key points chronic orofacial pain Flashcards
neuralgia
intense stabbing pain brief severe along course of affected nerve usually irritation/damage to nerve
typical epidemiology of TN pt
elderly >60s
F
causes of TN
idiopathic *classical - vascular compression CN5 secondary - MS - intracranial tumours - others: skull-base bone deformity, CT disease, AV malformation
TN red flags
younger pt (<40yrs)
sensory deficit in facial region
- hearing loss - acoustic neuroma
other CN lesions
TN investigations
test CNs
MRI - all pts get one
TN presentation
unilateral stabbing - 5-10s - attack: cluster of stabs (few mins) triggers - cutaneous, wind/cold, touch, chewing/jaw movements paroxysmal (no pain between attacks) or concomitant continuous pain (superimposed stabbing attacks) remissions and relapses can be on continuum with other CN nerve pain disorders mask like face excruciating pain no obv ppt pathology
TN drug therapy
1st line - carbamazepine - oxcarbazepine - lamotrigine (slow onset) 2nd line - gabapentin - pregabalin - phenytoin - baclofen
carbamazepine SEs - clinical
blood dyscrasias - thrombocytopenia, neutropenia, pancytopenia electrolyte imbalances (hyponatraemia) - caution with PPIs/diuretics neurological deficits - paraesthesia - vestibular problems - dizziness liver toxicity skin reactions (potentially life-threatening)
carbamazepine blood monitoring
weekly for 1st month then monthly
FBC, urea, LFT, electrolytes
TN surgery indications
significant SEs
approaching max tolerable medical management even if pain controlled
‘younger’ pts with significant drug use
TN surgical options
*MVD - need vessel impinging on CN5 nerve root destructive central procedures - radiofrequency thermocoagulation - retrogasserian glycerol injection - balloon compression stereotactic radiosurgery - y-knife destructive peripheral neurectomies
TN surgical complications
local effects - peripheral txs (cryotherapy) sensory loss - corneal reflex - general sensation - hearing loss motor deficits reversible/irreversible
PTN causes
HSV
trauma (<6m)
idiopathic
PTN presentation
pain localised to distribution of CN5
burning/squeezing/pins and needles
primary pain continuous/near continuous
- superimposed brief pain paroxysms may occur, but not
the predominant pain type
often cutaneous allodynia (much larger than punctuate trigger zones in TN) and/or sensory deficits
TACs
unilateral head pain - predominantly V1 v severe/excruciating usually prominent cranial p/s autonomic features (ipsilateral) - conjunctival injection/lacrimation - nasal congestion/rhinorrhoea - eyelid oedema - ear fullness - miosis and ptosis (Horner's syndrome) orbital and temporal pain
cluster headache - attack
rapid onset and cessation duration: 15mins-3hrs pt restless and agitated during attack migrainous symptoms often present - premonitory symptoms: tiredness, yawning - associated symptoms: nausea, vomiting, photophobia, phonophobia - aura in 14%
cluster headache - bout
episodic 80-90%
chronic cluster 10-20%
cluster headache - bout - episodic
cluster of attacks into bouts - 1-3m with remission at least 1m
attack freq: one every other day to 8 per day
may be continuous background pain/symptom free between attacks
alcohol triggers attack during bout but not in remission
cluster headache circadian periodicity
striking
attacks same time each day
bouts same time each year
cluster headache - bout - chronic cluster
bouts >1yr without remission or remissions last less than 1m
cluster headache drug therapy groups
abortive (attack)
abortive (bout)
preventative
CGRP monoclonal ABs
cluster headache drug therapy - abortive (attack)
SC sumitriptan/nasal zolmatriptan
100% O2
cluster headache drug therapy - abortive (bout)
occipital depomedrone/lidocaine injection
tapering course prednisolone
cluster headache drug therapy - preventative
verapamil (not if cardiac conduction problems)
lithium (renal toxicity and diabetes insipidus)
methysergide
topiramate
cluster headache drug therapy - when would CGRP monoclonal ABs be indicated?
failed normal drug tx
paroxysmal hemicrania
rapid onset and cessation
duration 2-30mins
2-40 attacks per day (no circadian rhythm)
50% restless and agitated
may have migrainous symptoms
10% attacks may be ppt by bending/rotating head
background continuous pain can be present
80% chronic PH, 20% episodic PH
absolute response to indomethacin
- one of diagnostic criteria
paroxysmal hemicrania tx
no abortive tx
prophylaxis with indomethacin
alternatives if can’t take NSAIDs not great - COX2 inhibitors, topiramate