Mycetoma is a chronic bacterial or fungal infection that affects the skin and subcutaneous tissues, usually in the foot. It is characterized by the formation of a painless swelling or mass beneath the skin that develops cavities and discharges fluid and grains. Over time, it can spread and cause deformity or disability by affecting muscles, bones, and surrounding tissue. Mycetoma is diagnosed based on symptoms, microscopy of discharge grains, biopsy, and culture. Treatment involves surgery to remove the infected tissue along with long-term antifungal or antibiotic drugs depending on the causative agent.
2. Mycetoma Definition
Mycetoma, or maduromycosis, is a slow-growing bacterial or fungal infection focused in one area of the body, usually the foot. For this
reasonand because the first medical reports were from doctors in Madura, Indiaan alternate name for the disease is Madura foot. The
infection is characterized by an abnormal tissue mass beneath the skin, formation of cavities within the mass, and a fluid discharge. As
the infection progresses, it affects the muscles and bones; at this advanced stage, disability may result.
Description
Although the bacteria and fungi that cause mycetoma are found in soil worldwide, the disease occurs mainly in tropical areas in India,
Africa, South America, Central America, and southeast Asia. Mycetoma is an uncommon disease, affecting an unknown number of people
annually.
There are more than 30 species of bacteria and fungi that can cause mycetoma. Bacteria or fungi can be introduced into the body through
a relatively minor skin wound. The disease advances slowly over months or years, typically with minimal pain. When pain is experienced,
it is usually due to secondary infections or bone involvement. Although it is rarely fatal, mycetoma causes deformities and potential
disability at its advanced stage.
Causes and symptoms
Owing to a wound, bacteria or fungi gain entry into the skin. Approximately one month or more after the injury, a nodule forms under the
skin surface. The nodule is painless, even as it increases in size over the following months. Eventually, the nodule forms a tumor, or mass
of abnormal tissue. The tumor contains cavitiescalled sinusesthat discharge blood-or pus-tainted fluid. The fluid also contains tiny
grains, less than two thousandths of an inch in size. The color of these grains depends on the type of bacteria or fungi causing the
infection.
As the infection continues, surrounding tissue becomes involved, with an accumulation of scarring and loss of function. The infection can
extend to the bone, causing inflammation, pain, and severe damage. Mycetoma may be complicated by secondary infections, in which
new bacteria become established in the area and cause an additional set of problems.
Diagnosis
The primary symptoms of a tumor, sinuses, and grain-flecked discharge often provide enough information to diagnose mycetoma. In the
early stages, prior to sinus formation, diagnosis may be more difficult and a biopsy, or microscopic examination of the tissue, may be
necessary. If bone involvement is suspected, the area is x rayed to determine the extent of the damage. The species of bacteria or fungi
at the root of the infection is identified by staining the discharge grains and inspecting them with a microscope.
Treatment
Combating mycetoma requires both surgery and drug therapy. Surgery usually consists of removing the tumor and a portion of the
surrounding tissue. If the infection is extensive, amputation is sometimes necessary. Drug therapy is recommended in conjunction with
surgery. The specific prescription depends on the type of bacteria or fungi causing the disease. Common medicines include antifungal
drugs, such as ketoconazole and antibiotics (streptomycin sulfate, amikacin, sulfamethoxazole, penicillin, and rifampin).
Prognosis
Recovery from mycetoma may take months or years, and the infection recurs after surgery in at least 20% of cases. Drug therapy can
reduce the chances of a re-established infection. The extent of deformity or disability depends on the severity of infection; the more deeply
entrenched the infection, the greater the damage. By itself, mycetoma is rarely fatal, but secondary infections can be fatal.
Prevention(Mycetoma is a rare condition that is not contagious)
4. Definition
A chronic, slowly progressive granulomatous
disease of the subcutaneous tissues,
Later spreads to skin and bones.
5. Characterized by formation of grains (Black,
White, yellow, or Red).
Is painless unless secondary bacterial infection
occur
Is progressively destructive with loss of
function of the organ affected.
6. Epidemiology
The disease is common throughout the
tropical & subtropical countries.
Organisms are soil saprophytes or plant
parasites, infection is acquired exogenously
by trauma (thorn prick).
Man to man infection doesn't occur.
Any age group can be affected.
8. Eumycetoma:
Caused by: e.g.
Madurella mycetomatis: commenst one > 75%
(in Sudan) big black grains.
Madurella grisea: black grains.
Aspergillus nidulans: big white grains.
Petriellidium boydii: white yellow grains.
悋愕悴悋惡悸 悋悋惆惘悸:悋愕惆悋悄 悋忰惡惡.
悋惺愆愆悸 悋惘愆悋愆悸:惡惘悸 惡惷悋悄 忰惡惡.
Petriellidium悋惡惆悸:
9. Actinomycetoma:
Caused by:
Actinomadura madurae: big white.
Actinomadura pelletieri: small red.
Streptomyces somaliensis: small hard yellow
grains (sand grains).
Nocardia braziliensis: small white yellow.
11. Clinical features
Incubation very lengthy (up to 30 yrs).
Initially present with hard subcutaenous
swelling
later on discharging sinus coloured grains.
Host response is the formation of granuloma.
12. Differences between the two types:
ActinomycetomaEumycetoma
Rapidly progressive.Slowly progressive
3 months30 years.
ill defined, non capsulated
more destructive.
Well demarcated &
capsulated.
Multiple sinuses.Few sinuses.
Early bone involvement.Late bone involvement.
21. Laboratory diagnosis
Specimens:
Depend on the stage of presentation:
If the patient present early with subcutaenous
swelling:
a- Blood for serology.
b- Biopsy for histopathology.
If the patient present with swelling &
discharging sinuses : specimen is pus and
grains.
26. Culture:
Grains are cultured as follow:
Eumycetoma: in Blood agar & subcultured on
sabouraud agar.
Actinomycetoma: in L.J medium then
subcultured on sabouraud agar.