Lecture 12 - No Pain, No Gain - What is pain?

• It is a biological function of stopping and/or reducing further injury (e.g. congenital analgesia) • Promotes learning to avoid future injury - pain makes you think, remember and prevent • sets the limits on activity forcing rest and allowing for recuperation and recovery

TRANSIENT - pain of brief duration having little consequence and rarely producing more than fleeting attention e.g. aches and pains you get during the day go away -> no tissue damage ACUTE - combination of tissue damage, pain and anxiety which resolves after the damaged tissues have healed (less than 6 months) e.g. tissue damage could be minor [paper cut] or major [fracture]; once the tissue heals, pain goes away CHRONIC - pain which persists after all possible healing has occurred (more than 6 months). e.g no injury to heal > 6months can impact working life, social life and relationships

• persists long after pain can serve any useful function • no longer a symptom of injury or disease • becomes a syndrome and a medical problem requiring urgent attention • the pain becomes an intolerable evil that serves no useful function • patients feel helpless and hopeless

SENSORY-DISCRIMINATIVE - intensity, duration, quality and location of a nociceptive (code for intensity) stimulus. MOTIVATIONAL-AFFECTIVE - aversive, emotional and automatic responses; the drive to reduce pain COGNITIVE-EVALUATIVE - learning, memory, attention-mechanisms

• pain is a subjective experience affected by more than the extent of injury or organic dysfunction • many factors are involved in the etiology, severity, exacerbation and maintenance of pain, suffering and disability • people’s experience of pain and responses to pain are influenced by: life stresses, perception, social support, emotions, expectations, cultural background, financial resources etc

• Physiological factors - CNS/Neural processing - Psychological factors - cognitions, expectations, beliefs

21.5%

LOW BACK PAIN - 65-80% of all people have back pain at some time in their life. Back pain is the most frequent cause of activity limitation in people younger than 45 yrs old ARTHRITIS PAIN - 2002/03 NZ health survey. 13.9% of men, 17.3% of women reported arthritis HEADACHE - 45mil Americans have chronic, severe, disabling headaches. More than $4billion spent each yr on over the counter pain medications OTHER PAIN DISORDERS - such as the neuralgias and neuropathies (Affect nerves throughout the body) • pain due to damage to the central nervous system (brain and spinal cord) • pain of unknown origin where no physical cause can be found

PHANTOM LIMB PAIN - pain away from part of body you don’t have -> nerve sends signal when it shouldn’t COMPLEX REGIONAL PAIN SYNDROME - show condition in extremities so limbs show inflammation (fluid) could lead to skin drying and could turn red, so accumulation of chemicals and temperatures difference and fluid in joints.

• the variability of pain experiences is indicative of numerous neural mechanisms that modulate our sensory experiences

• Describes how a complex arrangement of neurons in the signal cord blocks certain pain signals and allow others to pass through to the brain which lead to the perception of pain • helps to explain phantom and chronic pain and is widely recognised

• Physiological and psychological factors contribute to the production, modulation, maintenance and experience of pain. • a relationship exists between psychological and physical changes and pain: > mental events (thoughts, memories, memories) influence physical changes which influence pain > psychological states (stress, depression, anxiety) and physical changes (automatic arousal, muscle tension) influence pain