Peripheral Nerve Disorders Flashcards
List clinical signs of PNS syndromes
- Motor Dysfunction
- Sensory Dysfunction
- ANS Dysfunction
- Neuropathic pain and/or muscle pain (myalgia) common
- Hyper-excitability of remaining nerve fibers
PNS symptom: Motor Dysfunction
- Weakness/paresis of denervated muscle
- hyporeflexia
- hypotonia
- atrophy
- fatigue
PNS symptoms: Sensory Dysfunction
- Paresthesias
- Proprioception losses may yield sensory ataxia
- insensitivity may yield limb trauma
PNS symptoms: ANS dysfunction
- Vasodilation and loss of vasomotor tone
- dryness
- warm skin
- edema
- OH
what does hyper-excitability of remaining nerve fibers look like in PNS syndromes?
- Sensory dysesthesia → hyperalgesia, pins and needles, numbness, tingling, burning
- Motor → fasciculations
Describe tropic changes due to denervaion in PNS syndromes
- muscle atrophy
- skin becomes shiny
- nails become brittle
- subcutaneous tissues thicken
- ulceration of cutaneous and subcutaneous tissues
- poor wound healing
- infections
- neurogenic joint damage
what is a mononeuropathy
- weakness, numbness, pain, paresthesias, confined to the distribution of the involved nerve
- most common causes:
- entrapment
- trauma
- prolonged limb immobility (e.g. surgery)
- Example → carpal tunnel syndrome
Classification of nerve damage in mononeuropathy
- Neuropraxia
- local myelin damage, axon remains intact
- Axontmesis
- continuity of axon is lost
- may or may not include damage to epinerium, perineurium, and/or endoneurium
- loss of continuity leads to Wallerian degeneration
- Neurotmesis
- complete transection of nerve
- surgery necessary
how are PNS injuries different from CNS injuries?
- PNS can regenerate under certain circumstances
- Axonal sprouting
- regenerative
- collateral
- Axonal sprouting
what is a multiple mononeuropathy?
- involves two or more nerves in different parts of the body
- Vasculitis = dangerous cause of multiple mononeuropathy
- if suspected, an urgent referral should be made for an electrodiagnostic eval
- Individual nerves are affected, producing a random, asymmetrical presentation of signs
what is a polyneuropathy?
-
symmetrical involvement: sensory, motor, autonomic
- Sensory → Motor → Autonomic
- Distal → Proximal
- Feet → legs → fingertips → hands
- Affects longest peripheral nerves in extremeties
- small nerve fibers → large nerve fibers
Motor symptoms for Polyneuropathies
- Weakness
- Cramping
- Fasciculations
- Muscle Loss
- Bone degeneration
- Loss of ankle reflexes
- trophic changes
Sensory Symptoms for Polyneuropathies
- Earlier in disease
- loss of temp
- pain (hypo or hyper)
- As disease progresses
- loss of vibration
- loss of light touch discrimination
- loss of proprioception/kinesthesia
Autonomic Symptoms for Polyneuropathies
Diverse manifestations
- impaired breathing
- dysarthria
- temp dysregulation
- in particular - decrease sweating
- GI dysfunction
- Loss of bowel/bladder control
- Erectile dysfunction
- Loss of BP control
- orthostasis very common
common causes of polyneuropathies
- Diabetes Mellitus
- 60-70% of pts with DM have mild-severe forms of PN
- Other
- Autoimmune disorders
- chronic kidney disease
- HIV and liver infections
- low level of vitamin B12
- Poor circulation in LEs
- Underactive thyroid gland
- Trauma
- Tumor
- Alcoholism
Risk factors for diabetic polyneuropathy
- Obesity
- Sedentary lifestyle
- HTN
- Decreased glycemic control
- Alcoholism
- Smoker
Diabetic Polyneuropathy prognosis
- CAN BE PREVENTED with appropriate disease management and compliance
- Progression of symptoms progresses slowly over years
- depends largely on how well the pt’s DM is managed
- Treating DM may halt progression and improve symptoms of the neuropathy, but recovery is exceptionally slow
Interventions for Diabetic Polyneuropathy
- Aerobic Conditioning
- Balance training
- Resistance training
- Patient education
parameters for aerobic conditioning in Diabetic Polyneuropathy
- 150 min/week
- 50-70% HRmax
- mRPE 5-7(RPE 14-16)
Balance training in Diabetic Polyneuropathy
- Cannot improve sensory loss
- strengthen other balance systems to compensate
Aspects of pt education for diabetic polyneuropathy
- skin care and inspection
- shoe consideration
- nutritional consult
- fall risk management
- importance of aerobic exercise
- strategies to reduce sedentary lifestyle
- compliance to program
what is CMT?
Charcot Marie Tooth Disease
- most common inhereted neuro disorder
- affecting 1 in every 2,500
- Males > Females
- progressive muscle weakness
- typically becomes noticeable in adolescence or early adulthood, but the onset of disease can occur at any age
- eventually effects both motor and sensory nerves
describe the pathology of CMT
- caused by a mutation in genes that produce proteins involved in the structure, maintenace, and formation or primarily the myelin sheath
- >50 genes causing CMT ID
- will see secondary degeneration of axons as disease progresses as well as axon-dominant CMT subtypes (though less common)
- Hallmark Pathologic sign
- hypertrophic onion bulb formation
what causes hypertrophic onion bulb formation in CMT?
repetitive segmental demyelination and regeneration of myelin that causes gross thickening of peripheral nerves
creates palpable, enlarged peripheral nerves