Neuromuscular Weakness - Guillain_Barre_Syndrome_Quesmed

Question 1

Definition

Answer 1

GBS is an ascending inflammatory demyelinating polyneuropathy, typified by an acute onset of bilateral and roughly symmetric limb weakness.

Question 2

Epidemiology

Answer 2

The prevalence of GBS is approximately 1-2 cases per 100,000 worldwide.

Question 3

Aetiology

Answer 3

GBS typically occurs 1-3 weeks following an infection, with common culprits being Campylobacter, mycoplasma, and Epstein-Barr Virus (EBV). 40% of cases are idiopathic. Other triggers include CMV, HIV, Hepatitis A, or vaccinations such as tetanus, rabies, or swine flu.

Question 4

Signs and symptoms

Answer 4

Clinical features include progressive ascending symmetrical limb weakness, lower back pain, paraesthesia, respiratory muscle involvement, cranial nerve involvement, lower motor neuron signs, and autonomic dysfunction (e.g., arrhythmias, labile BP).

Question 5

Variants

Answer 5

Variants include Paraparetic variant, Miller-Fisher syndrome, Pure motor variant, Bilateral facial palsy with paraesthesias, Pharyngeal-brachial-cervical weakness, and Bickerstaff’s Brainstem Encephalitis.

Question 6

Differential diagnosis

Answer 6

Differentials include vascular causes (e.g., brainstem strokes), infective/inflammatory conditions (e.g., Polio, Lyme disease, HIV, TB), traumatic/structural causes (e.g., spinal cord compression), and metabolic causes (e.g., porphyrias, electrolyte derangements).

Question 7

Investigations

Answer 7

Key investigations include monitoring of FVC, cardiac monitoring, blood tests, serological tests (anti-ganglioside antibodies), lumbar puncture (albuminocytological dissociation), and nerve conduction studies.

Question 8

Management

Answer 8

Management includes supportive care (monitoring FVC, VTE prophylaxis, analgesia, cardiac arrhythmia management, enteral feeding if needed) and specific treatments like IVIG or plasmapheresis for significant disability.

Question 9

Prognosis

Answer 9

While GBS can be life-threatening, most patients experience full recovery. Prognostic indicators include speed of onset, severity at nadir, age, and the presence of preceding diarrhoeal illness.