Search terms used; various combinations and permutations of chronic mercury poisoning progression symptoms.
I have a character who has chronic mercury poisoning. He's suffering various neurological symptoms (mood swings, personality changes, memory disruption, isordered sleep) as well as some more obvious physical symptoms (damage to gums and teeth, drooping facial muscles, drooling, squamous hands/fingers, digestive complaints). His exposure has been to small amounts of elemental mercury, over a period of years (he's an alchemist; this is a slightly alternate universe, in which alchemy is still around well into the 19th century). What I can't find is how fast the symptoms will develop, and how long he will live once they do; most of the case studies I've seen were either fairly large doses which were fatal within days or weeks, or they were chronic cases which were diagnosed and successfully treated. However, given that, around the period I'm looking at, hatters were generally thought to be mad, an that this was due to chronic mercury poisoning, I'm assuming that it's possible to live for a reasonable length of time while exhibiting symptoms. My character will not receive any medical intervention, and indeed while he will know that he is ill and probably dying, he won't know that it's due to mercury. So, are we looking at a few months from first symptoms to death? Or a few years?
Also, am I right in assuming that the damage, once done, is basically irreversable without treatment, even if he isn't exposed to any more mercury? That is, if he gives up using mercury, will he still continue to suffer the symptoms and eventually die, or will he recover completely once the mercury is out of his system?