Biomedical Engineering Reference
In-Depth Information
Of the potential exposure routes, ingestion of methanol is by far the
largest current concern and most of the recent reports of methanol
toxicity in humans are due to ingestion of methanol either accidentally
or deliberately (Delbrick et al., 1982).
There are many reports of more recent mass methanol poisoning
because of accidental ingestion. Some of the specific reports are
discussed below to give an overview of outcome of these poisoning.
In one study, only 50 out of 200 people who report drinking the same
amount of methanol became ill and 12 died (Uhthoff, 1915). There
appears to be a wide range of susceptibility in the human population to
the effects of ingestion of methanol. One also has to question the
accuracy of the ingestion data reported by the different individuals.
In one incident, 15ml of a 40% solution of methanol was fatal to
one individual, but another person survived 500ml of 40% methanol.
Von Burg (1994) also states that 80-150ml of 80 proof methanol is
usually fatal. No references or data were presented (Von Burg, 1994).
There appears to be a great deal of variation in people's response to
methanol.
In a review of acute methanol poisoning due to adulterated whiskey
was published in 1953 (Bennett et al., 1953). The review contained a
good history of 323 cases, clinical history, symptoms, laboratory
finding, and potential treatment. Speculation as to the mode of action
and earlier cases was discussed. One clear observation in the 323 cases
was a latent period of general 24-48 hours following the ingestion of
methanol to symptoms. Visual effects may be noted earlier in some
patients. Of changes related to the metabolism of methanol, formic acid
was noted in the blood and urine of methanol-poisoned individuals. This
observation, more than 50 years ago, appears to be a key in the
mechanism of methanol poisoning. The role of ethanol on the toxicity
of methanol was also discussed, especially its effect on the rate of
breakdown of methanol and the buildup of formic acid in cases of
poisoning. Acidosis was reported to be the most striking metabolic
disturbance in human poisoned with methanol. Symptoms attributed to
methanol poisoning included visual disturbances. It fact it was seen to
some degree in all 115 patients that reported acidosis out of the 323
cases reported in this review, others who had normal serum bicarbonate
