Eumycetoma - Clinicals, Diagnosis, and Management

Infectious diseases

Clinicals - History

Fact Explanation
Skin rash Mycetoma also known as mycotic mycetoma is a chronic subcutaneous fungal infection of the skin and soft tissue caused by more than 30 species of fungi or higher bacteria (actinomycotic mycetoma or actinomycetoma). The organism is inoculated into the skin by minor injuries such as cuts. Mycetoma generally presents as single lesion. Commonest site is the foot. The initial lesion is a painless skin lump which grows gradually to involve the underlying muscles or rarely bones. With time an ulcer appears in the middle of the lesion, followed by a pus or grains discharging from it. The lump develops into a large extent that considerable deformity often makes it difficult to walk. Other than that, the lesion is rarely painful, but it often itches or burns. Skin rash
Mycetoma also known as mycotic mycetoma is a chronic subcutaneous fungal infection of the skin and soft tissue caused by more than 30 species of fungi or higher bacteria (actinomycotic mycetoma or actinomycetoma). The organism is inoculated into the skin by minor injuries such as cuts. Mycetoma generally presents as single lesion. Commonest site is the foot. The initial lesion is a painless skin lump which grows gradually to involve the underlying muscles or rarely bones. With time an ulcer appears in the middle of the lesion, followed by a pus or grains discharging from it. The lump develops into a large extent that considerable deformity often makes it difficult to walk. Other than that, the lesion is rarely painful, but it often itches or burns.
At risk population Although the cases have been reported worldwide, mycetoma is common among individuals (especially males) in their 30s to 50s living in developing countries of tropical and subtropical regions.
Individuals with history of trauma, walking barefoot, involve in agricultural work, have poor personal hygiene, poor nutrition and wounds or multiple infections are predisposed to mycetoma.
At risk population
Although the cases have been reported worldwide, mycetoma is common among individuals (especially males) in their 30s to 50s living in developing countries of tropical and subtropical regions.
Individuals with history of trauma, walking barefoot, involve in agricultural work, have poor personal hygiene, poor nutrition and wounds or multiple infections are predisposed to mycetoma.

Clinicals - Examination

Fact Explanation
Initial skin lump Eumycetoma develops as a skin lump initially and grows gradually to a large mass. With time, an abscess develops. The surface skin is scarred and pale. Apart from the foot, upper extremities, eyelids, lacrimal glands, trunk, buttocks, paranasal sinuses, scalp and mandible are rarely affected. Initial skin lump
Eumycetoma develops as a skin lump initially and grows gradually to a large mass. With time, an abscess develops. The surface skin is scarred and pale. Apart from the foot, upper extremities, eyelids, lacrimal glands, trunk, buttocks, paranasal sinuses, scalp and mandible are rarely affected.
Tumorous lesion Patients who seek medical attention after many months usually present with very large tumorous lesions. This tumor may cover the most of the foot/ sole making the patient difficult to walk. Secondary bacterial infection is common. Tumorous lesion
Patients who seek medical attention after many months usually present with very large tumorous lesions. This tumor may cover the most of the foot/ sole making the patient difficult to walk. Secondary bacterial infection is common.
Sinus tracts The middle of the lesion caves in, ulcerates to make a sinus tract which may secret serosanguineous or seropurulent discharge. It may contain white-to-yellow or black granules and pus. Most of the times multiple sinus tracts may occur in a single lesion. Sinus tracts
The middle of the lesion caves in, ulcerates to make a sinus tract which may secret serosanguineous or seropurulent discharge. It may contain white-to-yellow or black granules and pus. Most of the times multiple sinus tracts may occur in a single lesion.
Lymphadenopathy Rarely localized tender lymph node enlargement can be observed. Lymphadenopathy
Rarely localized tender lymph node enlargement can be observed.

Investigations - Diagnosis

Fact Explanation
Microscopic examination Etiological agent can be identified by microscopic examination. The colour of the grains may suggest the likely diagnosis; black grains suggest a fungal infection, minute white grains suggest nocardia and red grains are due to Actinomadura pelletieri. Larger white grains or yellow-white grains may be fungal or actinomycotic in origin. Microscopic examination
Etiological agent can be identified by microscopic examination. The colour of the grains may suggest the likely diagnosis; black grains suggest a fungal infection, minute white grains suggest nocardia and red grains are due to Actinomadura pelletieri. Larger white grains or yellow-white grains may be fungal or actinomycotic in origin.
Polymerase chain reaction (PCR) Species-specific diagnosis can be made by polymerase chain reaction and DNA sequencing. Polymerase chain reaction (PCR)
Species-specific diagnosis can be made by polymerase chain reaction and DNA sequencing.
Fine-needle aspiration FNAC FNAC of lesions using special stains may be useful for the diagnosis. Fine-needle aspiration FNAC
FNAC of lesions using special stains may be useful for the diagnosis.
X-ray The extent of the tumor into the underlying bones can be identified by X-rays.
A radiograph of the heel may reveal extensive loculated lytic areas of destruction within the body of the calcaneum and other affected bones with a typical "honeycomb" appearance. Radiography shows infiltration of soft tissue, associated more or less with bone resorption.
X-ray
The extent of the tumor into the underlying bones can be identified by X-rays.
A radiograph of the heel may reveal extensive loculated lytic areas of destruction within the body of the calcaneum and other affected bones with a typical "honeycomb" appearance. Radiography shows infiltration of soft tissue, associated more or less with bone resorption.
CT scan Multislice CT is highly useful for assessing osteoarticular damage. It shows a mass isodense to muscle, heterogeneous, which can contain denser rounded nodules that infiltrate the skin and the subcutaneous fat tissues. The affected muscles are thickened or partially destroyed. Enhancement is heterogeneous and moderate. CT is more sensitive than MRI for detecting osteoperiosteal damage and for early visualization of small cortical lesions. CT scan
Multislice CT is highly useful for assessing osteoarticular damage. It shows a mass isodense to muscle, heterogeneous, which can contain denser rounded nodules that infiltrate the skin and the subcutaneous fat tissues. The affected muscles are thickened or partially destroyed. Enhancement is heterogeneous and moderate. CT is more sensitive than MRI for detecting osteoperiosteal damage and for early visualization of small cortical lesions.
MRI scan MRI is the most helpful examination for a positive diagnosis and for staging mycetoma, which appears, in comparison to muscle, as a discrete hyperintense signal with T2 weighting and as a hypo- or isointense signal with T1 weighting. Contrast uptake after gadolinium injection is moderate and heterogeneous; the signal from the mycelial granules remains clearly hypointense. The characteristic appearance is that of an infiltrating mass made up of small cavities, hyperintense on T2 weighting, and circumscribed by hypointense fine partitions containing central dots, hypointense on all sequences and creating a nearly pathognomonic sign, called the “dot-in-circle”, especially useful when clinical, microbiological and histological findings are not determinative. MRI scan
MRI is the most helpful examination for a positive diagnosis and for staging mycetoma, which appears, in comparison to muscle, as a discrete hyperintense signal with T2 weighting and as a hypo- or isointense signal with T1 weighting. Contrast uptake after gadolinium injection is moderate and heterogeneous; the signal from the mycelial granules remains clearly hypointense. The characteristic appearance is that of an infiltrating mass made up of small cavities, hyperintense on T2 weighting, and circumscribed by hypointense fine partitions containing central dots, hypointense on all sequences and creating a nearly pathognomonic sign, called the “dot-in-circle”, especially useful when clinical, microbiological and histological findings are not determinative.
Biopsy Biopsy samples can be taken from small abscess or from the sinus tract. It may show extensive granulation tissue containing abscesses. Gram-negative septate hyphae are also visible. Eosinophilic material may be seen deposited around the granule. Actinomycotic grains contain very fine filaments. Biopsy
Biopsy samples can be taken from small abscess or from the sinus tract. It may show extensive granulation tissue containing abscesses. Gram-negative septate hyphae are also visible. Eosinophilic material may be seen deposited around the granule. Actinomycotic grains contain very fine filaments.

Management - Specific

Fact Explanation
Antifungal therapy In vitro antifungal sensitivity of organisms is not necessarily correlated with that of in vivo. So, the decision making regarding the most suitable antibiotic remains difficult. Single or combination treatment should be tried. Itraconazole
and Ketoconazole are most commonly used drugs in mycetoma. Streptomycin injections, Oral cotrimoxazole, Amikacin, Dapsone and Rifampicin can be tried in case of mycetoma.
Antifungal therapy
In vitro antifungal sensitivity of organisms is not necessarily correlated with that of in vivo. So, the decision making regarding the most suitable antibiotic remains difficult. Single or combination treatment should be tried. Itraconazole
and Ketoconazole are most commonly used drugs in mycetoma. Streptomycin injections, Oral cotrimoxazole, Amikacin, Dapsone and Rifampicin can be tried in case of mycetoma.
Surgical treatment Surgical resection with a wide surgical margin or Surgical debulking can be used in combination with the medical therapy. Rarely, amputation of the affected limb has to be done. Surgical treatment
Surgical resection with a wide surgical margin or Surgical debulking can be used in combination with the medical therapy. Rarely, amputation of the affected limb has to be done.

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