Multifocal motor neuropathy (MMN) is a neuromuscular disease that usually presents with asymmetric weakness in a limb. The clinical pattern is that of mononeuropathy multiplex. The condition is treatable.
Clinical features:
- Asymmetric weakness, usually upper limbs, spares cranial nerves, reflexes may be preserved, fasciculations may occur
- Note this is a form of mononeuropathy multiplex
Investigations:
- Serum Anti-GM1 IgM positive, titre >1:350
- Nerve conduction studies NCS:
- Multifocal motor demyelination
- Conduction block
- Normal sensory response
Pathology/Nerve biopsy:
- In some cases evidence of demyelination & remylination
- In some cases: inflammatory cells
Treatment options:
- Intravenous immunoglobulin (IVIg)
- In refractory cases Cyclophosphamide intravenously may be considered
- There appears to be no benefit from Mycophenolate mofetil.
Related articles:
- Neuromuscular disease patterns, mononeuropathy,