N116, Pain 1 new2025

Heart Attack and Pain Types

• Heart Attack: Refers to a medical emergency where blood flow to the heart is blocked.

• Types of Pain:

  • Acute Pain:

    • Defined as normal physiological response, serves as a warning mechanism.

  • Chronic Pain:

    • Persists for extended periods, often associated with specific conditions.

Omega-3 Fatty Acids

• Known as non-health products (NHPs) used for inflammation treatment.

• Believed to inhibit the arachidonic acid-conversion pathway.

• Related drugs that target similar pathways should be identified in further studies.

Assessing Pain as a Symptom

• LATERSNAPS for assessment:

  • Location: Identify where the pain is.

  • Associated Symptoms: Identify any other symptoms (e.g., fever).

  • Timing: Onset and duration of pain.

  • Mechanism: Query how it started.

  • Severity: Measured on a scale of 0-10; for pediatrics, using a faces tool.

  • Radiating Pain: Is pain felt in other areas?

Nervous System Overview

• Central Nervous System (CNS): Includes brain and spinal cord.

• Peripheral Nervous System (PNS): Includes all nervous tissues outside the CNS and ENS.

  • Afferent Division: Carries sensory information to the CNS.

  • Efferent Division: Carries motor commands from the CNS.

    • Divided into:

      • Somatic Nervous System (SNS): Controls voluntary movements.

      • Autonomic Nervous System (ANS): Regulates involuntary body functions, further divided into:

        • Parasympathetic Division: Rest and digest functions.

        • Sympathetic Division: Fight or flight responses.

Sensory Receptors

• Various types of receptors:

  • Pressure Sensitive: Ruffini's endings, Pacinian corpuscles.

  • Fine Touch: Meissner's corpuscles, Merkel disks.

  • Temperature and Pain: Free nerve endings are responsible for sensing cold, warmth, and pain.

Afferent Pathway

• Pathway for sensory information from PNS to CNS:

  • Begins at sensory receptors, ends in the Somatosensory Cortex.

  • Requires a strong enough stimulus to create an action potential.

  • Nociceptors: Detect hurtful stimuli, first order neurons are part of the PNS.

CNS Transmission Pathway

• Pathway from PNS to CNS involves:

  • Nociceptors -> A or C nerve fibers -> spinal nerve -> dorsal root & ganglion -> posterior horn synapse (using substance P neurotransmitter) -> second order neuron -> decussation -> ascent in spinal cord via spinothalamic tract -> thalamus (relay station) -> synapse with third order neurons -> somatosensory cortex (localizing pain).

Pain Transmission Dynamics

• Speed of transmission: A alpha fibers are fastest; C fibers are slowest, relevant in gate control theory.

Somatosensory Cortex

• Sensory Homunculus: Maps sensory input to regions of the cortex based on anatomical structure and innervation density.

• Association areas link sensations to past experiences.

Pain Awareness

• Large stimuli may activate multiple receptors leading to higher pain awareness (e.g., trauma).

Pain Experiences and Management

• Questions for patient experiences include:

  • What treatments did they use?

  • Duration of pain?

Non-Pharmacological Techniques

• Techniques to manage and reduce pain:

  • Application of ice to decrease inflammation.

  • Massage and physiotherapy for alleviation.

  • Distraction methods and cognitive behavior therapy (CBT) to manage perception of pain.

Pain Terminology

• Types of Pain:

  • Visceral Pain: Deep pain, organ-related.

  • Cutaneous Pain: Superficial, surface-related pain.

  • Referred Pain: Pain felt in areas connected to organ innervation.

  • Chronic Pain: Lasts longer than 6 months, often involves C fibers and neurogenic inflammation; can lead to complicated symptoms and treatment challenges.

  • Neuropathic Pain: Nerve irritation leading to allodynia, hyperalgesia, and paresthesias.

  • Phantom Pain: Pain felt in an area where a limb has been amputated due to remaining activity in spinal cord neurons.

Dermatomes Application

• Clinical use of dermatomes: assess cutaneous segments serviced by the same spinal nerve for sensory and motor pathway diagnostics.

Reflexes

• Flexor Withdrawal Reflex: Triggered by sharp pain, involving sensory neurons activating interneurons for immediate withdrawal from the painful stimulus without cerebral control.

Acute vs. Chronic Pain

• Acute Pain: Generally lasts less than 10 days, is self-limiting, responds well to treatment, and signifies protective mechanisms.

• Chronic Pain: Lasts longer than 6 months, can be a result of untreated acute pain or chronic conditions, and demands multi-modal treatment approaches.

Endogenous Modulators of Pain

• Neuromodulators: Endogenous opioid peptides (endorphins, enkephalins, dynorphins), serotonin & norepinephrine, act within the efferent pain pathways to inhibit pain signals by binding to opioid receptors.

Pain Gate Theory Homework

• Review the Pain Gate theory:

  • A proposed mechanism by which pain signals can be interrupted in the substantia gelatinosa of the spinal cord.