Tropical infections: Determine underlying etiology by culturing bacteria, taking biopsy

October 1, 2008

Clinicians need to determine the underlying etiology when managing wounds that are the result of tropical infections. They can do this by culturing bacteria or taking a biopsy.

Key Points

Toronto - When managing wounds that occur as a result of tropical infections, the key is to find the underlying etiology by culturing bacteria or taking a biopsy, according to a professor of surgery in the department of surgery at the University of Zimbabwe in Harare, Zimbabwe, who spoke at the World Union of Wound Healing Societies in Toronto.

"We know, as with all wounds, that it is important to examine the whole patient and not just the wound," says Kent Jonsson, M.D., Ph.D., noting that adequate therapy cannot be administered without performing a culture or taking a biopsy of the wound margin.

Piomyositis

However, in the era of human immunodeficiency virus (HIV), piomyositis now typically occurs in patients with immune deficiencies and is being recorded as an opportunistic infection in patients with HIV.

With appropriate therapy, such as surgical drainage and the use of antibiotics, mortality due to this infection is less than 2 percent.

The common pathogen in patients is Staphylococcus aureus. Patients with necrotizing fasciitis have pain, fever and gangrene, but no swelling. This infection is not related to HIV.

Cancrum oris

Cancrum oris, or noma, is an uncommon condition that occurs primarily in children between the ages of 2 and 6.

"As a general surgeon in Zimbabwe, I usually see about one patient every two years who has this condition," Dr. Jonsson tells Dermatology Times.

"The children who are getting this infection are older and usually have poor dental health. There are several conditions that predispose children to develop the infection, such as measles, malaria, typhoid, or poor nutrition," he says.

As a gangrenous process of the mouth, the tropical infection starts rapidly and involves adjacent tissues of the face. The condition can destroy deeper tissues, teeth and skeleton and disfigure patients.

In terms of acute care, penicillin should be administered in large doses, as well as metronidazole. The child should also be fed and an adequate electrolyte balance maintained.

Leprosy

Leprosy is a rare tropical infection in Zimbabwe, Dr. Jonsson says.

Antibiotics are used to treat the condition, such as dapsone, clofazimine and rifampicin. These antibiotics are available at no cost by the World Health Organization. Referral can be delayed if physicians do not recognize the condition.

"Most of the referrals in Zimbabwe originate from nurses," Dr. Jonsson says. "We have to think if we are teaching our doctors how to diagnose the disease."

Deep mycoses

Deep mycoses primarily affect rural populations, and they affect men more than women.

"It can be very hard to diagnose for those who are working as general practitioners," Dr. Jonsson says.

"It's also helpful to perform a biopsy and histology in these patients," he adds.

Tuberculosis

"We are not very good at recognizing the early signs of tuberculosis in patients with HIV (in the developing world), and treatment is often started very late," Dr. Jonsson says.

Buruli ulcer

The Buruli ulcer has proven to be a challenge for clinicians. One study has shown that the use of antibiotics, in combination with adequate surgical debridement and hydrogels bandaging, improves wound healing in these patients.

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