Neuromuscular weakness - Guillain_Barre_Syndrome passmed

Question 1

What is Guillain-Barre syndrome?

Answer 1

An immune-mediated demyelination of the peripheral nervous system often triggered by an infection (classically Campylobacter jejuni).

Question 2

What is the pathogenesis of Guillain-Barre syndrome?

Answer 2

• Cross-reaction of antibodies with gangliosides in the peripheral nervous system.
• Correlation between anti-ganglioside antibody (e.g., anti-GM1) and clinical features.
• Anti-GM1 antibodies in 25% of patients.

Question 3

What is Miller Fisher syndrome?

Answer 3

• A variant of Guillain-Barre syndrome.
• Associated with ophthalmoplegia, areflexia, and ataxia.
• Typically presents as descending paralysis.
• Anti-GQ1b antibodies are present in 90% of cases.

Question 4

What are the initial symptoms of Guillain-Barre syndrome?

Answer 4

Around 65% of patients experience back/leg pain in the initial stages of the illness.

Question 5

What are the characteristic features of Guillain-Barre syndrome?

Answer 5

• Progressive, symmetrical weakness of all the limbs (ascending).
• Reflexes are reduced or absent.
• Mild sensory symptoms (e.g., distal paraesthesia).

Question 6

What are some other features of Guillain-Barre syndrome?

Answer 6

• History of gastroenteritis.
• Respiratory muscle weakness.
• Cranial nerve involvement (e.g., diplopia, bilateral facial nerve palsy, oropharyngeal weakness).
• Autonomic involvement (e.g., urinary retention, diarrhoea).

Question 7

What is a less common finding in Guillain-Barre syndrome?

Answer 7

Papilloedema, thought to be secondary to reduced CSF resorption.

Question 8

What are the key investigations for Guillain-Barre syndrome?

Answer 8

• Lumbar puncture: rise in protein with a normal white blood cell count (albuminocytologic dissociation) in 66%.
• Nerve conduction studies: decreased motor nerve conduction velocity, prolonged distal motor latency, increased F wave latency.