Guillain-Barre Syndrome

This week we explored 2 different (potential) cases of Guillain-Barre Syndrome, or GBS. First during Physical Examination Rounds and then again in Morning Report.

The most common form of GBS is an idiopathic acute inflammatory demyelinating polyneuropathy (AIDP), and in fact GBS is often synonymous for AIDP. It is an autoimmune process directed against Schwann cell membranes. There are 5 other variants of GBS, including the Miller Fisher Variant which often presents with the triad of ophthalmoplegia, ataxia, and areflexia.

GBS occurs anywhere from 1 - 2 per 100,000 per year. It is often (~2/3 of cases) preceded by either a respiratory or GI infection, most commonly Campylobacter. GBS has also been reported after vaccinations and to be associated with systemic illnesses, such as SLE, Hodgkin's Lymphoma, Sarcoidosis, etc.

Patients with GBS often present with parasthesias in their limbs, followed soon after by ascending weakness. This progresses over days to weeks. GBS can also be associated with autonomic dsyfunction such as orthostasis, urinary retention, constipation, and tachycardia.

Physical examination most often reveals symmetrical motor weakness in an ascending pattern, with absent reflexes, flaccid tone, and a normal sensory exam.

Patients with GBS need to be monitored closely for respiratory failure due to involvement of the diaphragm. A good rule of thumb for consideration of intubation is the 20/30/40 rule:

• 20: Vital Capacity less than 20 cc/kg
  
• 30: Maximum Inspiratory Pressure less than 30 cm H2O
  
• 40: Maximum Expiratory Pressure less than 40 cm H2O

Treatment for GBS is most often supportive, and may require an ICU setting for ventilatory support, hemodynamic support, nutritional support, and pain control. If diagnosed within the first 4 weeks then IVIG or plasmapheresis can be considered. A recent Cochrane review suggests that IVIG treatment has similar outcomes to plasmapheresis in the setting of early (ie: within 2 weeks) diagnosed GBS.

Outcomes for patients with GBS are quite good with ~80% achieving full recovery within a few months to a year; however, minor deficits often persist. 5-10% will have permament disabling deficits, and another 2-3% will die as a result of their GBS. Approximately 5-10% of patients may develop one or more relapses of their GBS, leading to a diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy (CIPD).

Here is a very thorough review of GBS from 2005, in The Lancet.