Neuro Case Studies
Pathophysiology case study week 7: Neurological
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?
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 grow back, so the target tissue (the tips of his fingers) will/should gain sensory function as these new nerve endings reach the tips of his fingers, depending on the amount of scar tissue involved in the healing process.
Mr. White, 39, a construction worker, was admitted to the emergency department with a ruptured disk. He and another worker were carrying a 125-pound bag of concrete when his partner tripped on a rock and fell. Mr. White tried to hold the bag but felt excruciating pain in his lower back. The x-ray revealed a ruptured disk in L4. What happened to Mr. White?
Mr. White has experienced spinal cord trauma resulting in a spinal cord injury. In laymen terms, Mr. White has a ruptured/herniated disc. This is where the outer, fibrous portion of the vertebral disc tears allowing the inner portion to push through the fibers. The inner portion, a softer, jelly-like material, pushes through and can compress the nerves around the disc. This compression can cause pain that radiates through the back and depending on the location of the ruptured disc, down the arms or legs of a patient. These discs, when healthy, act as shock absorbers for the spine and help to keep the spine flexible. Herniated discs are usually associated with a sudden twisting movement, sports-related injuries, and in Mr. White’s case, poor lifting habits. The risk factors that can increase you change of disc herniation include the age of an individual (most common in 35-45 year olds), the individuals body weight (high BMI can cause added stress on the lower back),and the individuals occupation. We know that Mr. White has two of these risk factors, age (he is 39) and occupation (works in construction/heavy lifting). In medical terms, a herniated disc is the rupturing of the tissue that separates the vertebral bones of the spinal column. The center of the disc is a soft, jelly-like material called the nucleus. The annulus, or the outer ring of the disc, helps to provide...
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