MISC - Pain management Flashcards
What is Pain?
“an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage”.
(3) types of Classification of Pain
- Duration
- Acute
- Chronic
- Acute on chronic - Cause
- Cancer (progressive)
- Non cancer - Mechanism
- Nociceptive (physiological)
- Neuropathic (pathological)
What is a chronic pain?
– Pain persisting beyond healing of injury
– Often no identifiable cause
– (Pain lasting for more than 3 months)
Describe nociceptive pain
- Obvious tissue injury or illness
- “Physiological pain”
• Can be further classified into
– Superficial somatic
– Deep somatic
– Visceral
• Descriptions include sharp, aching, dull, throbbing, cramping and pressure
Describe neuropathic pain
- Nervous system damage or abnormality
- “Pathological pain”
- Tissue injury may not be obvious
• Description
– Burning, shooting ± numbness, pins and needles
– Not well localised
How is nociception not the same as pain?
Pain is multifactorial not only injury based.
Factors include: beliefs/concerns, psychological factors (anxiety, depression, anger), cultural issues, other illnesses, coping strategies, social factors.
What are the 4 steps of pain physiology (sequence)?
– Periphery
– Spinal cord
– Brain
– Modulation
What happens at the periphery as one of the 4 steps of pain physiology?
- Tissue injury
- Release of chemicals
- Stimulation of pain receptors (nociceptors)
- Signal travels in Aδ or C nerve to spinal cord
What happens at the spinal cord as one of the 4 steps of pain physiology?
- Dorsal horn is the “first relay station”
- Aδ or C nerve synapses (connects) with second nerve
- Second nerve travels up OPPOSITE side of spinal cord (decussate at the level of spinal cord)
What happens at the brain as one of the 4 steps of pain physiology?
• Thalamus is the “second relay station”
• Connections to many parts of the brain
– Cortex
– Limbic system
– Brainstem
• Pain perception occurs in the cortex
What happens during modulation as one of the 4 steps of pain physiology?
- Descending pathway from brain to dorsal horn
* Usually decreases pain signal
What is the “second relay station” for pain?
Thalamus
What is the “first relay station” for pain?
Dorsal horn
Compare peripheral vs. central neuropathic pain
• Peripheral
– Damaged nerves (e.g. trauma, diabetes)
– Abnormal firing of nerves
• Central
– Changes in “wiring”
– Abnormal firing
– Loss of modulation
List (6) medications used for analgesia
Paracetamol (Acetaminophen) NSAIDs Opioids Tramadol Amitriptyline Anti-epileptic drugs