Lecture 11- PNS Pathologies: Peripheral nerve injuries and diseases Flashcards by Tempo Sabatier

where does the facial nerve originate from?

pon

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what type of nerve fibers is the facial nerve?

mixed - somatic (sensory and motor) and automatic fibers

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what is the somatic sensory function of the facial (CN VII) nerve?

sensation of touch, pain, temp and proprioception

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what is the somatic motor function of the facial nerve?

facial expression (innervates scalp, facial and neck muscles)

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what is the autonomic motor (parasympathetics) function of the facial nerve?

-secretion of saliva and tears
-taste of anterior 2/3 of tongue (supply taste buds)
(salivary, sublingual, parotid, lacrimal glands)

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what is another name for idiopathic facial paralysis?

Bell’s palsy

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what is Bell’s Palsy?

facial nerve is unilaterally affected = paralysis of facial muscles - most commonly seen in 15-45 year olds (can affect any age group)

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is Bell’s palsy unilateral or bilateral?

it can be either, but more commonly unilateral

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what are 2 possible characteristic presentation of Bell’s palsy, noted days before onset?

severe pain in mastoid area

sensation of fullness in ears

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what is a viral component associated with Bell’s palsy?

reactivated latent HERPES ZOSTER virus (shingles)

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what is a bacterial component associated with Bell’s palsy?

bacteria that causes lyme disease could damage facial nerver

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what canal does the facial nerve lie in?

auditory canal

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what are 2 possible outcomes of a mass developing in the auditory canal?

compression of the facial nerve leading to swelling (inflammation) and demylinisation of the facial nerve

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how can acoustic neuromas impact the facial nerve?

they may compress the facial nerve- but symptoms are slow progressing

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what are 2 systemic risk factors related to an increased risk of Bell’s palsy?

DM (impacts somatic and autonomic nerves due to impacted/damaged blood supply)
pregnancy (hormones by placenta may = nerve damage)

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does unilateral facial paralysis develop slow or fast?

rapidly (over night)

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what are 4 presentations seen with paralysis of the muscles of facial expression?

asymmetrical facial appearance
corner of mouth drops
nasolabial fold is flattened
palpebral fissure is widened (eye does not close)

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what can happen is the stapedius muscle (innervated by facial nerve) is damaged (Bell’s palsy)?

sounds will be louder than normal

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what can happen is the autonomic fibers of the facial nerve are damaged?

loss of taste on affected side of tongue (ant 2/3)
less/thicker saliva (salivary gland impacted)
dry eyes (lacrimal gland impacted)

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how much may pairing corticosteroids with antiviral treatment, increase the recovery rate from Bell’s palsy?

may increase recovery rate to 95%

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what is an ASAP treatment of Bell’s palsy?

high dose of corticosteroid for 5 days than lowered for 5 more days to prevent permanent damage

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what is the difference in recovery rate from Bell’s palsy if treated within 3 days of onset, compared to 4 days after?

within 3 days = 100%

after 4 days = 86%

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why might an eye patch be used in the treatment plan of Bell’s palsy?

to protect the cornea of the open eye (due to palpebral fissure widening)

what are 3 categories that can result in a poor prognosis of Bell’s palsy?

60+
co morbidities: diabetes or HBP
ANS involvement

what is the sensory function of the trigeminal nerve?

touch, pain and temp sensation

what is the motor function of the trigeminal nerve?

mastication (innervates chewing muscles)

what is the characteristic presentation of trigeminal neuralgia?

intense paroxysms

define 'intense paroxysm' in relation to trigeminal neuralgia?

attack of lancinating (piercing/ stabbing) pain within the trigeminal nerve distribution

what is another name for trigeminal neuralgia?

tic douloureux

what group does trigeminal neuralgia typically affect?

women age 50-70

what are 6 possible causes of trigeminal neuralgia?

``` herpes zoster virus MS (affects myelin sheath) vascular lesions tumors (nerve infiltration) lack of B12 (vit D possibly too) idiopathic ```

what is a hypothesis for the pathogenesis of trigeminal neuralgia?

damaged nerve demylinisation can cause paroxysm of pain

how can the pain be described by someone suffering from trigeminal neuralgia?

lightening bolt pain inside head that may last seconds to minutes

what is the primary area most commonly involved in pain sensation of trigeminal neuralgia?

maxillary division (ophthalmic division is less likely involved)

with trigeminal neuralgia what are a few mechanical stimuli that may trigger the pain?

chewing, smiling, breeze

is trigeminal neuralgia unilateral or bilaters?

mostly unilateral (10% bilateral)

what anticonvulsant medication is prescribed for the treatment of trigeminal neuralgia?

oral carbamazepine = tegretol (depresses nervous system/nerve relay)

what are 6 side effects of using tegretol to treat trigeminal neuralgia?

``` blurred vision dizziness drowsiness anemia hepatotoxicity teratogenic ```

list 4 surgery options for treatment of trigeminal neuralgia?

- radio frequency - decompression surgery (ex removal of tumor that is compressing nerve) - nerve section (cut out damaged nerve section and reconnect) - alcohol ablation (concentrated alcohol injected directly into nerve)

what is the mechanism of radio frequency based surgery for treating trigeminal neuralgia?

an electrical current produced by a radio wave is used to heat up a small area of nerve tissues, which will decrease pain signals from that specific area.

what is Erb's palsy?

paralysis of the upper limb from TRACTION INJURY to brachial plexus (C5-C6) at birth

what are 6 common symptoms of Erb's palsy?

1. infant unable to move upper or lower arm/hand from shoulder 2. arm is limp/bent at elbow and held against body 3. decreased grip strength 4. inability to externally rotate arm 5. loss of motor and/or sensory function over lateral PROX arm 6. partial/complete arm paralysis

what are 2 methods of treatment for Erb's palsy?

1. non surgical (gentle massage/ ROM of affected arm; intermittent immobilization; electrical stimulation) 2. surgery (if neurological function does not return in 6-8 weeks)

why can intermittent immobilization be beneficial for treatment of Erb's palsy?

helps prevent contractures

what is the difference between Erb's and Klumpke's palsy?

``` Erb's = C5-C6 Klumpke's = C8 - T1 ```

what are 2 other names for Klumpke's palsy?

Klumpke's paralysis or Dejerine-Klumpke palsy

what are 2 causes of Klumpke's palsy?

``` difficult vaginal birth sports injuries (adults or older children) ```

what are 6 signs and symptoms of Klumpke's palsy?

1. severe pain 2. C8-T1 dermatome distribution numbness 3. weakness/lack of ability to use specific muscles of shoulder, arm, hand 4. limp/paralyzed arm 5. stiff joints 6. atrophy of muscles = "claw hand"

what are 3 treatment methods for Klumpke's palsy?

RMT PT immobilization (very similar to Erb's)

what area does the phrenic nerve supply?

diaphragm (C3-C5 *somatic fibre)

how does unilateral diaphragmatic paralysis present?

asymptomatic in most patients

what is the most common diagnosed cause of unilateral diaphragmatic paralysis?

a malignant lesion (metastatic lung cancer) leading to nerve compression (30% of patients)

if malignancy is not the cause of unilateral diaphragmatic paralysis, what is the cause?

if not malignancy, many times etiology cannot be determined -but could be: blunt cervical trauma or surgical trauma to thoracic region; HERPES ZOSTER; cervical spondylosis; upper cervical radiculopathies

if the etiology is not know, can unilateral diaphragmatic paralysis go away?

if unknown etiology, usually resolves on its own (month to more than year)

what are the 4 most common causes of BILATERAL diaphragmatic paralysis?

1. secondary to motor neuron disease ( ALS; post-polio syndrome) 2. thoracic trauma (cardiac surgery) 3. MS, myopathies, muscular dystrophy 4. Guillain-Barre syndrome

what is the main treatment of bilateral diaphragmatic paralysis if respiratory failure develops?

invasive ventilation (endotracheal tube)

how can patients without intrinsic lung pathology be treated for bilateral diaphragmatic paralysis?

use of non-invasive ventilation = not using endotracheal tube