Mycetoma is a chronic subcutaneous infection caused by aerobic actinomycetic bacteria (actinomycetoma) or fungi eumycetoma.[1] While most cases of mycetoma occur in Sudan, Venezuela, Mexico, and India, its true prevalence and incidence are not well-known.[1][2] It appears most frequently in people living in rural areas, particularly farmers and shepherds.[3] It is listed by the World Health Organization (WHO) as a neglected tropical disease.[2]
Risk
Frequent exposure to penetrating wounds by thorns or splinters is a risk factor.[3] This risk can be reduced by disinfecting wounds and wearing shoes.[4]
Pathogenesis
Mycetoma is caused by common saprotrophs found in the soil and on thorny shrubs in semi-desert climates.[4] The most common causative agents are:
- Madurella mycetomatis (fungus)
- Nocardia brasiliensis (bacteria)
- Actinomadure madura (bacteria)
- Streptomyces somaliensis (bacteria)
- Actinomadura pelletieri (bacteria)[2]
Infection is caused as a result of localized skin trauma, such as stepping on a needle or wood splinter, or through a pre-existing wound.[4]
The first visible symptom of mycetoma is a typically painless swelling beneath the skin; over several years, this will grow to a nodule (lump).[3] Affected people will experience massive swelling and hardening of the area, in addition to skin rupture and the formation of sinus tracts that discharge pus and grains filled with organisms.[3] In many instances, the underlying bone is affected.[5][4] Some people with mycetoma will not experience pain or discomfort, while others will report itching and/or pain.[3]
Diagnosis
There are currently no rapid diagnostic tools for mycetoma.[2] Mycetoma is diagnosed through microscopic examination of the grains in the nodule and by analysis of cultures.[4] Since the bacterial form and the fungal form of mycetoma infection of the foot share similar clinical and radiological features, diagnosis can be a challenge.[1] Magnetic resonance imaging is a very valuable diagnostic tool. However, its results should be closely correlated with the clinical, laboratory and pathological findings.[5][6]
Treatment
While treatment will vary depending on the cause of the condition, it may include antibiotics or antifungal medication.[3] Actinomycetoma, the bacterial form, can be cured with antibiotics.[1] Eumycetoma, the fungal form, is treated with antifungals.[6] Surgery in the form of bone resection may be necessary in late presenting cases or to enhance the effects of medical treatment.[5] In the more extensive cases amputation is another surgical treatment option.[7][4] For both forms, extended treatment is necessary.[1]
In cats, mycetoma can be treated with complete surgical removal. Antifungal drugs are rarely effective.[8]
References
- ^ a b c d e Welsh O, Al-Abdely HM, Salinas-Carmona MC, Fahal AH (October 2014). "Mycetoma medical therapy". PLOS Neglected Tropical Diseases. 8 (10): e3218. doi:10.1371/journal.pntd.0003218. PMC 4199551. PMID 25330342.
- ^ a b c d van de Sande WW, Maghoub El S, Fahal AH, Goodfellow M, Welsh O, Zijlstra E (March 2014). "The mycetoma knowledge gap: identification of research priorities". PLOS Neglected Tropical Diseases. 8 (3): e2667. doi:10.1371/journal.pntd.0002667. PMC 3967943. PMID 24675533.
- ^ a b c d e f "Mycetoma". Genetic and Rare Diseases Information Center (GARD). National Institutes of Health. Retrieved 2018-04-17.
- ^ a b c d e f RESERVED, INSERM US14 -- ALL RIGHTS. "Orphanet: Mycetoma". www.orpha.net. Retrieved 2018-04-17.
- ^ a b c El-Sobky, TA; Haleem, JF; Samir, S (2015). "Eumycetoma Osteomyelitis of the Calcaneus in a Child: A Radiologic-Pathologic Correlation following Total Calcanectomy". Case Reports in Pathology. 2015: 129020. doi:10.1155/2015/129020. PMC 4592886. PMID 26483983.
- ^ a b Karrakchou, B; Boubnane, I; Senouci, K; Hassam, B (10 January 2020). "Madurella mycetomatis infection of the foot: a case report of a neglected tropical disease in a non-endemic region". BMC Dermatology. 20 (1): 1. doi:10.1186/s12895-019-0097-1. PMC 6953183. PMID 31918687.
- ^ Efared, Boubacar; Tahiri, Layla; Boubacar, Marou Soumana; Atsam-Ebang, Gabrielle; Hammas, Nawal; Hinde, El Fatemi; Chbani, Laila (December 2017). "Mycetoma in a non-endemic area: a diagnostic challenge". BMC Clinical Pathology. 17 (1): 1. doi:10.1186/s12907-017-0040-5. ISSN 1472-6890. PMC 5288886. PMID 28167862.
- ^ Eldredge, Debra M.; Carlson, Delbert G.; Carlson, Liisa D.; Giffin, James M. (2008). Cat Owner's Home Veterinary Handbook. Howell Book House. p. 160.
External links
- DermNet NZ: an online resource about skin diseases from the New Zealand Dermatological Society Incorporated.
- Orphanet: a reference portal from Europe that provides information on rare diseases and orphan drugs.
- ClinicalTrials.gov: a list of clinical trials related to mycetoma.