes are absent. Vegetative responses predominate, including sleep disorders, irritability, depression and decreased motor activity.
Psychological factors are important in chronic pain; withdrawal and depression are common, causing severe strain on social and family support systems. Opioid tolerance is frequent, adding to the complexity of treatment. While chronic pain can be somatic or visceral, it is very often neuropathic in nature. Nervous system tissue has been damaged, and abnormally maintains the sensation of pain without any external stimulus. Neuropathic pain is usually associated with some form of sensory deficit, and is described as typically raw or burning in nature.
Treatment of chronic pain states involves the use of a multimodal approach, incorporating
Additionally, diagnostic and therapeutic nerve blocks can be helpful. Psychological counselling and support is equally important.
- local anaesthetics