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Neurofibromatosis 1
associated pain syndromes
Thomas J Geller, MD
NF clinic director, CGCHAssoc Prof Neurology, SLU
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Frequency of Pain as a complaint inNeurofibromatosis patients
Though numerous neurologiccomplications of NF-1 appear (optic
gliomas, subcutaneous neurofibromas,macrocephaly, plexiform neurofibromas,seizures, LDs), the most common
symptoms causing disability for adultpatients are pain symptoms. (11.3 % inZellers 1 year study of 158 adults)
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Headache studies in NF-1
North reports an incidence of 9% of severeheadache.
Zeller found adult incidence of disablingheadache to be 18%, but did not break out thepatients with common migraine.
Recurring headache in DiMaurios study occurredin 46% of NF patients; 14% met criteria for
migraine, 18% tension headache. Other studies show that migraine incidence inthe general population is about 18%, regardlessof severity.
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Age and Pain in NF-1
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Quality of life with painfulcomplications of NF-1
French dermatology study of mixed adult/ pedNF-1 demonstrated that for all aspects of the
general questionnaire, including bodily pain, ptswith NF-1 reported lower QOL scores than thegeneral population.
Increased severity of the disease was assoc with
increased negative effect on bodily pain.
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Pediatric NF Pain study
Oostenbrink studied 34 NF Dutch childrenfrom 1 to 6 yrs of age using the
infant/toddler QOL index.Added 7 questions on pain and limitationsof activity
A significant difference in QOL wasidentified from kids with bodily pain vsthose without bodily pain.
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Non-headache pain: (bodily pain)
In the 18 adults with chronic pain,symptoms began in childhood in 7.
Pain was felt to be clearly organic in 83%. In 17% the cause was unknown.
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Causes of peripheral pain
Peripheral nerve or root- 39% Surgical pain- 22%
Malignant peripheral nerve sheath tumor-17%
plexiform neurofibroma- 11%
Subcutaneous neurofibroma-11%
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Outcome of peripheral pain in NF-1
77% were able to achieve at least partialremission of pain.
Pain was intermittent in of patients.
Chronic pain was complicated by breakthruwith movement or contact of the affected nerveregion in most patients.
Optimal pain management was considered to be
analgesics, antidepressants and/oranticonvulsants. Some required neuro-stimulation or spinal procedures.
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Theoretical mechanisms of painsupersensitivity in NF-1
Changes in the excitability of dorsal rootentering the spinal cord
Study of sensory cultured neurons revealsenhanced excitability of neurons, andincreased release of painneurotransmitters CGRP and substance P.
Anxiety in the subject over the risk of painbeing associated with a malignancy
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Neuropathic
May be caused by several processes
Direct tumor infiltration
Nerve damage / demyelination
Nerve compression
Radiation
Chemotherapy (taxols & vincristine)
Viral
Metabolic
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Neuropathic
Spontaneous burningIntermittent
Radiating
Shooting
Light touch (allodynia)
Sharp
Stabbing
Pins & needles
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Cornerstones of treatment ofneuropathic pain
Because neuropathic pain has bothperipheral and central mechanisms of
development and enhancement, treatmentis probably best when multiple methods ofattack are applied.
Treatment should be applied early toavoid wind-up mechanisms of enhancedpain
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Agents for neuropathic pain
Analgesics including opioids when needed Ketotifen for neurofibromas (esp with itching) Calcium channel blocking anticonvulsants,
(Neurontin and Lyrica) Norepinephrine and serotonin blockers,
(tricyclics and Cymbalta) Possibly sodium channel blockers
PHYSIOTHERAPY Relaxation therapies Surgical management