trigeminal neuralgia and facial pain Flashcards
what is TN?
> A disorder of the trigeminal nerve that consists of episodes of unilateral, intense, stabbing, electric shock-like pain in the areas of the face where the branches of the nerve are distributed.
> Universally considered to be one of the most painful afflictions known: tic doloreux
what are the subtypes of TN?
- Idiopathic without other disease/cause
- Classical: signs of trigeminal nerve root comression
- Secondary TN may occur in presence of organic disease such as =
> Tumours of trigeminal nerve (neuromas)
> Lesions affecting the trigeminal nerve at the cerebellopontine angle
> MS or demyelination
> Cerebral neoplasms
what causes Primary/ idiopathic/ classical TN?
> No clinically obvious neurological cause
> May be due to pressure on the trigeminal nerve root in the posterior cranial fossa from an adjacent vessel pressing on nerve root causing demyelination/neuronal discharge)-classical
> No predisposing factors but emotional or physical stress can increase frequency and severity of attacks
> No neurological deficit in Primary TN but 2TN needs to be excluded eg is there any sign of demyelination, any tumours?
what is mandatory if you suspect TN?
> MRI scan
how many people in the population are affected by primary TN?
> 4/ 100000
what is the pain history of TN?
> Sudden, sharp, severe stabbing pain
> Lasts few seconds to <2mins
> Attacks may be more common in the morning
> Occurs spontaneously but can be triggered by touch/movement of face: shaving, cold air
> Affects normally one branch of trigeminal nerve V1, V2, V3 and unilateral: if different to this ? secondary cause
> Entirely asymptomatic between attacks (rarely patients report dull ache at other times): atypical variant (read articles by P. Eldridge)
is TN bilateral or unilateral?
> unilateral
> does not cross the midline
is TN more common in males or females?
> females
when is the onset of TN?
> onset usually 50-70 years old
> if younger think of MS
does TN effect sleep?
> no. doesn’t disturb
what do patients tend to do when experiencing TN?
> bring there hands up to their face
> Mask like expression
> quality of life severely affected?
how do you diagnose TN?
> Based on history
> Neurological assessment (negative)
> rule out dental cause
> May identify trigger areas on examination
> Otherwise NAD
> Special investigations
what special investigations do you carry out to diagnose TN?
> MRI brain
> MR angiography can identify neurovascular compression of trigeminal nerve
> Trial of Carbamazepine
what is the treatment for TN?
> Carbamazepine 100mg bd for 2 weeks
> If pain control not achieved, increase to 100mg tds
> Can continue further staged increases of Carbamazepine, or consider Phenytoin, Baclofen, Gabapentin, Pregabalin, Lamotrigine
> Medical management successful in >80% of cases, most respond to low dose
> FBC,U&E, LFT initially and monitored (quite easy to cause a drug induced hepatitis, and hyponeutrimia)
what type of drug is carbamazepine?
> Anticonvulsant, not an analgesic
> Most patients respond to 200-400mg tds daily
do patients suffer from adverse affects with carbamazepine and if so what are they ?
> yes, adverse effects occur in up to one third of patients
> Ataxia
Drowsiness
Visual disturbance
Headache
GI upset
Folate deficiency
Hypertension
Rashes
Pancytopenia or, rarely, leucopenia (typically within first 3 months of treatment)
> common that patients have problems at the start by symptoms will go away after they get used to the drug
what should patients on carbamazepine be monitored on ?
> Blood pressure
> U&E
> LFT
> FBC (bone marrow function)
> Folate
what is an alternative for carbamazepine?
> Oxcarbazepine may be better tolerated: doses slightly different-see BNF
what are the examples of surgery for TN management in patients?
- Peripheral surgery
- Cryosurgery of affected branch of nerve
- Radiofrequency thermocoagulation - Intracranial surgery
- Microvascular decompression (Gold Standard) - pad goes in between the artery and the nerve - Percutaneous surgery
- Radiofrequency lesioning (risk of anaesthesia dolorosa) - Stereotactic gamma knife radiosurgery
- 80% pain control, takes 6 weeks to work
what is giant cell arteritis?
> Immunological/vasculitic condition in which there is inflammation of medium sized arteries especially in the head and neck
what are the symptoms of giant cell arteritis?
> Severe burning pain in distribution of the affected vessel – temporal, tongue or masticatory muscle region
> Headache is intense, deep, aching, throbbing, persistent
> May be worse when lying flat in bed
> Affected artery may be enlarged and tender
who does Giant cell arteritis tend to affect?
> affects older patients (>50)
> F>M
what are the associated symtoms of giant cell arteritis?
> May experience jaw claudication (pain on chewing)
> Can cause pain and necrosis in tongue or lip
> If retinal artery affected, risk of blindness-DO NOT MISS THIS!
