Mrs. R.B. is a 52-year-old woman with a 40-year history of type 1 diabetes mellitus. Although she has been dependent on insulin since age 12, she has enjoyed relatively good health. She has been very careful about her diet, exercises daily, sees

Mrs. R.B. is a 52-year-old woman with a 40-year history of type 1 diabetes mellitus. Although she has been dependent on insulin since age 12, she has enjoyed relatively good health. She has been very careful about her diet, exercises daily, sees her primary care provider regularly for checkups, and is very conscientious about monitoring her blood glucose levels and self-administration of insulin.

She is slightly overweight and was diagnosed with hypertension four years ago. Her high blood pressure has been well controlled with a thiazide diuretic. She does not smoke and rarely drinks alcoholic beverages.

Mrs. B. was planning to shop at the local supermarket on Saturday, but her son telephoned her at the last minute and apologized that he had to work and could not drive her. Since she had only a few necessary items to pick up, she decided to walk the five blocks to the store. Rather than wear her usual walking shoes, she wore a pair of more fashionable shoes.

Upon her return home, Mrs. B. removed her shoes and noticed a small blister on the ball of her right foot. She felt no discomfort from the blister. However, two days later, she was alarmed when she found that the blister had developed into a large, open wound that was blue-black in color.

For the next two days, she carefully cleansed the wound and covered it with sterile gauze each time. The wound did not heal and, in fact, became progressively worse and painful. Her son urged her to seek medical attention, and five days after the initial injury she made an appointment with her primary care provider.