Iatrogenic symptomatic hypoadrenocorticism after treatment with trilostane for hyperadrenocorticism in dogs: eight cases (2008‐2019)

• Published in: Journal of small animal practice Vol. 64; no. 6; pp. 409 - 414
• Main Authors: Lamoureux, A., Cadoré, J. L., Hugonnard, M., Chabanne, L., Krafft, E.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2023; Wiley Subscription Services, Inc; Wiley
• Subjects: Adrenal glands; Adrenal Insufficiency - veterinary; Adrenocortical Hyperfunction - drug therapy; Adrenocortical Hyperfunction - veterinary; Animals; Diagnosis; Dihydrotestosterone - adverse effects; Dog Diseases - diagnosis; Dog Diseases - drug therapy; Dogs; Glucocorticoids; Hydrocortisone - therapeutic use; Iatrogenesis; Life Sciences; Medical records; Medical treatment
• ISSN: 0022-4510; 1748-5827
• DOI: 10.1111/jsap.13594

Objectives
Trilostane is the medical treatment of choice for hyperadrenocorticism. Iatrogenic hypoadrenocorticism is thought to be rare, with most cases being transient and only a few cases of permanent hypoadrenocorticism have been reported. This study reports findings from eight cases of iatrogenic hypoadrenocorticism and examines the presence of concurrent diseases at the time of diagnosis.
Materials and Methods
Medical records of dogs treated for hyperadrenocorticism with trilostane since 2008 were reviewed, and cases of clinical iatrogenic hypoadrenocorticism were extracted. Cases were considered permanent if long‐term replacement therapy was required.
Results
Eight dogs met the inclusion criteria. The time between the beginning of trilostane treatment and the diagnosis of hypoadrenocorticism ranged from 4 days to 13 months, and the dosage of trilostane ranged between 1 and 8 mg/kg/day. Six dogs had a suspicion of concurrent disease at the time of hypoadrenocorticism diagnosis. The trilostane dose was decreased in two dogs; trilostane was withdrawn in one case without further relapse of hyperadrenocorticism; and glucocorticoids with or without mineralocorticoid supplementation were prescribed in five dogs. Two of these five dogs were lost to follow‐up, and the other three had a diagnosis of permanent hypoadrenocorticism. Adrenal gland ultrasonography in these three dogs showed a progressive reduction in gland sizes with heterogeneous echogenicity.
Clinical Significance
Iatrogenic hypoadrenocorticism is a rare but potentially life‐threatening complication of trilostane treatment in dogs with hyperadrenocorticism. The occurrence of a concurrent disease might trigger the development of clinical signs of hypoadrenocorticism in previously subclinical dogs.