Was the Battle of Fort McHenry the Beginning of the End for Major Armistead?-- Part 1

I have been looking for information on what George Armistead died of in 1818 and not having much luck.

From NPS.gov site.  "Reading 1:  Armistead's Account of the Battle.

In a report written to Secretary of War James Monroe, George Armistead gave his account of the famous battle.  It was dated September 24, 1814.  Of interest, it was written ten days after the battle.  You'd have thought he would have written right away after winning such an important battle, yet, the letter was dated ten days after the battle.

It opened with:  "A severe indisposition, the effect of great fatigue and exposure, has prevented me heretofore from presenting you with an account of the attack on this Post...."

Did this problem continue after the attack to his death.

I have read that he continued to command Fort McHenry until his death.

--Brock-Perry