Page 784 - TNFlipTest

N42 Neurology
Pain Syndromes Toronto Notes 2019
Symptoms and Signs
• hyperalgesia, allodynia
• subjectivelydescribedasburning,heat/cold,pricking,electricshock,perceptionofswelling,numbness • canbespontaneousorstimulusevoked,distributionmaynotfallalongclassicalneuro-anatomicallines • associatedissues:sleepdifficulty,anxiety/stress/moodalteration
Causes of Neuropathic Pain
• sympathetic:CRPS
• non-sympathetic:damagetoperipheralnerves
■ systemic disease: DM, thyroid disease, renal disease, rheumatoid arthritis, multiple sclerosis
■ nutritional/toxicity: alcoholism, pernicious anemia, chemotherapy
■ infectious: post-herpetic, HIV
■ trauma/compression: nerve entrapment, trigeminal neuralgia, post-surgical, nerve injury, cervical/
lumbar radiculopathy, plexopathy • central:abnormalCNSactivity
■ phantom limb, post spinal cord injury, post stroke, MS
Treatment
• identify/treatunderlyingcause • pharmacotherapy
■ Stepwise approach (Canadian Pain Society, 2014) ◆ 1st line: gabapentinoids, TCA, SNRI
◆ 2nd line: tramadol, opioid analgesics
◆ 3rd line: cannabinoids
◆ 4th line: topical lidocaine (second line for postherpetic neuralgia), methadone, lamotrigine, lacosamide, tapentadol, botulinum toxin
• commonnon-pharmacologictherapies ■ neuropsychiatry: CBT, psychotherapy ■ rehabilitation: physiotherapy
• surgicaltherapies:dorsalcolumnneurostimulator,DBS(thalamus) Trigeminal Neuralgia
Clinical Features
• recurrentepisodesofsuddenonset,excruciating,unilateral,paroxysmal,shooting“electric”painin trigeminal root territory (V3>V2>>V1)
• mayhavenormalsensoryexam
• painlastsseconds/minutesoverdays/weeks;mayremitforweeks/months
• triggers:touchingface,eating,talking,coldwind,shaving,applyingmake-up
Etiology
• classicTN:idiopathic
• 2oTN:compressionbytortuousbloodvessel(superiorcerebellarartery),cerebellopontineangle
tumour (5%), MS (5%)
Epidemiology
• F>M;usuallymiddle-agedandelderly
Diagnosis
• clinicaldiagnosis
• investigateforsecondarycauses,whicharemorelikelyifbilateralTNorassociatedsensoryloss
■ MRI to rule out structural lesion, MS, or vascular lesion
Treatment
• firstline:carbamazepineoroxcarbazepine
• secondline:baclofenorlamotrigine
• narcoticsnotgenerallyrecommended
• ifmedicaltreatmentfails:trigeminalganglionpercutaneoustechnique,gammaknife,invasive
percutaneous denervation (radiofrequency/glycerol), percutaneous balloon microcompression, microvascular decompression
Postherpetic Neuralgia
Clinical Features
• painpersistingintheregionofacutaneousoutbreakofherpeszoster
• constantdeepacheorburning,intermittentspontaneouslancinating/jabbingpain,allodynia • distribution: thoracic, trigeminal, cervical, lumbar, sacral
• associatedsymptoms:impairedsleep,decreasedappetite,decreasedlibido
Herpes Zoster of Trigeminal Nerve
Typically involves V1 (ophthalmic division)
Hutchinson’s Sign
Tip of nose involvement predicts corneal involvement