Compare and contrast the clinical and diagnostic features of ascending polyneuritis (Guillain Barre Syndrome), myasthenia gravis and motor neurone disease.
This could be answered using a table format. Suggestions include the following:
|
ascending, |
myasthenia |
motor neurone |
|
|
weakness |
yes |
yes |
yes |
|
reflexes |
absent |
present |
May be increased (eg. amyotrophic lateral sclerosis) |
|
characteristic distribution |
ascending |
Eyes & cranial |
asymmetrical` |
|
progression |
acute and |
relapsing |
progressive |
|
fatigue |
no |
characteristic |
no |
|
fasiculation |
no |
no |
characteristic |
|
increased CSF protein |
yes |
no |
no |
|
UMN signs present |
no |
no |
May be present(eg. amyotrophic lateral sclerosis) |
|
sensory features |
often dysthesia |
no |
no |
|
pain |
May be |
no |
no |
|
delayed nerve conduction |
yes |
no |
no |
|
fade + post tetanic facilitation |
no |
yes |
no |
|
‘jitter’ on EMG |
no |
no |
yes |
|
response to anticholinesterases |
no |
yes |
no |
|
response to plasmapheresis |
May occur |
yes |
no |
Discussion
Approach to the ICU patient with generalised weakness is discussed elsewhere.
This table is a detailed version. The features listed by the college here have been incorporated into the greater table in the abovelinked summary ("Causes of Weakness in Intensive Care Patients ")
In short:
- Only Guillain-Barre will have delayed nerve conduction, increased CSF protein and sensory features
- Only myasthenia will have characteristic fatiguability, and will respond to anticholinesterase treatment (or plasmapheresis)
- Only motor neuron disease will have increased reflexes, and will be assymetrical.
References
Chapter 51 (pp. 568) Acute cerebrovascular complications by Bernard Riley and Thearina de Beer
Chapter 57 (pp. 617) Neuromuscular diseases in intensive care by George Skowronski and Manoj K Saxena
Reeves and Swenson have an excellent online textbook chapter (12) entitled "Evaluation of the Patient with Weakness"