Epidemiology and pathogenesis

Epidemiology and pathogenesis

The condition predominantly occurs in the ‘mycetoma belt’ that lies between latitudes 15° south and 30° north, compris - ing the countries of Sudan, Somalia, Senegal, India, Y emen, Mexico, V enezuela, Columbia, Argentina and a few others. The route of infection is inoculation of the organism that is resident in the soil through a traumatised area. Although in the vast majority there is no history of trauma, the portal of entry is always an area of minor unrecognised trauma in a bare-footed individual walking in a terrain full of thorns. Hence the foot is the commonest site a ff ected. Mycetoma is not contagious. Once the granuloma forms it increases in size, and the overlying skin becomes stretched, smooth, shiny and attached - -

Figure 6.23 Mycetoma of the foot.

develop. Eventually it invades the deeper structures. This is usually gradual and delayed in eumycetoma. In actinomyce toma, invasion to deeper tissues occurs earlier and is more extensive. The tendons and nerves are spared until late in the disease. This may explain the rarity of neurological and tro phic c hanges even in patients with longstanding disease. Tro phic changes are rare because the blood supply is adequate. Summary box 6.15 Mycetoma: pathogenesis /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Mostly occurs in the ‘mycetoma belt’ There are two types – eumycetoma and actinomycetoma Caused by fungi or bacteria entering through a site of trauma, which may not be apparent; hence the foot is most commonly affected Produces a chronic, speci /f_i c, granulomatous, progressive, destructive in /f_l ammatory lesion Results in tissue destruction, deformity, disability and sometimes death

Epidemiology and pathogenesis

The condition predominantly occurs in the ‘mycetoma belt’ that lies between latitudes 15° south and 30° north, compris - ing the countries of Sudan, Somalia, Senegal, India, Y emen, Mexico, V enezuela, Columbia, Argentina and a few others. The route of infection is inoculation of the organism that is resident in the soil through a traumatised area. Although in the vast majority there is no history of trauma, the portal of entry is always an area of minor unrecognised trauma in a bare-footed individual walking in a terrain full of thorns. Hence the foot is the commonest site a ff ected. Mycetoma is not contagious. Once the granuloma forms it increases in size, and the overlying skin becomes stretched, smooth, shiny and attached - -

Figure 6.23 Mycetoma of the foot.

develop. Eventually it invades the deeper structures. This is usually gradual and delayed in eumycetoma. In actinomyce toma, invasion to deeper tissues occurs earlier and is more extensive. The tendons and nerves are spared until late in the disease. This may explain the rarity of neurological and tro phic c hanges even in patients with longstanding disease. Tro phic changes are rare because the blood supply is adequate. Summary box 6.15 Mycetoma: pathogenesis /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Mostly occurs in the ‘mycetoma belt’ There are two types – eumycetoma and actinomycetoma Caused by fungi or bacteria entering through a site of trauma, which may not be apparent; hence the foot is most commonly affected Produces a chronic, speci /f_i c, granulomatous, progressive, destructive in /f_l ammatory lesion Results in tissue destruction, deformity, disability and sometimes death

Epidemiology and pathogenesis

The condition predominantly occurs in the ‘mycetoma belt’ that lies between latitudes 15° south and 30° north, compris - ing the countries of Sudan, Somalia, Senegal, India, Y emen, Mexico, V enezuela, Columbia, Argentina and a few others. The route of infection is inoculation of the organism that is resident in the soil through a traumatised area. Although in the vast majority there is no history of trauma, the portal of entry is always an area of minor unrecognised trauma in a bare-footed individual walking in a terrain full of thorns. Hence the foot is the commonest site a ff ected. Mycetoma is not contagious. Once the granuloma forms it increases in size, and the overlying skin becomes stretched, smooth, shiny and attached - -

Figure 6.23 Mycetoma of the foot.

develop. Eventually it invades the deeper structures. This is usually gradual and delayed in eumycetoma. In actinomyce toma, invasion to deeper tissues occurs earlier and is more extensive. The tendons and nerves are spared until late in the disease. This may explain the rarity of neurological and tro phic c hanges even in patients with longstanding disease. Tro phic changes are rare because the blood supply is adequate. Summary box 6.15 Mycetoma: pathogenesis /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Mostly occurs in the ‘mycetoma belt’ There are two types – eumycetoma and actinomycetoma Caused by fungi or bacteria entering through a site of trauma, which may not be apparent; hence the foot is most commonly affected Produces a chronic, speci /f_i c, granulomatous, progressive, destructive in /f_l ammatory lesion Results in tissue destruction, deformity, disability and sometimes death