Tuesday, 14 September 2010

MRCP revision battle 11.1: Guillain Barre Syndrome

When you're working 12 hr days (plus commute) fitting in revision can feel a bit like trying to squeeze that extra towel into the suitcase - you may manage it, but the suitcase is then stretched and prone to snap open at unfortunate times.  If you extend this metaphor to the suitcase being your sanity it explains why junior doctors can often become more emotionally incontinent/irrational as MRCP exams get nearer.  So whats the solution?  Well, in the suitcase scenario you'd add some of those rubber bands round to keep it closed.  In real life, your friends, family and managing to keep some form of hobby/interest going are your rubber bands.

Since I don't want to overpressure my 'rubber bands' I'm going to limit today's battles to

MRCP revision battle 11.1: Guillain Barre Syndrome
MRCP revision battle 11.2: Miller Fisher Syndrome
MRCP revision battle 11.3: Syringomyelia
MRCP revision battle 11.4: Kallmans
MRCP revision battle 11.5: Carcinoid Syndrome

MRCP revision battle 11.1: Guillain Barre Syndrome

Guillain Barre Syndrome is a rare, post-infective demyelinating polyneuropathy.

It tends to occur a few weeks after 'the flu' or a minor illness.  The most commonly associated pathogens are:
  • campylobacter jejuni
  • mycoplasma
  • CMV
  • EBV
  • HIV
  • zoster

Guillain Barre Syndrome is characterised by an ascending, symmetric muscle weakness.  Proximal muscles are more affected than distal ones.  Cranial nerves may also be involved, with CN VII being the most common.

There is usually a 'progressive' phrase for around 4 weeks, after which the patient starts to improve.

Features associated with GBS that appear in MRCP questions include:
  • papilloedema
  • urinary retention
  • arrhythmias

Diagnostically GBS is characterised by:
  • very high protein in CSF
  • decreased nerve velocity on EMG
  • areflexia

The prognosis for patients with GBS is worse if:
  • rapid onset of symptoms
  • older age
  • axomal neuropathoes
  • preceeded by campylobacter infection

Management is:
  • 4 hourly FVC, to check the patient's respiratory muscles aren't affected
  • ventilation if needed
  • plasma exchange
  • IV IG

Overall, 85% of patients make a complete/new complete recovery.
10% will relapse
Less than 5% will die.

Now to to meet a close relative of GBS, Miller Fisher Syndrome.