Injury either mechanical or infectious causes inflammation. Inflammation leads to myelin sheath destruction and death of nerve cells. Dead nerve cells cause a host of degradative diseases - MS, Alzheimer's, Parkinson's etc.

The effects of inflammation caused by an overreactive immune response are astounding. In my email yesterday I received a link to an article. When I saw the title to the article I knew I had to read it because the connection was obvious to me but I guess not the scientists involved in the research. "New evidence furthers link between depression and stroke". What do both have in common? inflammation.

https://newatlas.com/health-wellbeing/depress...new-study/