Unit 5 - Rare Neurological Diseases & Management

Amyotrophic Lateral Sclerosis (ALS)

• Also known as Lou Gehrig disease

• Most common motor neuron disease (MND) in adults

• Upper motor neuron and lower motor neuron clinical signs and symptoms

ALS

Epidemiology

• In 2022, 32,893 cases in the USA

• Projected to increase more than 10% in 2030 as population ages 66 years and older

• Male is a risk factor (ratio of male to female between 1 to 2).

• Mean and median age of onset: 51 and 66 years

• Younger age of onset for familial compared to non-familial (sporadic)

ALS

Etiology

• Neurodegenerative disorder affecting the corticospinal tract, motor neurons in the motor cortex and brainstem and anterior horn cells in the spinal cord

• Familial ALS – 10%

• Nonfamilial or sporadic ALS – 90%

  • Genetic mutation (C9orf72, superoxide dismutase 1 or SOD1)

  • Excess glutamate

  • Intraneural protein aggregate

  • Neuroinflammation

  • Lack of neurotrophic factor

  • Environmental factors

  • Apoptosis and viral infection

ALS

Clinical Presentation — Limb-Onset or Spinal Onset

• 58 to 82 % of ALS

• Starts with a focal, asymmetrical weakness of LE or UE and progress proximally to the trunk

• UMN: Spasticity, hyperreflexia, pathologic reflexes, muscle weakness

• LMN: Fasciculations, atrophy, muscle weakness, muscle cramps, hyporeflexia, hypotonicity

ALS

Clinical Presentation — Bulbar Onset

• 25% of ALS

• Progresses faster

• More common in women, patients with cognitive impairments, older patients

• Dysphagia, dysarthria, sialorrhea, pseudobulbar affect

ALS

Clinical Presentation — Respiratory Onset

• Less than 3% of the cases

• Inspiratory and expiratory muscle weakness

• Dyspnea at rest and during exertion, orthopnea, ineffective cough

ALS

Clinical Presentation — Frontotemporal Dementia Onset

• presence of the C9 or f72 gene

• Cognitive and behavioral impairments

ALS

Pathophysiology

• Progressive degeneration and loss of motor neurons

  • Motor Cortex

  • Corticospinal tract

  • Brainstem

  • Anterior horn cell in the spinal cord

• Nonmotor areas

  • Autonomic nervous system

  • Basal ganglia

  • Cerebellum

  • Frontotemporal

  • Oculomotor

  • Sensory Systems

• Degeneration>Regeneration

ALS

Diagnosis — Definite ALS

Presence of upper motor neuron and lower motor neuron signs in three anatomical regions

ALS

Diagnosis — Probable ALS

Presence of upper motor neuron and lower motor neuron signs in at least two regions with upper motor neuron sign rostral to lower motor neuron signs

ALS

Diagnosis — Probable ALS, laboratory results supported

Presence of upper motor neuron and lower motor neuron signs in one region with evidence by EMG of lower motor neuron involvement in another region

ALS

Diagnosis — Possible ALS

Presence of upper motor neuron and lower motor neuron signs in one region or upper motor neuron signs in two or three regions, such as monomelic ALS, progressive bulbar palsy, and primary lateral sclerosis

Stages of ALS

Milano-Torino Staging

• Based on the ALS Functional Rating Scale (ALSFRS)/ALSFRS- Revised

• Four Domains:

  • Movement

  • Swallowing

  • Communication

  • Breathing

Stages of ALS

Milano-Torino Staging — Stage 0

No loss of independence in any domain

Stages of ALS

Milano-Torino Staging — Stage 1

Loss of independence in one domain

Stages of ALS

Milano-Torino Staging — Stage 2

Loss of independence in two domains

Stages of ALS

Milano-Torino Staging — Stage 3

Loss of independence in three domains

Stages of ALS

Milano-Torino Staging — Stage 4

Loss of independence in four domains

Stages of ALS

Milano-Torino Staging — Stage 5

Death

Stages of ALS

King’s Staging

• Based on affected regions:

  • Upper limb

  • Lower limb

  • Bulbar

Stages of ALS

King’s Staging — Stage 1

involvement of first clinical region

Stages of ALS

King’s Staging — Stage 2

involvement of second clinical region

Stages of ALS

King’s Staging — Stage 3

involvement of third clinical region

Stages of ALS

King’s Staging — Stage 4

Nutritional or Respiratory failure

Stages of ALS

King’s Staging — Stage 5

Death

ALS

Prognosis

• Average: 27 to 43 months

• Five years: 9-40%

• Greater than 10 years: 10%

• Death usually occurs from respiratory failure

ALS

(+) Prognostic Factors 

• Younger age

• Limb-onset

• Less severe involvement at the time of diagnosis

• Delayed time between onset and diagnosis

• Psychological well-being

ALS

(-) Prognostic Factors

• Older age

• Bulbar-onset

• Respiratory-onset

• Frontotemporal dementia-onset

• Poor respiratory status

• Poor nutritional status

ALS

Medical Management

• Disease-Modifying Agents

  

• Symptomatic Management

  • Sialorrhea and pseudobulbar affect; dysphagia; respiratory impairment; communication impairment; muscle cramp, spasticity, fasciculation and pain; fatigue, and anxiety and depression

ALS

Referral or Consultation

Neurologist
Support Group Liaison
Social Worker
SLP
Registered Dietitian
Occupational Therapist
Physical Therapist
Respiratory Therapist
Mental Health Professional
Nurse

ALS

Evidence-Based Rehabilitative Treatment

Early and early-middle stage

• Preventive: Falls, physical inactivity (disuse atrophy)

• Restorative/ Maintenance: Physical function

• Compensatory: Assistive device, orthosis

ALS

Evidence-Based Rehabilitative Treatment

Late-middle to late stage

• Compensatory: caregiver education, adaptive equipment and home modifications to maximize function and quality of life, DMEs (hospital bed, transfer equipment e.g. mechanical lift, wheelchair)

• Preventive/ Restorative: secondary complications from immobility (pressure ulcer, VTE, limited passive range of motion e.g. adhesive capsulitis, pulmonary complications)

ALS

Physical Therapy Examination

• Communication and Cognition

• Cardiovascular and Pulmonary System

  • Cardiovascular – blood pressure, heart rate, RPE

  • Pulmonary – breathing pattern, respiratory rate, lung auscultation, oxygen saturation, cough strength, Dyspnea ALS-15, Motor Neuron Disease Dyspnea Scale, Fatigue Severity Scale

• Integumentary

  • Skin integrity

  • Edema

• Musculoskeletal

  • ROM

  • MMT

  • Pain

• Neuromuscular

  • Cranial nerve integrity

  • Postural alignment, control and balance

  • Gait

  • Sensation

  • Tone and reflexes

  • Outcome measures to check for risk for falls

• Functional

  • ALSFRS-R

• Psychosocial

  • ALS Depression Inventory

• Environmental

• Quality of life

  • ALS Assessment Questionnaire

  • ALS Quality of life short form

ALS

Physical Therapy Interventions

Cervical Muscle Weakness

• Head falls forward, overstretched posterior muscles, tight anterior muscles

• Difficulty in eating, drinking, swallowing

• Difficulty seeing forward and communicating

• Acute cervical pain, Chronic cervical syndrome

• Accompanied by shoulder girdle and thoracic extensor weakness

ALS

Physical Therapy Interventions

FOR Cervical Muscle Weakness 

• Collars

  • soft collar – mild weakness

  • semirigid or rigid collar – moderate to severe weakness

  • Head up collar

  • Cervical-thoracic orthosis

• Frequent rest periods

• Supportive seating

  • Head and neck support for high back chairs, reclining or tilt-in space wheelchair

ALS

Physical Therapy Interventions

FOR Dysarthria and dysphagia

• Referral to a SLP and nutritionist

• Head and trunk control

• Sitting position

ALS

Physical Therapy Interventions

Pain

• Shoulder, neck, back pain

• 20% incidence of adhesive capsulitis

• Shoulder subluxation

ALS

Physical Therapy Interventions

FOR Pain

• Modalities

• ROM exercises

• Passive stretching

• Joint mobilizations

• Proper positioning in bed, wheelchair, chair

• Joint support and protection

• Intraarticular analgesics or anti-inflammatory injection

ALS

Physical Therapy Interventions

FOR UE weakness

• Referral to Occupational Therapist for ADL

• Adaptive equipment

• Splinting such as wrist and hand splint

ALS

Physical Therapy Interventions

Respiratory muscle weakness

Breathing or coughing

ALS

Physical Therapy Interventions

FOR Respiratory muscle weakness

• Referral to a respiratory therapist, physician

• Energy conservation techniques

• Breathing exercises and positioning

• Airway clearance techniques

ALS

Physical Therapy Interventions

FOR LE weakness and gait impairments

• Orthosis
  § AFO for weak ankle dorsiflexion
  Assistive device
  § Wheeled walker

ALS

Physical Therapy Interventions

FOR Decreased mobility

• Bed mobility

• Transfers

• Ambulation and stair climbing

• Wheelchair mobility

• DMEs:

  • Hospital bed, transfer board, hydraulic or mechanical lifts, power mobility device

ALS

Physical Therapy Interventions

FOR Muscle cramps and spasticity

• Massage, stretching and passive ROM

• Postural and positioning technique

ALS

Physical Therapy Interventions

Psychosocial issues

Anxiety, depression

ALS

Physical Therapy Interventions

FOR Psychosocial issues

Referral to an appropriate healthcare provider.

ALS

Exercise Prescription

• To prevent disuse atrophy (cardiovascular deconditioning and muscle weakness) caused by
  physical inactivity

• Prescribing exercise for people with ALS

  • ROM and stretching

  • Aerobic/endurance and strengthening exercises for early or early-middle stage and more slowly progressive disease

  • Resistance exercise for unaffected muscle and possibly affected muscle which can tolerate resistance (greater than a grade 3) using a low to moderate load and intensity

  • Aerobic exercise e.g. walking, cycling, swimming) at submaximal levels (50 to 65% of heart rate reserve)

ALS

Overwork Weakness

• Overuse damage

• Caused by excessive exercise or activities to the point of extreme fatigue

  • High repetition

  • High intensity

  • Heavy resistance

  • Eccentric exercise

• Signs and symptoms

  • Inability to perform ADL post-exercise because of exhaustion or pain

  • Decreased muscle force that gradually recovers

  • Increased or excessive muscle cramping, soreness, fatigue, or fasciculations

Research Study: Is exercise safe and effective for ALS?

Intervention: 24 sessions over 12 weeks (2 sessions per week), 50-60 minutes

• Aerobic training (20-30 minutes) recumbent cycling 40-60% of HRR

• Flexibility (10 minutes) achieved by stretching and PROM

• Strength training (20 minutes) functional exercise using body weight 8-12 reps, 1-2 sets on large muscle groups of trunk, UE and LE, e.g planks

• Outcomes: Improved maximum expiratory pressure, 2-minute walk test, ALSFRS-R, SF-36 (physical functioning, energy fatigue and wellbeing) in the aerobic-strength group. No adverse events

Research Study: Is exercise safe and effective for ALS?

Interventions (3 days per week for 24 weeks)

• Resistance exercise group: concentric upper limbs and hip flexion using cuff weights, knee flexion and extension using weight bench, 2 sets of 8 reps at 40% (weeks 0-2), 50% (weeks 3-4) and 70% of 1RM (weeks 5 to 24)

• Endurance exercise group: minicycles 10 minutes UE, 10 minutes LE, 5 minutes warm-up and cool down 40-70% target HR, RPE somewhat hard to hard

• Stretching and ROM (SROM) exercise group: 4 reps 30 seconds: shoulder flexion, stretching of triceps, hands and wrist, quadriceps, hamstrings, gastrocnemius

• Outcomes:

  • SROM, endurance and stretching tolerable for 12 and 24 weeks, with endurance less well-tolerated than SROM at both time-points

  • Compliance was highest for both SROM and resistance than endurance

  • Most common adverse effect was falling but less in endurance and resistance exercise groups.

  • No increase in fatigue, pain or muscle cramps

Electrodiagnostic Testing

Nerve Conduction Studies

• Evaluate motor/sensory nerve function:

  • Involvement of PNS

  • Location of PNS involvement

  • Intensity of PNS involvement

  • Systemic/localized involvement

  • Motor/Sensory involvements

• Equipment needed

  • Surface electrodes

  • Adjustable stimulation trigger

  • Computer/computer software

  • Speakers

Electrodiagnostic Testing

Influential Factors

• Age – Normal nerve conduction velocity values are not achieved until age 7 (mature at 18)

• UE/LE injury

  • UE NCV is faster

• Height/limb length

  • Longer limbs have slower conduction velocities

• Extremity temperature

  • Colder limbs conduct signals more slowly

• Anomalies with innervation patterns

Electrodiagnostic Testing

Who can administer NCS?

• Depends on the state

• Most states allow PTs to administer

• Some states allow Chiropractors to administer

• States may require specific certifications before administration

Electrodiagnostic Testing

Motor Nerve Conduction Study

• Compound Muscle Action Potential (CMAP)

  • Simultaneous depolarization of all motor units under a recording electrode

• Procedure

  • 1. Surface electrodes on distal musculature supplied by the nerve

    • Active electrode: close to motor point

    • Reference electrode: over tendon (somewhere not excitable)

    • Ground: over bony prominence

  • 2. Nerve stimulated at various sites within the path

  • 3. Second stimulation site for consistency

Electrodiagnostic Testing

Orthodromic

• When the max intensity stimulus is given, like a lightning bolt feeling, the motor signal is conducted along the motor fibers in its normal direction toward the muscle, which causes a contraction.

• This contraction is seen on the nerve conduction screen as an M-wave and measures the distal latency from the stimulus to the muscle

Electrodiagnostic Testing

Antidromic

• At the same time the signal's conducted orthodromically, it is also conducted away from its normal direction to the anterior horn cells of the spinal cord

• The spinal cord then sends an action potential back to the muscle orthodromically and you see another small contraction.

• This smaller contraction is called the F-wave and measures distal latency in both proximal and distal directions

Electrodiagnostic Testing

Calculation of NCS

• Two sites are stimulated

• Nerve conduction values are given:

  • Linear measurement between the 2 sites

    • (R = reference electrode, 1 = site 1 and 2 = site 2)

  • The following calculation can be made:

    • MNCV (m/sec) = Dist. between prox/distal sites(m) / prox latency – distal latency (msec)

  • Compare MNCV to a chart with normal values

  • Increased NCV = Slow/latency

Electrodiagnostic Testing

H-Reflex

• Another long loop reflex that can be taken similar to the F-wave.

• Monosynaptic stretch reflex

• Acquired by stimulating the Ia afferent (as opposed to the motor nerve that is stimulated to obtain the F-wave)

Electrodiagnostic Testing

Sensory Nerve Conduction Study

• Similar to Motor NCS

• Differences:

  • SNAP (sensory nerve action potential)

  • No NMJ shows a direct response

  • Single point rather than 2

  • Smaller amplitudes

Electrodiagnostic Testing

Clinical Electromyography (EMG)

• To assess the motor point more specifically

  • Uses a needle electrode – “Current density”

• Eliminates extraneous noise of overlying tissues

• More Uncomfortable

• Identifies a more clear understanding of location of injury and which specific motor units are injured

Electrodiagnostic Testing

Equipment for EMG

• Same as for Nerve Conduction Studies

• No electrical stimulation involved

• Needles for specificity

Electrodiagnostic Testing

EMG Outcomes

Provides information regarding:

• Innervation integrity

• Evidence of motor unit recovery

• Neuropathic or myopathic findings

• Localization of injury to specific patterns

  • ie. Injury consistent with anterior horn cell (ALS, polio), nerve root (tumor, HNP), plexus (stretch/compression), or NMJ (MG) disorder

Electrodiagnostic Testing

EMG Procedure

1. Insertion

2. Rest

3. Minimal Activation

4. Maximal Activation

Electrodiagnostic Testing

Insertion

• Normal, increased, sustained, decreased or absent

• Stability of the muscle membrane

• NORMAL = brief electrical activity then activity ceases

• ABNORMAL= Prolonged or Absent

Electrodiagnostic Testing

Rest

• When needle ceases to move

• Electrical silence

  

• MEPs (miniature end plate potentials)

  • When tip of needle is near NMJ

    

• End-plate Spikes

  • Short duration

    

  • Begin with upward (negative) wave

Electrodiagnostic Testing

Rest (abnormal output)

• Positive Sharp waves (downward spike)

  • Sound similar to a dull thud

  • Abnormally sensitive muscle membrane

    

• Fibrillations

  • Similar to Positive Sharp waves

  • Very short duration

  • Sounds like rain on a tin roof

    

• Fasiculations

  • Popping sound

    

Electrodiagnostic Testing

Minimal Activation

• Assesses motor units with voluntary contraction (MUP)

• NORMAL = Biphasic or triphasic

  

• ABNORMAL = polyphasic (5 + phases)

  • Low amplitude, long duration

    • Early re-innervation

      

  • Large amplitudes

    • Chronic neuropathies

      

  • Low amplitude, short duration

    • Myopathic disease

      

Electrodiagnostic Testing

Maximal Activation

• To observe the orderly recruitment of MUPs

• NORMAL = “interference pattern”

• ABNORMAL =

  

  • Neuropathic recruitment pattern

    • Decreased recruitment due to denervation

      

  • Myopathic recruitment pattern

    • Small amplitude with little to no effort

  • Decreased activation

    

Brain Tumors

• 1.5% of all cancer diagnoses

• Primary versus secondary brain tumors

• Malignant versus nonmalignant

Brain Tumors

Incidence and Etiology

• In 2019, nonmalignant tumors new cases > malignant tumors

• Overall prevalence as of December 31, 2019, was 1,323,121 cases, 14.6% were malignant.

• In children (ages 0–14 years), majority was malignant

• Adults ages 40+ years, Glioblastoma was most prevalent primary malignant brain and other CNS tumor

• Astrocytoma was the most prevalent of all malignant brain and other CNS tumors

• Meningioma had the highest overall prevalence (1/3 of all brain tumors), the majority of which were non-malignant (99%)

• 95% are nonhereditary; exposure to ionizing radiation is a risk factor

Classification of Tumors

Gliomas

the most common malignant tumor in adults and children; arise from supportive tissues of the brain

Classification of Tumors

Gliomas — Astrocytomas

From astrocytes (star-shaped glial cells); frontal lobe in adults, cerebellum in children

Classification of Tumors

Gliomas — Glioblastomas

Highly malignant grade IV astrocytoma; more common in older adults, males>females; medical prognosis is poor

Classification of Tumors

Gliomas — Oligodendrogliomas

Slow-growing but progressive; frontal and temporal lobes; 4th to 6th decade of life, male>female

Classification of Tumors

Gliomas — Ependymomas

From ependymal cells; most common site is 4th ventricle, primarily treated with surgical resection and shunt

Classification of Tumors

Gliomas — Medulloblastomas

Malignant embryonal tumors; cerebellum and 4th ventricle; children and adult <45, males>females

Classification of Tumors

Meningiomas

slow-growing; dura and arachnoid membrane; increases with age; female>males

Classification of Tumors

Pituitary adenomas

benign epithelial tumors; frequently encroach the optic chiasm; hypersecretion or hyposecretion of hormones; more common in older people; females>males

Classification of Tumors

Schwannomas

Schwann cells; cranial or spinal nerves; example: acoustic neuroma

Classification of Tumors

Primary CNS lymphomas

rare; from lymphatic system; male>female; 6-8th decades; poor prognosis;

Classification of Tumors

Secondary Brain Tumors: Metastatic Brain Tumors

• Tumor originate outside of CNS and spread to the brain through arterial circulation

• 80% in cerebral hemisphere

• 20% posterior fossa

• Origin: (1) lungs, (2) breast, (3) skin, (4) gastrointestinal tract, (5) kidney

Brain Tumors

Signs and Symptoms

• Headaches § 50 % of cases

  • Interrupts with sleep or worse when waking up, improves during the day

  • Elicited by postural changes, coughing or exercise

  • Location is determined by tumor’s location

• Seizures

  • Frequent symptom, 20-50% of adults with brain tumor

  • First seizure during adulthood is suggestive of seizure

  • > 50% of gliomas, 11% of brain metastases

• Altered mental status

  • Common in front lobe tumors and elevated ICP

• Papilledema

  • Swelling of optic nerve

  • Temporary visual loss with position changes 

  • More common in children

• Vomiting and dizziness

  • Tumor in posterior fossa

  • Elevated ICP

• Specific signs and symptoms

  • Depends on the functional areas of the brain

Brain Tumors

Diagnosis

• MRI

• Diffusion-Weighted Imaging (DWI)

• Magnetic Resonance Spectroscopy

• Functional MRI

• Perfusion Weighted Imaging

• Molecular Imaging

• Stereotactic Biopsy

• Molecular diagnosis

Brain Tumors

Medical and Surgical Treatment

Traditional Surgery

• Craniotomy

• Partial and complete tumor resections

Brain Tumors

Medical and Surgical Treatment

Chemotherapy

Intravenously via peripherally inserted central catheter (PICC) or tunneled access central catheter (TACC); disrupt ability of tumor cells to replicate

Brain Tumors

Medical and Surgical Treatment

Radiation therapy

Tumors too large or inaccessible for surgical resection; residual tumor cells; limited by maximum lifetime dosage of radiation

Brain Tumors

Medical and Surgical Treatment

Stereotactic Radiosurgery

High dose of ionizing radiation on a precisely defined volume of tissue; disrupt tumor DNA; for lesions less than 3cm; Gamma Knife, linear accelerators, cyberknife

Brain Tumors

Medical and Surgical Treatment

Hormonal Therapy

Pituitary tumors

Brain Tumors

Medical and Surgical Treatment

Immunotherapy

Biotherapy; most infrequently used and least-proven; improve immune system

Brain Tumors

Intracranial Surgery Considerations

• Observe for intracranial bleeding or seizure for at least 24 hours

• Monitor blood pressure, deep vein thrombosis (1/3 of patients) or pulmonary embolism, CSF leakage, wound infection, periocular edema, pneumocystis carinii, meningitis

• CSF leaks: Avoid Valsalva, coughing, sneezing or blowing of nose

• If bone flap is removed, avoid positioning on the operative side

Brain Tumors

Increased Intracranial Pressure (ICP)

• Major complication of intracranial surgery

• Resulting from cerebral edema or bleeding

• Positioning: Avoid lowering of the head. Elevate head 20-30 degrees in bed.

• Symptoms: decreased level of consciousness, headache, visual and speech disturbances, muscle weakness, pupil changes, seizures, vomiting, respiratory changes

• Emergency treatment for ICP >20mmHg: mannitol, hyperventilation and corticosteroid

• Surgical intervention: shunt

Brain Tumors

Side Effects and Considerations for Chemotherapy & Radiation Treatment

• Hair loss

• Fatigue

• Nausea

• Skin burns or irritation

• Difficulty eating or digesting food

• Anorexia

• Dry, sore mouth

• Low blood count (Anemia, infection, hemorrhage)

• Vomiting

• Diarrhea or constipation

• Cognitive or personality changes

Brain Tumors

Steroid Effects

• Reduce Cerebral Edema From Surgery or Radiation

• Side-effects Of Long-term Use:

  • Proximal Weakness

  • Behavioral Changes

  • Osteoporosis

  • Increased Appetite

  • Bloating

  • Hypertension

Brain Tumors

Cancer-Related Fatigue

• Causes:

  • myelosuppression, anorexia, pain, sleep deprivation, side effect of cancer treatment

• Screen:

  • European Organization for Research and Treatment of Cancer – Quality of Lift (30 core questionnaire)

• Assessment:

  • Piper Fatigue Scale-revised, Functional Assessment of Chronic Illness Therapy – Fatigue, Patient Reported Outcome Measurement Information System (PROMIS) Fatigue SF.

• Intervention:

  • Structured progressive exercise program: 50 to 70% of heart rate reserve, RPE of 11 to 14, avoid isometrics and vigorous resistive exercises

Brain Tumors

Physical Therapy Evaluation — Karnofsky performance scale

• Evaluate impact of tumor or treatment

• Functional outcomes similar to stroke or TBI

• Functional outcome scales

• Determine the meaning of quality of life from a patient’s perspective

Brain Tumors

Physical Therapy Intervention

• Physical conditioning

• Functional Training

• Range of motion

• Lymphedema management

• Pain management

• Recommendation of appropriate assistive device, adaptative equipment and home modification

• Caregiver education and training

Postpolio Syndrome (PPS)

• Postpolio muscular atrophy

• New neuromuscular symptoms after recovery from acute poliomyelitis

• Review of Acute Poliomyelitis:

  • caused by the polio virus (enterovirus) affected mainly children under 3 years old

  • Inflammation of the meninges and anterior horn cell resulting to loss of spinal and bulbar motor neuron.

  • Led to asymmetric, flaccid paralysis with LE more affected than UE, and bulbar weakness in 10 to 15% of cases.

  • Polio vaccines: Salk (1950s) and Sabin (1960s) vaccine

Postpolio Syndrome

Etiology

• Unknown

• Most common theory: increase size of innervation ratio, wherein a small axon innervates many muscle fibers which leads to an overworked motor unit. Giant motor units cannot sustain the metabolic demands of their sprouts.

• Muscle fiber type changed from Type II (fast twitch) to Type I (slow twitch)

Postpolio Syndrome

Pathogenesis

• Muscle denervation

• Attrition of motor neuron that can no longer support axonal sprouts

Postpolio Syndrome

Clinical Presentation

• New muscular weakness

  • Muscle fasciculation, cramps, atrophy and elevation of muscle enzyme in the blood

• Fatigue

  • Major complaint

  • Most common and debilitating

  • Generalized, focal or central

• Pain

  • Parts of body previously affected by polio, cramping of lower extremity, aching of neck and shoulders, associated with mechanical stress, related to physical activity

• Loss of function

• Bulbar

  • Respiratory and swallowing

• Cold intolerance