I don't know if this will help, but it's certainly coincidental.
My g.g.grandparents were Mary P. Adams and LeRoy Cole Downing Hatchett, who married in Pike County, MO, 1846, 8 years after your Louisa.
Also, Mary P.'s and LeRoy's grandaughter -- my grandmother (b. 1891) -- was named LOUISA French Hatchett, and she -- like your Louisa -- went by Louise and/or Lou.Might they have been sisters?
If so, I found an article that lists Mary P. as "a daughter of Lebanon Adams, of Kentucky, and the descendant of an old family of that state. Her father became an early settler of Louisana, Pike county, Mo., where he spent his last years."http://www.rootsweb.ancestry.com/~okcanad2/bios12.htmlhttp://www.rootsweb.ancestry.com/~okcanad2/bios12.html
That said, I'll add that I've also come across a "Levin" Adams, so I don't know if they are two separate Adams' or perhaps one is a mispronunciation of the other.
Hope this helps.If you find out Louisa and Mary P. were sisters, please let me know!