Page 95 - Clinical Small Animal Internal Medicine

7 Pituitary-Dependent Hyperadrenocorticism in Dogs and Cats 63

that series of 181 dogs with PDH, mean tumor height the continued collections of tumor tissue allowing for
VetBooks.ir was 6 mm, mean width 6.2 mm, and mean height 5.4 mm additional studies regarding pathogenesis and novel
therapies for both man and pets.
with a median P/B ratio of 0.3.
Forty‐three percent of the dogs had a normal P/B ratio.
Interestingly, Hanson et al. concluded that pituitary size
(height) was the most significant predictor of postopera­ Prognosis
tive survival and mortality. In those studies, initial remis­
sion of PDH occurred in 85% of dogs with relapse in 28% With medical treatment, survival time after diagnosis
by three years. of PDH ranges from two to 61 months (mean 26.9
Similarly, Hara et al. evaluated outcomes in 25 dogs months; median,25 months). Another study evaluating
that had TSH using the protocol of Meij et al. Median ketoconazole found that after diagnosis, 50% of the
P/B ratio was 0.38 (range 0.24–0.71) with 24% of dogs dogs died approximately 1.8–2 years (range 0.6–3)
having a normal P/B ratio. Initial remission was attained after starting therapy. A recent study evaluated sur­
in 84% with 12% of dogs having relapse within four years. vival times in dogs left untreated for PDH. Median sur­
Survival at one, two, three, and four years was 92%, 81%, vival time for the trilostane group was not reached
81%, and 81%. No data on DFI were reported. (95% confidence interval 443 days–not applicable)
Continued experience with surgery for pituitary and was significantly longer than the 506 days (95%
tumors in both dogs and cats will be important not only confidence interval 292–564 days; P = 0.016) for the
in improving survival and DFI, but it will also allow for untreated group.

Further Reading

Arenas C, Melián C, Pérez‐Alenza MD. Long‐term survival hypercortisolism treated with trilostane. Vet Rec 2015;
of dogs with adrenal‐dependent hyperadrenocorticism: a 176(2): 49–54.
comparison between mitotane and twice daily trilostane Lottati M, Bruyette DS. Outcomes of the addition of
treatment. J Vet Intern Med 2014; 28(2): 473–80. pasireotide) to traditional adrenal‐directed treatment
Burkhardt WA, Boretti FS, Reusch CE, et al. Evaluation of for dogs with pituitary‐dependent hyper­
baseline cortisol, endogenous ACTH and cortisol/ adrenocorticism secondary to macroadenoma:
ACTH ratio to monitor trilostane treatment in dogs 9 cases (2013–2015). J Am Vet Med Assoc 2018;
with pituitary‐dependent hypercortisolism. J Vet Intern 252: 1403–8.
Med 2013; 27: 919–23. Macfarlane L, Parkin, T, Ramsey I. Pre‐trilostane and
Fracassi F, Corradini S, Floriano D, et al. Prognostic factors three‐hour post‐trilostane cortisol to monitor trilostane
for survival in dogs with pituitary‐dependent therapy in dogs. Vet Rec 2016; 179; 597.