Eumycetoma

Revision as of 16:20, 12 January 2021 by Rossdonaldson1 (talk | contribs) (→‎References)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

Background

  • Also known as “mycotic mycetoma” and "Madura foot"
  • Chronic subcutaneous fungal skin and soft tissue infection
  • Caused by many different types of molds
  • Infection occurs following inoculation of conidia into skin or subcutaneous tissue
  • Usually confined to subcutaneous tissue but can spread to fascia, bone, and lymph nodes via continguous dissemination [1]

Microbiology

  • There are at least 41 organisms capable of causing eumycetoma
  • Most frequent pathogens include
    • Madurella mycetomatis
    • Nigrograna mackinnonii
    • Trematosphaeria grisea
    • Falciformispora senegalensis
    • Scedosporium apiospermum

Clinical Features

Madura foot.
  • Located in uncovered areas that have been traumatized (mostly feet, legs, and hands)
  • Most often affects lower extremities (typically a single foot) [2]
  • Characteristic triad is tumor, sinus tracts, and macroscopic grains
  • Progression
    • Initial lesions are painless, often begin as slowly growing indurated subcutaneous nodules
    • Extension occurs due to nodule swelling and coalescence, resulting in large tumors that can evolve into necrotic abscesses with sinus tracts
    • May progress over months to many years
    • Can extend from skin and subcutaneous tissue to muscle, bone, and lymphatic vessels
  • Pain is usually associated with secondary bacterial infection

Complications

  • Fibrosis
  • Ankylosis
  • Lymphedema
  • Joint destruction

Differential Diagnosis

Evaluation

Plain x-ray of Madura foot.
  • Physical exam looking for characteristic triad (tumor, sinus tract, and macroscopic grains)
  • Microscopy of grains using 20% potassium hydroxide solution
  • Gram stain can be considered to evaluate for alternative diagnoses
  • Deep biopsy with culture
  • Imaging: CT or MRI (although MRI more sensitive) to determine bony involvement and extent of soft tissue involvement
  • PCR can be done to evaluate for specific causative pathogens

Management

  • Extended antifungal therapy, depending on causative agent, generally at least 12 months (3 months after clinical and radiographic resolution)
    • Possibilities include itraconazole, voriconazole, posaconazole
  • Surgery is not first line as relapse rates are high (109),if performed it should be done in conjunction with antifungal therapy

Disposition

  • Disposition will depend on severity of lesion and overall clinical status of patient
  • Providers should consider possibility of secondary bacterial infection

External Links

See Also

References

  1. el Hassan AM, Mahgoub ES. Lymph node involvement in mycetoma. Trans R Soc Trop Med Hyg. 1972;66(1):165-169. doi:10.1016/0035-9203(72)90065-x
  2. Zijlstra EE, van de Sande WWJ, Welsh O, Mahgoub ES, Goodfellow M, Fahal AH. Mycetoma: a unique neglected tropical disease. Lancet Infect Dis. 2016;16(1):100-112. doi:10.1016/S1473-3099(15)00359-X