CHAPTER 26 HYPERADRENOCORTICISM, CANINE 403
COMMENTS
Patient Monitoring (see each drug)
Response to therapy.
Use periodic ACTH stimulation test; test after the initial 7–10 days therapy to ensure
adequate response.
Repeat at 1, 3, and 6 months of maintenance therapy and every 3–6 months thereafter.
Adequacy of any necessary reloading period is monitored with an ACTH stimulation
test before higher maintenance dose initiated.
Depending on the cause (PDH versus ADH), clinical signs resolve within several days
to months of appropriate therapy.
L-deprenyl therapy: current label recommendations are to evaluate efficacy solely on
the basis of resolution of clinical signs of HAC; the ACTH stimulation test is not
indicated for assessing the response to treatment.Some clinicians perform a low-dose dexamethasone suppression test every 4–6 weeks
to evaluate for normalization (or improvement) of the pituitary-adrenal axis.
Expected Course and Prognosis
Untreated HAC: generally a progressive disorder with a poor prognosis.
Treated PDH: good prognosis; the average survival time for a dog is 2 years; at least
10% survive 4 years; dogs living longer than 6 years tend to die of causes unrelated
to HAC.Macroadenomas with neurologic signs: poor to grave prognosis.
Adrenal adenomas: usually a good to excellent prognosis.
Small carcinomas (not metastasized): fair to good prognosis.
Large carcinomas and ADH with widespread metastasis: generally poor to fair prog-
nosis; response to high doses of mitotane is occasionally seen.