Systemic Fungal Infections

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Systemic Fungal Infections

in Small Animals

Colleen Hock

May 12, 2010

http://atlas.arabslab.com/data/8/blasto10.gif



The Mycotic Agents

Blastomyces dermatitidis

Histoplasma capsulatum

Coccidioides immitis

– All are dimorphic (mold and yeast forms)

– Cause primarily respiratory disease by

evasion of the host immune response



Blastomycosis

Blastomyces dermatitidis

South east, south central, and upper

midwest near river valleys and lakes

Moist and shaded areas with increasedorganic matter (soil and wood)

http://www.familyvet.com/Dogs/Fungi.html



Blastomycosis: Clinical Signs

Dogs: Dyspnea Anorexia

DepressionLamenessLymphadenopathySkin Lesions

+/- occularmanifestations+/- Orchitis

Cats: DyspneaNasal dischargeCough

LethargyWeight loss

**Pneumonia and weight loss are the

most common presentations**



Blastomycosis

Occular blastomycosis:Panophthalmitis

http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/596603

http://www.njmoldinspection.com/vetmycology/vetblastomycosis.html

Cutaneous blastomycosis:Dermatitis

http://www.njmoldinspection.com/vetmycology/blasto1.jpg



Blastomycosis: Pathogenesis

Inhale spores

Deposit in the alveoli

Acute Pulmonary Phase

Self-limiting control

of asexual reproduction Asexual budding, not eliminated

by the immune system OR the patient

is immunocompromised

PyogranulomatousInflammation within

the lungs

Lymphatic and HematogenousSpread of spores

Inflammation in skin, bones, LN’s,eyes, CNS, and/or reproductive tract



Blastomycosis: Diagnosis

History, Clinical signs, and Diagnosticfindings

Definitive diagnosis must show the organism

Cytology: TTW, BAL, LN aspirates, fluidfrom the anterior chamber of theeye, draining tracts, prostatic

fluid, and CSF Never Culture Blastomyces because of

danger to personnel

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Blastomycosis: Diagnosis

Serology (AGID) is helpful if the organismcannot be definitively diagnosed.

- Sensitivity and Specificity > 90% Thoracic Radiographs indicated when

respiratory signs present:- interstitial pattern

- nodular interstitial pattern/diffuse miliary

- tracheobronchial lymphadenopathy



http://www.vet.uga.edu/vpp/clerk/mordecai/index.php

Blastomycosis: Pyogranulomatous

Inflammation



Nodular InterstitialPattern/Diffuse Milliary Pattern

www.vet.uga.edu/vpp/clerk/mordecai/figure1.jpg

Differentials-Lymphoma-Fungalpneumonia

-Pneumoconiosis-Hematogenousbacterialpneumonia-Metastases fromthyroid or

mammarycarcinoma



Blastomycosis: Fungal

Granuloma


Differentials-Tumor metastases-Fungal granuloma

-Parasitic granuloma-Abscesses-Lymphoma-Malignant histiocytosis-Lymphoid granulomatosis-Cysts/Fluid filled bullae



Fungal Osteomyelitis:Blastomyces dermatitidis

http://cal.vet.upenn.edu/p

rojects/saortho/chapter_37/37mast.htm



Fungal Osteomyelitis vs. Bone Tumors

http://www.acvs.org/AnimalOwners/HealthConditions/SmallA nimalTopics/BoneTumorsinCatsandDogs/

http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20

341%20Lecture%207%20Musculoskeletal%20Part%201.ppt#362,49,Fungal Osteomyelitis



Blastomycosis: Treatment

Amphotercin B- IV, nephrotoxic

- Lipid soluble form that is less toxic Iatroconazole

- less toxic

- oral administration- more expensive

http://www.cvs.com/CVSApp/images/health/A1055050.JPG



Histoplasmosis

Histoplasma capsulatum

Found in soil near avian species (especiallystarlings) and bats

3 forms in dogs: pulmonary, disseminated,and subclinical

Rare and progressive in cats




Histoplasmosis: Clinical

Signs Dogs

- coughing- dyspnea- anorexia

- weight loss- depression- ascites- ulcerated oral and/ornasal mucosa

- anemia

- lymphadenopathy- thrombocytopenia- fever- diarrhea

Cats- weight loss- lethargy- fever (fluctuant)

http://cat.uab.cat/Publications/2005/SEP05/starlings.jpg



Histoplasmosis: Pathogenesis

Inhale or ingestmicroconidia or hyhae

Conversion to yeast within the host

Yeasts engulfed by macrophagesand they replicate intracellularly

Immune system isoverwhelmed

Hematogenous andLymphatic spread

Clear infection



Histoplasmosis: Diagnosis

Cytology: exudates, TTW, FNA (LN’s),

and Bone Marrow

Histopathology

Serology

Blood smear

http://www.google.ca/imgres?imgurl=http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ



Histoplasmosis: Diagnosis

Radiographs:- pulmonary interstitial pattern withmiliary or nodular infiltrates

- Abdomen: hepatomegaly, splenomegaly, andascites

- Gastogram: Barium highlights thickening of theintestinal wall and mucosa

- Abdominal Ultrasound for gi thickening- Bone: osteolysis with periosteal proliferation

Endemic areas: may see patients with calcificationin the thorax or abdomen secondary to persistenceof the organism



Histoplasmosis

http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ.jpg



Histoplasmosis

http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51108.htm



Histoplasmosis

http://www.vet.uga.edu/vpp/clerk/edison/index.php



Histoplasmosis: Fungal

osteomyelitis

http://cal.vet.upenn.edu/projects/saortho/chapter_37/37F8.jpg



Histoplasmosis: Treatment

Iatroconazole: lower toxicity

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Coccidiomycosis

Coccidioides immitis

Soil in arid or semi-arid regions

Virulent reputation Epidemics after rainy season followed by a

drought




Coccidiomycosis: Clinical Signs

Dogs- dyspnea- anorexia- cough- weight loss- lameness- draining tracts- abscesses- lymphadenopathy

- meningitis

Signs can range fromflu-like symptoms tosevere pneumoniawhen pulmonary tissueinvolved

Can see extensivedamage to bones, joints, skin, and CNSwhen dissemination

occurs Fatal when

immunocompromised



Coccidiomycosis: Pathogenesis

Inhalation of infectivearthroconidia

Deposition in the lung

Microenvironment inducesendosporulation

Endospores released

Removed bymononuclear cells

Subclinical or clearance of organisms

Immunocompromised patients

Extensive lungdamage

Dissemination



Coccidiomycosis: Diagnosis

Cytology: exudate, TTW, LN or bonebiopsy

Wet mount with 10% KOH- endospores 2-5 um- spherules 10-100 um- mycelial form= dangerous

Serology

Radiographs: Thorax and bones



Coccidiomycosis: wet mount




Coccidiomycosis




Coccidiomycosis: Fungal

osteomyelitis




Coccidiomycosis: fungalosteomyelitis

http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm



Coccidiomycosis: Treatment

Ketoconazole: helps to prevent

dissemination Iatroconazole

www.amercianvetonline.com

http://www.google.ca/imgres?imgurl=http://americanvetonline.com/vetstore/images/Ketoconazole200mg.jpg&imgrefurl=http://americanvetonline.com/vetstore/index.php%3Fmain_page%3Dindex%26cPath%3D&usg=__uwJF50a2AA7D5H4LhHHBLcDySWk=&h=420&w=420&sz=35&hl=en&start=5&um=1&itbs=1&tbnid=8csaZoV86rGFYM:&tbnh=125&tbnw=125&prev=/images%3Fq%3Dketoconazole%26um%3D1%26hl%3Den%26sa%3DN%26rls%3Dcom.microsoft:en-us:IE-SearchBox%26rlz%3D1I7SKPB_en%26tbs%3Disch:1





Systemic mycoses

•Systemic mycoses are fungalinfections affecting internal organs

In the right circumstances the fungi

enter thebody via the lungs throughthe gut,paranasalsinuses or skin.

The fungi can then spread via the

bloodstream to multiple organs including the skin, oftencausing

multiple organs to fail and eventually

resulting in the death of the patient



Histoplasmosis•

Histoplasma capsulatuma dimorphic fungus exists as a mold in soil and asa yeast intissues.• It forms 2 types :- Macroconidia (finger like projection) imp. Indiagnosis- Microconidia (smooth wall spores) if inhaled

transmit the infection



Systemic Fungal InfectionsFungus Specimen Source Aspergillis spp. Respiratory secretions, skin, bone, oropharyngealulcers, prostate

Blastomyces dermatitidis Respiratory secretions, skin, bone, oropharyngealulcers, prostateCandidia albicans Respiratory secretions, blood, stool, transtrachealaspiration, CSF, bone, peritoneal fluid, urineCoccidioides immitis Respiratory secretions, skin, bone, CSF, synovialfluid, urine

Cryptococcus neoformans Respiratory secretions, skin, bone, CSF, synovialfluid, urineHistoplasma capsulatum Respiratory secretions, bone marrow, blood, urine,skin, CSF, eye, pleural fluid, liverNocardia spp. Respiratory secretions, skin, blood, brain,conjunctiva, bone

Paracoccidiodes brasiliensis Respiratory secretions, biopsy, lesions, pusRhizopus Respiratory secretions, skin, nose, brain, stool, eye,woundsScedosporium apiospermum Respiratory secretions, skin, corneaSporothrix schenckii Respiratory secretions, skin, subcutaneous tissue,sinuses, bone marrow, CSF, synovial fluid, lymph

f



References http://www.vet.uga.edu/vpp/clerk/mordecai/index.php



http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/BoneTumorsinCatsandDogs/

http://www.pharmacy-and-drugs.com/illnessessimages/blastomycosis2.jpg







http://www.vet.uga.edu/vpp/clerk/edison/index Songer, J.G., & Post, K.W. (2003). Veterinary Microbiology. St Louis: Elsevier.


http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20341%20Lecture%207%20Musculoskeletal%20Part%201.ppt#362,49,Fungal Osteomyelitis














http://www.vet.uga.edu/vpp/clerk/edison/index





http://www.vet.uga.edu/vpp/clerk/edison/index


















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Systemic Fungal Infections