morning report steven hart. hpi 45 year old female presents to clinic to establish new pmd cc: left...
TRANSCRIPT
Morning Report
Steven Hart
HPI 45 year old female presents to clinic to
establish new PMD CC: left leg pain Recent medical history
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 C/w left AKA
Incisions clean and healing well Non-tender, no erythema, skin intact
Exam otherwise unremarkable
Topics Phantom Limb Pain (PLP)
Definitions Epidemiology Etiology / Pathophysiology Evaluation / Differential Treatment
Prevention / Short term Long term
Definitions Stump pain
Pain in the residual portion of the limb
Phantom Limb Pain (PLP) A painful sensation perceived in a missing limb
after amputation
Phantom Limb Sensation (PLS) Any sensation of the missing limb (paresthesia,
dysesthesia, hyperpathia) except pain.
Epidemiology Phantom Limb Sensation (PLS)
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 Proximal ie. Above the knees or elbows Dominant extremity
Phantom Limb Pain (PLP) 60-70% of amputes experience PLP Location again an important factor
Proximal 68-88% hemipelvectomy 40-88% hip disarticulation 51% upper limb 20% AKA 0-2% BKA
Epidemiology
Epidemiology Phantom Limb Pain (PLP) – continued
Time 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 Headache Joint pain Sore throat Abd pain Back pain
Epidemiology Stump Pain
Occurs in about 50% of amputees Frequently associated with phantom
pain
Etiology Neuromas
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. Only resulted in temporary improvement Eventually pain returned, frequently worse
Modern thought - One of many factors causing PLP
Etiology Neuroma – their role
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
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
Anatomical reorganization (rewiring) 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
Somatosensory cortex remapping PLS/PLP evoked by
touching face in a hand amputee
Verified by multiple neuroimaging studies in humans
Etiology - Central mechanism
Plastic changes occur in the Thalamus Stimulation of thalamus in amputees
causes PLP and PLS Similar stimulation does not cause
any pain in non-amputees
Differential Diagnosis of PLP Radicular pain
Disk herniation Angina Post herpetic neuralgia Metastatic cancer Infection / poor wound healing
Treatment of PLP -Overview
Poorly studied field placebo effect common Spontaneous resolution does happen
Fewer than 10% of PLP patients receive lasting relief
Frequently, neuropathic treatment recommended, but few studies to support this Most neuropathic treatment trials do not include
PLP Prevention of PLP is a new area of interest
Treatment of PLP -Overview
Multiple approaches Prevention Medical Physical Therapy Nerve Blocks Nerve stimulation
Transcutaneous, spinal cord, deep brain, motor ECT Psychological Therapy
Treatment of PLP -Prevention
Goal – avoid/control the changes that lead to chronic pain
Prevent or control pre, peri and post-operative pain 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
Calcitonin infusions Ketamine Transcutaneous electrical
stimulation
Treatment of PLP -Prevention
Treatment of PLP -Medical Management
Anti-depressants Tricyclic anti-depressants Anti-convulsants NMDA receptor antagonists Opiates Beta Blockers Misc
Treatment of PLP -Medical Management
Tricyclic anti-depressants Frequently used Well studied in other neuropathic pain
syndromes Diabetes, post herpetic neuralgia
Poorly studied in PLP One randomized study showed no
effect, other studies showed some benefit
Treatment of PLP -Medical Management
Anti-convulsants Carbamazepine
Effective for intense, brief, lancinating type of pain
Gabapentin Effective in one small randomized trial
Topiramate Small randomized study supported it
effectiveness
Opiates Effective for both stump pain and PLP May affect cortical reorganization Considered the mainstay of treatment Tolerance/Addiction
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
NMDA receptor antagonists Ketamine – effective, must be IV Memantine – oral, ineffective Dextromethorphan
Small randomized studies have supported its use.
Improved feeling No, small sedation No increased side effects from placebo
Treatment of PLP -Medical Management
Treatment of PLP -Physical Therapy
Sensory discrimination training Designed to alter the cortical map Shown to significantly reduce PLP and
cortical reorganization
Transcutaneous electrical nerve stimulation
Spinal Cord Stimulation Deep brain stimulation Motor cortex stimulation
All very preliminary
Treatment of PLP -Neurostimulation
Treatment of PLP Acupuncture
May provide short term relief ECT
Several case reports of pain resolution after treatment
Psychological Therapy Relaxation training hypnosis
Conclusion 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.