Somatosensory Function, Pain, & Headache Flashcards Preview

Pathophysiology 212 > Somatosensory Function, Pain, & Headache > Flashcards

Flashcards in Somatosensory Function, Pain, & Headache Deck (42):
1

Describe the function of the somatic nervous system

The somatic nervous system provides awareness of the body, both conscious and autonomic

2

What aspects does the somatic nervous system cover?

1. tactile
2. thermal
3. position
4. pain

3

Describe tactile, thermal, position, & pain

1. Tactile
Pressure/vibration
Initial response, often total adaptation
2. Thermal (thermoception)
Initial response, partial adaptation
3. Position (proprioception)
Sense of limb/body movement without using vision
4. Pain (nociception)

4

What is pain?

“Unpleasant sensory & emotional sensation associated with actual & potential tissue damage”

- Warns of impending injury
- Motivates seeking help
- Motivates avoidance of future injury

5

What are the two main pathways of pain?

A & B – “fast pain”
-Large, myelinated
-Pressure/touch, cold, mechanical pain, heat pain

C – “slow pain”
-Small, non-myelinated fibers
-Mechanical/chemical/heat/cold pain

6

Three Levels of Neurons Involved inSomatic Sensation

First-order: detect the sensation

Second-order: in the spinal cord; transmit message to brain

Third-order:
in the brain

7

What is a dermatome?

Region of body wall supplied by single pair of dorsal root ganglia

8

Pain theories: Specificity theory

Pain is a separate modality caused by activity of a specific receptor (nociceptor)

9

Pain theories: Pattern theory

Pain receptors share pathways and/or nerve endings with other sensory modalities
Example: light touch may not cause pain, but heavy touch of same area may.

10

Pain theories: Gate control theory

- Neural gate mechanisms in spinal cord can block pain info from going to brain by, for example, involving fibers that sense touch
- Recent research suggests this is a simplistic approach

11

Pain theories: Neuromatrix theory

-Multifactoral
-Widely distributed neural network with genetic, cognitive and sensory influences
-Helps explain phantom & chronic pain

12

Describe pain threshold

- Point at which a nociceptive stimulus is perceived as painful
- Uniform from person to person

13

Describe pain tolerance

- Maximum intensity or duration of pain a person is willing to endure
Variable:
- psychological, familial, cultural, environmental

14

Describe acute pain

Short duration; ceases when cause removed
Serves as a warning
1. Early wave
- Hyperexcitability of neurons

2. Secondary wave
- Longer lasting
- Inflammatory reaction to tissue injury

15

Describe chronic pain

- When pain persists longer than normally expected
- Highly variable
- Often not “usual” pain characteristics
- Peripheral (m/s, organ, vascular)
- Peripheral-central (neuralgias, PLP)
- Central (CNS disease/injury)

16

Possible negative consequences of Chronic Pain

1. Physiological
- Loss of appetite
- Sleep disorders
2. Psychological
- depression
3. Familial
4. Economic
chronic pain serves no useful purpose

17

Cutaneous pain

-Arises from skin/subcutaneous tissue
-Sharp, burning, abrupt/slow
-Usually localized

18

Deep somatic pain

-From deep structures (muscles, tendons, joints, blood vessels)
-Diffuse, radiation
E.g. angina

19

Visceral pain

-From activation of nociceptors of thoracic, pelvic, abdominal viscera (organs)
-Highly sensitive to distension, ischemia, inflammation (i.e. diseases)

-Relatively insensitive to cutting/burning
-Diffuse, often referred
-Deep/squeezing/sickening
-Accompanied by nausea, vomiting, emotional changes

20

Referred pain

-Originating in viscera; experienced as pain more near body surface
-Alone or concurrent with localized pain from source
Why?
-Visceral and peripheral neurons converge
-Structures develop nearby as embryo

21

Describe pain terms

Analgesia: absensce of pain
Hyperalgesia: increased sensitivity to pain
Hypoalgesia: decreased sensitivity to pain
Hyperpathia: unpleasant, prolonged response to pain, explosive
Hyperesthesia: Abnormal increase in sensitivity to sensation
Hypoesthesia: Abnormal decrease in sensitivity to sensations
Paresthesia: Abnormal touch sensation without external stimuli; tingling, pins/needles
Allodynia: Pain produced by stimuli that do not normally cause pain




22

Causes of neuropathic pain & focal/global

Causes (pathology of nervous system)
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

23

Neuropathic pain

Occurring without evidence of provocation
Widespread pain
Sensory deficits
Occurring with light touch (example of allodynia)
Burning/stabbing/etc.
Persistent/intermittent

24

Neuralgias

Severe, brief, repetitive attacks of lightening-like/throbbing pain along spinal or cranial nerve
Usually precipitated by stimulation of cutaneous region supplied by nerve
So not “neuropathic” as stimulus begins in non-neuronal tissue
Trigeminal neuralgia
Postherpetic neuralgia

25

Trigeminal Neuralgia

-Most common
-Most severe
-Facial tics/spasms
-Triggers:
-Light touch
-Movement
-Drafts
-Eating
-Possibly d/t trigeminal nerve damage

26

Postherpetic Neuralgia

-Chronic pain after shingles (herpes zoster)
-Varicella-zoster virus causes damage
-Dormant in dorsal root ganglia
-Variable pain types
Triggers
-Light touch
-Cold wind
-Clothing

27

Complex Regional Pain Syndrome (CRPS)

-Rare
-Autonomic & vasomotor instability more sensitive that -associated injury warrants
-Begins with one limb, then expands
-Severe pain or hyperalgesia
-Edema, skin blood flow changes
-Abnormal sensorimotor activity
-CRPS-I: no definable injury to nerve
-CRPS-II: allodynia/hyperalgesia after injury

28

Describe headaches: Primary & Secondary

1. Primary
-Migraine/tension-type/cluster/chronic daily
2. Secondary
-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

29

Describe migraine headaches

-Thought to be inherited
-Without aura (85%)
Pulsatile, throbbing, unilateral
Lasts 1-2 days
-Aggravated by physical activity
-Accompanied by
nausea/vomiting
Light/sound sensitivity
Visual hallucinations (sparks, flashes, etc)

30

Migraine with Aura

Similar symptoms plus pre-symptoms (aura)
Aura develops over 5-20 minutes, lasts up to one hour
- Characteristics vary but are fully reversible
Visual symptoms
- Flickering lights/spots, loss of vision
Sensory symptoms
- pins/needles, numbess
Speech or neurological disturbances

31

Retinal Migraine

-Rare
-Recurrent, fully reversible scintillations (light flashes), scotomata (blind spots), blindness in one eye

32

Chronic migraine

15+ days/month x 3 months

33

Transformed Migraine

-Similar symptoms to tension-type or sinus headache
-Possibly d/t cranial parasympathetic activation

34

Childhood periodic syndrome Migraine

- Often related to a serious disease process
3 of the following:
-Abdominal pain
-N/V
-Throbbing h/a
-Unilateral location
-Aura
-Relief with sleep
-Positive family hx.

35

Patho of Migraines

Not well understood
Trigeminal cranial nerve activation is common
Altered hormonal levels
- Estrogen thought to be related

Possible triggers
- Monosodium glutamine, chees, chocolate, etc.

36

Cluster Headache

Uncommon
Possibly hereditary
Activation of trigeminal nerve and ANS
Possible hypothalamus involvement
Men > women
30-70 years old
Lasts for weeks/months, then remission

37

Cluster Headache Manifestations

-Rapid onset pain, lasting 15-180 minutes
-Severe, constant, unilateral
-Orbital most common area
-Can radiate to temple, cheeks, gums
Accompanied by:
-Restlessness/agitation
-Conjunctival redness, lacrimation
-Nasal congestion, rhinorrhea
-Facial sweating
-Miosis (pupil constriction), ptosis, eyelid edema

38

Tension-Type Headache

-Usually don’t interfere with daily activities
-Dull, aching, diffuse
-Not associated with nausea/vomiting
-Possibly type of migraine
Associated with
-Scalp/neck muscle tension
-Oromandibular dysfunction
-Stress, anxiety, depression

39

Chronic Daily Headache (CDH)

15+ days/month
No known cause
Often resembles other headache types

40

Tempomandibular Joint (TMJ) Pain

-Imbalanced joint movement
-Poor bite, bruxism (clenching), inflammation, trauma, degeneration
-Pain: facial, head, neck, ear

41

Children and Pain

-Respond to nociceptive stimuli as neonates
-Demonstrate pain memory as infants
-Reliable/accurate reporters of pain at young age

42

Older Adults and Pain

-Common types
-Musculoskeletal (OA, back)
-Rheumatologic (RA)
-Neurologic (DN, postherpetic neuralgia)
-Unrelieved pain can result in
-Gait disturbances, muscle wasting
-Impaired appetite
-Sleep disturbances
-Decreased cognition
-Economic impact