Wallerian Degeneration

- Discussion:
    - arises from severe nerve injury (axonotmesis or neurotmesis)
    - characterized by axonal enlargement into an amorphorous mass, breakdown of the axons, and schwann cell ingestion of fragmented 
            myelin to provide clean endoneural tubes for advancement of regenerating axons;
            - axonal sprouting begins within 96 hours;
            - if axonal regeneration is delayed, tubes undergo shrinkage that becomes more severe with time;

- Pathologic Findings:
    - cell body:
           - increases in size;
           - migration of nucleus to the cell periphery;
    - proximal nerve segment:
           - degeneration occurs proportionate to severity of injury;
           - degeneration extends proximally to the next node of Ranvier;
    - distal nerve segment:
           - Schwann cell proliferation;
           - collapse of endoneurial tubes;
           - distally the entire axonal material is phagocytosed from the site of injury to the endplates

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, September 9, 2011 11:32 am