I am not sure what they thought killed him. I do know it has been said that he was passed out drunk but I have never actually looked it up.
I’ll have to look it up about Poe.
Looks like lots of speculated causes:
http://en.wikipedia.org/wiki/Edgar_Allan_Poe
On October 7, 1849, at age 40, Poe died in Baltimore; the cause of his death is unknown and has been variously attributed to alcohol, brain congestion, cholera, drugs, heart disease, rabies, suicide, tuberculosis, and other agents.