Acute and Chronic Polyneuropathies Flashcards
Pain Pathways
Stimulus (painful stimuli) –> Relay (synapses in the spinal cord that connect neural pathways) –> Pain (pain signals are processed in different parts of the brain) –> Regulation (the brain generates signals that descend along the spine and either inhibit or amplify the pain signals in the spine)
Types of Pain
Acute, Chronic, Referred, Central neuropathic, Autonomic, Peripheral
Acute Pain
- Normal predicted physiological response
- Serves as a warning
- Localized
- Occurs in proportion to the intensity of the stimuli or tissue damage
- Associated with anxiety, increased autonomic activity
- Usually relieved by interventions correcting the injury
Chronic Pain
- Referred to as “intractable pain” if persists for 6 months or greater
- Pain that continues after the stimulus has been removed and tissue is healed
- Believed to result from hyper-sensitization of pain receptors and enlargement of the receptor field in response to localized inflammation that follows tissue damage
- Poorly localized, has ill-defined time of onset and is strongly associated with subjective components
- Associated with: depression, difficulty sleeping, poor mental and physical function and fatigue
- *Pt’s with high anxiety and other personality traits may be able to be flagged as people that may turn into pt’s with chronic pain. **
Referred Pain
- Pain felt at a point other than it’s origin
- Can be referred from an internal organ, a joint, a trigger point or a peripheral nerve to a remote musculoskeletal structure
- Usually follows a specific pattern (ex/ cardiac pain to left UE/jaw)
- Result of a convergence of the primary afferent neurons from deep structures and muscles to secondary neurons that also have a cutaneous receptive field
Central Neuropathic Pain
- Pain initiated or caused by a primary lesion or dysfunction of the CNS, can be at many levels: nerves, nerve roots and central pathways in the spinal cord and brain
- Medically diagnosed by it’s defining neurological signs and symptoms
- Verified with neuroimaging tests
- Can be caused by vascular insult; traumatic, neoplastic and demyelintating diseases; surgery (including vascular compromise during surgery)
- Patients have difficulty describing their pain and report burning, aching, pricking, squeezing or cutting pain after cutaneous stimulation
- Difficult to treat
Autonomic Pain
- Under normal conditions there is a fine balance between parasympathetic and sympathetic branches of the ANS
- Parasympathetic activity maintains homeostasis, whereas sympathetic activity function to make “flight or fight” changes in response to stress
- Stimulation of the autonomic efferent fibers is not normally painful, but the balance between afferent input and descending sympathetic nervous system is disrupted when there is injury resulting in exaggerated and prolonged sympathetic activity, allodynia and hyperalgesia and therefore autonomic pain (CRPS)
Peripheral Pain
- Results from noxious irritation of the nociceptors
- character of peripheral pain depends on location and intensity of the noxious stimulation as well as which fibers carry the information into the dorsal gray matter
Phantom Limb
- Any non painful sensation in the amputated limb
- Cortically perceived
- Sensations such as:
- ->Kinesthetic (posture, length, volume)
- ->Kinetic (willed movements, spontaneous movements
- ->Exteroceptive sensations (touch, temperature, coldness, bugs crawling = formication)
Phantom Limb Pain
- Painful sensations that seem to occur in the lost limb
- Cortically perceived
- Cannot usually be ended by nerve blocks
- Often described as excruciating, sticking, cramping, burning, squeezing
- Cortical map still retains the anatomic image of the amputated part.
Another name for residual limb pain
“stump pain”
Residual Limb Pain
- Painful sensations localized to the stump of an amputated body part.
- Pain in the residual limb with an organic reason: blister, in grown hair, etc.
- Mediated by peripheral nerves
What kind of therapy works well for pt’s with amputation experiencing phantom limb pain?
Mirror therapy
Is phantom limb pain a CNS or PNS phenomenon?
CNS
When a pt is experiencing phantom limb pain and they undergo Transcranial Magnetic Stimulation (TMS) does their cortical map change to show amputation?
No, the cortical map is the same as it would be before the amputation, the brain does not recognize that a limb was amputated.
Over time will other areas of the cortical map eventually appropriate the cortical region that once mediated the sensation/movement of the amputated limb? Will TMS show these changes?
Yes and yes.
What is one thing that is good about phantom limb pain?
Pt can use these sensations (as long as they are not painful) to propel prosthesis.
Treatments for phantom limb pain
- Often ineffective, TENS
- Vibration
- Analgesics or painkillers may work temporarily
- Compression such as residual limb wrapping, shrinkers, or wearing the prosthesis may decrease the pain.
- *Mirror therapy works well for these patients**
Can phantom limb sensations occur in patients with SCI?
Yes, these tend to resolve quickly.
Guillain-Barre Syndrome describes a broad group of ___
demyelinating inflammation poly radiculoneuropathies
What are the two forms of GBS (guillain-barre syndrome)?
Dymyelinating polyradiculoneuropathy (AIDP)
Acute Axonal Neuropathy (AMAN)
Why does GBS result in flaccid paralysis?
Because nerve roots (radiculopathy) and peripheral nerves (polyneuropathy) are affected
What kind of motor neuron lesion is GBS considered?
Lower motor neuron lesion
Cranial nerves may be affected in GBS. What kind of lesion is this? upper/lower
Cranial nerves are LMN
What age group are affected by GBS?
Trick question: Occurs in all age groups
What symptoms of GBS do pts experience before the onset of weakness and sensory?
Most experience respiratory or GI illness before weakness and sensory.
