Dear Dr. B: What is flesh-eating disease?
Flesh-eating disease is a form of streptococcal infection that leads to death of tissues. It is a deep-seated infection under the skin. It progressively destroys fat, fascia and muscles. The condition is also known as necrotizing fasciitis.
Streptococci (invasive group A hemolytic streptococci) may act alone or in combination with other bacteria. The infection spreads rapidly. Shock and multiorgan failure are common. Mortality is high up to 58 percent.
Fortunately, the disease is not that common. In Canada, it is estimated that 90 to 200 cases of necrotizing fasciitis occur each year. From time to time the disease hits the headlines. Then there is long silence before another case is reported. This leaves people wondering what is this all about.
The most famous case of flesh-eating disease was Loucien Bouchard, the former premier of Quebec. He luckily survived and had to have one leg amputated.
An editorial in British Medical Journal (BMJ) says that the condition was first described in a specific body region by Fournier in 1883 and as a more generalized condition by Meleney in 1924.
The most common sites of infection are perianal and groin areas and post surgical wounds. Infection around the umbilicus in a new born can be life-threatening. Among children the necrotizing fasciitis can be a serious complication of varicella infection.
Is it possible to make an early diagnosis before things get worse?
Unfortunately, no! The diagnosis is clinical. Initially, it is hard to differentiate from ordinary infection of the skin. But gradually patients get very sick. The pain is more severe than the clinical findings. There are only minor changes in the skin in early phases.
An article in the Canadian Medical Association Journal says the factors that help distinguish necrotizing fasciitis from ordinary skin infection include a generalized rash, toxic appearance, fever and low platelet count. Unfortunately, the current state of knowledge on diagnoses and management is limited. More research is required.
The main diagnostic tool, however, is surgical exploration, says the BMJ editorial. The characteristic finding is of grey, edematous fat, which strips off the underlying fascia with a sweep of the finger. Deeper changes are invariably more widespread than the skin changes.
Patient requires immediate hospitalization for medical and surgical management. Three specific treatments have been suggested:
-antibiotics,
-hyperbaric oxygen, and
-surgery.
The BMJ editorial says that no evidence exists that antibiotics halt the infection in necrotizing fasciitis and their use may tempt the surgeon to perform less mutilating but less effective surgery. Nevertheless, broad spectrum cover is routine and should specifically target anaerobes and streptococci.
Hyperbaric oxygen is strongly advocated by some. But there are no controlled studies to prove its usefulness. Using it would seem reasonable if it was readily available but not if the need for interhospital transfer delayed definitive surgery, says the editorial.
Surgery is the mainstay of management. Patient should be taken to the operating room as soon as flesh-eating disease is suspected. Massive removal of dead and dying tissue is undertaken. Sometimes amputation becomes necessary. Patient may require surgery more than once.
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