Guillain-Barré Syndrome (GBS) Overview

• Guillain-Barré Syndrome (GBS) is an acute inflammatory demyelinating neuropathy
• Professors Guillain and Barré first noted GBS while caring for WWI soldiers

Introduction

• GBS is an autoimmune disease affecting the peripheral nervous system
• GBS is a rare condition, with a global prevalence of 1.9 per 100,000
• The incidence of GBS is on the rise annually and increases with age
• GBS is most prevalent in individuals aged 5-9 years and 60-64 years
• It is more common in males than females and has increased rates in high-income countries

Etiology

• The exact cause of GBS is unknown
• GBS commonly occurs 5 days to 3 weeks after a viral respiratory or GI tract infection, immunization, or surgery
• There is no direct evidence of direct viral infection of peripheral nerves or nerve roots

Anatomy Recap

• Structural organization of the nervous system is categorized into central vs. peripheral
• The central nervous system (CNS) includes the brain and spinal cord
• The peripheral nervous system (PNS) includes the nerves and ganglia
• Structurally, nerves in the PNS are classified as cranial or spinal
• Cranial nerves extend from the brain, while spinal nerves extend from the spinal cord
• The PNS is subdivided into autonomic nervous system and sensory neurons

PNS Damage

• PNS damage occurs within the LMN (Lower Motor Neuron) near the NMJ (Neuromuscular Junction)

Neuropathy: Injury or Damage

• Neuropathy: any damage/injury to the peripheral nerves (spinal or cranial nerves)
• Classification of neuropathy is according to location and cause

Demyelinating Disorders of the PNS

• Glial cells in the PNS include satellite cells and neurolemmocytes (Schwann cells)
• Satellite cells are arranged around neuronal cell bodies in a ganglion and electrically insulate and regulate the exchange of nutrients and waste
• Neurolemmocytes (Schwann cells) are elongated, flat cells that ensheath PNS axons with myelin and allow for faster action potential propagation

Pathophysiology

• Neurotransmission is impaired due to failure of conduction of individual impulses along the nerve (can't cross the demyelinated segment)
• Neurotransmission is also impaired because of delayed conduction of individual impulses, slowed by non-saltatory conduction

Demyelination Diseases

• Demyelination diseases cause destruction of the myelin sheath while the other elements of the nervous system (e.g., axon) remain intact
• Demyelination of CNS: Multiple sclerosis
• Demyelination of PNS: Guillain-Barré syndrome (characterized by acute onset of peripheral and cranial nerve dysfunction)

Pathology

• Autoimmune disease: peripheral nerve biopsies lymphocytes infiltrate the interstitium and perivascular spaces
• GBS is characterized by focal segmental demyelination, with lesions scattered throughout the peripheral nerves, nerve roots, and cranial nerves
• In severe lesions axonal degeneration is observed

Variants of Demyelination in PNS

• AIDP is the most common type, accounting for 80-90% of cases
• CIDP: The chronic counterpart to Guillain-Barré syndrome, characterized by symmetrical weakness and sensory changes
• Miller Fisher Syndrome opthalmoplegia (weak eye muscles that cause diplopia), ataxia, and areflexia (5%)
• AMAN is selective involvment of motor nerves, DTRs are preserved, more common in Japan/China, almost all preceded by Campylobacter infection. AMAN infection often often progresses sufficiently to require ventilator support
• AMSAN: more severe form of AMAN with sensory involvement

Clinical Features

• Limb weakness: The first symptom of GBS is symmetric limb weakness, often accompanied by paresthesias
• Abnormal Sensations: About 50% of patients develop abnormal sensations/tingling of the feet or fingers
• Muscle Weakness: 25% develop muscle weakness e.g. difficulty climbing stairs, getting up from a chair and/or cramping)
• Weakness progression: Weakness usually progresses from distal to proximal
• Respiratory involvement: 70% of patients lose some strength in respiratory muscles, leading to shortness of breath. In around one-third of patients,intubation and a ventilator temporarily become required.
• Facial involvement: The face is occasionally the first area to be affected (10% develop weakness in face or arms)
• Oropharyngeal weakness: occurs in ~50% of patients.
• Many patients experience flaccid paralysis of nearly all skeletal muscles, with talking, swallowing and breathing frequently being affected
• DTR may be normal in the first few days, then disappear
• Flaccidity (low tone) is symptomatic
• Sensory impairment varies:
  • Some patients have all sensory modalities are intact
  • Others have marked loss of JPS, vibration, pain and temperature in stocking-and-gloves distribution -Autonomic Nervous System: low cardiac output, cardiac dysrhythmias, BP fluctuation, poor venous return and urinary retention
  • Pain: usually symmetrical and reported in the large bulk muscles: gluteal, quadriceps, hamstring and leg muscles
  • The sensation is often referred to as muscle aching associated with vigorous or excessive exercise
• GBS does NOT affect cognition/communication. Which these patients are frequently very frightened/frustrated with the inability to communicate if proceed to tracheostomy
• Patients may need a communication board, which requires eye movements if no hand function

GBS Prognosis

• Symptoms are most severe within one week of onset but may progress for 3 weeks or more
• GBS typically is self-limiting with improvement usually beginning spontaneously after weakness maximizes
• Mortality rates range 3% (mainly dysautonomia rather than respiratory failure)
• The recurrence rate is less than 5% and full recovery occurs in 50-95% of cases
• Many patients can walk without aid after three months and experience only minor residual symptoms by the end of the first year following onset

Differential Diagnosis

• CIDP is similar to GBS, but is a slow onset, progressive nature, and present symptoms for months with limited activities of daily living
• CIDP manifests in a variety of patterns, most commonly recurrent relapses and remissions of ascending weakness
• CIDP rarely involves the cranial nerves/respiratory function.
• Treatment for CIDP & prognosis: 2/3 respond to steroids, PE or IVIg
  • 30% symptom free
  • 45% mild disability
  • 25% severe disability

GBS Diagnosis

• Lumbar puncture will show a raised CSF protein level (breakdown of myelin sheath)
  • May not occur until >1/52
• Nerve conduction testing indicates conduction block, prolonged distal latencies, and decreased motor conduction studies

Medical Management

• There is no known cure for GBS.
• Drugs can lessen its severity and hasten recovery
• Acute life-saving management may be required for respiratory/bulbar management
• Plasma exchange (PE) is best if done in the first week, but stops being effective later than two weeks after onset
  • PE complications include hypotension and arrhythmias and risk of septicaemia and thrombosis Plasma exchange (PE) is expensive and require highly skilled personnael.
• Intravenous immunoglobulin (IVIg) ‘Intragam' is as effective as plasmapheresis but with less complications
• Both IVIg and PE has shown to shorten recovery time by <50%
• Urgent respiratory supportive care may be required if FVC <18ml/kg ie <1.31 in 70kg man
• Tracheostomy may be needed if ventilation is likely to be required >2/52

Physiotherapy

• Respiratory Function
  • Respiratory management including, Is there an airway/ humidification & O2 support?
  • Oxygen saturation (sats), RR, respiratory depth, respiratory pattern and secretions
• Observe
  • Cough and ausc
  • Position in bed, attachments etc.
• Function
  • Patient being functional in any way -Patient being sat out by nursing staff
• Active movement
  • Assessment of active mvt may not be possible due to Decreased LOC and Effects of sedation/ paralysing medications
  • Look for spontaneous movement. Comment on quality
  • Active movement if patient can follow verbal commands.
• Passive movement (Assess joint ROM and muscle length)
• Assess tone
• Sensation and proprioception
• Co-ordination (finger to nose, heel to shin, dysdiadochokinesia test)
  • Not possible in the unconscious patient
• Reflexes

Objective Measurement includes

• Objective strength tests using a dynamometer
• Validated measurements include
  • TUG
  • Clinical Test of Sensory interaction and balance (CTSIB)
  • 10m walk test
  • Step test

Acute Phase PT interventions

• Respiratory management includes
  • Monitoring of FVC
  • Appropriate positioning in bed
  • Assistance in optimising oxygenation
  • Assistance in clearing secretions
  • Treatment of established lung pathology (eg aspiration pneumonia)
• Neuromuscular management includes
  • Prevention of weakness due to inactivity
  • Maintenance/strengthening of weakened muscles
  • Restoration/maintenance of PROM
  • Restoration/maintenance of safe mobility
  • Pain management
• Note: care with autonomic dysfunction, monitor of HR, BP during exercise
• Muscle strength/strengthening weakened muscles.
  • Maintain rapid strength improvement in first 6/12 and continues more slowly for 18/12 post onset in treated GBS
  • There is no evidence the exercise can overcome active pathological process
• Facilitating movement with Demonstrate the movement passively and Ask the patient to contract his muscles
  • Facilitatory techniques: skin stroking, brushing, vibration, tapping
  • As the patient gains strength, the movement is translated into functional activities
  • As reinnervation progress increase PNF can be tied in with functional pattern
  • Be careful not to over-work the weaker components of the movement pattern.

Guidelines for PT Interventions

• To prevent over-use give frequent rest period
• Vigorous exercise may damage muscle if fewer than 1/3 of motor unit are functional, or Vigorous exercise may cause hypertrophied muscle if more than 1/3 of motor units are functional
• Short periods of non-fatiguing exercise appropriate to the patient strength, low repetition is key

Maintaining Joint ROM

• Maintain Maintaining/restoring passive range of movement from Habitual postures that cause shortening of hamstrings
• Use of positioning and splinting regimes to help, weight bearing stretches, with Measurement of outcome
• Hydrotherapy and Suspension Therapy

Subactute PT Interventions

• Retraining of function with bed mobility, sitting balance, standing balance, gait retraining

End Stage

• Most patients recovering from GBS have VO2 max values lower than expected for their age which can be attributed to altered muscle function
• It is important to not over work the patient and focus on endurance training, community ambulation and reintegration.