Peripheral Nervous System: Evaluation and Treatment Flashcards
definition, mechanism, symptoms and management of radiculopathy
Definition: lesion of an individual spinal nerve root
Mechanism: repetitive wear and tear→ dehydration/age leads to radial fissures in the annulus fibrosus annular tear→ nucleus pulposus extrudes along the annular tear→ contained disc rupture→ with further degeneration, the nucleus pulposus protrudes beyond the perimeter → radiculopathy
- All radiculopathies: pain in the territory supplied by the nerve root, sensory loss in the corresponding dermatome, muscle weakness or flaccid paralysis, muscle atrophy, fasciculation, decreased tendon reflexes at those muscles supplied by nerve root, vertebral column signs or symptoms
- Lumbar radiculopathies: pain radiating from back to leg, sciatica pain exacerbated by flexion, sitting, coughing, straining
Management: Management: 80-90% spontaneously recover within 6-12wk. If hasn’t improved consider imaging +/- surgery
Which muscles and pattern of sensory changes are affected by each nerve root radiculopathy: C5, C6, C7, C8, L4, L5, S1
C5= deltoids/biceps (axillary)
C6= biceps (musculocutaneous)
C7= triceps, finger extensors (radial)
C8= finger extensors, abductors fo the 2nd and 5th fingers
L4: quads
L5: greater toe extensor
S1: plantar flexors
Outline the weakness type, sensory loss prevalence, etiologies of different damage patterns of peripheral nerve disease (focal, multifocal, diffuse demyelinated vs diffuse axonal)
Focal
- LMN-type monoplegia
- Motor and sensory loss
- Sharp boundaries for sensory loss
- Typical etiology: compressions.
Multifocal
- More than one focal neuropathy occurring simultaneously
- Typical etiology: autoimmune disease
Diffuse
- Individual axons each affected simultaneously
- Longest neurones typically most vulnerable
- Demyelinating or axonal character
- Typical aetiology; diabetes mellitus
Compare this list of features in Axonal vs demyelinating PN
stocking glove pattern is classic axonal degeneraton, and affects sensory more than motor. in demyelinating PN, axons have variable degrees of insulation, and are transmitting at different speeds. tends to affect motor >sensory
Axonal Peripheral Nerve Disease : Heidi’s Notes Summary
Definition: a mild, slowly progressive loss of sensory function in a stocking glove pattern
Etiology: idiopathic, DM, alcohol, thyroid, B12, SPEP, iatrogenic (chemo, amiodarone, pyridoxine) Investigations: bloodwork (TSH, T3/T4, B12, SPEP, glucose), neurophysiology NOT helpful
Management:
- Treat underlying cause: treat DM, alcohol cessation, stop drug
- Neuropathic pain meds: gabapentin, pregabalin, amitriptyline, topiramate
C7 radiculopathy vs radial neuropathy
Radial Neuropathy/ Saturday Night Palsy/ Honeymoon Palsy
Definition: compression along the spiral groove of the humerus
Symptoms: wrist drop due to weakness, minimal sensory loss to dorsal hand + wrist– will not affect the triceps–> if it was a C7 injury, the triceps would also be affected
Investigations: NCS for prognosis Management: usually spontaneous recovery in weeks, wrist splint
L5 radiculopathy vs peroneal neuropathy
Peroneal nerve palsy will have no radicular pain, no straight leg raise pain, no weakness of foot inversion
In L5 radiculopathy, the patient should have hip abductor and ankle inverter weakness, in addition to the foot drop.
In sciatic neuropathy, the patient should have knee flexor and plantar flexor weakness as well as foot drop. \
And in peroneal neuropathy only, the patient should have only foot drop.
Definition, etiology and symptoms of Guillain Barre Synrome (Neuropathy– acute inflammatory demyelinating polyneuropathy).
- Key clinical finding?
- investigations
- Management
- subacute demyalinating autoimmune disease
etiology: POST INFECTION (Campylobacter jejuni, or post-influenza vaccination)
symptoms: motor symtoms wiht ASCNEDING PATTERN, autonomic dysfinctioN(cardiac), respiratory failure ,bulbar weakness, AREFLEXIA ***
Investigations: CSF (modest protein elevation), MRI, EMG (F-WAVE LATENCY), LP: Elevated CSF protein, lower WBC and RBC
Management: IVIG, plasma exchange therapy, monitor repsiraory and cardiac function.
prognosis; typically excellent.
Definition, etiology, symptoms and investigations and management of mononeuritis multiplex
Mononeritis Multiplex
Definition: subacute onset of malfunction in multiple peripheral nerves due to damage to vessels upplying the peripheral nerves
Etiology: connective tissue diseases** MOST COMMON (polyarteritis nodosa, eGPA, GPA, cryoglobulinemia, SLE, Sjorgen, sarcoidosis), infection (HIV), Lyme, leprosy, malignancy (lymphoma)
Symptoms: patchy/asymmetric, distal>proximal pain
Investigations: Connective Tissue Disease workup, nerve/muscle biopsy, EMG/NCS
Management: treat underlying + immunosuppression
pain progression in mononeuritis multiplex
distal > proximal,
Read: charcot-Marie Tooth Disease (Type Ia CMTIA)
Definition: duplication of PMP22 gene, hereditary demyelinating neuropathy
Etiology: autosomal dominant, duplication of PMP22 gene (codes for a structural protein in the transmembrane space of compact myelin)
Epi: 1:10000; childhood onset (typically described as being clumsy, non-athletic)
Symptoms: distal weakness, distal atrophy of hands and feet (interosseous wasting, claw hand, hammertoes, pes cavous, Champagne bottle legs)
Sensory symptoms tend not to occur early on.
Investigations: genetic testing, neurophysiology (demyelinating neuropathy, diffuse)
Management: ankle surgery is common due to repeated injury
Prognosis: normal life expectancy, often maintain ambulation
Read: Herreditary Neuropathy with Liability to Pressure Palsies
Hereditary Neuropathy with Liability to Pressure Palsies (HNPP)
Definition: deletion of PMP22, hereditary demyelinating neuropathy
Unusual example of diffuse neuropathy causing focal neuropathy symptoms.
The strange myelin is susceptible to compression injury
Repeated injury to nerves caused after short compression.
Etiology: autosomal dominant, deletion of PMP22 gene
Epi: 1:200000
Symptoms: diffuse neuropathy that produce focal neuropathy symptoms due to susceptible of myelin to compression injuries, usually more motor and no pain
Investigations: neurophysiology findings are worse than clinical symptoms
Identify which roots innervate the biceps, brachioradialis, triceps, knee jerk, and ankle jerk reflexes
Biceps– musculocutaneus
Triceps– radial nerve
Brachioradialis– radial nerve
The knee jerk reflex is mediated by the L3 and L4 nerve roots, mainly L4. Insult to the cerebellum may lead to pendular reflexes. Pendular reflexes are not brisk but involve less damping of the limb movement than is usually observed when a deep tendon reflex is elicited.
The ankle jerk reflex is mediated by the S1 nerve root. The plantar reflex (Babinski) is tested by coarsely running a key or the end of the reflex hammer up the lateral aspect of the foot from heel to big toe. The normal reflex is toe flexion.
