Transcript Systemic Fungal Infections
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 increased organic matter (soil and wood) http://www.familyvet.com/Dogs/Fungi.html
Blastomycosis: Clinical Signs
Dogs: Dyspnea Anorexia Depression Lameness Lymphadenopathy Skin Lesions +/- occular manifestations +/- Orchitis Cats: Dyspnea Nasal discharge Cough Lethargy Weight loss
**Pneumonia and weight loss are the most common presentations**
Blastomycosis
http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Articl e/detail/596603 Occular blastomycosis: Panophthalmitis http://www.njmoldinspection.com/vetmycology/vetblastomycosis.html
Cutaneous blastomycosis: Dermatitis
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 Lymphatic and Hematogenous Spread of spores Inflammation in skin, bones, LN’s, eyes, CNS, and/or reproductive tract Pyogranulomatous Inflammation within the lungs
Blastomycosis: Diagnosis
History, Clinical signs, and Diagnostic findings Definitive diagnosis must show the organism Cytology: TTW, BAL, LN aspirates, fluid from the anterior chamber of the eye, draining tracts, prostatic fluid, and CSF Never Culture Blastomyces because of danger to personnel http://www.pharmacy-and-drugs.com/illnessessimages/blastomycosis2.jpg
Blastomycosis: Diagnosis
Serology (AGID) is helpful if the organism cannot be definitively diagnosed.
- Sensitivity and Specificity > 90% Thoracic Radiographs indicated when respiratory signs present: - interstitial pattern - nodular interstitial pattern/diffuse miliary - tracheobronchial lymphadenopathy
Blastomycosis: Pyogranulomatous Inflammation
http://www.vet.uga.edu/vpp/clerk/mordecai/index.php
Nodular Interstitial Pattern/Diffuse Milliary Pattern Differentials
-Lymphoma -Fungal pneumonia -Pneumoconiosis -Hematogenous bacterial pneumonia -Metastases from thyroid or mammary carcinoma www.vet.uga.edu/vpp/clerk/mordecai/figure1.jpg
Blastomycosis: Fungal Granuloma Differentials
-Tumor metastases -Fungal granuloma -Parasitic granuloma -Abscesses -Lymphoma -Malignant histiocytosis -Lymphoid granulomatosis -Cysts/Fluid filled bullae http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/596603
Fungal Osteomyelitis: Blastomyces dermatitidis
http://cal.vet.upenn.edu/p rojects/saortho/chapter_3 7/37mast.htm
Fungal Osteomyelitis vs. Bone Tumors
http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20 341%20Lecture%207%20Musculoskeletal%20Part%201.
ppt#362,49,Fungal Osteomyelitis http://www.acvs.org/AnimalOwners/HealthConditions/SmallA nimalTopics/BoneTumorsinCatsandDogs/
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 (especially starlings) and bats 3 forms in dogs: pulmonary, disseminated, and subclinical Rare and progressive in cats
http://www.familyvet.com/Dogs/Fungi.html
Histoplasmosis: Clinical Signs
Dogs - coughing - dyspnea - anorexia - weight loss - depression - ascites - ulcerated oral and/or nasal 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 ingest microconidia or hyhae Conversion to yeast within the host Yeasts engulfed by macrophages and they replicate intracellularly Immune system is overwhelmed Clear infection Hematogenous and Lymphatic spread
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/cler k/edison/Fig4ADJ
Histoplasmosis: Diagnosis
Radiographs: - pulmonary interstitial pattern with miliary or nodular infiltrates - Abdomen: hepatomegaly, splenomegaly, and ascites - Gastogram: Barium highlights thickening of the intestinal wall and mucosa - Abdominal Ultrasound for gi thickening - Bone: osteolysis with periosteal proliferation Endemic areas: may see patients with calcification in the thorax or abdomen secondary to persistence of 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/c hapter_37/37F8.jpg
Histoplasmosis: Treatment
Iatroconazole: lower toxicity http://www.my-online-pharmacy.net/i/products/sporanox.jpg
Coccidiomycosis
Coccidioides immitis Soil in arid or semi-arid regions Virulent reputation Epidemics after rainy season followed by a drought
http://www.familyvet.com/Dogs/Fungi.html
Coccidiomycosis: Clinical Signs
Dogs - dyspnea - anorexia - cough - weight loss - lameness - draining tracts - abscesses - lymphadenopathy - meningitis Signs can range from flu-like symptoms to severe pneumonia when pulmonary tissue involved Can see extensive damage to bones, joints, skin, and CNS when dissemination occurs Fatal when immunocompromised
Coccidiomycosis: Pathogenesis
Inhalation of infective arthroconidia Deposition in the lung Microenvironment induces endosporulation Removed by mononuclear cells Endospores released Subclinical or clearance of organisms Immunocompromised patients Extensive lung damage Dissemination
Coccidiomycosis: Diagnosis
Cytology: exudate, TTW, LN or bone biopsy Wet mount with 10% KOH - endospores 2-5 um - spherules 10-100 um - mycelial form= dangerous Serology Radiographs: Thorax and bones
Coccidiomycosis: wet mount
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm
Coccidiomycosis
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm
Coccidiomycosis: Fungal osteomyelitis http://www.familyvet.com/Dogs/Fungi.html
Coccidiomycosis: fungal osteomyelitis http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm
Coccidiomycosis: Treatment
Ketoconazole: helps to prevent dissemination Iatroconazole www.amercianvetonline.com
References
http://www.vet.uga.edu/vpp/clerk/mordecai/index.php
http://www.familyvet.com/Dogs/Fungi.html
http://cal.vet.upenn.edu/projects/saortho/chapter_37/37mast.htm
http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/Bon eTumorsinCatsandDogs/ http://www.pharmacy-and-drugs.com/illnessessimages/blastomycosis2.jpg
http://veterinarymedicine.dvm360.com/vetmed/ArticleStandard/Article/detail/ 596603 http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51108.htm
http://www.vet.uga.edu/vpp/clerk/edison/Fig4ADJ.jpg
http://www.vet.uga.edu/vpp/clerk/edison/index.php
http://cal.vet.upenn.edu/projects/saortho/chapter_37/37F8.jpg
http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/51104.htm
http://www.vet.uga.edu/vpp/clerk/edison/index Songer, J.G., & Post, K.W. (2003). Veterinary Microbiology. St Louis: Elsevier.
http://www.acvs.org/AnimalOwners/HealthConditions/SmallAnimalTopics/Bon eTumorsinCatsandDogs/ http://people.upei.ca/lpack/vetrad/VCA%20341/VCA%20341%20Lecture%20 7%20Musculoskeletal%20Part%201.ppt#362,49,Fungal Osteomyelitis