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Chapter 25 Peripheral Nervous System

Terms in this set (46)

Disorder of the PNS symptoms
Lower motor neuron injury symptoms
Neuropathies
Myopathies
Will follow dermatome/myotome pattern of affected spinal nerve
Structure of a nerve
Endoneurium - innermost covering
Derineurium - middle (blood) layer
Epineurium - outermost covering (provides cushion)
Wallerian degeneration
Degeneration occurs distal to the site of the lesion
Loss of myelin in segments
Neurapraxia
Degeneration of myelin sheath with all other structures in tact
Axonotmesis
Degeneration of myelin sheath & axon
Neurotmesis
Degeneration of myelin sheath, axon & connective tissue structures
Difference between Myopathy & Neuropathy
Myopathy - proximal involvement first
Neuropathy - distal involvement first
Mononeuropathy
Involvement of 1 peripheral nerve
Polyneuropathy
Involvement of several peripheral nerves
Radiculoneuropathy
Involvement of one spinal nerve root
Polyradiculitis
Involvement of several spinal nerve roots
Charcot-Marie-Tooth disease
Peroneal muscular atrophy
Peroneal nerve and corresponding muscles in the foot and lower leg
Can progress to forearms and hands
Hereditary - dominant, recessive or X linked
Protein mutation causing demyelination
Charcot-Marie-Tooth disease - manifestations
Distal symmetrical muscle weakness
Pets cavus (high arch)
Hammer toes
Foot drop
Possible atrophy of forearms & hands
Charcot-Marie-Tooth disease treatment and prognosis
Slowly progressive
No cure
Orthotic devices
Stretching & strengthening
Sciatica
Radiculopathy caused by compression of sciatic nerve
Herniated disk, spinal stenosis, spondylolisthesis
Diagnosed by SLR test - straight leg raise - pain with 30-70 degree hip flexion
Treatment: nerve root injection
Physical therapy: stretching hamstrings, core strengthening
Bell's Palsy
Facial nerve palsy (unilateral)
High risk: DM or pregnant women
Associated with latent herpes virus
Inflammation and swelling to facial nerve
Neurapraxia injury (axonotmesis in severe cases)
May also affect taste, salivation, tear production & hearing
94% full recovery rate
Diabetic Neuropathy
Must have Diabetes Mellitus
Bilaterally symmetrical
Hyperglycemia leads to lack of nutrient absorption in Schwann Cells
Ischemic damage to myelin
- Slowed nerve conduction
- sensory loss
- pain & hypersensitivity
- Hyporeflexia

Monofilament testing/nerve conduction tests
Slowly progressive
Commonly leads to amputation
Guillain-Barre syndrome
Acute inflammatory demyelination disorder leading to motor paresis & sensory deficits
Demyelination in both motor and sensory nerve fibers
Distal to proximal - rapidly ascending
Stocking-glove neuropathy (begins in fingers/toes)
Symmetrical
Factors predicting poor outcome: older ages, axonal degeneration, progression to chest/respiration
PT: ROM, aquatic therapy, sensory stimulation
Post Polio syndrome
New neuromuscular symptoms decades following Polio virus
Weakness/atrophy
Myalgia
Respiratory/swallowing impairments
Fatigue
Loss of function

Progressive disorder
PT: submaximal & nonexhaustive exercise
Energy conservation
Pain management
Postural & gait exercises
myasthenia gravis (MG)
Autoimmune disorder of weakness and rapid fatigue
Caused by breakdown of communication between nerve and muscle
Commonly associated with dysfunction of Thymus
*Loss of ACH receptors*
*autoimmune response may produce antibodies that block binding sites for ACH*
Slowly progressive - commonly fluctuating
Respiratory complications or chronic infection = worse prognosis
*Key diagnostic test - fatigue with repetition, improves with rest*
PT: moderate exercise, fatigue management, respiration management
Peripheral Nervous System
disorders of the PNS produce symptoms of LMN injuries (hypotonicity, hyporeflexia, weakness), neuropathies, and/or myopathies
Wallerian Degeneration (anterograde)
degeneration occurs DISTAL to the site of the lesion

occurs in a Proximal to Distal direction
Neurapraxia
degeneration of myelin sheath with all other structures intact
Axonotmesis
degeneration of myelin sheath and axon but connective tissue structures remain intact
Neurotmesis
degeneration of myelin sheath, axon, and connective tissue structures are severed
Mononeuropathy
involvement of ONE peripheral nerve
Polyneuropathy
involvement of SEVERAL peripheral nerves
Radiculoneuropathy
involvement of ONE spinal nerve root
Polyradiculitis
involvement of SEVERAL spinal nerve roots
Neuropathy motor problems
motor symptoms occur distally
Myopathy motor problems
motor weakness occurs proximal
Myopathy
involvement of the motor endplate or muscle itself
Charcot-Marie-Tooth Disease
peroneal muscular atrophy

affects the peroneal nerve and corresponding muscles in the foot and lower leg

may progress to forearms and hands

most common inherited disorder affecting motor and sensory nerves
Charcot-Marie-Tooth Disease
distal symmetrical muscle weakness and atrophy with decreased deep tendon reflexes (DTRs)

feet have pes cavus (high arch) and hammer toes

proprioception lost in feet

foot drop

UE involvement includes atrophy of the intrinsic muscles of the hand, and then the forearm
Sciatica
radiculopathy typically caused by compression of the sciatic nerve or lumbosacral plexus

sciatic nerve- largest nerve in body

causes: herniated disk, spinal stenosis, DDD, spondyloliethesis
Diagnosis of Sciatica
SLR Test- Straight Leg Raise Test

+ if pain radiates down leg below knee when leg is raised 30-70 degrees of hip flexion
Bell's Palsy
facial nerve palsy- typically unilaterally

DM and pregnancy at higher risk

associated with latent herpes virus
Bell's Palsy
inflammation and swelling from latent herpes virus causes damage of the facial nerve and unilateral palsy signs and symptoms

typically a neurapraxia injury but can be axonotmesis in severe cases
Diabetic Neuropathy (DN)
diabetic polyneuropathy

a syndrome of symptoms/conditions in the presence of diabetes mellitus without any other viable explanation for the presence of peripheral neuropathy

occurs in a distally and bilaterally symmetrical pattern
Diabetic Neuropathy (DN)
hyperglycemia leads to nutrient absorption problems in Schwann cells producing ischemic like damage to the myelin

slowed/blocked nerve conduction
sensory loss
pain, hypersensitivity, Allodynia
hyporeflexia
may incorporate autonomic neuropathy and include cardiovascular and GI symptoms
Guillian-Barre Syndrome (GBS)
acute, inflammatory, demyelinating disorder leading to motor paresis and sensory deficits

immune-mediated disorder- demyelinating lesions can occur throughout the PNS

axonal degeneration can occur in severe cases

occurs in a DISTAL to PROXIMAL direction
Guillian-Barre Syndrome (GBS)
rapidly ascending motor and sensory loss

paresthesia symptom is commonly referred to as a stocking/glove neuropathy

begins in fingers and toes and spreads proximally toward the trunk and head
Post-Polio Syndrome (PPS)
polio virus attacks and damages the motor neuron in the anterior horn leading to motor neuron degeneration and muscle atrophy

new neuromuscular symptoms that present decades following recovery from acute Poliomyelitis virus infection

asymptomatic
nonparalytic and flu-like symptoms
paralytic with flu-like symptoms
Post-Polio Syndrome (PPS)
marked muscle weakness and atrophy
Myalgia
respiratory and swallowing impairments
fatigue
loss of function
Myasthenia Gravis (MG)
autoimmune disorder causing fluctuating weakness and extreme fatigue in skeletal muscles due to compromised transmission at the neuromuscular junction and motor end plate.

due to loss of Ach receptors at junction or antibodies that block binding sites for Ach at the neuromuscular junction
Myasthenia Gravis (MG)
linked to dysfunction of the Thymus, DM, RA, and lupus erythematosus

skeletal muscle weakness
ocular muscle weakness
fatigability with repetition that improves with rest- key diagnostic test
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