BIOS252 Week 2 Case Study: Multiple Sclerosis

BIOS252 Week 2 Case Study: Multiple Sclerosis
Introduction recap
The nervous system comprises the central nervous system (CNS), which includes the brain and
spinal cord, and the peripheral nervous system (PNS), consisting of nerves extending throughout
the body. Neurons are the basic functional units of the nervous system, transmitÝng
electrochemical signals. Myelin sheath, produced by oligodendrocytes in the CNS and Schwann
cells in the PNS, acts as a protective sheath and an insulating layer around axons, facilitating
rapid signal conduction.
Discussion of Multiple Sclerosis (MS)
Pathophysiology
In MS, the immune system erroneously attacks myelin, leading to inflammation and
demyelination. This inflammatory response results in the formation of plaques or lesions in the
CNS, disrupting nerve conduction. Oligodendrocyte degeneration and axonal damage also occur,
contributing to neurodegeneration. Rebuilding of myelin, termed remyelination, can occur in
the early stages of the disease but becomes less efÏcient over time, contributing to disease
progression. Some of it is replaced by scar tissue, which explains the partial recovery of the
patient.
The exact cause of MS remains unknown, but genetic predisposition, environmental factors, and
immune dysfunction are implicated.
Signs, Symptoms, Diagnosis:
Common signs and symptoms of MS include sensory disturbances (e.g., paresthesia,
numbness), motor deficits (e.g., weakness, spasticity), visual disturbances (e.g., optic neuritis),
fatigue, cognitive impairment, and autonomic nervous system involvement as bladder/bowel
dysfunction. Diagnosis relies on a combination of clinical assessment, neuroimaging (e.g., MRI),
and laboratory tests (e.g., cerebrospinal fluid analysis, evoked potentials). The McDonald
criteria are commonly used for diagnosis, requiring evidence of dissemination of CNS lesions in
space and time.
Complications:
MS can lead to various complications, including muscle weakness, gait impairment, falls,
depression, anxiety, cognitive decline, and bladder/bowel dysfunction. Additionally, individuals
with MS are at increased risk of developing secondary conditions such as osteoporosis, pressure
ulcers, and infections.