PNS & NMJ disorders 4/24

guillain-barré syndrome

inflammatory demyelinating polyneuropathy

immune-mediated demyelination of the peripheral nerves (LMN, sensory, autonomic involvement)

macrophages & antibodies cause segmental demyelination or axonal damage

acute onset, rapid paralysis

GBS etiology and risk factors

autoimmune: system cross re-activity causes attack on peripheral nerves, often post-infection (viral or bacterial)

less common triggers: surgery, vaccinations, trauma

males more affected than females

GBS imaging and diagnostic tools

diagnosis: clinical presentation + no fever

EMG/NCS—gold standard

CSF analysis via lumbar puncture

GBS EMG/NCS

+ slowed conduction velocity & prolonged distal latencies

fibrillation potentials if axonal degernation

CSF analysis via lumbar puncture GBS

increased IVIG/albumin proteins at 1 week

normal WBC

GBS prognosis

stabilization of symptoms by 3 weeks

recovery: descending phase, demyelinating, takes weeks to years, 20% have residual disability 1 year after

negative factors: preceding diarrhea, older age, rapid progression

GBS clinical manifestations

symmetrical, ascending weakness

typically starts in legs, arms, then face

distal→proximal

progression can be hours/days/weeks

peak of weakness within first 3 weeks

areflexia/hyporeflexia

paresthesia

pain

autonomic dysfunction (70%)—arrhythmias, BP fluctuations

severe cases: respiratory distress/failure (requiring ventilation) due to weakness of diaphragm

GBS pharmacologic management

plasmapheresis: removes circulating antibodies, side fx of hypotension, infection, electrolyte imbalance

IVIG (intravenous immunoglobulin): blocks autoimmune attack w/ side fx of headache, thrombosis, renal dysfunction

typicaaly administered within 2 weeks of symptom onset

pain management: gabapentin and NSAIDs, NOT STEROIDS

GBS complications

respiratory failure, aspiration, DVT, pressure ulcers

GBS contraindications

overexertion in early rehab

GBS precautions

autonomic instability (monitor vitals), pain and fatigue

GBS PT ICF

body function and structure: strength, sensation, pain, fatigue, reflexes

activity: bed mobility, transfers, gait, ADLs

participation: work, school, community mobility

environment: access to adaptive equipment, caregiver support

personal factors: age, motivation, comorbidities

GBS acute PT

aka ascending phase

positioning/splinting

PROM

respiratory capacity/training

monitor vitals/autonomic response

prevent secondary complications/overfatiguing

GBS subacute PT

aka descending phase

gradual resistance, mobility training—avoid excessive fatigue, max strength training, over stretching

monitor vitals/autonomic response

monitor for overwork weakness

energy conservation strategies

pain management strategies

GBS chronic PT

progress toward modified independence with transfers and ambulation

consideration of orthotics for foot drop/gait efficiency

charcot marie tooth (CMT)

inherited peripheral neuropathies affecting motor and sensory nerve conduction

genetic origin: mutations in over 40 genes that produce proteins involved in structure/function of axon/myelin sheath—most common is PPMP22 gene or chromosome 17

aka hereditary motor sensory neuropathy or peroneal muscular atrophy

onset: usually in adolescence or early adulthood

progressive length-dependent neuropathy—distal weakness and sensory loss

autosomal dominant inheritance CMT

if 1 parent affected=50% chance affected child regardless of sex

autosomal recessive CMT

if both parents carry=25% affected child, 50% child carries regardless of sex

X-linked CMT

if 1 parent carries=25% affected male child, 25% carrier female child

pathogenesis of CMT1 (demyelinating)

schwann cell dysfunction→slowed nerve conduction

pathogenesis of CMT2 (axonal)

direct axonal degernation with preserved myelin

CMT diagnosis

medical and family hx

genetic testing

neuro exam—observable atrophy, weakness, decreased DTRs, sensory loss

foot deformities: high arches, hammertoes, claw toes, inverted heel, rigid foot, supinated

may have enlarged nerves visible or felt through skin due to thickened myelin sheath

CMT symptom onset

adolescence or early adulthood

severity: varies in individuals and between family members

progression: gradual, slow

pain: mild to severe

rare: respiratory muscle weakness

most forms of CMT: normal life expectancy

CMT treatment

no cure/disease modifying treatment

surgical management of orthopedic deformities if severe

medications

PT/OT

pain management

CMT pharmacologic management

no curative pharmacologic treatment

neuropathic pain management: gabapentin, pregabalin, etc

muscle cramping: magnesium, quinine (rare)

anti-inflammatory meds post-op

CMT complications

contractures, falls, pressure injuries, scoliosis

CMT contraindications

heavy resistance training (in advanced stages)

CMT precautions

avoid overwork weakness

monitor skin due to sensory loss

CMT PT ICF

body structure & function: strength, sensation, foto deformity (AROM/PROM) balance

activity: gait stair ADLs

participation: school work community recreation mobility

environmental factors: orthoses mobility aids home modifications

CMT PT

orthotic management

strengthing: low resistance high rep exercises for prox muscles, start early to delay/reduce atrophy

aerobic: moderate intensity, low impact

gait training: with orthotics and/or ADs, various environments and distances

stretching: PFs, hamstrings, finger flexors

posture corrections

avoid excessive fatigue, max exertion, pain

myasthenia gravis (MG)

autoimmune disorder of NMJ

antibodies block/destroy Ach receptors at presynaptic membrane→impaired NM transmission→weakness

higher incidence in those w/ other immune disorders (RA, lupus)

predominance in younger adult females, older males

genetic presdisposition

environmental triggers: infection/stress

abnormality of thymus in 75% of cases

MG imaging and diagnostics

CT or MRI of chest to detect thymoma

single-fiber EMG (most sensitive test)

repetitive nerve stimulation to detect decremental response

antibody testing

MG clinical manifestations

fluctuating muscle weakness worsening with activity and improving with rest

first signs: diplopia, ptosis, generalized weakness/fatigue, dysphagia, difficulty chewing, talking

active stage: fluctuation of symptoms, progressive weakness for several years

inactive stage: fluctuations still occur, associated w/ other illnesses

burnt-out stage: 15-20 years, weakness→fixed atrophy

MG diagnosis

+ serum antibodies

- edrophonium chloride test

improved strength following tensilon

EMG/repetitive nerve stimulation shows decline in compound muscle AP

MG treatment

cholinesterase inhibitors: prolong Ach at receptor sites

thymectomy

corticosteroids

immunosuppressants

plasmapheresis

IVIG

MG complications

myasthenic crisis: respiratory muscle failure

cholinergic crisis: overmedication

MG contraindications

avoid overexertion, high heat

may exacerbate symptoms

monitor respiratory status

MG PT ICF

body function & structure: fatigability, cranial nerve involvement, respiration, vitals

activity: gait, ADLs

participation: school work home social mobility

environment: accessibility, family support

MG PT interventions

energy conservation techniques

aerobic, resistance training

low and moderate intensity

intervals with rests for recovery

use of ADs

postural training

respiratory training