Peripheral Neuropathy Flashcards
What are the 3 main disorders relating to peripheral neuropathy
- Trigeminal neuralgia
- Idiopathic facial palsy (Bell’s palsy)
- Acute inflammatory demyelinating polyneuropathy
Define: trigeminal neuralgia
It is the abbraviation of primary trigeminal neuralgia
- transcient recureent paroxysmal pain in the territory of the trigeminal nerve
What is the etiology of trigeminal neuralgia
- peripheral hypothesis: compression of trigeminal nerve before it enters the lateral surface of the pons
- central hypothesis (sensory): abnormal discharge may be in nucleus of spinal tract of trigeminal nerve or brainstem
What is the mechanism of trigeminal neuralgia
compression –> demyelination –> hyperexcitable and electrically couples with smaller unmyelinated or poorly myelinated pain fibres in close proximity
List the main clinical findings of trigeminal neuralgia
- middle aged and elderly people are most affected
- 60% of cases are in women
- sudden lacinating facial pain
- trigger points
- spontaneous remission
- symptoms may be confined to distribution of trigeminal nerve on one side only
- neurological examination may show no positive signs
- CT and radiology is normal
How is trigeminal neuralgia diagnosed?
- brief episodes of stabbing facial pain
- pain is in territory of the second and third division of the trigeminal nerve
- pain is exacerbated by touch
- sensory deficit cannot be differentiated
What is the differential diagnosis for trigeminal neuralgia
- secondary trigeminal neuralgia
- glossopharyngeal neuralgia
- atypical facial pain
- post therpetic neuralgia
What is the treatment plan for trigeminal neuralgia
- Pharmacologic treatment
- carbamazepine
- phenytoin
- baclofen
- gabapentin
- pregabalin - microvascular decompression
What is Idiopathic facial palsy (Bell’s palsy)
idiopathic facial nerve paresis of LMN type that has been attributed to an inflammatory reaction involving the facial nerve near the stylomastoid foramen in the bony facial canal
List the clinical findings of Bell’s palsy
- paresis usually comes on abruptly (may worsen over the next day)
- pain around ear only lasts a few days
- face feels stiff and pulled to one side; ipsilateral restriction of eye closure and difficulty with eating and fine facial movement
- disturbance of taste
- hyperacusis
- full recovery within several weeks or months in 80%
- incomplete paralysis in first week is a favorable prognosis sign
How is Bell’s palsy diagnosed
- sudden onset of LMN facial palsy
- hyperacusis or impaired taste may occur
- no risk factors or pre-exisitng symptoms that may cause palsy
- no lesions of herpes zoster in external ear canal
- normal neurologic examination except for facial nerve
List some of the differential diagnoses of Bell’s palsy
- Ramsy Hunt syndrome
- Acoustic Neuroma
- Infection
- Bilateral facial weakness
- Hemifacial spasm
- belpharospasm
What is the treatment of Bell’s palsy
- Protecting eye during sleep (eyedrops)
- corticosteroids appear to shorten recovery period and improve functional outcome (within 5 days of onset)
- Hunt syndrome (acyclovir + prednisone)
- acupuncture and rehabilitation to help function recovery
What aspects of Bell’s palsy have poor prognosis
- advanced age
- hyperacusis
- severe initial pain
What is acute inflammatory demyelinating polyneuropathy (AIDP)
Guillian-Barre syndrome
- acute, frequently severe and fulminant polyradiculoneuropathy that is autoimmune in nature
