Cranial Neuralgias Flashcards
What is neuralgia?
- Intense stabbing pain
- Pain usually brief but may be severe
- Pain extends along course of the affected nerve
- Usually caused by irritation of or damage to nerve
What nerves can be included in cranial neuralgias?
- Trigeminal CN V
- Glossopharyngeal CN IX
- Vagus CN X
- Nervus intermedia (part of facial nerve CN VII)
- Occipital
What is the Incidence of Trigeminal neuralgia?
- F:M 6:3
- Usually elderly pt (60s or above )
- 4 in 100 000 people per year
What is Trigeminal neuralgia?
- A sudden usually unilateral severe brief stabbing recurrent episode of pain in the distribution of one or more branches of the trigeminal nerve
What are the classifications of TN?
- Idiopathic
- Classic
- Secondary
What is the clinical presentation of TN?
- Stabbing, paroxysmal, reminiscent of electric shock or burning limited to area innervated by one or more branches of trigeminal nerves
- Each episode of pain followed by refractory period lasting few seconds to several mins
- Mask like face
- No obvious precipitating pathology
Give some triggers for TN
- Slight touch to face
- Toothbrushing
- Activation if masticatory muscles and facial during speech or feeding
- Even slight wind breeze or cold
What is the pathophysiology of Classic TN?
- Neurovascular compression mostly the superior cerebelalr artery of the trigeminal nerve roots into the pons
- Compression results in demyelination of nerve fibres leading to ectopic firing
- Compression leads to nerve root atrophy or displacement
What causes secondary TN?
- Ass with underlying disease such as MS , Space occupying lesion, connective tissue disease, arteriovenous malformation
State the order of what branches are affected in TN with most affected at the start
Only one either max or mand > both max and mand > opthalmic
Give some TN red flags
- Younger pt >40yrs
- Sensory deficit in facial region like hearing loss (acoustic neruoma)
- Other cranial nerve lesions
Test cranial nerve
MRI
What is the first line drug therapy for TN?
- Carbamazepine
- Oxcarbazepine
- Lamotrigine (slow onset of action)
What is the second line drug therapy for TN?
- Gabapentin
- Pregablin
- Phenytoin
- Baclofen
What are the side effects of carbamazepine?
- Thrombocytopenia
- Neutropenia
- Pancytopenia
- Electrolyte imbalances
- Paraesthesia
- Vestibular problems
- Liver toxicity
- Skin reactions
What are the surgery indications for pts with TN?
- When approaching max tolerable medical management
- Younger pt with sig drug use (as will have many years of drug use)
What are the surgical options for TN?
- Microvascular decompression (MVD)
- Destructive central procedures like balloon compression
- Stereotactic radiosurgery using a gamma knife to kill trigeminal nerve cells
- Destructive peripheral neurectomies
What are some complications after surgery of TN?
Sensory loss of
- Corneal reflex
- General sensation
- Hearing loss
Motor deficits
Reversible or irreversible
What are some causes of painful trigeminal neuropathy? (Not TN)
- Herpes Zoster Virus (post herpetic neuralgia
- Trauma (can present <6months of traumatic event
- Idiopathic
What are the characteristics of painful trigeminal neuropathy?
- Pain localised to distribution of trigeminal nerve
- Burning or squeezing or pins and needles
- Continuous or near continuous pain
- Accompanied with clinically evident cutaneous allodynia (pain from stimulus not usually painful)
Name some trigeminal autonomic cephalalgias
- Cluster headache
- Paroxysmal hemicrania
- SUNCT
Describe a cluster headache attack
- Pain mainly orbital and temporal region
- Unilateral
- Rapid onset and can last 15mins to 3 hrs
- Rapid cessation of pian
- Excruciatingly severe (suicide headache)
- Prominent ipsilateral autonomic symptoms
- Migraine symptoms
Describe the bout of cluster headaches
- Attacks cluster into bouts typ 1-3 months with remission lasting 1 month
- 1 every other day to 8 per day
- Alcohol triggers attack in bout but not in remission
- Attacks occur at same time each day
- Bouts occur same time each year
Describe paroxysmal hemicrania
- Pain from orbital and temporal region
- Attacks are unilateral
- Rapid onset
- Duration 2-30mins
- Rapid cessation of pain
- 2-40 attacks per day (no circadian rhythm ass)
- Excruciatingly severe
- Prominent ipsilateral autonomic symptoms
- 10% attacks started by bending or rotating head
What is the drug therapy for cluster headache?
Abortive attack:
- Subcutaneous sumatriptan 6mg or nasal zolmatriptan 5mg
- 100% oxygen 7-12 L/min via non-rebreathing mask
Abortive bout
- Occipital depomedrone / lidocaine injection
- tapering course oral prednisolone
Preventative
- Lithium
- Verapamil
- Methysergide
What is the drug therapy of paroxysmal hemicrania?
- No abortive txt
- Prophylaxis with indomethacin
- COX-II inhibitors , Topiramate
