The diagnostic features of GBS are summarised below:
GBS characteristics
GBS is characterised by a rapidly-progressive, bilateral weakness, accompanied by reduced or absent tendon reflexes.
The symptoms and signs of GBS typically, but not invariably, move proximally.
Diagnostic features
Precipitants
The most common presentation is a post-infectious disorder in an otherwise healthy patient. Approximately two-thirds of patients report symptoms of an infection (gastrointestinal or upper respiratory) in the preceding three weeks.
Organisms implicated in preceding infections include:
Bacteria
Viruses
Early symptoms
Early symptoms are pain, numbness, weakness or paraesthesia in the limbs, followed by a rapidly progressive symmetrical bilateral weakness.
This may extend to respiratory muscles or those innervated by cranial nerves.
Whilst the typical pattern of ascending weakness is well described, the weakness may affect arms and/or legs, and may take on a variety of patterns.
There are generally decreased or absent tendon reflexes in affected limbs.
Labratory findings
Albuminocytological dissociation on CSF analysis after a week of symptom onset is seen in about 66% of patients. This is characterised by raised Cerebrospinal fluid (CSF) protein (>0.4 g/L), with normal white cell count (WCC).
Progression of GBS
The weakness will reach its maximum within four weeks of onset and, in most cases, does so within two weeks.
There is normally a plateau period of varying length followed by a slow recovery phase of weeks, months or even years.
Disease progression beyond 8 weeks is classified as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).