Somatosensory Modalities, chap 35 Flashcards
Tactile
pressure/vibration
Initial response often total adaptation. Put shirt on but get used to it
Thermal
Initial response partial adaptation. Go into the sun and feel it stronger at first, but still feel it
Position
(proprioception)
Sense of limb /body movement without using vision
Somatic Nervous system:
Provides awareness of the body, both conscious and autonomic
- Tactile
- Thermal
- Position
- Pain
Pain
An unpleasant sensory and emotional sensation associated with actual or potential tissue damage.
- warns of impeding injury
- motivates to seek help
- motivates avoidance of future injury
Two main pathways of pain:
A and B: “fast pain”-
- large myelinated fibers
- Pressure/touch…… cold, mechanical/heat pain.
C: “slow pain”
- small non-myelinated fibers
- Warm/hot, chemical…… mechanical/ heat/cold pain
3 levels of neurons involved in somatic sensation:
1st order- transmit sensory info from perifery to CNS
2nd- communicate sensory paths in spinal cord to thalamus
3rd- from thalamus to cerebral cortex
Dermatome
region of body wall supplied by single pair of dorsal root ganglia
Pain Theories: 4
- specificity theory
pain is a separate modality caused by activity of a specific receptor (nociceptor)
Pain Theories: 4
- Pattern theory
Pain receptors share pathways and/or nerve endings with other sensory modalities
ex. light touch may not cause pain, but heavy touch might cause pain in that same area
Pain Theories: 4
- Gate control theory
combined specificity and pattern.
Neural gate mechanisms in spinal cord can block pain info from going to brain by involving brain fibers that sense touch
Research: simplistic approach
Pain Theories: 4
- Neuromatrix
Multifactorial: genetic, cognitive, sensory influences of the neural network
helps explain phantom pain
Pain threshhold
point at which a nociceptive stimulus is perceived as painful
uniform from person to person
Pain tolerance
Maximum intensity or duration of pain a person is willing to endure 3/10?
Variable: psychological, familial, cultural, environmental
Acute Pain
short term duration
serves as a warning
- Early wave: activates nociceptive stimuli at site of injury and hyperexcites the neurons in the CNS
- Second wave: longer lasting
- -> inflam reaction to tissue injury ex. papter cut hurts at first but goes away bc of inflam process
Chronic Pain
when pain persists longer than normal ex ca
Highly variable- often not usual pain characteristics
- Peripheral: musculoskeletal
- Peripheral-Central: neuralgias, phantom, limb pain
- Central: CNS disease/injury
Possible negative consequences of chronic pain
- Physiological: loss appetite, sleep
- Psychological: depression
- Familial: everyone suffers
- Economic
Cutaneous pain
> skin/sc tissue
> sharp, burning, abrupt/slow
> usually localized
Deep Somatic pain
> from deep structures: muscle, tendon, bone
> diffuse, radiation
Visceral Pain
> from activation of nociceptors of thoracic, pelvic, abd vescera. Very deep!
- highly sensitive to distension, ischemia, inflam
- not to cutting and burning
Reffered Pain
> Originating in viscera: experienced as oain more near body surface ex. heart attach and pain felt in arm
> alone or concurrent with localized pain from source
WHY?
> the visceral and peripheral neurons converge
> structures develop as embryo and stay connected
Analgesia
Absence of pain
Hyperalgesia
increased sensitivity to pain
Hypoalgesia
Decreased sensitivity to pain
Hyperpathia
Unpleasant, prolonged, response to pain. Explosive. An overreaction
Pain threshold is elevated
Hyperesthesia
Abnormally increase in sensitivity to sensation
ex. hearing, smells, touch
Hypoesthesia
Abnormal decrease in sensitivity to sensation
ex, hearing, smells, touch
Paresthesia
Abnormal touch sensation without external stimuli; tingling, pins/needles
Allodynia
Pain produced by stimuli that do not normally cause pain.
A mild touch that hurts someone
Neuropathic pain
Causes:
> pressure on nerve
> physical/chemical injury to neuron
> infection/ischemia/inflammation of neuron
Focal: trauma/disease of neuron
Global: endocrine disease (DM), neurotoxic meds, chronic alcoholism
- unexplainable pain
- occurring without evidence of provocation
- widespread pain
- sensory deficits (paresthesia/numb)
- occurring with light touch (allodyna)
- burning/stabbing ect.
- persistent/intermittent
Neuralgias
> severe, brief, repetitive attacks of lightening-like throbbing pain along spinal cranial nerve
> usually percipitation by stimulation of cutaneous region supplied by nerve
- Trigeminal neuralgia (5th)-face and jaw
- postheraputic neuralgia (after shingles)
Trigeminal Neuralgia (Tix Douloureux)
most common, most severe
Facial spasms
Triggers: > light touch >movement >drafts > eating
possibly d/t trigem nerve damage
Postherpetic Neuralgia
> chronic pain after shingles (herpes zoster)
- -dormant in dorsal root ganglia
- variable pain types
> Triggers:
- -light touch
- cold wind
- clothing can hurt
Complex Regional Pain Syndrome (CRPS)
- rare, has variable changes
- Autonomic and vasomotor instability more sensitive than associated injury warrants
- begins with one limb then expands
- severe pain or hyperalgesia
- edema, skin blood flow change
- abnormal sensory motor activity
CRPS-1: no definable injury, allodynia
CRPS-2: allodynia/hyperalgesia after injury
Headaches
Primary:
Secondary:
P:
>migraine/tension-type/cluster/chrinic daily
S:
>with/following serious disease
–meningitis, cerebral tumor or aneurysm
> triggered by disturbed sleep or over-exertion
> accompanied by neurologic symptoms
– mentation changes, visual or limb disturbances
Migraine Headache:
Without aura:
> thought to be inherited
> Pulsatile, throbbing, unilateral
> lasts 1-2 days
> aggravated by physical activity
> accompanied by
- N/V
- Light/sound sensitivity
- Visual hallucinations (sparks, flashes, ect)
- -some ppl without aura may have prodromal symptoms such as fatigue, irritable for hrs or days bfr
Migraine Headache:
With aura:
> similar symptoms plus pre-symptoms (aura)
> aura develops over 5-20 min, lasts up to one hr
– characteristics vary but are fully reversible
> visual symptoms
–flickering light/spots, loss of vision
> sensory symptoms
– pins/needles, numbness
> speech or neurological disturbances
Retinal Migraine
Rare
> recurrent, fully reversible scintillations (flash or spark of light), scotomata (area or alteration in feild of vision), blindness in one eye
Chronic migraine
15 days/month x 3 months
Transformed Migraine
> similar symptoms to tension-type or sinus ha
> possibly d/t parasympathetic activation.
> increase in frequency
Childhood Periodic Syndrome Migraine
> often r/t a serious disease process***
> 3 of the following to be diagnosed
- abd pain
- N/V
- throbbing ha
- unilateral location ha
- aura
- relief with sleep
- positive family hx
Patho of migraines
> not well understood
> trigeminal cranial nerve activation is common
> altered hormonal levels
–estrogen thought to be related
> possible triggers
– monosodium glutamate, cheese, chocolate
Cluster Headache
- uncommon
- possibly hereditary
- activation of trigeminal nerve and ANS***
- possible hypothalamus involvement
- Men > women
- 30-70 yo
- last for weeks/months –> then remission
- rapid onset pain, lasting 15-18min
- severe, constant, unilateral
- orbital most common area
- can radiate to temple, cheeks, gums
Accompanied by:
- restless/aggitation
- conjunctival redness, lacrimation
- nasal congestion, rhinorrhea
- facial sweating
- Miosis (excessive constricting of pupil), ptosis (lid drooping), eyelid edema
Tension headache
> usually dont interfere with daily activities >dull, aching, diffuse > not associated with N/V > possible type of migraine > Associated with: -- scalp/neck muscle tension -- oromandibular dysfunction -- stress/anxiety/depression
Chronic Daily Headache (CDH)
- 15+ days/month
- no known cause
- often resembles other ha types
TMJ pain
> imbalanced joint movement**
–poor bite, bruxism (teeth grinding), inflam, trauma, degeneration
> pain: face, neck, ears, head
Children and pain
> respond to nociceptive stimuli as neonates
demonstrate pain memory as infants
reliable/accurate reporters of pain at young age
Older adults and pain
Common types:
- musculoskeletal
- Rheumatologic- joints, CT disorders, autoimmune
- Neurologic
Unrelieved pain can result can result in:
- gait disturbances, muscle waisting
- impaired appetite
- sleep disturbances
- decreased cognition
- economic impact
