Mycetoma

Mycetoma is the pathologic process in witch exogenous fungal or actinomycot ic etiological agents generate grains. This entity can be divided in two gr oups: eumycetoma (caused by fungi) and actinomycetoma (caused by aerobic ba cteria). They must be distinguished as their treatments are different. Main causative agents are: Madurella mycetomatis, Leptosphaeria senegalensis, P seudallecheria boydii (fungii); Actinomadura pelletieri, Actinomadura madur ae, Streptomyces somaliensis, Nocardia brasiliensis (actinomycetes). They a re harbored in the soil and vegetation of endemic areas and introduced by t raumas. Mycetoma occur mainly in the northern tropical zones (Mexico, afric an countries from Senegal to Somalia, India). The climate of this part of t he world is hot and dry with a short rainy season. In the three major endem ic zones the frequency of etiological agents is rather different. IN each z one rainfall has an influence on the distribution of the different actinomy cetes and fungi implicated. Mycetoma is more frequent in males and affects the age group between the second and fourth decade. Most of the patients ar e farm workers. There has been few studies concerning immunological status of mycetoma patients, the most recent study did not find immunological alte rations in this type of patients. Host tissue reaction to mycetoma grains, morphology of the grain by light microscopy are well documented. Electron m icroscopy helped in the understanding of host-parasite relationships. The m ost frequent localization of the disease is the foot. Extra-podal localisat ions are often encountered with Norcardia sp. in Mexico and A. pelletieri i n Senegal. Mycetoma is a chronic subcutaneous inflammatory tumor characteri sed in most cases by discharging sinuses. The evolution is chronic, gradual ly the tissues and bones are invaded. Bone involvement is more common in fo ot localization and in actinomycetoma than in eumycetoma. It is often painf ul causing a functional disability. In case of bone invasion medical treatm ent cure becomes more uncertain so its early recognition:is essential. Radi ography is of great value and recently ultrasonography was found to be very useful showing characteristic features of mycetoma. Patients are often see n after some years of evolution because of the absense of pain during a lon g period and because they live in isolated regions far from medical centers . Positive diagnosis is, made by direct examination of grains, biopsy and c ultures. Cultures are often difficult to achieve as there are few specializ ed laboratories. Surgical treatment for actinomycetoma is rarely needed bec ause of the good results obtain with antibiotics. Sulfamethoxazole-trimetho prime is the most commonly therapy used. The duration is at least one year. For treating resistant and extensive cases the combination of sulfamethoxa zole-trimethoprime and amikacin has been successful in Nocardia sp. mycetom a. Medical treatment of eumycetoma remains unsatisfactory and surgical trea tment is often the only alternative. Earlier diagnosis of mycetoma will pre vent mutilating excision or amputation.