Mycetoma

Key Features

• Mycetoma is a chronic local, slowly progressive, destructive infection

• Begins in subcutaneous tissues, frequently after implantation trauma, and spreads to contiguous structures with sinus tracts and extruding grains

• Eumycetoma (also known as maduromycosis) is mycetoma caused by true fungi

• Actinomycetoma is mycetoma caused by Actinomadura, Streptomyces, and Nocardia

Clinical Findings

• Lesion begins as a papule, nodule, or abscess that, over months to years, forms multiple abscesses and sinus tracts ramifying deep into the tissue

• Secondary bacterial infection may occur in large open ulcers

Diagnosis

• Radiographs may show destructive changes in underlying bone

• Causative species can often be suggested by the color of the characteristic grains and hyphal size within the infected tissues

• Definitive diagnosis requires culture

Treatment

• Prognosis of eumycetoma is poor

  • However, surgical debridement with prolonged oral itraconazole therapy (200 mg twice daily) or combination therapy including itraconazole and terbinafine yields a response rate of 70%

  • Amputation is necessary in far-advanced cases

• For actinomycetoma

  • Trimethoprim-sulfamethoxazole, 8/40/mg/kg/day orally for 5 week cycle plus

  • Amikacin, 15 mg/kg/day intravenously or intramuscularly in two divided doses for first 3 weeks of cycle

  • Debridement assists healing

• Prognosis of actinomycetoma is good because it usually responds to sulfonamides plus aminoglycosides