Acute motor axonal neuropathy cases in Van region

Area of Science:

• Neurology
• Clinical Neuroscience
• Immunology

Background:

• Acute Motor Axonal Neuropathy (AMAN) is a variant of Guillain Barré Syndrome (GBS).
• AMAN is prevalent in Northern China, causing epidemics, but is rare in Western countries (<5% of GBS cases).
• This neuropathy typically presents with motor deficits and lacks sensory findings.

Purpose of the Study:

• To investigate the prevalence and electrophysiological characteristics of AMAN in a GBS patient cohort.
• To understand the clinical significance of AMAN in a region with high incidence of acute inflammatory neuropathies.

Main Methods:

• Nerve conduction studies and needle electromyography (EMG) were performed on 25 patients diagnosed with AMAN.
• Patients ranged in age from 1 to 77 years.
• Electrophysiological findings including motor action potential values, motor unit potential (MUP) activity, and F response were analyzed.

Main Results:

• AMAN was identified in 39.7% of the investigated GBS patients.
• Motor nerve conduction velocities were normal, but combined muscle action potentials were significantly reduced.
• Needle EMG revealed diminished MUP activity and spontaneous denervation; no F response was obtainable.

Conclusions:

• AMAN represents a significant GBS variant with a high prevalence in this region.
• Electrophysiological findings in AMAN include normal motor conduction velocities with reduced compound muscle action potentials and absent F responses.
• The study underscores the importance of recognizing AMAN due to its high prevalence and distinct clinical and electrophysiological features.