Wallerian Degeneration
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Clinically Relevant Anatomy[edit | edit source]
Wallerian degeneration is an active process of retrograde degeneration of an axon that is a result of a nerve lesion.
Within a nerve, each axon is surrounded by a layer of connective tissue called the endoneurium. The axons are bundled together into groups called fascicles, and each fascicle is wrapped in a layer of connective tissue called the perineurium. Finally, the entire nerve is wrapped in a layer of connective tissue called the epineurium.[1]
Mechanism of Injury[edit | edit source]
The pathological process of Wallerian degeneration is in 4 stages;
Axon Degeneration[edit | edit source]
Within approximately 30 minutes of injury, there is a separation of the proximal and distal ends of the nerve. After a short latency period of the transected membranes are sealed until degeneration. This is marked by the formation of axonal sprouts. this occurs in less than a day and allows for nerve reservation and regeneration
Mylien Clearance[edit | edit source]
Usually, the rate of clearance is slower in the Central Nervous System than the peripheral Nervous system due to the clearance rate of myelin. Another reason for the different rate is the change in permeability of the blood-tissue barrier in the two systems. In PNS, the permeability increases throughout the distal stump, but the barrier disruption in CNS is limited to just the site of injury. In the CNS, olingodendrocites inhibit regeneration.
If soma/ cell body is damaged neuron can not generate, However if the injury is at the end of the axon, 1mm per day. distal segment undergoes granular disintegration over several days to weeks. by the 7th day macrophages clears axonal and myelin debris. schwann cells multiply to fill are previously occupied by former segment completed by mutubles leaving endometrial tube and swancells.
in regeneration cytoplasmic elements bgin to reaccyumulate
axonal
- regeneration
Clinical Presentation[edit | edit source]
Most patients have presentations of nerve damage.
These presentations may include[2]
- Paralysis of associated structures to denervated nerves
- Gradual onset of numbness, prickling, or tingling in your feet or hands, which can spread upward into your legs and arms
- Sharp, jabbing, throbbing, freezing, or burning pain
- Extreme sensitivity to touch
- Lack of coordination and falling
- Muscle weakness or paralysis if motor nerves are affected
- Neuromatous or causalgia pain
Diagnostic Procedures[edit | edit source]
Electromyography
Nerve Conduction Studies
Pain assessment
Sensation deficit and skin condition
Muscle strength/loss
Functional deficits
Outcome Measures[edit | edit source]
Depends on various criteria including pain and psychosocial skills but could include:
- Oxford scale
- Visual analogue scale
- Short form McGill pain questionnaire
(see Outcome Measures Database)
Management / Interventions[edit | edit source]
Wallerian Degeneration is a nerve repair mechanism. Managing nerve damage can include the use Cryotherapy[4], Exercise,
Resources[edit | edit source]
add appropriate resources here
References[edit | edit source]
- ↑ Purves, Dale; Augustine, George J.; Fitzpatrick, David; Hall, William C.; LaMantia, Anthony-Samuel; McNamara, James O.; White, Leonard E. (2008). Neuroscience (4 ed.). Sinauer Associates. pp. 11–20. ISBN .
- ↑ The Young Orthopod. Nerve Regeneration. Available from https://www.youtube.com/watch?v=kbzYML05Vac (last accessed 5 March 2021)
- ↑ The Young Orthopod. Nerve Regeneration. Available from https://www.https://www.youtube.com/watch?v=P02ea4jf50g&t=192s (last accessed 6 March 2021)
- ↑ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315870/
