Mycetoma
Introduction This fungal infection was first described
in southern India, where in the region of Madura people who walked barefoot came
down with a local fungal/bacterial infection termed "Madura foot". We
now know that they had sustained a small skin cut when walking barefoot, which
was superinfected by a number of pathogens. One of these pathogens was the Nocardia
asteroides. This in combination with bacterial superinfections
that cause a festering wound of the foot is what was leading to ulcerations and
eventually after years of neglect to gangrene and death. This condition would
never be allowed in industrialized countries to go on that long without treatment,
but in inner cities the occasional such case can be found among the homeless and
in poor AIDS patients who run out of options. Since the AIDS epidemic there are
also more resistant pathogens around and mycetoma is possibly seen more often
these days for this reason. Signs and Symptoms In
the beginning there might be just a small pimple where the infection started.
This then develops into an abscess that may break open, then heal over, only to
eventually develop into a fistula with a draining opening and a festering wound
in the subcutaneous skin of the foot. Here is an image of a Madura
foot, which is due to mycetoma. The body reacts by forming
scar tissue around this, but the infection eats its way deeper and deeper into
the foot. This is amazingly pain free as the superficial nerve fibers are eaten
up by the granulation tissue and pain impulses are not generated. Over months
and years of not treating the Madura foot the infectious process extends deeper
into the tissue of the foot infecting muscles, tendons, ligaments, bones and joints.
Initially the patient may just limp a bit. Later as the muscle function is affected,
there will be muscle atrophy on the affected side not only in the foot area, but
also in the lower leg and in the thigh area. Eventually the patient can no longer
walk. Grotesque swelling and tissue deformities around the affected area occur.
Thick bloody discharge and pus ooze from the unsightly infected mass of the affected
foot. The infection tends to stay local for a long period of time, but eventually
it sheds into the blood stream and the patient dies very quickly of septicemia
unless the infection can be stopped in a heroic amputation surgery coupled with
massive antimicrobial therapy. Diagnostic Tests The
key is to diagnose early before permanent damage is done to the foot and amputation
would be the only hope for rescuing the patient. Fluid from the discharging wound
should be cultured for bacterial and fungal pathogens. Slides should be stained
for bacteria and fungi and studied under the microscope by a microbiological expert.
X-rays, CT scans, bone scans and blood tests are all helpful to establish the
depth of infection. Treatment When all the tests
have come back, treatment would be given directed at the pathogens isolated. If
Nocardia asteroides is isolated, this is treated with trimethoprim-sulfamethoxazole
(brandname: Bactrim). For people allergic to sulfonamides the alternative
would be ceftriaxone, tetracycline or imipenem. Several fungal infectious agents
respond to itraconazole (brand name: Sporanox) and ketoconazole orally or amphotericin
B intravenously. After this initial clearing of most of the infection, surgical
debridement might be necessary, followed by further prolonged antifungal and antibiotic
therapy. In some cases, where the disease has gone too deep and osteomyelitis
has set in, the only alternative is amputation, particularly in cases where the
immune system is suppressed (AIDS, malnutrition, cancer) (Ref. 1, p. 1224).
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