Cushing's Disease (Pituitary Dependent) in Dogs: its Treatment with Cabergoline
V. Castillo; J. Lalia; N. Gomez
Hospital Escuela, Unidad endocrinologia y Clinica Medica de Pequenos Animales, Facultad de Ciencias Veterinarias, UBA, Chorroarin
The objective of this study was to prove the effectiveness of Cabergoline (Cbg), dopaminergic drug, to treat Cushing Disease (CD).
54 Dogs with CD were included in two groups: 1-Control group: 20 dogs treated with Ketoconazole, 20 mg/kg/day. 2-Cabergoline group (Cbg): 34 dogs treated with 0,1 mg/kg every 3 days. All these animals were evaluated with a longitudinal study for 4 years. The diagnosis and ulterior controls were carried out measuring: cortisol/creatinine ratio (RC/C normal range:5-65 cort /mg on three samples obtained in the morning, in the night and in the morning of the second day and measuring plasmatic ACTH obtained were between 10 AM to 2 PM. Both, cortisol and ACTH, were analyzed by radioimmune assay. Scan tomography (ST, multislice helicoidal equip of sellar and adrenal glands was performed in order to evaluate the size and shape of adenoma. Pituitary tumors were classified in intrasellar (smaller than 5 mm) and extra sellar (bigger than 6mm). Biochemical, clinical and endocrine controls were carried out every 4 months. Statistical analysis was done with Student T or Chi test when appropriate, with 0,05 of significance. Values were expressed as mean +/- SD and median and range.
Cbg (70%) had a good response to treatment (TR) and 30% did not (NTR). Survival Time for NRT was 1,3 years +/-2 months and survival time for TR was 5 years +/- 7 months at present moment. Tumor size average and area was 5,1 +/- 0,5 mm and 15,4 mm2 respectively at starting time of treatment and 3,5+/- 0,5 mm and 9,45 mm2 after a year of treatment showing significant differences of p < 0,03 (diameter) and p<0,01 (area) in respect to initial values. Between control and Cb groups there were significant differences of size (6,1 +/- 0,6, p<0,01) and tumoral area (26,1, p<0,001, Chi). Concentration of ACTH at the beginning of the study was 73,8 +/- 3,6 and 57,9 +/- 3,3after a year, p<0,001. In the control group ACTH did not show significant intragroup changes at the beginning of study (79,5 +/- 5,3) or at time of reappraisal (78,7 +/- 4,6) but differences (p<0,001) were present in the Cbg. C/C ratio showed significant differences (p<0,008) between initial values (134,9 +/- 1,1) and at the time of reappraisal (74,1 +/- 1,2) in Cb group and no differences between both groups (51,3 +/- 1,15) at the end of study. NTR dogs showed significantly larger tumor size than TR (6,7 +/- 0,9 vs 4,1 +/- 0,4, p< 0,01), being only intrasellars 4 out of 13 tumors in the NTR.
Cabergoline was effective in 70% of cases. A reduction in size of 31,4% in diameter and 38,6 % in area were observed and normalization of biochemistry endocrine values were also found. Cabergoline is useful in cases of tumors not larger than 5mm to control CD in dogs. Larger tumors did not respond due to a different behavior than those intrasellar