© Kirrawee Veterinary Hospital FELINE DISEASES
Cryptococcosis
Cryptococcus neoformans is a yeast infection of cats which most
commonly effects the nasal cavity and sinuses. Cryptococcus is
readily found in the environment but has been associated with
bird droppings. Infection is mostly through inhalation of the
yeast. It can occur at any age and typically shows as sneezing,
snorting breathing, a nasal discharge which can range from serous
(clear) to mucopurulent (opaque) or blood stained. One or both
nostrils can be effected. As the condition progresses swelling
in the sinuses pushes out the frontal bones giving a "Roman nose"
appearance. The infection can spread to local lymph nodes (glands) producing
swelling, or in some cases spread locally through the cribriform
plate (back of the nasal cavity) to the brain producing a range
of neurological symptoms. Cats effected with cryptococcus don't
usually shows signs of generalized illness. Concurrent infection with Feline Leukaemia Virus is not uncommon
in clinically effected cats and this greatly reduces the chance
of recovery. Feline Immunodeficiency Virus does not appear to
significantly influence the outcome of cryptococcosis. Diagnosis can be difficult and requires identification of the
organism in a biopsy of the nasal lining. Swabs of the discharge
alone may not detect the presence of the yeast. A blood test is
also available, the latex cryptococcal antigen test (LCAT). This
test can be used both to identify infection and monitor response
to therapy. Treatment involves surgical removable of the bulk
of the infected material where possible and a prolonged course
of antifungal drugs. Ketoconazole at a rate of around 10mg/kg
for 2-3 months is a standard regime. Newer drugs which have also
been effective are itraconazole and fluconazole. The prognosis (outlook) for the nasal form of cryptococcosis is
quite good however where the brain involvement in present the
prognosis is grave. Related sites |