Dating girl multiple sclerosis
These lesions most commonly affect the white matter in the optic nerve, brain stem, basal ganglia, and spinal cord, or white matter tracts close to the lateral ventricles.
The long-term outcome is difficult to predict, with good outcomes more often seen in women, those who develop the disease early in life, those with a relapsing course, and those who initially experienced few attacks.
The prevalence hypothesis proposes that the disease is due to an infectious agent more common in regions where MS is common and where, in most individuals, it causes an ongoing infection without symptoms.
Only in a few cases and after many years does it cause demyelination.
Proposed mechanisms include the hygiene hypothesis and the prevalence hypothesis.
The hygiene hypothesis proposes that exposure to certain infectious agents early in life is protective, the disease is a response to a late encounter with such agents.