Talk about bad dogs.
"She didn't feel it at all," Dr. Lee C. Rogers, a podiatrist who treated the Des Moines woman, told CBS News. "When she woke up, there was blood everywhere. The dog had been tracking it all over the place."
Rogers, who now directs the amputation prevention center at Valley Presbyterian Hospital in Van Nuys, Calif., said he eventually had to amputate the woman's leg - leaving her a double amputee.
The three-year-old case, which Rogers described in the May-June 2011 issue of the Journal of the American Podiatric Medical Association, is an unusual one. But he said it serves as a reminder that patients with diabetic neuropathy should cover their feet and any wounds while sleeping.
"Pets have a tendency to lick wounds, and that simple lick can turn into a bite, if there is no response from the owner," he said in a written statement, adding that there have been cases in which dogs' saliva had infected their owners with dangerous bacteria.
About 26 million Americans have diabetes, and 60 to 70 percent of them have neuropathy. Diabetes is a leading cause of amputations, as severe tissue damage associated with diabetic neuropathy often cannot be successfully treated any other way.
The National Institute of Diabetes and Digestive and Kidney Diseases has more on diabetic neuropathy.