Jan, a 60 year-old type I diabetic on insulin for many years, is brought to the emergency department where you are working triage. She has an extremely swollen right lower leg. You see what appears to be an old surgical wound in the mid-calf, with rough scar tissue surrounded by purplish-red skin. She is in a lot of pain and her husband speaks for her. He tells you that three weeks ago she had several moles removed from that area. The area had appeared to heal initially, but three days ago the incision area started looking bigger rather than smaller. She did not return to the physician, hoping the condition would resolve itself. In the past three days the area has begun to swell and become very red, hot and is spreading down the calf.
You immediately call Dr. Phil Good Soon who is making rounds because you know that this is a serious condition.The patient is sent straight to surgery where the wound is debrided. Gram-positive cocci growing in chains are recovered from the wound. She is transferred to intensive care and put on high-dose intravenous antibiotics for the next 18 hours, but the next evening her leg is amputated below the knee. She remains in the hospital for two months following surgery and requires long-term antibiotic therapy and multiple skin grafts on her upper leg.
1. What condition did this patient have?
2. What features suggest that it is not Clostridium perfringens gangrene?
3. Why was amputation the best solution for the infection in this case?
4. How is the bacteria acquired?
5. What are some predisposing factors for development of this disease?
6. The disease may destroy tissues as fast as the surgeon removes it. A mortality rate exceeding 40% is a result of what? (tip: what causes the dead tissue?)