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Acute motor axonal neuropathy
A rare pure motor axonal form of Guillain-Barré syndrome (GBS).
ORPHA:98918Classification level: Disorder
- Acute pure motor GBS
- Acute pure motor Guillain-Barré syndrome
- Prevalence: -
- Inheritance: Multigenic/multifactorial or Not applicable
- Age of onset: All ages
- ICD-10: G61.0
- OMIM: -
- UMLS: -
- MeSH: -
- GARD: -
- MedDRA: -
The overall annual incidence of GBS is estimated at between 1/91,000 and 1/55,000. The axonal forms (AMAN and acute motor-sensory axonal neuropathy, AMSAN; see this term) account for only 3-5% of cases in Western countries but are much more frequent (30%-50% of GBS cases) in Asia and Latin America.
AMAN presents with rapid onset of muscle weakness and absent reflexes. The clinical course in AMAN tends to be more severe than in the more frequent, demyelinating form of GBS, acute inflammatory demyelinating polyradiculoneuropathy (AIDP; see this term), with an increased number of patients requiring artificial ventilation due to respiratory involvement. However, there is no sensory deficit in AMAN and cranial nerve involvement is rare.
In the majority of cases, AMAN occurs following Campylobacter jejuni infection, in particular following infection with strains of C jejuni that cause enteritis. Although the exact pathological mechanism is not fully understood, AMAN is associated with the presence of antiganglioside antibodies (primarily, anti-GM1/GD1a) and may be caused by antibody-mediated primary axonal degeneration or antibody-mediated inhibition of voltage-gated sodium channels.
Although the clinical course initially can be severe in AMAN, recovery can be rapid. However, recovery may be significantly prolonged in patients with extensive axonal degeneration.
- Clinical practice guidelines
- Deutsch (2012)