Part 2 book “Manual of neurologic therapeutics” has contents: Chronic pain, headache and facial pain, stroke and cerebrovascular disorders, movement disorders, behavioral neurology and dementia, neuroophthalmology, toxic and metabolic disorders, infections of the central nervous system. | 10 Chronic Pain Robert D. Helme Ian Yi-Onn Leong BACKGROUND PATHOPHYSIOLOGY PROGNOSIS DIAGNOSIS TREATMENT BACKGROUND Part of "10 - Chronic Pain " Definitions Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage. Chronic pain is described as pain continuing after the time of normal healing or pain present for more than 6 months. Other useful terms, especially in cancer pain: o o Breakthrough pain is pain that occurs unexpectedly in the presence of stable background analgesia. o Incident pain is pain on movement and implies a musculoskeletal origin or bony involvement by cancer. End-of-dose failure is pain that occurs between regular doses of analgesic due to decreasing effective tissue levels between doses. Epidemiology Depending on the definition used, approximately 20% of patients seen by primary care physicians have chronic pain. Annual costs of pain treatment both direct and indirect is estimated to be $125 billion in the United States. Chronic pain increases with age from 20 to 60. It probably reaches a plateau and declines from age 80. About 50% of patients with cancer will experience pain at some stage of their disease, with 60% to 80% of patients experiencing pain in the advanced stages of their disease. The Biopsychosocial Model of Chronic Nonmalignant Pain The relationship between the amount of nociceptive stimulus and the pain reported or the pain behaviors exhibited are dependent on social, psychological, and biomedical factors. The level of pain experienced (suffering) and the affective and behavioral expression of the pain are mediated by the cognitive appraisal of the nociceptive stimulus and its environmental variables. Changes in the pain experienced, the mood of the patient, and the behaviors exhibited by the patient is often not synchronous. An improvement in pain is not always followed by a similar .
