To simulate the fatal iron poisoning reported in children and to study the mechanism of the iron toxicity, dissociable iron salts were given by stomach or duodenal tube or by enema to rabbits and dogs. In either route of administration, the lethal dose was found to be approximately 150 to 200 mg. Fe per kilogram body weight.
Dissociable iron salts in toxic doses were rapidly absorbed through the histologically intact mucosa both from the small and from the large bowel. In the majority of the animals, no histological changes were seen in the intestinal mucosa, but intestinal bleeding occurred in some instances by diapedesis from the greatly congested capillaries.
Serum iron levels of several milligrams per cent developed within sixty minutes after ingestion of the iron salts, and with the exception of 300 to 400 micrograms per cent, the serum iron was non-beta1-globulin bound and in ferric state.
Although only a fraction of the total dose administered was found to be absorbed within nine hours, the observed serum iron rise was roughly proportional to the dose ingested, and the survival time varied inversely with the dose.
Acute intestinal iron poisoning must therefore be considered as a true absorptive intoxication. Any possibly occurring mucosal damage in stomach and intestines is of secondary importance.