Pain Flashcards
What physiological responses are associated with acute pain?
Physiological responses associated with acute pain include increased blood pressure, heart rate, pupil diameter, and plasma cortisol levels.
What local muscle reactions are often present with acute pain?
Local muscle contractions, such as limb flexion and abdominal wall rigidity, are often present with acute pain.
What is pain sensitization?
Pain sensitization is the process where intense, repeated, or prolonged stimuli lower the threshold for activating primary afferent nociceptors and increase their firing frequency.
What are the inflammatory mediators involved in sensitization?
Inflammatory mediators such as bradykinin (BK), nerve-growth factor, certain prostaglandins (PGs), and leukotrienes contribute to sensitization.
Where does sensitization occur in damaged or inflamed tissues?
Sensitization occurs at both the peripheral nerve terminal (peripheral sensitization) and the dorsal horn of the spinal cord (central sensitization).
How does peripheral sensitization occur?
Peripheral sensitization occurs when inflammatory mediators activate intracellular signal transduction in nociceptors, leading to increased production, transport, and membrane insertion of ion channels, thereby increasing nociceptor excitability.
What is central sensitization?
Central sensitization happens when activity generated by nociceptors during inflammation enhances the excitability of nerve cells in the dorsal horn of the spinal cord.
What are silent nociceptors?
Silent nociceptors are Aδ and C fiber afferents that are normally insensitive in noninjured, noninflamed tissue but become sensitive to mechanical stimuli in the presence of inflammatory mediators.
Can you provide a clinical example of sensitization?
Sunburned skin is a striking example of sensitization, where severe pain can be produced by a gentle slap or a warm shower. This demonstrates how normally innocuous stimuli can cause significant pain in sensitized tissues.
What role do primary afferent nociceptors play in tissue protection?
Primary afferent nociceptors play an active role in tissue protection through a neuroeffector function, releasing polypeptide mediators such as substance P, calcitonin gene related peptide (CGRP), and cholecystokinin when activated.
How does substance P contribute to inflammation, and why is it clinically significant?
Substance P contributes to inflammation by promoting vasodilation, mast cell degranulation, leukocyte recruitment, and increased release of inflammatory mediators. Clinically, understanding its role in inflammation is crucial for managing conditions where inflammation plays a significant role, such as arthritis.
Can you provide examples of conditions where substance P-mediated inflammation is relevant in clinical practice?
Conditions such as arthritis, neuropathic pain, and inflammatory bowel disease involve substance P-mediated inflammation, emphasizing the clinical significance of understanding its role and developing targeted therapies to mitigate its effects.
