PNS Part III Flashcards

1
Q

Describe Guilian Barre Syndrome

A
  • Overall rare, but most common rapidly evolving inflammatory PND characterized by rapid-onset motor paresis and sensory deficits (since after the eradication of polio)
  • Autoimmune inflammatory disorder where body’s immune system mistakenly attacks the PNS
  • Often, the immune destruction is triggered/preceded by respiratory/GI infections
  • Initially, it was described as a single disorder characterized by PNS demyelination, but now considered as having several variants, where axons may also be attacked, depending on the type of infection
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2
Q

Incidence, etiology, and risk factors of Guilian Barre

A
  • 1-2 cases per 100,000
  • Can occur at all ages, but peaks during young adulthood and in 5th-8th decades
  • Men slightly more affected than women, whites more than blacks
  • 90% of GBS had prior illnesses (GI or respiratory infections) during preceding 30 days
  • Bacterial and viral infections are associated with it, Campylobacter jejuni (associated with axonal form), cytomegalovirus (associated with greater sensory involvement), haemophilus influenza, etc.
  • Sometimes reported to occur following surgery or vaccinations…also reported following COVID 19 (but rare)
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3
Q

Pathogenesis of Guilian Barre syndrome

A
  • Antibodies are produced after possible infections, which mistakenly label antigens on surface of myelin sheath, as per molecular mimicry autoimmune theory
  • Immune cells (T-cells, macrophages) attack myelin sheaths and start to strip myelin at the Nodes of Ranvier
  • Schwan cells remyelinate axons, forming shorter internodes
  • Inflammation causes a longer-term effect - products released by T-cells and macrophages also destroy neighboring axons: ‘bystander effect’
  • If axonal damage, recovery of Wallerian degeneration would take longer time
  • Auto-immune destruction of myelin sheath and axons can occur throughout the PNS from spinal roots to nerve terminals
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4
Q

Clinical manifestations of Guilian Barre syndrome

A
  • Classic presentation is of rapid onset of weakness, beginning distally in legs or arms, progressing to trunk, reaching peak weakness in 2-3 weeks. Sometimes facial, palatal and muscles of mastication may be get affected.
  • Initial symptoms: tingling/paresthesia often in toes, followed within hours-to-days by distal weakness
  • Rapidly ascending symmetric motor weakness
  • Generally, progression of symptoms stop by 4 weeks, then a static phase lasts for 2-4 weeks, then recovery begins in proximal to distal direction. Recovery may take months to years.
  • Flaccid paralysis accompanies loss of DTRs
    ANS might be involved, abnormalities in cardiac rhythm, BP changes
  • Severe cases: respiratory muscles can be involved, may need artificial ventilation
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5
Q

Slide 6

A
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6
Q

How to diagnose Guilian Barre syndrome

A
  • Medical history
  • Disease progression
  • Clinical exam
  • NVC/EMG
  • Lab tests like lumbar puncture for CSF proteins
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7
Q

Treatment for Guilian Barre syndrome

A
  • Plasmapheresis or plasma exchange: filtering circulating antibodies out of plasma or removing plasma & substituting with a fluid; typically 4-6 exchanges of 500ml per treatment over a period of a week
  • High dose IV IGs: 0.4 g/kg/day for 5 days
  • Outcomes for both approaches are equivalent
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8
Q

Prognosis fo Guilian Barre syndrome

A
  • Most people recover completely
  • 20% can have residual neurologic deficits
  • Complications that can persist: neuropathic pain, autonomic changes, distal weakness
  • Factors that predict poor outcomes: onset at older age, protracted time before recovery begins, need for artificial respiration
  • 5% mortality rate
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9
Q

Guilian Barre syndrome implications for PT during progressive phase

A
  • Focus is to prevent complications associated with immobility (mostly in ICU setting)
  • Maintain ROM, prevent contractures
  • Meticulous skin care to prevent skin breakdown, strict turning schedule
  • Hot packs and gentle massage for musculoskeletal pain
  • Monitor ABGs, SpO2, for respiratory function
  • Encourage deep breathing and coughing to maintain clear airway and prevent atelectasis
  • Precautions to prevent respiratory infections
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10
Q

Guilian Barre syndrome implications for PT when disease stabilizes & recovery begins

A
  • Gentle stretching
  • Avoid over stretching and over use of painful muscles, can prolong recovery
  • Active-assisted exercises -> progressing to active exercises - PNFs are good options
  • If tolerated, higher intensity exercises are more beneficial than lower intensity exercises
  • Continued impairment may require ADs, w/c
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11
Q

Describe Postpolio syndrome/Postpolio muscular atrophy

A
  • Polio infection was virtually irradiated in the 1950-60s by polio vaccine (Salk/Sabin vaccines)
  • Survivors of polio attack are older adults now
  • PPS refers to new neuromuscular symptoms that occur to polio survivors decades after recovery from the acute paralytic episode of poliomyelitis infection
  • PPS is known to affect 20-50% of polio survivors
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12
Q

Pathogenesis of Polio

A
  • Polio virus gets transmitted by ingesting contaminated food or water
  • Polio infection followed one of the 3 patterns: Asymptomatic (~70%); Non-paralytic, that produced GI or flu-like symptoms and muscular pain (~25%), recover in 1-2 weeks; Paralytic, began with flu-like symptoms, with asymmetric paralysis within a week, due to virus killing anterior horn cells
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13
Q

Clinical presentation following initial Polio attack

A
  • Unique peripheral neuropathy presentation: focal asymmetric motor involvement without any sensory deficits
  • Extent and degree of paralysis depended on AHC involvement, wallerian degeneration of axons and muscle atrophy. Many suffered temporary paralysis, others permanent.
  • Of the people with acute spinal polio attack, many recovered (50%), some had mild residual paralysis (25%), others had moderate to severe paralysis (25%)
  • Recovery occurred due to various reasons: survival of AHCs, collateral sprouting from intact peripheral nerves connecting to denervated muscles (next slide) and hypertrophy of spared muscles
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14
Q

Etiology of post polio syndrome

A
  • Polio was thought to be a self limiting disease with no progression after initial paralytic episode
  • Later studies confirm that denervation occurs again decades later in both clinically affected & unaffected muscles
  • Progression is more rapid than that occurring in normal aging, rate of motor unit loss is twice of that occurring in healthy older people
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15
Q

Pathogenesis of post polio syndrome (PPS)

A
  • PPS is manifested when the nervous system cannot maintain the compensatory re-innervation of the muscles by collateral sprouts, that resulted in recovery/stabilization of the disease after the initial attack
  • The nervous system starts pruning back axonal sprouts of the enlarged motor units that it cannot metabolically support any longer, thus new denervation occurs
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16
Q

Clinical manifestations of post polio syndrome

A
  • New weakness, muscle atrophy, pain and fatigue in the limbs that were originally affected, or in limbs that were not affected previously
  • Very slowly progressing condition marked by periods of stability followed by new declines in the ability to carry out ADLs, but deterioration of strength occurs faster than normal aging
  • Excessive fatigue even with minimal activity
  • Pain: commonly in low back, UE joints, worse at night or with increased activity, and with climate changes
  • Problems breathing or swallowing, sleep-related breathing disorders
17
Q

How to diagnose post polio syndrome

A
  • Can be difficult as symptoms can be non-specific
  • Requires exclusion of other neurologic or orthopedic disorders that could explain new symptoms
  • EMG
  • Muscle biopsies
  • Prognosis: slowly progressive condition
18
Q

Treatment for post polio syndrome

A
  • Symptomatic treatment, consisting of rest, analgesics
  • Modification of lifestyles using education about energy conservation strategies, home modifications
  • ADs and surgery for residual deformities (e.g., arthrodesis, tendon transfers)
19
Q

Post polio syndrome implications for PT

A
  • Use of submaximal intensity exercises are recommended to maintain/improve endurance and functional capacity
  • Fatigue should be avoided, vitals to be monitored before, during and after exercises, energy conservation techniques
  • Contraindications to exercise would be increased pain and weakness
  • Reassessment/modification of orthoses for gait, as previous orthoses may not be sufficient anymore
  • Per research, individuals with PPS who engage in physical activity twice weekly demonstrate better gait than those who are less active.
20
Q

Describe Myasthenia Gravis

A
  • Most common disorder of the NMJ (others are LEMS, botulism)
  • Chronic autoimmune disorder
  • Characterized by fluctuating weakness and fatigability of skeletal muscles
  • Incidence: 1 in 200,000
  • Can affect people in any age group, but peak in women in 20s-30s and in men in 50s-60s
  • Women more than men
21
Q

Risk factors for Myasthenia Gravis

A
  • Associated with thymic disorders like hyperthyroidism, thymic tumor, thyrotoxicosis
  • Thymus produces/matures T-lymphocytes, trains them to recognize foreign and self antigens
  • Also associated with RA, lupus, diabetes
  • Hormonal associations: exacerbations can occur before menstrual cycle or shortly after pregnancy
  • Any chronic infections can exacerbate MG
22
Q

Describe the neuromuscular junction

A
  • Motor end plate: site where axon & muscle fiber meet; sarcolemma folded; nuclei & mitochondria are abundant
  • Muscle contractions are triggered when nerve impulses are conducted by neurotransmitter Ach at the synaptic junction. Post synaptic receptors are called nicotinic Ach receptors
23
Q

Pathogenesis of Myasthenia Gravis

A
  • In MG, nicotinic acetylcholine receptors at the junction between the nerve and muscle are blocked/destroyed by antibodies, which prevents nerve impulses from being transmitted
  • Also, motor end plates are flattened, resulting in less receptors
24
Q

Clinical manifestations of Myasthenia Gravis

A
  • Cardinal features are fluctuating muscle weakness and fatigability
  • Repetition of activity causes fatigue, rest restores normal activity
  • Muscles affected in MG: Ocular >50% of cases (ptosis & diplopia usually the first signs), Muscles of face & throat, Sometimes weakness of respiratory muscles (could be triggered by stress, infection, fever, etc), Neck & limb muscles affected (UEs more often affected the LEs), waddling gait
  • Typically MG starts with ocular muscles, then evolves into generalized type involving extremity and other muscles
25
Q

How to diagnose Myasthenia Gravis

A
  • Using physical exam to observe fatigue with continued use, and improvements with rest
  • Blood tests for presence of anti-Ach receptor antibodies
  • EMG: normal EMG at rest, rapid decrement in action potential amplitude with repeated activity
  • Absence of sensory deficits and normal DTRs also help to confirm MG
  • Tests for ocular MG: Simpson’s test, Ice test, rest test
26
Q

Treatment for Myasthenia Gravis

A
  • Using medications known as acetylcholinesterase inhibitors such as neostigmine and pyridostigmine
  • Corticosteroid immunosuppressants such as prednisone or azathioprine
  • Surgical removal of the thymus gland
  • Plasmapheresis and high dose intravenous immunoglobulin
27
Q

Prognosis of Myasthenia Gravis

A
  • Course of MG is variable, with remission and exacerbations
  • Overall slowly progressive, reaching worst condition within a few years from onset
  • Symptoms fluctuate in intensity during the day
  • Daily fluctuations are superimposed on longer term relapses
  • Myasthenia crisis is medical emergency: failure of respiratory and/or oropharyngeal muscles causing airway obstruction or aspiration , requires ventilator assistance, sometimes it is the first manifestation of MG
28
Q

Myasthenia Gravis implications for PT

A
  • In ICU setting: if respiratory muscles are affected, encourage deep breathing exercises and coughing
  • During eating, person should sit upright and swallow with chin tipped downward towards chest, and never extended, to prevent aspiration
  • Never speak with food in mouth
  • Avoid strenuous exercise programs, stress, allow frequent rest periods to minimize fatigue
  • Per research, for mild-moderate MG cases, strength training program using maximal isometric contractions can be beneficial
  • Outcome measures: MG_DIS (self reported outcome measure), QMG (quantitative measure for MG severity)
29
Q

Describe complex regional pain syndrome (CRPS)

A
  • A group of chronic pain syndromes that often worsens with time, generally characterized by severe pain out of proportion to the original injury
  • Characterized by sensory, motor changes and sympathetic dysfunction w/ or w/o known trauma
30
Q

What are the types of CRPS

A
  • CRPS I (formerly RSD) – caused by injury that did not directly damage the nerves in the affected limb, most (90%) CRPS is of this type.
  • CRPS II (formerly causalgia) – associated with known nerve trauma
  • CRPS-NOS (not otherwise specified) – partially meets CRPS criteria
31
Q

Etiology and pathogenesis of CRPS

A
  • No known cause, not understood well
  • Associated with a variety of conditions –PNI, fractures, amputation, surgical procedures, TBI, CVA, MI, bites, infections, falls, shoulder subluxation/dislocation, any event that causes traction in brachial plexus, or just sprained ankle.
  • Exaggerated pain is associated with sympathetic overactivity
  • Normally sympathetic activity after trauma causes vasoconstriction. This process shuts down automatically in minutes
  • In CRPS, there is abnormal facilitation of sympathetic nervous system, causing cycle of pain and swelling, initially increasing skin temperature and later causing cyanosis and cold temperature.
32
Q

Clinical manifestations of CRPS

A
  • Abnormally exaggerated pain processing (hyperalgesia, allodynia) – may spread proximally, and also from ipsi to contra side
  • Edema
  • Vasomotor changes - skin color and temperature changes (initially red/warm, later cold/cyanotic skin)
  • Trophic changes (changes in sweating, changes in hair growth, brittle nails, thin glossy skin)
  • Motor dysfunctions (weakness, atrophy, joint stiffness, tremors, spasms)
  • Bone changes
33
Q

What are the 3 progressive clinical stages of CRPS

A
  • Acute inflammation: pain, swelling, redness, sensitivity to touch
  • Dystrophic: alternating between sweaty and cold, skin color changes from red-to-white-to-blue
  • Atrophic: severe muscle and bone changes, atrophy, osteoporosis, contractures
34
Q

How to diagnose and treat CRPS

A
  • No “gold standard”
  • Diagnosis using hx and clinical exam
  • Budapest criteria for diagnosis
  • Diagnosis may be delayed due to its evolutionary nature
  • Bone scans, sympathetic nerve blocks helps diagnosis
  • Needs prolonged multidisciplinary treatment using meds (steroids, NSAIDS, spinal cord stimulators, intrathecal pumps) and physical therapy
35
Q

CRPS implications for PT

A
  • Goals of rehab to reduce pain and encourage use of involved extremity
  • Desensitization techniques – progressive stimulation with very soft materials to more textured fabrics, from light touch to deep pressure, from consistent to intermittent touch
  • Modalities like TENS during the earlier stages of CRPS
  • Graded exposure techniques - motor imagery -> mirror therapy -> movements
  • Stress loading activities (loading and scrubbing) followed by distraction force (carrying weights)