Pathophysiology case study week 7: Neurological
Question #1
Brett reached into a clogged snow blower to clear the chute while it was still running. He completely severed one finger and partially severed another on his left hand. After lengthy surgery to reattach his fingers, he has regained much of his motor ability but has lost some of his sensory function. What factors are involved that affect the regeneration of Brett’s neurons and neuron function?
Clinical answer:
For regeneration of neurons (getting sensory feeling back), his type of injury involves the PNS neurons that were involved, rather than CNS neurons, so the chances of his neurons regenerating increase.
Nerve generation depends on location of the injury, inflammatory responses, and the process of scarring. When nerves are cut, they often form connective tissue scars that block or slow regenerating axonal branches.
This process of the nerves “healing” is called Wallerian degeneration. This is a neurological cellular is a process that results when a nerve fiber is cut or crushed (in this case severed), in which the part of the axon separated from the neuron 's cell body degenerates distal to the injury. This is also known as anterograde or orthograde degeneration. During this process, after a few days, the nerve fiber 's neurolemma does not degenerate and remains as a hollow tube. Within 96 hours of the injury, the distal end of the portion of the nerve fiber proximal to the lesion sends out sprouts towards those tubes and these sprouts are attracted by growth factors produced by Schwann cells in the tubes. If a sprout reaches the tube, it grows into it and advances about 1 mm per day, eventually reaching and re-innervating the target tissue. This is all dependent on Schwann cells and neurilemma remaining intact (to form a guiding tunnel) if scar tissue does not block the distal ends. Layman’s terms:
After a healing process, the new nerve “endings” will
References: Approach to the diagnosis and evaluation of low back pain in adults (n.d.), Uptodate. Retrieved on February 28, 2013, from www.uptodate.com/contents/approach-to-the-diagnosis-and-evaluation-of-low-back-pain-in-adults/search_results&search. Health conditions: herniated or ruptured disc (n.d.), Cedars-Sinai. Retrieved on February 28, 2013, from www.cedars-sinai.edu/Patients/Health.Conditions/Herniated-or-Ruptured-Disc.aspx. Herniated disc (n.d.), The Mayo Clinic. Retrieved on February 28, 2013, from www.mayoclinic.com/health/herniated-disk/DS00893/PAGE=all&METHOD. McCance, K.L., Huether, S.E., Brashers, V.L., & Rote, N.S. (2010). Pathophysiology: The Biological Basis for Disease in Adults and Children (6th ed.). Maryland Heights, MO: Mosby Elsevier. Pillow, M.Y. (2011). Seizure Assessment in the Emergency Department. Medscape. Retrieved From http://emedicine.medscape.com/article/1609294-overview Ruptured disc definition (n.d.), Spine-Health. Retrieved From www.spine-health.com/glossary/r/ruptured-disc.