5. Guillain-Barre Syndrome

Question 1

What is Guillain-Barre syndrome (GBS)?

Answer 1

-> An acute, paralytic polyneuropathy.
-> Inflammatory, demyelinating, ascending polyneuropathy
-> Affecting the PNS = SCHWANN CELLS TARGETED
-> Following an upper respiratory tract infection of GI infection.

Question 2

Is GBS symmetrical?

Answer 2

Yes

Question 3

Give 3 causes of GBS.

Answer 3

1. Campylobacter jejuni
2. Cytomegalovirus (CMV)
3. Epstein-Barr virus (EBV)
4. Mycoplasma

Question 4

What is the pathophysiology of GBS?

Answer 4

Autoimmune!!
Theory: Molecular mimicry mechanism

1. B-cells create antibodies against the antigens of a pathogen that causes infection.
   (bacteria don’t directly damage myelin)
2. These antibodies match proteins on motor nerve cells myelin sheaths or the myelin sheath of nerve axons.
3. Macrophages use those antibody markers to bind to and strip myelin sheath of peripheral neurones.
4. Demyelination occurs in patches along the length of the axon called SEGMENTAL DEMYELINATION.

Question 5

Clinical course / time-frame of GBS?

Answer 5

• Usually start within 4 weeks preceding infection
• Typically start in the feet and progress upward
• Symptoms peak within 2-4 weeks
• Recovery period can last months to years

Question 6

Describe the symptoms seen in Guillain-barré syndrome.

Answer 6

1. Symmetrical ascending muscle weakness (starting at the feet and moving up the body)
   - PROXIMAL MUSCLES are more affected e.g. trunk, respiratory and cranial nerves (ESPECIALLY CN 7)
2. Reduced reflexes
3. Pain common (neuropathic)
   - e.g. back pain
4. No sensory signs - peripheral loss of sensation
   - Parasthesia
5. Facial nerve weakness
6. Autonomic dysfunction
   - Sweating, raised pulse, BP changes (orthostatic hypotension), urinary incontinence, palpitations, arrhythmias

Question 7

Diagnosis of GBS - Investigations.

Answer 7

• Brighton criteria can be used

1. Lumbar puncture
   - Rise in protein + normal WBC count
   
   • albuminocytologic dissociation
2. Nerve conduction studies = GOLD STANDARD if diagnosis uncertain
   - Slow conduction
3. LFTs
   - Elevated AST and ALT
4. Spirometry
   - To monitor FVC if there is respiratory involvement
   * Decreased FVC indicates the need to admit to ITU to maintain airways
   
   • Should be carried out at 6-hour intervals initially at bedside

Question 8

If you were to perform lumbar puncture on a patient with Guillain-Barre syndrome, what might you see?

Answer 8

Increased protein
Normal WBC count

Question 9

Management of GBS.

Answer 9

NOTE: Aimed at reducing symptoms

1. IV Immunoglobulins for 5 days - 1st LINE
   - Contraindicated in patients with IgA deficiency!!
2. Plasma Exchange
3. Low-molecular weight heparin e.g. SC ENOXAPARIN
   -> to help prevent DVT
4. Give patient supportive treatment for complications
   - If FVC < 1.5L/80% then ventilate and admit to ITU
   - MONITOR FVC 4 HOURLY!

Question 10

Describe the prognosis of GBS.

Answer 10

1. 80% making a complete/near-complete recovery
2. 15% will be left with some neurological disability
   e.g. are unable to walk alone at 1 yr
3. 5% will die

Question 11

Give 3 complications of GBS.

Answer 11

1. Respiratory compromise (the leading cause of death in GBS patients)
2. Venous thromboembolism
3. Persistent neuropathic pain or fatigue
4. Long-term disability, requiring a wheelchair or walking aid or paralysis
5. Aspiration pneumonia

Question 12

Differential diagnosis of GBS.

Answer 12

Other causes of acute paralysis e.g. hypokalaemia, stroke, brainstem compression, encephalitis, spinal cord compression, poliomyelitis, vasculitis, myasthenia gravis