To understand the ‘anatomy of pain’ Flashcards
To understand the ‘anatomy of pain’ Defining ‘pain’ o physical, emotive, and psychological aspects • Types of pain o Nociceptive: somatic – soft tissue, bone, visceral o Neuropathic • Physiology of nociceptive pain: o Nociception, transmission, perception, modulation
What is the definition of pain according to the International Association for the Study of Pain (IASP, 2012)?
An unpleasant, subjective sensory and emotional experience associated with actual or potential tissue damage.
What are the main 4 purposes of pain?
- Alert System: Warns of injury or potential injury-causing stimulus
- Protective Mechanism: Information about the environment or tissue injury
- Emotional Impact: Can cause irritability, anxiety, and behavioral changes
- Psychological Aspect: Pain can exist without physical injury.
What are the two main types of pain?
- Nociceptive Pain
- Neuropathic Pain
What causes nociceptive pain?
Activation of pain receptors (nociceptors) by noxious stimuli.
What is neuropathic pain?
Pain caused by damage to nerves, leading to chronic (long-term) pain.
What are nociceptors?
Free nerve endings present everywhere except the brain, activated by thermal, mechanical, or chemical noxious stimuli.
What are the main neurotransmitters involved in nociceptive pain?
- Glutamate
- Substance P
What are the two types of fibers involved in nociceptive pain transmission?
- A-Delta Fibers: Detect sharp, localized pain
- C-Fibers: Detect dull, aching pain
What is hyperalgesia?
Increased pain sensitivity after an injury.
What is allodynia?
Pain from non-painful stimuli.
What are the four stages of nociceptive pain?
- Nociception
- Transmission
- Perception
- Modulation
What happens during the nociception stage of pain?
Nociceptors detect noxious stimuli, and signals are transmitted via spinal nerves to the dorsal horn of the spinal cord.
What is the role of the thalamus in pain perception?
Processes pain information and relays it to higher brain centers.
True or False: Chronic pain is temporary and resolves with healing.
False
What is the difference between acute and chronic pain?
- Acute Pain: Temporary, resolves with healing
- Chronic Pain: Persistent, independent of initial cause
What is phantom limb pain?
Perceived pain in an amputated limb experienced by nearly all amputees.
What are some pharmacological approaches to pain management?
- Mild pain: Paracetamol, NSAIDs
- Moderate pain: Weak opioids (e.g., codeine)
- Severe pain: Strong opioids (e.g., morphine)
Fill in the blank: The _______ regulates pain signals in the dorsal horn according to the Gate Control Theory of Pain.
nerve gate
What is the role of prostaglandins in pain sensitization?
Prostaglandins lower the activation threshold of nerve endings, increasing sensitivity to stimuli.
What are some non-pharmacological approaches to pain management?
- Cognitive Behavioral Therapy (CBT)
- Physiotherapy & Exercise
- Transcutaneous Electrical Nerve Stimulation (TENS)
- Mindfulness & Meditation
- Acupuncture
What is neuroplasticity in the context of chronic pain?
The brain rewires itself, potentially leading to persistent pain.
What can prolonged muscular contractions lead to?
Ischemia and pain.
What is the role of A-Beta fibers in pain modulation?
Inhibit nociceptive signals in the dorsal horn.
What is the impact of psychological factors on pain perception?
They can influence pain perception, creating a pain-anxiety cycle.
What are common symptoms of neuropathic pain?
- Sharp pain
- Burning pain
- Tingling pain
- Paraesthesia
- Hypoesthesia (reduced sensation)
What is the WHO Analgesic Ladder used for?
Guides pain management strategies.
What can reduced prostaglandins due to NSAIDs lead to in the stomach?
Gastric ulcers and increased risk of stomach bleeding.
What is the effect of NSAIDs on kidney function?
Can impair kidney function, leading to fluid retention and high blood pressure.
Where are nociceptors found, and what activates them?
Found in skin, joints, muscles, and internal organs; activated by thermal, mechanical, or chemical noxious stimuli.
What neurotransmitters are involved in nociceptive signalling?
Glutamate and substance P.
What are the two types of nociceptive fibers?
A-Delta Fibers: Myelinated, fast, detect sharp, localized pain.
C-Fibers: Unmyelinated, slow, detect dull, aching pain.
How do prostaglandins contribute to pain sensitivity?
They lower the activation threshold of nociceptors, leading to hyperalgesia (heightened pain response) and allodynia (pain from non-painful stimuli).
What happens in the transmission stage?
Pain signals travel via A-Delta fibers (sharp pain) and C-Fibers (dull pain).
Neurotransmitters glutamate and substance P relay signals to spinal neurons.
Signals are sent to the thalamus via the spinothalamic tract.
What happens in the perception stage?
The thalamus processes pain and sends signals to the cortex and limbic system for sensory and emotional processing.
What happens in the modulation stage?
Gate Control Theory: A-Beta fibers inhibit pain signals.
Brainstem pathways release endorphins, serotonin, and noradrenaline to reduce pain perception.
What causes neuropathic pain?
Damage to nerves, brain, or spinal cord.
What are examples of conditions causing peripheral and central nerve damage?
Peripheral: Diabetes, chemotherapy-induced neuropathy.
Central: Stroke, multiple sclerosis, spinal cord injuries.
What are the two types of neuropathic pain sensations?
Continuous (burning/tingling) or episodic (electric-shock sensations).
What causes nerve sensitisation?
Prostaglandins and other inflammatory chemicals lower the pain threshold.
How does counter-stimulation reduce pain?
A-Beta fibers inhibit nociceptive signals in the dorsal horn.
How does descending modulation reduce pain?
The brainstem releases neurotransmitters like endorphins, serotonin, and noradrenaline that block pain signals.
