This is an acute inflammatory demyelinating polyneuropathy
(AIDP). It typically comes on several weeks after viral infection,
usually, GI or URTI (also sometimes flu vaccine [controversial
is also known to be a cause.
In up to 40% of cases, no precipitating factor can be found.
- 1-2 per 100 000
- In 40% of cases, no cause is found
Usually signs involve a polymyopathy, that is almost always motor, and sometimes also sensory.
- Symmetrical muscle weakness, that usually begins in the lower legs, and ascends to the upper limbs, and even the face. Usually it progresses over about 4 weeks before recovery
- It may advance very quickly, affecting all limbs at once, and resulting in paralysis
- Sensory signs often absent
- Pain is common
- Proximal muscles more affected – which helps differentiate it from other peripheral neuropathies.
- Trunk, respiratory and cranial nerves can also be affected – again helping differentiate from other neuropathies.
- Respiratory involvement can be life-threatening.
- Autonomic signs – sweating, tachycardia, dysrythmias.
The viral infection causes the production of auto-immune antibodies against peripheral nerves. Myelin is damaged, and transmission is reduced or even blocked.
- Lumbar puncture – increased protein in the CSF, white cell count normal.
- Nerve conduction – slowed
- 85% make complete or almost complete recovery
- 10% unable to walk at one year
- 10% mortality
- The severity of the initial paralysis is NOT related to the recovery
- Don’t be afraid to intubate and refer to ITU at signs of respiratory problems. These occur when the respiratory muscles are affected.
- DO NOT USE CORTICOSTEROIDS – no evidence that they help
- IV immunoglobulin may help
- Recovery often occurs without specific treatment