Pain Flashcards
Define pain
An unpleasant sensory and emotional experience associated with actual or potential tissue damage
Why do we feel pain?
Early warning system
Alerts to danger
Waning of actual or potential harm
Elicits change in behaviour
To try and avoid danger/ harm
What are the three different types of pain?
Somatic superficial, somatic deep, visceral
Somatic superficial=
On the skin, sharp (fast) pain, localised (brief)
Somatic deep=
In deep layers of skin, muscles and joints, is a burning/ itching/ aching (slow) pain, is diffuse (Long lasting)
Visceral=
In organs, is a dull ache/ burning/ gnawing (slow) pain, can cause nausea and sweating
Acute vs chronic pain
Acute= monetary or severe, weeks/ months, resolvable
Chronic= persistant, remains despite the healing process and lasts 3+ months
What is the congenital absence of pain disorder?
Someones central perception of pain mechanisms are disrupted so no pain is felt. This means there is an issue with the SCN9A voltage gated sodium channel.
Nociception=
neural process of encoding noxious stimuli
Pain perception=
the body’s interpretation of these signals
Nociceptor=
are sensory receptors that respond to pain. There are many types e.g., mechanoreceptors, bradykinin, prostaglandins, histamine, substance P. They are located on free nerve endings and respond to inflammatory mediators.
What are the role of free nerve endings?
- Free nerve endings play an important role in nociception by detecting noxious stimuli. This initiates perception of pain.
Describe the differences between Aɗ (A-delta) and C-fibres.
- Aɗ (A-delta) = sharp, pricking, fast pain. They are myelinated.
- C-fibres= hot and burning sensation, slow deep pain. They are un-myelinated.
Describe the process of central sensitisation.
- Involves two types of presynaptic cells which are both glutamate receptors: AMPA and NMDA. If there is a transient stimulus of the nociceptor then AMPA receptors are activated, releasing sodium ions into the cell. On a stronger stimulus of the nociceptor, NMDA receptors are activated on the 2nd order neuron allowing release of calcium ions into the cell, increasing the sensitivity of the neuron.
Describe the process of peripheral sensitisation.
- It is a substance P mediated feedback loop where 1st order neurons are sensitised. There is an increase in nociceptive neurons so the pain will just get worse and worse.
Referred pain=
- When you have an injury in one area of the body, but the pain is felt elsewhere. For example: issues with the gallbladder can cause pain on the skin of the shoulder. This is because of the interconnecting sensory nerves of the body.
What is the neuromatrix theory of pain.
- Suggests pain comes from a pattern of nerve impulses in the body. These impulses come from a neural network in the brain called ‘body’s-self neuromatrix’.
Hyperalgesia=
- Increased sense of painful sensation, primary/ secondary.
Allodynia=
- Pain from a stimulus that does not usually provoke pain.
Explain the biomedical approach to pain.
- Pain is felt in response to a painful situation. Meaning pain is felt as a sensation and has a singular cause.
What are the pain paradoxes.
- Battle wounds= Individuals with the same degree of injury will experience differences in reports to their painful situation. E.g., a study showed significant differences in soldiers requesting pain relief.
- Phantom limb pain= 5-10% of amputees will experience pain in their absent limb.
- Placebos.
What is the biopsychological approach to understanding pain.
- Acknowledges that pain is not just a psychical phenomenon but also a social, psychological and biological response.
- Biological e.g., pain intensity, medication use and trauma/ injury
- Psychological e.g., depression, pain perception and fear avoidance
- Social e.g., work, disability, cultural and economic factors.
