Overview
Definition
An acquired, immune-mediated inflammatory disorder of the peripheral nervous system, characterized by progressive or relapsing demyelinating neuropathy for at least 8 weeks.
Epidemiology
Prevalence ~1-3 per 100,000. Affects males more than females, onset usually in middle age.
Etiology & Risk Factors
- Autoimmune attack against peripheral nerve myelin sheath and Schwann cells
- Loss of immune tolerance
Clinical Symptoms
- Symmetric proximal and distal muscle weakness
- Symmetric sensory loss (numbness, paresthesias)
- Areflexia or hyporeflexia
- Difficulty walking or climbing stairs
Clinical Approach
Diagnosis
- Electromyography (EMG) and Nerve Conduction Studies (NCS) showing demyelinating features
- Lumbar puncture showing albuminocytologic dissociation (elevated protein with normal cell count)
- Nerve biopsy showing 'onion bulb' formations in chronic cases
Management
- Intravenous Immunoglobulin (IVIG)
- Corticosteroids
- Plasmapheresis
- Immunosuppressive agents for refractory cases
Complications
- Permanent muscle atrophy
- Loss of mobility
- Respiratory weakness (rare)