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
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)
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
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
5
Q
Slide 6
A
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
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
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
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
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
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
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
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
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
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
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
How to diagnose Myasthenia Gravis
- 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
Treatment for Myasthenia Gravis
- 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
Prognosis of Myasthenia Gravis
- 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
Myasthenia Gravis implications for PT
- 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
Describe complex regional pain syndrome (CRPS)
- 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
What are the types of CRPS
- 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
Etiology and pathogenesis of CRPS
- 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
Clinical manifestations of CRPS
- 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
What are the 3 progressive clinical stages of CRPS
- 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
How to diagnose and treat CRPS
- 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
CRPS implications for PT
- 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)
