Introduction

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]). HIV is also known to be a cause.
In up to 40% of cases, no precipitating factor can be found.

Epidemiology

  • 1-2 per 100 000
  • In 40% of cases, no cause is found

Clinical features

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.

Pathology

The viral infection causes the production of auto-immune antibodies against peripheral nerves. Myelin is damaged, and transmission is reduced or even blocked.

Investigations

  • Lumbar punctureincreased protein in the CSF, white cell count normal.
  • Nerve conduction – slowed

Prognosis

  • 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

Treatment

  • 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

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