Oral Med - trigeminal neuralgia Flashcards
what nerves can be affected by neuralgia? (4)
- Trigeminal – most common
- Glossopharyngeal and Vagus (vagoglossopharyngeal neuralgia)
- Nervus intermedius – branch of the facial nerve (geniculate neuralgia)
- Occipital – less common
Whos most at risk of TG neuralgia? (2)
Usually elderly patient - predominantly in 60’s and above.
Females more than men
what are the causes of TGN? (4)
which is the most common?
- Idiopathic – no cause
- Classical = Vascular compression of the trigeminal nerve = most common cause
- For it to be causative = must be evidence of compression/vascular trigeminal conflict – use MRI with contrast
(not just a close relationship) - Secondary
Common causes:
- Multiple sclerosis
- Space-occupying intracranial tumours/lesion
- Others/less common: skull-base bone deformity, connective tissue disease, arteriovenous malformation
Describe the cause of classical neuralgia.
how to we diagnose this?
Vascular compression of the trigeminal nerve
- For it to be causative = must be evidence of compression/vascular trigeminal conflict
– use MRI with contrast
Describe the causes of secondary TGN. (2)
- Multiple sclerosis
- Space-occupying intracranial tumours/lesion
What are the two ways TGN can present?
what do patients complain of? (4)
2 different presentations:
* Purely paroxysmal (no pain/symptomless in between the attacks)
* concomitant continuous pain with superimposed stabbing attacks
- One of the main characteristics:
Unilateral maxillary or mandibular division pain - Stabbing pain (each attack, even if only a couple of seconds is a group of stabs)
- stabbing lasts 5 - 10 seconds (can be up to a few mins)
- pain Triggered by
- Cutaneous = defined triggers on the skin/face
- Wind, cold
- Touch
- Chewing/speaking/jaw movement
What characteristics would describe a non-typical TGN patient (red flags) (3)
- Younger patient (>40yrs) – misdiagnosis or secondary cause
- Sensory deficit in facial region = uncommon in TG more like trigeminal neuropathy
- hearing loss = consider acoustic neuroma?
- Other Cranial nerve lesions/deficits
How do we manage a non-typical TGN patient/red flag patient? (2)
ALWAYS test all the cranial nerves (identify sensory deficits and where)
ALL patients now get MRI
What is the first line management of TGN? (3 + 1)
Medications:
* Carbamazepine (antiepileptics)
if this drug is tolerated = most TG Should be responsive
* Oxcarbazepine (antiepileptics)
* Lamotrigine (slow onset of action)- if others cannot be tolerated
Can also be responsive to local anaesthesia (maxillary and mandibular branch)
- Use if there is an attack in the chair
Name the drugs used in second line management of TGN? (4)
- Gabapentin
- Pregabalin
- Phenytoin
- Baclofen
How do we manage TGN morning pain?
increase night time dose
List the side effects of carbamazepine. (5)
- Blood dyscrasias
- Thrombocytopenia
- Neutropenia
- Pancytopenia
- Electrolyte imbalances (hyponatreamia)
- Neurological deficits
- Paraesthaesia
- Vestibular problems
- Liver toxicity
- Skin reactions (including potentially life threatening)
What are the indications for surgical management of TGN? (2)
Not usually recommended if patient managing on medical therapy with moderate drug dose and no significant side effects
Consider surgery when approaching maximum tolerable medical management even if pain controlled
‘Younger’ patients with significant drug use – will have many years of drug use
What causes painful trigeminal neuropathy? (3)
- Herpes Zoster Virus (related to active varicella zoster virus infection, post-herpetic ‘neuralgia’)
- Trauma (pain develops <6 months of traumatic event)
- Idiopathic
What are the characteristics of PGN? (5)
presentation is usually a hybrid between this and TG neuralgia – consider them as a continuum/spectrum
- pain is localized to the distribution(s) of the trigeminal nerve
- commonly described as burning or squeezing or tingling or likened to pins-and-needles.
- primary pain is usually continuous/nearly continuous and there can be a superimposed brief stabbing pain – however the stabs are not the predominant pain type, px complain of the background continuous burning pain
- commonly accompanied by a clinically evident cutaneous allodynia
where pain elicited on innocuous stimuli = touch
(area which elicits pain in this case is much larger than the punctate trigger zones present in trigeminal neuralgia and is distributed all over the affected branch) - sensory deficits common (less common but not impossible in TG neuralgia)
