GBS Flashcards
definition of GBS
acute inflammatory demyelinating polyneuropathy
varients of GBS
chronic inflammatory demyelinating polyradiculopathy - slower onset and recovery
miller fisher syndrome - compromises of ophthalmoplegia, ataxia, areflexia. Associated with anti-GQ1b Ab in the serum
aetiology of GBS
an inflammatory process where Ab after a recent infection reacts with self-ag on myelin or neurons
rare axial variants with no demyelination
idiopathic - 40% cases
Post-infection (1–3 weeks): bacterial (e.g.Campylobacter jejuni, mycoplasma), HIV, herpes viruses (e.g.zoster, CMV,), EBV
malignancy - lymphoma, hodgkin’s disease
post-vaccination
may advance quickly affecting all limbs at once - can lead to paralysis
progressive phase of up to 4wks, followed by recovery
epidemiology of GBS
Annual UK incidence is 1–2 in 100000
all age groups
sx of GBS
progressive symptoms for <1mo: ascending symmetrical limb weakness (lower>upper), ascending parasthesia
CN involvement - dysphagia, dysarthria, facial weakness
in severe cases the resp muscles may be affected
Miller–Fisher variant (rare): Opthalmoplegia, ataxia and arreflexia.
proximal muscles involved - trunk, resp, CN especially CN7
signs of GBS
a few weeks after infection a symettrical ascending muscle weakness starts
proximal muscles more affected
can lead to paralysis
general motor examination
- hypotonia
- flaccid paralysis
- arreflexia - typically ascending upward from feet to head
general sensory exam - impairment of sensation in multiple modalities - typically from feet to head
CN palsy
- less frequent
- facial nerve weakness (lower motor neuron pattern)
- abnormality of external ocular movements
- signs of bulbar palsy
- if pupil constriction affected - consider botulism
T2 resp failure
- identify early - CO2 flap, bounding pulse, drowsiness
- can be insidious - needs regular assessment
autonomic function
- assess for postural BP change and arrhythmias
- sweating
- high pulse
pain common - back and limb
botulism
caused by botulinum toxin by Clostridiuym botulinium anaerobe
typically ingested from improperly cooked meat, can be iatrogenic eg Botox IM or via wounds
presents: descending paralysis affecting bulbar and ocular muscles 1st = bilateral fixed pupils
treatment - supportive airway managment and antitoxin - doesnt reverse the weakness
Ix for GBS
LP
- high CSF protein
- cell count and glucose normal
nerve conduction study - reduced conduction velocity or conduction block, can be normal in early phase of the disease
blood
- anti-ganglioside Ab +ve in Miller-Fisher variant and 25% of Gillain Barre syndrome cases
- consider C jejuni serology
spirometry
- reduced fixed vital capacity - indicates ventilatory weakness
- do FVC every 4hr
ECG - arrhythmias
mx of gbs
IVIG or plasma exchange
measure FVC regularly
