A challenging case: A German shepherd with a decreasing appetite and azotemia - Veterinary Medicine
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A challenging case: A German shepherd with a decreasing appetite and azotemia
Obtaining samples by using ultrasound guidance and re-reviewing results helped these clinicians identify a rare and easily overlooked disease.


VETERINARY MEDICINE


Fluconazole is a synthetic fungistatic triazole compound that penetrates the blood-brain, blood-prostate, and blood-ocular barriers well, and high drug concentrations are found in cerebrospinal fluid, urine, and ocular fluids. In addition, it is often used to treat systemic mycoses in cats when itraconazole is contraindicated or has been ineffective.24

Itraconazole, another synthetic fungistatic triazole compound that is widely distributed throughout the body, reaches high concentrations in the skin, sebum, and female reproductive tract and minimal concentrations in cerebrospinal fluid, urine, aqueous humor, and saliva. Paradoxically, fungal infections involving the central nervous system, prostate, or eyes often respond well to itraconazole. Adverse effects of itraconazole are dose-dependent and include gastrointestinal toxicity and hepatotoxicity.24

Ketoconazole, a less expensive imidazole antifungal agent, reaches high concentrations in the liver, adrenal glands, and pituitary gland and moderate concentrations in the kidneys, lungs, and bladder. Adverse effects include gastrointestinal signs, hepatotoxicity (cats are more prone), and thrombocytopenia.25

Amphotericin B, a macrolide antifungal agent, penetrates well into most tissues with the exception of the pancreas, muscle, bone, and aqueous humor. It must be administered intravenously and can be nephrotoxic.25

When dealing with invasive fungal diseases, it is important to administer antifungal therapy based on clinical signs until microbiologic identification is available. Antifungal therapy is typically required for several months.

In this dog, fluconazole would have been our treatment of choice because a high urine concentration is achieved. Amphotericin B would have been contraindicated because of its nephrotoxicity potential.

Paecilomyces species infection is an uncommon but devastating disease. To date, all cases with disseminated paecilomycosis have not responded favorably to treatment, although two dogs did achieve temporary remission. One dog was in remission for 12 weeks while being treated with amphotericin B and ketoconazole.8 A second dog temporarily responded to ketoconazole until it was euthanized nine months after initial diagnosis.16

Although our patient's lesions were not pathognomonic for fungal disease, it is recommended to further investigate urine fungal hyphae, particularly in German shepherds, because it may lead to an antemortem diagnosis of disseminated fungal disease. Early culture and sensitivity testing may offer assistance in determining effective antifungal therapy. An effective systematic approach and early diagnosis are paramount to potentially successfully treating paecilomycosis.

ACKNOWLEDGMENTS

We gratefully acknowledge John Keating, DVM, DACVP, for his assistance in providing the photomicrographs, helpful corrections, and suggestions. We also wish to thank Joyce Knoll, DVM, DACVP, for her assistance with the cytologic diagnosis.

Kristina Feigin, DVM
Dominique Penninck, DVM, DVSc, DACVR, DECVDI
Mary Anna Labato, DVM, DACVIM
Mark Acierno, DVM, DACVIM*
Department of Clinical Sciences
Cummings School of Veterinary Medicine
Tufts University
North Grafton, MA 01536

*Current address:
Department of Veterinary Clinical Sciences
School of Veterinary Medicine
Louisiana State University
Baton Rouge, LA 70803

REFERENCES

1. Chandler FW, Watts JC. Pathologic diagnosis of fungal infections. Chicago, Ill: ASCP Press, 1987.

2. Castro LG, Salebian A, Sotto MN. Hyalohyphomycosis by Paecilomyces lilacinus in a renal transplant patient and a review of human Paecilomyces species infections. J Med Vet Mycol 1990;28:15-26.

3. Van den Hoven E, McKenzie RA. Letter: suspected paecilomycosis in a dog. Aust Vet J 1974;50:368-369.

4. Patnaik AK, Liu SK, Wilkins RJ, et al. Paecilomycosis in a dog. J Am Vet Med Assoc 1972;161:806-813.

5. Jang SS, Biberstein EL, Slauson DO, et al. Paecilomycosis in a dog. J Am Vet Med Assoc 1971;159:1775-1779.

6. Littman MP, Goldschmidt MH. Systemic paecilomycosis in a dog. J Am Vet Med Assoc 1987;191:445-447.

7. Patterson JM, Rosendal S, Humphrey J, et al. A case of disseminated paecilomycosis in the dog. J Am Anim Hosp Assoc 1983;19:569-574.


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