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