Exam 3 - Pathophysiology of CNS Disorders (Long) Flashcards
Pain physiology
- pain is subjective
- unpleasant and linked to emotional experiences
Nociception
- a type of pain
- process by which information about a noxious (harmful) stimulus is conveyed to the brain
Nociception is the sum of…
Neural activity prior to the cognitive processes to identify a sensation as pain (perception)
Neural activity that identify a sensation as pain (perception)
Transduction
Transmission & conduction
Descending modulation
Transduction definition
Process whereby a noxious stimulus activates sensory receptors to initiate an action potential (electrical impulse)
Explain transduction
Noxious stimuli induce the release of chemicals
These bind to increase the excitability of the neuronal cell membrane and lead to generation of propagated action potentials (electrical impulse)
Where does transduction occur
At nociceptors
Conduction
Nociceptor activation leading to action potentials that continue along afferent fibers to the spinal cord
Transmission: excitation
Na+ increases
K+ and Cl- decrease
Depolarization
Define transmission
Action potentials (nerve impulses) conducted to the CNS from activation of Na+ channels at synaptic junctions of neurons
Transmission: inhibition
Increased influx of K+ and Cl-
Polarization
Perception
Process by which a noxious event is recognized as pain
In transmission, where does the nerve impulse go after excitation and inhibition
Continues to the thalamus
Impulses are then relayed to multiple areas of the brain (eg somatosensory cortex = the processing center)
Modulation
Descending input from the brain that affects nociceptive transmission in the spinal cord
Migraine triggers: Limbic system
Affective emotional response to the noxious stimulus
Perception: somatosensory cortex and insular cortex
Involved in sensory-discriminative component
Pain physiology types: nociceptive
Due to noxious insult or injury of tissues (adaptive pain)
Pain physiology types
Nociceptive
Neuropathic
Inflammatory
Pain physiology types: neuropathic
Due to lesion or disease in the somatosensory nervous system (maladaptive pain)
Pain physiology types: inflammatory
Activation and sensitization of the nociceptive pain pathway by mediators released at a site of tissue inflammation (eg. proinflammatory cytokines)
Headache pathophysiology
- most are either migraine or tension headaches
- may be preceded by warning signs/symptoms (auras)
- activation of trigeminal sensory nerves triggers release of proinflammatory neuropeptides (eg. Neurokinin A, substance P —> potent vasodilators) to induce manifestation
Migraine epidemiology
Occurs more in women than men
What do vasodilators do and give examples of them
Widen (dilate) blood vessels to decrease BP
Examples:
- Neurokinin A
- Estrogen
- Bradykinin
- Substance P
- Histamine
- Prostacyclin (PGI2)
- Prostaglandin E2 (PGE2)
(Never Ever Be Sucking Hairy PP)
What do vasoconstrictors do and give examples of them
Narrow (constrict) BP to increase BP
Examples:
Serotonin
Caffeine
Angiotensin II
Neuropeptide Y
Testosterone
Epinephrine/norepinephrine
Cortisol
NSAIDs (non-salicylates)
Vassopressin
(She CANT Even Catch New Vag)
Tension headaches are usually due to
Vasoconstriction
What is the most commonly reported trigger for tension headaches
Stress
How do tension headaches differ from migraines
- Not associated w/ visual disturbances or auras
- Does NOT cause nausea/vomiting
- Not intensified by physical activity
- Not throbbing or pulsatile
- Bilateral pain, on both sides of head
Cluster headache
- severe pain (worse than migraine) in the orbital, supraorbital, or temporal region of head
- unilateral, pulsating pain
- more common in men
- associated w/ vasodilation
Are cluster headaches primary or secondary
Primary
What causes exercise headaches
Vasodilation
Pathophysiology of fever
- elevation of body temp
- core body temp is controlled by the hypothalamus and regulated by feedback mechanisms
- the thermostatic set point of the hypothalamus’ thermoregulatory center is set so that the core temperature is regulated within the normal range
Medication use headaches occur from
Medication overuse
Aka “rebound headaches”
Core body temp is controlled by the _______ and regulated by ________
Hypothalamus
Feedback mechanisms
What is a pyrogen
Any substance that causes fever
Where do most exogenous pyrogens come from
Microbes
Lipopolysaccharide endotoxin (LPS) is a pyrogen and is _______ bacteria
Gram-negatice
What does LPS initiate
Macrophage secretion of endogenous pyrogens (ie. Cytokines, prostaglandins, leukotrienes, thromboxane)
________ also produce pyrogens that activate macrophages
Gram-positive bacteria
Gram-positive bacteria
Some strains of S aureus and S pyogenes also release superantigen
Fever occurs in _______, caused by S aureus and S pyogenes
Toxic shock syndrome
Fever pathogenesis
Pyrogens induce prostaglandin E2 (PGE2) formation, which increases the thermostatic set point in the hypothalamus
Induces vasoconstriction, shivering, and increased metabolism can increase body temp
Pathogenesis of musculoskeletal pain: what is included in the musculoskeletal system
Muscles
Tendons
Ligaments
Cartilage
Bones
Pathogenesis of musculoskeletal pain: Somatic pain
Musculoskeletal, skin
Due to noxious stimuli
Pathogenesis of musculoskeletal pain: What is tendonitis?
Tendon inflammation due to acute injury or from repetitive movements
Pathogenesis of musculoskeletal pain: Stains
Muscle or tendon injury due to hyperextension causing them to tear
Pathogenesis of musculoskeletal pain: Myalgia
Muscle pain
Instigated by a variety of noxious stimuli
Pathogenesis of musculoskeletal pain: What are the types of tendonitis
Carpal tunnel syndrome
Sports-related tendonitis
Medication-related tendonitis
Carpal tunnel syndrome
Tingling or numbness of the first digits of the hand
Sports related tendonitis
Overuse of elbow, shoulder, or knee
Medication related tendonitis
Drugs that weaken tendons
eg. Fluoroquinolones like cipro, levaquin
Pathogenesis of musculoskeletal pain: Bursitis
Inflammation of the fluid-filled pads (bursae)
Pathogenesis of musculoskeletal pain: Sprains
Most common problem with ligaments
Pathogenesis of musculoskeletal pain: Low back pain
May arise due to:
- nerve compression (eg pinched nerve)
- trauma related and degenerative disorders
Pathogenesis of musculoskeletal pain: Osteoarthritis
- degenerative joint disease
- results in gradual softening and destruction of the cartilage between bones, leading to loss of space between joints
- joint deformities
John is considering two types of local analgesics for sports related tendonitis. Both are numbing agents that block Na+ channels in rapid-firing neurons. What are the two analgesics?
A. Camphor
B. Lidocaine
C. Hydrocortisone
D. Capsaicin
E. Diphenhydramine
Lidocaine and diphenhydramine
What physiological effects does aspirin have on the body? SATA
A. Increases TXA2 synthesis
B. Causes vasodilation
C. Increases gastric acid secretion
D. Increases the thermostatic set point
E. Decreases PGI2 synthesis
Increases gastric acid secretion
Decreases PGI2 synthesis
Which cytokine is primarily responsible for increasing the set point of hypothalamic thermoregulatory center to induce fever?
A. PGI2
B. PGE2
C. TXA2
D. Arachidonic acid
PGE2
Which toxicity and medication is mismatched?
Statin - myalgia
Fluoroquinolone - tendonitis
Tylenol - antithrombotic
Advil - GI bleeding
Bayer - gastric ulcer
Tylenol - antithrombotic
Tension type headaches are the result of cerebral vasoconstriction. Which two endogenous chemicals would be involved in the pathology of these headache types?
A. Serotonin
B. Substance P
C. Neurokinin
D. Norepinephrine
E. Bradykinin
F. Prostacyclin
Serotonin
Norepinephrine
Which statements below are FALSE?
A. Migraines are induced by vasodilators
B. Cluster headaches are more common in females
C. Auras are common w/ tension headaches
D. Epinephrine is a vasoconstrictor
B and C
B is wrong because cluster headaches are more common in men
C is wrong because auras only occur with migraines
Which statement below is true?
A. Nerve excitation is caused by polarization
B. Nerve excitation is caused by increased potassium permeability
C. Nerve excitation is caused by increased sodium permeability
D. Nerve excitation is caused by increased chloride permeability
C. Nerve excitation is caused by increased sodium permeability
What bacterial species is implicated in toxic shock syndrome?
A. Escherichia coli
B. Enterococcus faecalis
C. Streptococcus pyogenes
D. Salmonella typhi
E. Pseudomonas aeruginosa
Streptococcus pyogenes
