Transcript Morning Report - Steve's Homepage

Morning Report
Steven Hart
HPI
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45 year old female presents to clinic to
establish new PMD
CC: left leg pain
Recent medical history
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Pain in left LE for 1 mo with several visits to ER
left femoral thrombus and emboli to left lower
extremity eventually diagnosed
Left AKA required
Now (6 weeks later) c/o persistent pain where
lower left leg was and sensations in left leg.
Started on coumadin prior to discharge
Physical exam
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C/w left AKA
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Incisions clean and healing well
Non-tender, no erythema, skin intact
Exam otherwise unremarkable
Topics
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Phantom Limb Pain (PLP)
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Definitions
Epidemiology
Etiology / Pathophysiology
Evaluation / Differential
Treatment
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Prevention / Short term
Long term
Definitions
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Stump pain
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Phantom Limb Pain (PLP)
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Pain in the residual portion of the limb
A painful sensation perceived in a missing limb
after amputation
Phantom Limb Sensation (PLS)
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Any sensation of the missing limb (paresthesia,
dysesthesia, hyperpathia) except pain.
Epidemiology
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Phantom Limb Sensation (PLS)
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Occurs in 85% - 98% of amputees within 3 weeks
of amputation
8% may occur after 1-12 months
Usually resolves after 2 – 3 years spontaneously if
PLP does not develop
Location affects intensity and likelihood of PLS
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Proximal ie. Above the knees or elbows
Dominant extremity
Epidemiology
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Phantom Limb Pain (PLP)
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60-70% of amputes experience PLP
Location again an important factor
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Proximal
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68-88% hemipelvectomy
40-88% hip disarticulation
51% upper limb
20% AKA
0-2% BKA
Epidemiology
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Phantom Limb Pain (PLP) – continued
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Time
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Occurs 1 week to decades after amputation
Pain onset after one year in < 10%
May diminish and eventually resolve with time
More likely, however, it will persist chronically
Pain in limb prior to amputation increases risk for
PLP
Pains in other parts of the body
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Headache
Joint pain
Sore throat
Abd pain
Back pain
Epidemiology
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Stump Pain
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Occurs in about 50% of amputees
Frequently associated with phantom pain
Etiology
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Neuromas
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Dominate theory until last 10-15 years
Irritation of the severed nerve endings
Inflammation resulted in anomalous signals to the
brain perceived as pain.
Treatments included removal of nerve endings or
further amputation.
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Only resulted in temporary improvement
Eventually pain returned, frequently worse
Modern thought - One of many factors causing
PLP
Etiology
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Neuroma – their role
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 mechanical/neurostimulation 
spontaneous and abnormal evoked activity 
 in sodium channel production 
 in sensitivity of neuromas to norepinephrine
Thus, pain with stress or other emotional states
A similar phenomenon occurs in the cell body of
the dorsal root ganglia just upstream
Etiology
-spinal cord level
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 signal from neuromas and doral root
ganglia cell bodies 
 activity of neurons in dorsal horns 
 upregulation of several genes
- especially receptive genes
-  in N-methyl-D-aspartate (NDMA)
Etiology
-spinal cord level
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Anatomical reorganization
(rewiring)
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Perph nerve transection 
degeneration of afferent C-fiber
terminals in Lamina II
These may replaced by A
mechanoreceptive afferents
Results in pain evoked by simple
touch
Etiology
- Central mechanism
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Somatosensory cortex
remapping
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PLS/PLP evoked by
touching face in a
hand amputee
Verified by multiple
neuroimaging studies
in humans
Etiology
- Central mechanism
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Plastic changes occur in the Thalamus
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Stimulation of thalamus in amputees
causes PLP and PLS
Similar stimulation does not cause any pain
in non-amputees
Differential Diagnosis of PLP
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Radicular pain
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Disk herniation
Angina
Post herpetic neuralgia
Metastatic cancer
Infection / poor wound healing
Treatment of PLP
-Overview
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Poorly studied field
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Fewer than 10% of PLP patients receive
lasting relief
Frequently, neuropathic treatment
recommended, but few studies to support
this
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placebo effect common
Spontaneous resolution does happen
Most neuropathic treatment trials do not include
PLP
Prevention of PLP is a new area of interest
Treatment of PLP
-Overview
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Multiple approaches
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Prevention
Medical
Physical Therapy
Nerve Blocks
Nerve stimulation
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Transcutaneous, spinal cord, deep brain, motor
ECT
Psychological Therapy
Treatment of PLP
-Prevention
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Goal – avoid/control the changes that
lead to chronic pain
Prevent or control pre, peri and postoperative pain
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Use of pre, intra and post-op epidural
blocks has been shown to reduce
occurrence of PLP at 12 mo post-op
Mixed results in follow up studies
Treatment of PLP
-Prevention
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Calcitonin infusions
Ketamine
Transcutaneous electrical stimulation
Treatment of PLP
-Medical Management
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Anti-depressants
Tricyclic anti-depressants
Anti-convulsants
NMDA receptor antagonists
Opiates
Beta Blockers
Misc
Treatment of PLP
-Medical Management
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Tricyclic anti-depressants
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Frequently used
Well studied in other neuropathic pain
syndromes
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Diabetes, post herpetic neuralgia
Poorly studied in PLP
One randomized study showed no effect,
other studies showed some benefit
Treatment of PLP
-Medical Management
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Anti-convulsants
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Carbamazepine
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Gabapentin
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Effective for intense, brief, lancinating type of
pain
Effective in one small randomized trial
Topiramate
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Small randomized study supported it
effectiveness
Treatment of PLP
-Medical Management
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Opiates
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Effective for both stump pain and PLP
May affect cortical reorganization
Considered the mainstay of treatment
Tolerance/Addiction
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Most amputees have a short life expectancy
because of underlying disease.
Balance quality of life vs risk of opiate
addiction/dependence
Treatment of PLP
-Medical Management
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NMDA receptor antagonists
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Ketamine – effective, must be IV
Memantine – oral, ineffective
Dextromethorphan
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Small randomized studies have supported its
use.
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Improved feeling
No, small sedation
No increased side effects from placebo
Treatment of PLP
-Physical Therapy
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Sensory discrimination training
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Designed to alter the cortical map
Shown to significantly reduce PLP and
cortical reorganization
Treatment of PLP
-Neurostimulation
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Transcutaneous electrical nerve
stimulation
Spinal Cord Stimulation
Deep brain stimulation
Motor cortex stimulation
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All very preliminary
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Treatment of PLP
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Acupuncture
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ECT
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May provide short term relief
Several case reports of pain resolution
after treatment
Psychological Therapy
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Relaxation training
hypnosis
Conclusion
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PLP is common in amputees
The cause is complicated and involves
virtually all levels of the nervous system
Prevention of chronic pain may be possible
but further investigation is needed
Chronic pain management is difficult and
should be multifaceted
There is little evidence to guide therapy at
this time.