Guillain-Barré Syndrome Flashcards
What is Guillain-Barre syndrome?
A type of acute inflammatory polyneuropathy.
It is a clinically defined syndrome characterised by:
- motor difficulty
- absence of deep tendon reflexes
- paraesthesias without objective sensory loss
- increased CSF albumin with absence of cellular reaction (albuminocytological dissociation).
What is the name of the condition considered to be the chronic variant of Guillain-Barre syndrome?
Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)
What is the cause of Guillain-Barre syndrome?
- immune-mediated attack on myelin sheath or Schwann cells of sensory and motor nerves.
- preceding infection triggers –> cellular & humoral immune mechanisms
What are the subtypes of Guillain-Barre syndrome?
- Acute inflammatory demyelinating polyneuropathy (AIDP)
- Acute motor axonal neuropathy (AMAN)
- Acute motor and sensory axonal neuropathy (AMSAN)
- Pharyngeal-cervical-brachial variant
- Miller Fisher syndrome
What is the difference between the subtypes of Guillain-Barre syndrome?
Acute inflammatory demyelinating polyneuropathy (AIDP)
= Sensory symptoms and muscle weakness, often with cranial nerve weakness and autonomic involvement
Acute motor axonal neuropathy (AMAN)
= Isolated muscle weakness without sensory symptoms in less than 10%; cranial nerve involvement uncommon
Acute motor and sensory axonal neuropathy (AMSAN)
= Severe muscle weakness similar to AMAN but with sensory loss
Pharyngeal-cervical-brachial variant
= Weakness particularly of the throat muscles, and face, neck, and shoulder muscles
Miller Fisher syndrome
What is the epidemiology of Guillain-Barre syndrome?
- UK incidence: 1-2/100,000
- Affects all age groups
What are the risk factors of Guillain-Barre syndrome?
- 2/3 of pts have had infections <6 weeks before symptom onset
- commonly upper respiratory tract infection or gastroenteritis
-
immunisations:
- swie influenza vaccines (US in 1976) - discontinued
- rabies vaccine
-
mosquito-borne viral infections e.g.
- Zika
- dengue
- chikungunya
- Japanese encephalitis
What are the common causative organisms of Guillain-Barre syndrome? (triggers the mechanism)
acute infectious illness due to
virus:
- cytomegalovirus [CMV]
- Epstein-Barr virus [EBV]
- hepatitis B or C
- HIV
bacteria (less common)
- Campylobacter jejuni >>>
- Mycoplasma species >>
- Mycoplasma pneumoniae >
What are the presenting symptoms of Guillain-Barre syndrome?
- Progressive symmetrical muscle weakness
- lower extremities before upper extremities
- proximal muscles before distal muscles
- paraesthesias in the feet and hands (80%)
- paralysis
- progresses acutely over days
- 50% reaching a lowest point within 1 week
- 98% by 4 weeks
- back and leg pain
- dyspnoea on exertion
- SOB
- slurred speed (50%)
- facial weakness (50%)
- dysphagia (50%)
- diplopia (15% before disease progresses)
- dysarthria (15% before disease progresses)
What is the % of Guillain-Barre patients that will require mechanical ventilation?
30%
What can back/leg pain + paralysis be misintrepeted as?
spinal cord compression
What is the cause of dysphagia in Guillain-Barre syndrome?
Bulbar dysfunction –> facial weakness
What are the signs of Guillain-Barre syndrome O/E?
General MOTOR Examination
- Hypotonia
- Flaccid paralysis
- Arreflexia (ascending upwards from feet to head)
General SENSORY Examination
- Impairment of sensation in multiple modalities (ascending from feet to head)
Cranial Nerve Palsies
- Facial nerve weakness
- Abnormality of external ocular movements
- If pupil constriction is affected, consider botulism
Type II Respiratory Failure
- Due to paralysis of respiratory muscles
Autonomic Function
- Assess postural blood pressure change and arrhythmias
What are the primary investigations for ?Guillain-Barre syndrome?
-
nerve conduction studies
- positive = slowing nerve conduction
-
bloods: LFTs (1-2days post-onset)
- elevated AST
- elevated ALT as high as 500 U/L
- bilirubin ~ be transiently elevated, rarely high –> cause jaundice
-
lumbar puncture (1 week post-onset)
- high cerebrospinal fluid (CSF) protein
- normal/slightly high lymphocytes (<50 cells/mm³)
- normal cell count & glucose
-
spirometry (6hr intervals)
- may show reduced vital capacity, maximal inspiratory pressure, or maximal expiratory pressure
-
bloods: antiganglioside antibody
- allows differentiation between subtypes
- GQ1b - tested for Miller-Fisher syndrome
When should ICU monitoring be considered for Guillain-Barre patients?
if according to spirometry:
- vital capacity is <20 mL/kg (odds ratio 15.0);
- maximal inspiratory pressure worse than -30 cmH₂O;
- maximal expiratory pressure <40 cmH₂O;
- reduction of 30% in vital capacity, maximal inspiratory pressure, or maximal expiratory pressure.
