Dr. N. M. Suryawanshi, MDAssistant Professor,

MIMSR Medical College, Latur.

Subcutaneous MycosesMycetoma & Rhinosporidiosis

• Heterogeneous group of fungal infections

characterized by development of clinical

lesions in subcutaneous tissues at the

site of inoculation of etiological agents.

• Disease process starts following trivial

trauma

Introduction

• Mycetoma

• Rhinosporidiosis

• Sporotrichosis

• Chromoblastomycosis

• Phaeohyphomycosis

• Lobomycosis

Subcutaneous Mycoses

• Slowly progressive, chronic

granulomatous infection of skin &

subcutaneous tissues with

involvement of underlying fasciae &

bones usually affecting extremities.

Mycetoma

• Characterized by triad of

– Tumefaction of affected tissue

– Multiple draining sinuses

– Oozing granules

• Madura foot / Maduramycosis

Madura foot

Caused by two groups

•Eumycetoma

– Eumycetes i.e. true fungi

•Actinomycetoma

– Actinomyctes i.e. aerobic

filamentous bacteria

Causative agents

•Fungal agents– Madurella mycetomatis– Madurella grisea Black grain

eumycetoma

– Exophiala jeanselmei– Curvularia geniculata

– Pseudallescheria boydii– Aspergillus nidulans White grain

eumycetoma

– Acreonium falciforme– Fusarium species

Causative organisms

•Bacterial agents– Actinomadura madurae– Actinomadura pelletieri– Nocardia brasiliensis– Nocardia caviae– Nocardia asteroides– Nocardiopsis dassonvillei– Streptomyces somaliensis

Causative organisms

• Prevalent in almost all parts of the

world

• More common in tropical & subtropical

countries

• In India

– Tamil Nadu

– Rajasthan

Epidemiology

• More prevalent in developing countries

• Incidence is more in rural areas

• Common in 20 to 40 years

• Common in men than women

• Occupational groups farmers, carpenters,

land workers

• Habit of working barefooted

Epidemiology

Introduction of causative agents• Mycetoma of extremities

– Thorn-prick injury

• Mycetoma of Ear– Use of wicks for removal of earwax

• Mycetoma of back– Carrying wood, grain bags, stone on back

• Mycetoma of head & neck– Carrying bundles of wood on head & neck

Pathogenesis

• After introduction disease evolves slowly

• Organisms are usually found in the center

of microabscess formed by PMN cells

• Main characteristic is the presence of

large aggregates of filaments of causative

organisms

Pathogenesis & Pathology

• Characterized by triad of

– Tumefaction i.e. Tumor-like swelling

– Formation of multiple draining sinuses

– Grains/granules oozing from sinuses

• Painless localized swollen lesions

• Sinuses discharge serous, sero-

sanguineous or purulent fluid

Clinical features

• Mainly affects feet but hands, shoulder,

buttocks, scalp have also been reported

• Disease progresses slowly takes often years

• Spreads by contiguity & continuity destroying

surrounding structures except tendons &

nerves

• Hematogenous spread seen in Nocardia &

Streptomyces species

• Detailed & proper history

– Occupation

– Trauma

– Geographical area of patient

Laboratory diagnosis

• Usually grains or granules

• Pus

• Exudates

• Biopsy

Sample

• Lesions cleaned thoroughly with antiseptics

• Grains are collected by pressing sinus from

periphery to enhance discharge

• Discharge collected on sterile gauze

• Alternatively, can be collected with loop

• If more grains needed, flap of orifice of sinus

are opened & collected in sterile petri dish

Collection of sample

• Size

• Shape

• Texture

• Colour

• Cement-like matrix

Gross examination of grains

Characteristics of grainsFungal agents Texture Size mm Shape Cement-like

matrix

1. Black grain Eumycetoma

Madurella mycetomatis Hard 0.5-5.0 Oval, lobed

Present

Madurella grisea Soft 0.3-0.6 Oval, lobed

Present

Exophiala jeanselmei Soft 0.2-0.3 Irregular Absent

Curvularia geniculata Hard 0.5-1.0 Oval Present

2. White grain Eumycetoma

Pseudallescheria boydii Soft 0.5-1.0 Oval, lobed

Absent

Aspergillus nidulans Soft 1.0-2.0 Oval Absent

Acremonium falciforme Soft 0.2-0.5 Oval Absent

Fusarium species Soft 0.2-0.6 Oval Absent

Characteristics of grains

Bacterial agents Colour Size mm

Actinomadura madurae White, yellow 2.0

Actinomadura pelletieri Pink, red 0.5

Nocardia brasiliensis Yellowish-white < 0.5

Nocardia caviae White-yellow < 0.5

Nocardia asteroides White-yellow < 0.5

Streptomyces somaliensis Yellowish white 1.0

KOH examination• Eumycotic grains

– Thick, 2-6 µm wide hyphae with large cells upto 15 µm at margin with or without chlamydospores

• Actinomycotic grains– Thin, 0.5- 1 µm wide filaments with

coccoid or bacillary forms

Microscopic examination

Gram stain– Gram-positive branching

filamentous bacteria embedded in grain material

Modified ZN stain (Kinyoun’s method with 1% H2SO4)– Pink colored filamentous bacteria

i.e. Nocardia spp.

Stains

When Actinomycetoma is suspected• Grains are washed with normal saline

without antibiotics – SDA without antibiotics– Blood agar– LJ media– BHI agar

When Eumycetoma is suspected• Grains are washed with normal saline with

antibiotics – Emmon’s modified SDA (SDA with antibiotics like

gentamicin, chloramphenicol )

Culture

Agents Colony Stain

Bacterial Agents

- Actinomadura Dry, wrinkled ,hard GM Positive, non Fragmented

madurae filaments

- Nocardia Dry,yellow-orange,chlaky, GM positive

branched filaments, brasiliensis fragment to form acid

fast bacilli

- Streptomyces Wrinkled, show yellow and GM positive branched filaments,

somaliensis brown sectoring non-fragmentary to form non-acid fast bacilli

Agents Colony LCB /stain

Fungal Agents - Madurella O- folded, leathery, Septate hyphae with

chalamydospores Mycetomatis white to yellow pointed conidiophore, flask-shaped

R- Dark – brown phialides with ovoid conidia

- M. grisea O- folded, leathery, gray Brown septate hyphae, arthrospores R- brown-black in chains

- Exophiala O- velvety black Pigmented hyphae, tapering

jeanselmei R- black Conidiophores with aggregates of oval conidia

- Curvularia O- Floccose brown black Conidiophores bearing transversely

geniculata R- Black septate, conidia, slightly curved

with large central cell

• Complement fixation test

• Immunodiffusion test

• Counterimmunoelectrophoresis

• ELISA

• Western blot

Immunodiagnosis

Eumycetoma– Oral ketoconazole 200 mg BD &

Itraconazole 100 mg BD for 8-24 months– Amphotericin B

Actinomycetoma– Co-trimoxazole– Tetracycline– Streptomycin– Amoxycillin-clavulanate– Amikacin

Treatment

• Chronic granulomatous disease of

mucous membrane characterized by

polyposis of nasal cavity, conjunctiva &

other body sites

• Causative agent

– Rhinosporidium seeberi

Rhinosporidiosis

3 principle stages

• Maturation of

trophocyte

• Development of

sporangia

• Production of

endospores

Life cycle

• Trophic stage in tissue

• Rounded or oval structure, 6-8 µm size with

cytoplasm, cell membrane, nucleus & nucleolus

• Mitotic division

• Increase in size (140 µm) & wall thickness

• Develops into sporangium containing

approximately 12,000 – 16,000 endospores

• Sporangium has outer chitinous & inner cellulose

membrane with germinal spore eccentrically

Release of endospores

Release occurs by two ways

• When inside pressure is high

– sporangium ruptures at weak point of wall

• When it is not high

– spores are released one by one through pore

• After release enter in surrounding tissue and

enter in connective tissue or carried by

lymphatics .

• Generally prevalent in India, Sri lanka,

Argentina & Brazil

• In India

– Tamil Nadu, Kerala, Pondicherry, Andhra

Pradesh, West Bengal & Chhattisgarh

• Fresh & stagnant water act as reservoir of

infection

Epidemiology

Epidemiology

• Age distribution:20-40 yrs

• Sex distribution :M >F

• Sites: Nose, Eyes, Skin, genitals

• Predisposing Factors:

Common in people who take bath along with

domestic animals in polluted water with acid PH

which favours growth of fungus

• Risk occupations: Paddy cultivators, Sand

workers

Clinical features

• Nasal Rhinosporidiosis

– Friable polypoid, vascular lesion, Bleed easily

– Papillary projections & lobules give raspberry, stawberry or

cauliflower-like appearance

– Epistaxis, unilateral nasal obstruction, foreign body sensation

• Occular Rhinosporidiosis

• Cutaneous Rhinosporidiosis

• Miscellaneous Rhinosporidiosis (genital

rhinosporidiosis)

Rhinosporidiosis of nose & eye

Laboratory diagnosis• Specimen

– Dischage / biopsy

• Collection and Transport

– Nasal washings collected by pushing saline and

aspirating back

• Microscopic exam

– Histopathological examination is important

– Hyperplastic connective tissue

– Sporangium with thick hyaline wall of size 200-300

µm in diameter filled with endospores

• Not possible to grow on artificial culture

media

• Can grow in vivo in an epithelial carcinoma

cell culture lines

• No serological tests available

Culture

• Radical surgery

• Dapsone-DDS for recurrent cases

Treatment