Autoimmune Archive Logo w Tag

Medical Disclaimer

🧬 Not sure where to start? Try searching for your diagnosis above or visit the “Diseases” section.

Suggest a Resource

Acute Motor Axonal Neuropathy (AMAN)

Also Known As: AMAN, Axonal variant of Guillain-Barré Syndrome, Motor axonal GBS, Chinese Paralytic Syndrome (historical/regional term)
System: Nervous System
Autoantibodies:

  • Often associated with:

    • Anti-GM1 antibodies

    • Anti-GD1a antibodies

  • These antibodies attack the axons of motor nerves

Primary Organ or Body Part Affected: Motor nerves of the peripheral nervous system
Acceptance as Autoimmune: Confirmed
Acute Motor Axonal Neuropathy

What is Acute Motor Axonal Neuropathy (AMAN)?

Acute Motor Axonal Neuropathy (AMAN) is a rare autoimmune disorder that affects the motor nerves responsible for muscle movement. It is considered a variant of Guillain-Barré Syndrome (GBS) and causes rapid muscle weakness or paralysis, typically starting in the legs and moving upward.

Unlike the more common type of GBS (AIDP), AMAN does not affect sensory nerves—meaning people usually do not have numbness or tingling, just motor weakness.

It often develops quickly after an infection, especially in children or young adults.

What are the signs and symptoms of Acute Motor Axonal Neuropathy (AMAN)?

  • Sudden weakness or paralysis, especially in the legs and arms

  • Reflexes are lost (areflexia)

  • No sensory loss – pain, touch, and temperature sensations usually remain intact

  • May involve difficulty breathing or swallowing in severe cases

  • Symptoms often worsen over days and may require hospitalization

What are the causes of Acute Motor Axonal Neuropathy (AMAN)?

AMAN is caused by an autoimmune attack on the axons (the long parts of motor nerves) rather than the myelin sheath. It is often triggered by:

  • Bacterial infections, especially Campylobacter jejuni

  • Viral infections

  • Less commonly after vaccinations or other immune stressors

Diagnosis

AMAN is diagnosed based on:

  • Clinical exam – weakness without sensory loss

  • Nerve conduction studies (NCS/EMG) – shows axonal rather than demyelinating damage

  • Spinal tap (lumbar puncture) – may show elevated protein with normal cell count

  • Antibody testing – may show anti-GM1 or anti-GD1a antibodies

Treatment

Like other forms of GBS, AMAN is treated with:

  • IVIG (intravenous immunoglobulin) – the first-line treatment

  • Plasmapheresis (plasma exchange) – alternative if IVIG doesn’t work

  • Supportive care – breathing support, nutrition, physical therapy

Steroids are not typically used in GBS or AMAN.

Prognosis

  • Many people recover completely or significantly, especially with early treatment

  • Recovery may be slower than in other GBS forms

  • Some people may experience long-term weakness or motor deficits

  • Children often recover faster and more fully than adults

Prevalence

  • Extremely rare in the U.S.; more common in Asia and Latin America

  • Often occurs in children or young adults

  • Usually appears in summer months, often after a stomach infection

Citations

  • National Institute of Neurological Disorders and Stroke (NINDS). (2023). Guillain-Barré Syndrome Fact Sheet.
    https://www.ninds.nih.gov

  • Yuki, N., & Hartung, H. P. (2012). Guillain–Barré syndrome. New England Journal of Medicine, 366(24), 2294–2304.
    https://doi.org/10.1056/NEJMra1114525

  • Willison, H. J., Jacobs, B. C., & van Doorn, P. A. (2016). Guillain-Barré syndrome. The Lancet, 388(10045), 717–727.

🔗Visit our Tools & Resources Section for guides, apps, podcasts, and more!

Frequently Asked Questions

No frequently asked questions found.

Related Articles

No related content found.

Related News

No related content found.

Related Patient Experiences

No related content found.

Related Research Studies

No related content found.

Support AutoimmuneArchive.com
If this website has been helpful to you, please consider supporting my work by donating through BuyMeACoffee.com.

Buy Me a Coffee

Back To Top

Follow Us On:

Facebook X-twitter Youtube
© 2025 AutoimmuneArchive.com. All rights reserved. No content may be used without our express written consent.
Autoimmune Archive
Powered by  GDPR Cookie Compliance
Privacy Overview

This website uses cookies so that we can provide you with the best user experience possible. Cookie information is stored in your browser and performs functions such as recognising you when you return to our website and helping our team to understand which sections of the website you find most interesting and useful.