Cranial and peripheral nerve disorders Flashcards
Peripheral nerve disease/injury - Wallerian degeneration
transection results in degeneration of the axon and myelin sheath distal to the site of axonal interruption
Chromatolysis and repair processes occur in nerve cell body
Endoneurium (sheath) does not degenerate but forms a tube directing regeneration
Peripheral nerve disease/injury - Segmental demyelination
axons are preserved (no wallerian degeneration)
remyelination restores function (like with GBS)
Peripheral nerve disease/injury - axonal degeneration
degeneration of axon cylinder and myelin, progressing from distal to proximal, “dying back” of nerves (peripheral neuropathy)
Peripheral nerve disease/injury - Neuropathy =
any disease of nerves characterized by deteriorating neural function
Peripheral nerve disease/injury - neuropathy - polyneuropathy =
bilateral symmetrical invovlement of peripheral nerves, usually legs more than arms, distal segments earlier and more invovled than proximal
Peripheral nerve disease/injury - neuropathy - mononeuropathy =
involvement of a single nerve
Peripheral nerve disease/injury - radiculopathy =
involvement of nerve roots
Peripheral nerve disease/injury - traumatic nerve injury - neurapraxia
Class 1
Injury to nerve that causes a transient loss of function (conduction block ischemia)
nerve dysfunction may be rapidly reversed or persist a few weeks
ex = compression
Peripheral nerve disease/injury - traumatic nerve injury - axonotmesis
Class 2
Injury to nerve interrupting the axon and causing loss of function and wallerian degeneration distal to the lesion
with disruption of endoneurium (sheath), regeneration is possible
ex = crush injury
Peripheral nerve disease/injury - traumatic nerve injury - neurotmesis
Class 3
Cutting of nerve with severance of all structures and complete loss of function
Reinnervation typically fails without surgical intervention because of aberrant regeneration (failure of regenerating axon to find its terminal end)
Peripheral nerve disease/injury - clinical sx of LMN syndrome
Weakness/paresis
Hyporeflexia
Hypotonia
Atrophy
Fatigue
Sensory loss corresponding to motor weakness
Autonomic dysfunction (VD, dryness, warm skin, edema, OH)
Sensory dysesthesias, motor fasciculations/spasms
Muscle pain
Trigeminal neuralgia - etiology
results from degeneration or compression
occurs in people over 50
abrupt onset
Trigeminal neuralgia - characteristics
brief paroxysms of neurogenic pain (stabbing and/or shooting) pain; reocurring frequently
Occurs along distribution of trigeminal nerve (mostly mandibular and maxillary)
Restricted to one side of the face
Trigeminal neuralgia - tend to have ___ instability
autonomic
exacerbated by stress or cold, relieved with relaxation
Bell’s Palsy - what is it
LMN involving facial nerve (7) - resulting in unilateral facial paralysis
Bell’s Palsy - etiology
acute inflammatory process of unknown etiology (immune or viral disease) resulting in compression of the nerve within the temporal bone
Bell’s Palsy - characteristics
Mm of facial expression on one side are weak or paralyzed
Loss of control of salivation or lacrimation
Onset is acute with max severity in hrs to days
Commonly preceeded with pain behind the ear
Most recover fully in wks to months
Bulbar palsy refers to
weakness of paralysis of the mm innervated by the motor nuclei of the lower brainstem, affecting the muscles of the face, tongue, larynx, and pharynx
Bulbar palsy - etiology
result of tumors, vascular degenerative diseases of lower cranial nerve motor nuclei
Bulbar palsy - characteristics - voice quality
dysphonia - hoarseness, or nasal quality
Bulbar palsy - characteristics - pseudobulbar palsy
bilateral dysfunction of corticobulbar innervation of brainstem nuclei; a central or UMN lesion analagous to coritcospinal lesions disrupting function of anterior horn cells
GBS -
polyneuritis with progressive mm weakness that develops rapidly
GBS - etiology
unknown
associated with an autoimmune attack, usually occurs after recovery from an infectious illness (resp or GI)
GBS - characteristics
Acute demyelination of both cranial and peripheral nerves
Sensory loss, paresthesias (sensory loss less than motor usually)
Motor paresis or paralysis
Dysarthria, dysphagia, diplopia, facial weakness
Progression evolves over days or weeks and recovery is usually slow (6 m to 2 yrs)
ALS
a degenerative disease affecting both UMNs and LMNs
Degeneration of anterior horn cells and descending corticobulbar and corticospinal tracts
ALS - etiology
unknown (viral/autoimmune)
5-10% genetic - autosomal dominant
ALS - Characteristics -
Progressive - typically pass away within 2-5 yrs Bulbar onset (progressive bulbar palsy) or spinal cord onset (mm atrophy) UMN and LMN signs Dysarthria, dysphagia dysphonia USUALLY ABSENCE OF SENSORY CHANGES Autonomic dysfunction Pain Resp impairments Typical sparing of BB function Cognition typically normal
Stages of ALS - stage 1
early disease
mild focal weakness
asymmetrical distribution
symptoms of hand cramping and fasciculations
Stages of ALS - stage 2
moderate weakness in groupd of muscles
some wasting (atrophy)
modified independence with assistive devices
Stages of ALS - stage 3
severe weakness in specific muscles
increasing fatigue
mild to moderate functional limitations, ambulatory
Stages of ALS - stage 4
Severe weakness and wasting of LEs
Mild weakness of UEs
Moderate assistance and assistive devices required
Wheelchair user
Stages of ALS - stage 5
progressive weakness wiht deterioration of mobility and endurance
increased fatigue
moderate to severe weakness of whole limbs and trunk
spasticity
hyperreflexia
loss of head control
max assist
Stages of ALS - stage 6
bedridden
dependent in ADLs
progressive resp. distress
Postpolio syndrome (PPS)
new. slowly progressive mm weakness occuring in individuals with a confirmed hisotry of acute poliomyelitis
follows a stable period of functioning
PPS - etiology
unknown
possible hyperfunctioning of motor neurons, long term over use at high levels resulting in new degeneration
PPS - characteristics
new weakness and atrophy - asymmetrical in distribution
abnormal fatigue
pain
slow progression, either steady or stepwise
brain fatigue - difficulty with concentrating
