Pathophysiology week 7b

The Weak Leg

Lynn is a 38 y.o. mother of two, a 10 y.o. girl and a 2 y.o. boy. She is active and has always enjoyed good health. For the past two weeks, Lynn has been having problems with her right lower extremity during her daily walks. She has noticed that she is tending to catch her toe more, especially toward he end of the walk. It is also harder for her to go upstairs. A physical therapist friend does a manual muscle test on her lower extremities and finds that the left lower extremity tests normal at 5/5, but the hip and knee muscles of Lynn’s right lower extremity only test 3/5. The physical therapist recommends Lynn see a neurologist, which she does. (Gould, B. E, p.516, 2011) (NationalMSSociety, 2012)
The neurologist performs several diagnostic tests and does two MRIs over the next few weeks. The findings of the the test include the following: MRI: Evidence of 4-5 plaques in the spinal cord. Visual Evoke Potential (VEP): Slowed response time. Blood tests: Normal. Cerebral Fluid Analysis:
Oligocional bands present. Elevated IgG antibodies. (Gould, B. E, p.516, 2011) (NationalMSSociety, 2012)
After approximately one month and several other tests, Lynn is given a diagnosis. She is told to expect exacerbations and remissions. Lynn is given glucocorticoids to take during exacerbations.
Lynn is diagnosed as having multiple sclerosis (MS). MS is a progressive, degenerative, autoimmune disease the attacks the central nervous system (brain, spinal cord and optic nerves). Autoimmune disorder is a condition where the immune system mistakenly attacks and destroys healthy body tissue (self). With MS, the immune system attacks the nerve’s myelin (demyelination) of the brain and the spinal cord and replaces it with scar tissue (also known as sclerosis or plaque) causing interruption in neuron transmissions resulting in variety symptoms depending where the the plaque damage has occurred. MS is a progressive degenerative disease characterized by remissions (recovery period) and exacerbations (increase severity of manifestations). (Gould, B. E, p.516, 2011) (NationalMSSociety, 2012)
Multiple sclerosis at present it is unknown what antigen is causing the immune cells to target the self cells or which immune cells are doing the attack. Other factors point to genetic make-up which can predispose an individual to the disease and environmental, in which MS is seen more in places farthest from the equator. Scientists believe environmental factors has something to do with Vitamin D and the amount of sunlight. The closer to the equator, the more exposure to sunlight, the more Vitamin D, resulting in more favorable impact on the function. Another factor are viruses which can cause demyelination and inflammation. It is thought that viruses can trigger MS; however, this has not been proved. MS is more commonly found in the northern latitudes. Most people are diagnosed with MS between ages 20- 50 and the disease is 2-3 times more common in women than in men, implying that hormones may have something to do with MS. Estimate incidence runs 30 to 100 per 100,000 persons. (NationalMSSociety, 2012)( Gould, B. E pg 516, 2011)
According to the National MS Society, majority of people who have MS do not become severely disable and have a normal to near-normal life expectancy. Symptoms of MS are sporadic and some
are more long lasting depending on the progression. MS symptoms are the following: Fatigue occurs in 80% of people and is the most prominent symptom. Numbness (paresthesias/ sensory nerve damage) usually the the first symptom to be experienced and weakness in legs occurring due plaque in the corticospinal tract. Problems with gait where one experiences difficulty in walking are the most common mobility limitation. Visual problems (affected cranial nerves) can be the first symptom for MS in many people. This includes double vision (diplopia) or spot in the visual field (scotoma), blurring vision, and eye pain. Episodes of vertigo (dizziness) can make one off balanced or lightheaded. Pain that can be experienced either intermittently or chronic. Bladder and bowel dysfunction can occur and many times can be maintained. Only 5-10% of people with MS may develop cognitive (high-level brain function) impairment such as memory (new), attention, executive function, visual-spacial and word finding. Long-term memory,conversational skill and reading comprehension remains intact. Emotional changes and depression may be caused by the disease itself or due the challenging situations and stress that occur due to MS. p.517 (NationalMSSociety, 2012)
There is no known individual test or finding that can be conclusive in determining MS; however, visual evoked potential(VEP) tests are considered the most useful. Doctors use a combination of strategies to determine if the individual meets the criteria which includes a thorough medical history, neurological exam, magnetic resonance imaging (MRI), visual evoked potentials (VEP) and a spinal analysis. According to the National MS Society, a physician must meet three MS criteria in order to make a diagnosis. First, evidence of damage must be at two separate areas of the CNS (brain, spinal cord, and optic nerve). Next, evidence that the damage occurred at least one month apart. Lastly, other possible diagnosis must be ruled out. MRI is the best technology to identify plaques and lesions in the CNS. The MRI can differentiate between old plaques from new plaques. The VEP test records the CNS electrical response to the stimulation of the visual specific sensory path way. Demyelination results in a slowing of response time due to the damaged myelin. VEP than becomes the most useful in providing evidence of scarring along the nerve pathways. Blood test are normally used to rule-out other conditions or diseases. Cerebral fluid analysis is done by a spinal tap in order to obtain spinal fluid. The analysis detects certain immune system proteins and the presence of oligoclonal bands. Oligoclonal bands indicate an immune response in the CNS. Ninety to ninety-five percent of MS individuals have oligoclonal bands in their spinal fluid. This test is not inclusive to MS, because other diseases have oligoclonal bands in the spinal fluid as well. (pg 517)(NationalMSSociety, 2012)
Lynn’s neurologist performed several diagnostic tests and two MRIs during the first couple weeks and proceeded to evaluate Lynn with additional tests over a month before she was finally diagnosed. Her MRI showed 4-5 plaques in the spinal cord. Lynn’s VEP showed a slow response time. Cerebral fluid analysis results showed oligoclonal bands present and an elevated IgG antibodies. Together these tests conclude Lynn’s diagnosis. (Gould, B. E, p.516, 2011) (NationalMSSociety, 2012)
During exacerbations, Lynn’s neurologist gave her glucocorticoids (usually a 4-5 day time period) in order to combat the inflammation process that occurs bring the relaps to an end quicker. Inflammation in the CNS damages the myelin and disrupts the transmission of nerve impulses. Acute exacerbations are followed by remissions as the inflammatory process subsides. Symptoms may also subside with remissions or there may be a continuum of some symptoms depending on the progression course. (Gould, B. E, pg 517, 2011)(NationalMSSociety, 2012)
Depending on what course of MS Lynn has will determine her out come in the next few years. If Lynn has relapsing-remitting MS, where the she may experience a clearly define attacks of worsening neurologic function. These attacks are followed by partial or complete recovery( remission) periods. No progression occurs. Primary- progressive MS is characterized by slowly worsening neurologic function from the beginning. The rate of progression may vary over time. Secondary-progression MS usually develops after the initial period of relapsing-remitting MS. The disease worsens more steadily with or without exacerbations and remissions. Lastly progressive-relapsing MS, Lynn may experience steadily worsening disease from the beginning, but with clear attacks of worsening neurologic function along the way. She may experience some remissions, but the disease will progress without remissions. (Gould, B. E , pg 517, 2011)(NationalMSSociety, 2012)

References
Gould, B. E. (2011) Chapter 23
(pg 517), Path physiology for the Health Professions, 4th Edition. Saunders Learning, printed in United States.
Anonymous. (2012). What we know about MS
Retrieved February 12, 2012, from NationalMSSociety website
http://www.nationalmssociety.org/about-multiple-sclerosis/what-we-know-about-ms/what-is-ms/index.aspx

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