Pain - Definition & Types

Study Notes

Pain - Definition & Types

Pain is an unpleasant sensory and emotional experience, often associated with tissue damage.
Serves as an alert system for potential harm.
Two primary types of pain:
- Acute pain: Lasts for a short duration, typically less than 3 months.
- Chronic pain: Persists for 3 months or longer.

Pain Categories

Somatic pain: Originates from tissues like skin, muscles, and bones.
- Usually well-localized and easy to identify.
Visceral pain: Arises from internal organs.
- Often poorly localized and may present in different areas of the body.
- Associated with nausea.
Psychological pain: Experienced without a clear physical cause.
- Can be triggered by emotions, thoughts, or anticipation.

Nociceptors - Pain Receptors

Specialized nerve endings that detect and transmit pain signals to the brain.
Three main types:
- Mechanosensitive nociceptors: Respond to pressure, stretch, or impact (e.g., stubbing your toe).
- Thermosensitive nociceptors: React to extreme temperatures (heat or cold).
- Chemosensitive nociceptors: Sensitive to chemicals like serotonin.

Referred Pain - Pain Perception

Pain may be perceived in a location different from the actual source of the injury.
Pain travels along the nerve pathway associated with the injured structure, leading to a different perceived location.

Radiating Pain

Pain that spreads from the initial location to a larger area.

Pain Characteristics

AM pain / stiffness / better with activity: Suggests chronic inflammation with swelling.
Pain increasing as day progresses: Indicates increased congestion in a joint.
Sharp, stabbing pain during activity: Associated with acute ligament sprain or muscle strain.
Dull, aching pain aggravated by muscle contraction: Chronic muscle strain.
Pain subsides during activity: Chronic inflammation.
Night pain: Compression of a nerve or bursa.
Deep / nagging / very localized: Bone pain.
Sharp / burning / numbness: Nerve pain.
General aching / referred to another area: Vascular pain.

Pain Questions

Location: Where is the pain most intense? Can you pinpoint the specific spot? Does the pain radiate?
Severity: How bad is the pain on a scale of 0-10?
OPQRST: (Onset, Provocation/Palliation, Quality, Radiation/Referral, Severity, Timing)

Physiology of Pain Pathway

Pain signals travel along a specific pathway:
- Nociceptor (pain receptor) → First-order neuron (spinal cord) → Second-order neuron (thalamus) → Third-order neuron (cerebral cortex).
Substance P: A neurotransmitter involved in pain transmission.

Pain Control Mechanisms

Gate Control Theory: Pain signals can be blocked at the spinal cord level.
- Faster nerve signals (touch, pressure) can "gate" out slower pain signals.
- Examples: Rubbing an injured area, using cold therapy.
Descending Pain Control: The brain can influence pain perception.
- Factors: Previous pain experiences, cultural factors, beliefs, expectations.
- Placebo effect: The expectation of pain relief can sometimes reduce pain.
β-Endorphin Theory: The body releases endorphins (natural pain killers) during painful experiences.

Coping with Pain

Taking control over pain is crucial for effective coping.
Learning to manage pain can reduce its negative impact.

Pain Perception - Psychological Factors

Previous pain experience: Prior exposure to pain influences current perception.
Pain expectations: Beliefs about pain can influence how it is felt.
Pain tolerance levels: Individual variations in pain threshold.
Effect of modalities: Treatment strategies can modify pain perception.
Body part / What the individual is doing : Pain can be perceived differently depending on the body part involved and the specific activity.

Description

This quiz explores the definitions and classifications of pain, including acute, chronic, somatic, visceral, and psychological pain. Additionally, it covers the role of nociceptors in pain perception and their types. Test your knowledge and understanding of these concepts.