Download - Subcutaneous Mycoses
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