University:
Camosun College
Course:
BIOL 252 | Pathophysiology for Nursing 1
Academic year:

2024
Views:

195

Pages:

3
Author:

Aysha A.

Multiple Sclerosis (MS) Definition: MS is a demyelinating disease that also involves chronic inflammation, causing neuronal loss and gliosis (an increase in the number of glial cells, such as astrocytes). It affects the central nervous system (CNS), with specific antibodies against oligodendrocytes. The most commonly affected areas include the CNS, particularly the optic nerves and spinal cord. Pathophysiology: The immune response in MS is dual, involving both humoral (antibody-mediated) and cell-mediated immunity. The immune response predominantly affects perivenous (around veins) regions in the CNS. T lymphocytes damage the blood-brain barrier (BBB), allowing them to access the CNS and activate B lymphocytes. B lymphocytes produce antibodies specific to myelin proteins, such as Myelin Basic Protein (MBP). The antibodies activate complement proteins, which further damage myelin, leading to cell death and the formation of a glial scar (gliosis). The glial scar formed is referred to as sclerosis, which means scarring of the brain tissue. Consequences: Delayed or Failed Conduction: The loss of myelin disrupts the conduction of nerve impulses, leading to neurological symptoms. Breakdown of Myelin Basic Protein (MBP): The breakdown of MBP due to T lymphocytes results in the decomposition of myelin, further damaging the axons. Clonally Restricted B Lymphocytes: These cells produce myelin-specific autoantibodies against myelin oligodendrocyte glycoprotein (MOG). Neurodegeneration: Axonal degeneration leads to irreversible disability. Retrograde degeneration can also damage the cell body, referred to as "dying-back axonopathy." Key Signs and Symptoms: Lhermitte's sign: An electric shock-like sensation running down the spine, triggered by neck flexion. Uhthoff's phenomenon: Symptoms that worsen with increased body heat. Dawson Fingers: Radiological sign on MRI, indicative of MS plaques. Oligoclonal bands: Presence of immunoglobulins (IgG) in the cerebrospinal fluid (CSF), a marker for MS. Diagnosis and Treatment: MRI with gadolinium contrast is used to visualize lesions. Medications like natalizumab, ocrelizumab, and glatiramer acetate are commonly used to modulate the immune response and slow disease progression.