Mycetoma
Encyclopedia
- "Mycetoma" redirects here. For the bacterial disease formerly known as "actinomycetoma", see ActinomycosisActinomycosisActinomycosis is an infectious bacterial disease caused by Actinomyces species such as Actinomyces israelii or A. gerencseriae. It can also be caused by Propionibacterium propionicus, and the condition is likely to be polymicrobial aerobic anaerobic infection.Actinomycosis occurs rarely in humans...
.
Eumycetoma is a chronic, specific, granulomatous, fungal disease. It mainly affects the foot; and Mycetoma pedis is also known as Madura foot. This infection is endemic in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, and Central and South America.
Causes and presentation
Eumycetoma usually involves the subcutaneous tissue after a traumatic inoculation of the causative organism. Tumefaction and formation of sinus tracts characterize mycetoma. The sinuses usually discharge purulent and seropurulent exudate containing grains. It may spread to involve the skin and the deep structures resulting in destruction, deformity and loss of function; very occasionally it could be fatal.Epidemiology
The true incidence and the geographical distribution of mycetoma throughout the world is not exactly known due to the nature of the disease which is usually painless, slowly progressive which may lead to the late presentation of the majority of patients. Mycetoma has a worldwide distribution but this is extremely uneven. It is endemic in tropical and subtropical regions. The African continent seems to have the highest prevalence. It is found in what is known as the mycetoma belt stretching between the latitudes of 15 south and 30 north. The belt includes Sudan, Somalia, Senegal, India, Yemen, Mexico, Venezuela, Colombia, Argentina and others.Mycetoma infection, Madura foot or maduromycosis, was originally described in Sanskrit in the Vedic texts from India. The first English language accounts occurred much later in the area of Madras (aka Chennai).
The geographical distribution of the individual mycetoma organism shows considerable variations, which can be convincingly explained on an environmental basis. Areas where mycetoma prevails are relatively arid zones with a short rainy season with a relative humidity.
The organisms are usually present in the soil in the form of grains. The infecting agent is implanted into the host tissue through a breach in the skin produced by trauma caused by sharp objects such as thorn pricks, stone or splinters.
Pathogenesis
The disease is usually acquired while performing agricultural workAgriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, and it generally afflicts men between 20 and 40 years old. The disease is acquired by contacting grains of fungal spores that have been discharged onto the soil. Infection usually involves an open area or break in the skin. Pseudoallescheria boydii is one of many fungi spp. that causes the fungal form of madura foot (see below). The disease is characterized by a yogurt-like discharge upon maturation of the infection. Hematogenous or lymphatic spread is uncommon. Infections normally start in the foot or hand and travel up the leg or arm.
Eumycetoma may be one of several varieties, depending upon color of the granulous discharge:
- red
- Actinomadura pelletieri
- white or yellow
- Acremonium strictumAcremonium strictumAcremonium strictum is a plant, animal, and human pathogen. The genus Acremonium contains around 100 species, most of which are saprophytic, being isolated from dead plant material and soil. Some species cause disease in man and animals, causing mycetoma, onychomycosis, and hyalohyphomycosis...
- Actinomadura madurae
- Aspergillus nidulansAspergillus nidulansAspergillus nidulans is one of many species of filamentous fungi in the phylum Ascomycota...
- Noetestudina rosatii
- Phaeoacremonium krajdenii
- Pseudallescheria boydii
- Acremonium strictum
- black
- CurvulariaCurvulariaCurvularia is a hyphomycete fungus which is a facultative pathogen of many plant species and of the soil. Most Curvularia are found in tropical regions, though a few are found in temperate zones....
lunata - Exophiala jeanselmeiExophiala jeanselmeiExophiala jeanselmei is an ascomycete fungus species that causes eumycetoma....
- LeptosphaeriaLeptosphaeriaLeptosphaeria is a genus of fungi in the family Phaeosphaeriaceae....
senegalensis - Leptosphaeria tompkinsii
- Madurella griseaMadurella griseaMadurella grisea is a species of Madurella....
- Madurella mycetomatisMadurella mycetomatisMadurella mycetomatis is a species of Madurella....
- PyrenochaetaPyrenochaetaPyrenochaeta is a genus of fungus.It includes the species Pyrenochaeta romeroi.Other species include:* Pyrenochaeta lycopersici* Pyrenochaeta terrestris...
romeroi
- Curvularia
The bacterial mycetoma species Nocardia
Nocardia
Nocardia is a genus of weakly staining Gram-positive, catalase-positive, rod-shaped bacteria. It forms partially acid-fast beaded branching filaments . It has a total of 85 species. Some species are non-pathogenic while others are responsible for nocardiosis. Nocardia are found worldwide in soil...
(including Nocardia asteroides
Nocardia asteroides
Nocardia asteroides is a species of Nocardia.It can cause Nocardiosis, a severe pulmonary infection in immunocompromised hosts....
and Nocardia brasiliensis
Nocardia brasiliensis
Nocardia brasiliensis is a species of Nocardia.It can cause Nocardiosis....
) produces yellow discharge, and Streptomyces
Streptomyces
Streptomyces is the largest genus of Actinobacteria and the type genus of the family Streptomycetaceae. Over 500 species of Streptomyces bacteria have been described. As with the other Actinobacteria, streptomycetes are gram-positive, and have genomes with high guanine and cytosine content...
(including Streptomcyes somaliensis) produce yellow or red discharge. These are not causes of Eumycetoma.
The further course of the sinuses differs according to the mycetoma present. In the black variety, the infection spreads mainly subcutaneously. In the red and yellow varieties deep spread occurs early, and muscle and underlying bones become infiltrated, but unexpectedly, nerves and tendons are highly resistant to invasion.
Diagnosis
Diagnosis of mycetoma is usually accomplished by radiologyRadiology
Radiology is a medical specialty that employs the use of imaging to both diagnose and treat disease visualized within the human body. Radiologists use an array of imaging technologies to diagnose or treat diseases...
, ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...
or by fine needle aspiration of the fluid within an afflicted area of the body. It depends upon isolating the causative organism along with a knowledge of local endemic infection.
Differential diagnosis
Following is the differential diagnosis:- Tuberculous ulcer
- Kaposi's sarcomaKaposi's sarcomaKaposi's sarcoma is a tumor caused by Human herpesvirus 8 , also known as Kaposi's sarcoma-associated herpesvirus . It was originally described by Moritz Kaposi , a Hungarian dermatologist practicing at the University of Vienna in 1872. It became more widely known as one of the AIDS defining...
- Tropical ulcerTropical ulcerTropical ulcer is a lesion occurring in cutaneous leishmaniasis. It is caused by a variety of microorganisms, including mycobacteria...
Treatment
There are several clinical treatments available for this disease. They include surgerySurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, ketoconazole
Ketoconazole
Ketoconazole is a synthetic antifungal drug used to prevent and treat fungal skin infections, especially in immunocompromised patients such as those with AIDS or those on chemotherapy. Ketoconazole is sold commercially as an anti-dandruff shampoo, topical cream, and oral tablet.Ketoconazole is...
, voriconazole
Voriconazole
Voriconazole is a triazole antifungal medication that is generally used to treat serious, invasive fungal infections. These are generally seen in patients who are immunocompromised, and include invasive candidiasis, invasive aspergillosis, and certain emerging fungal infections.-Invasive...
, itraconazole
Itraconazole
Itraconazole , invented in 1984, is a triazole antifungal agent that is prescribed to patients with fungal infections. The drug may be given orally or intravenously.-Medical uses:...
and amputation
Amputation
Amputation is the removal of a body extremity by trauma, prolonged constriction, or surgery. As a surgical measure, it is used to control pain or a disease process in the affected limb, such as malignancy or gangrene. In some cases, it is carried out on individuals as a preventative surgery for...
. There is no vaccine
Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
for mycetoma.
Scientists at such institutions as The Mycetoma Research Center at The University of Khartoum in the Sudan
Sudan
Sudan , officially the Republic of the Sudan , is a country in North Africa, sometimes considered part of the Middle East politically. It is bordered by Egypt to the north, the Red Sea to the northeast, Eritrea and Ethiopia to the east, South Sudan to the south, the Central African Republic to the...
are working on a cure.