Guillain Barre Syndrome (Temporary Degeneration Of PNS)

Question 1

Definition

Answer 1

Type 4 hypersensitivity reaction where there is autoimmune rapidly progressive demyelination response of the peripheral nervous system due to a infection trigger (gastroenteritis/URTI)

Question 2

Epidemiology

Answer 2

Males
Bimodal age: 15-30, 50-70

Question 3

Risk factors

Answer 3

Malignancies: lymphoma may increase the risk of GBS
Vaccines: association with the influenza vax (uncommen)

Question 4

Aetiology

Answer 4

Bacterial:
- Campylobacter jejuni
- Mycoplasma pneumoniae
Viral:
- Zika virus
- Influenza
- EBV
- Cytomegalovirus

Question 5

Pathophysiology

Answer 5

GBS = caused by ‘molecular mimicry’
A pathogenic antigen (e.g. Campylobacter jejuni) resembles myelin gangliosides in the peripheral nervous system
The immune system targets the antigen and attacks the myelin sheath of sensory and motor nerves
This autoimmune process involves the production of anti-ganglioside antibodies (anti-GMI is positive in 25% of patients)
Acute polyneuropathy = 85% recover = Good prognosis

Question 6

Subtypes

Answer 6

Acute inflammatory demyelinating polyneuropathy (ADIP): ~90% of cases
Acute motor axonal neuropathy (AMAN)
Acute motor and sensory axonal neuropathy (AMSAN)
Miller-Fisher Syndrome (MFS):
Classic triad: ataxia, areflexia, and ophthalmoplegia
- Eye muscles are typically affected first
- Usually causes descending (rather than ascending) paralysis and anti Gq1b antibodies present in 90% of cases

Question 7

Signs

Answer 7

• Reduced sensation in affected limbs
• Symmetrical weakness in lower extremities first, progressing to upper limps (proximal first then distal muscles)
• Ataxia with hypoflexia
• Autonomic dysfunction e.g. tachy, HTN, postural hypotension, urinary retention
• Respiratory distress (SOB)
• Cranial nerve involvement and bulbar dysfunction e.g diplopia, or facial droop

Question 8

Symptoms

Answer 8

• Tingling and numbness in hands and feet: often precedes muscle weakness
• Symmetrical. progressive, ascending weakness
• Unsteady when walking
• Back and leg pain: common at some point in disease course
• SOB
• Facial weakness and speech problems

Question 9

Investigations

Answer 9

Typically clinical diagnosis
Nerve conduction studies
Lumbar puncture: L3/4 = raised protein with normal WBC count = inflammation with no infection

Question 10

Treatment

Answer 10

First-line:
IV immunoglobulins (IVIg): 5 day treatment course commenced within the first 2 weeks of symptom onset
- CI in IgA deficient patients = ALLERGIC REACTION
or
Plasma exchange: 5 treatments of 2-3L over 2 weeks commenced within the first 4 weeks of symptom onset
Also if FVC < 0.8; consider INTUBATION + ITU

Question 11

Complications

Answer 11

T2RF
Impaired mobility
Psychiatric impact: depression, PTSD, anxiety