Acute Pain Feature
• Pain usually concordant with degree of tissue damage, which remits with resolution of the injury
• Reflects activation of nociceptors and/or sensitized central neurons
• Often associated with autonomic nervous system and other protective reflex responses (e.g., muscle spasm, “splinting”)
Chronic Pain Feature
• Low levels of identified underlying pathology that do not explain the presence and/or extent of the pain
• Perpetuated by factors remote from the cause.
• Continuous or intermittent with or without acute exacerbation.
• Symptoms of autonomic nervous system hyperactivity less common.
• Irritability, social withdrawal, depressed mood and vegetative symptoms (e.g., changes in sleep, appetite , libido), disruption of work, and social relationships
• Strong relationship between tissue pathology and levels of pain
• Limited time frame that permits aggressive pain management
• Rarely involves medical-legal or disability issues.
Chronic Non-cancer Pain
• Weak relationship between tissue pathology and pain levels
• Prolonged, potentially life-long, pain
• May involve medical, legal, disability issues/conflicts, work or relationship problems, physical de-conditioning, psychological symptoms (see chronic pain above)
• May progress to chronic pain syndrome
Chronic Pain Syndrome
• Preoccupation with somatic functioning
• Lifestyle centered on seeking immediate pain relief, with excessive, nonproductive, and often harmful use of health care
• Repeated attempts to obtain pain-related financial compensation (e.g., Social Security,. Veterans’ benefits)
• Numerous symptoms and signs of psycho-social dysfunction that the patient attributes to the pain (e.g., anger, depression, anxiety, substance abuse, disrupted work or personal relationships)