Case 10

Choosing itraconazole or fluconazole in this case makes sense since Histoplasma species has a cell wall that will be sensitive to inhibition of ergosterol synthesis. Other drugs such as amphotericin and terbinafine may be considered as well but may be more expensive. Azoles would not be helpful against an organism such as Pythium species, for example, since it lacks a significant concentration of membrane ergosterol (although it may work synergistically with terbinafine).

Your plan for Max at this time is to discontinue the clindamycin and begin fluconazole at a dosage of 10 mg/kg given orally every 12 hours with food. Because of your concerns about possible side effects from the medication (anorexia, vomiting, elevated liver enzyme activities), you recommend that Max return in one to two weeks for a recheck examination and CBC and serum chemistry profile.

In the meantime, you recommend that the owners monitor Max's respiratory pattern closely at home and inform you of any changes. Drug therapy will take some time to work, so you inform the owners that Max may not show response to therapy for seven to 10 days.

QUESTION 5

The owners ask about the risk of infection for their other cat and the risk H. capsulatum poses to them. How do you respond?

a) They should consider boarding Max until he has completed his treatment to limit his contact with them and the other cat.

b) Since we don't know how Max became infected, it is hard to know for sure. Since potted houseplants have been implicated, they can consider either removing the plants from the house or repotting them (while wearing a mask). Cat-to-cat and cat-to-human transmission has not been reported.

c) As long as the cats do not share a litter box and the owners wear masks while cleaning the litter boxes, there should not be a concern.

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