Hyperadrenocorticism (Cushing's syndrome) is one of the most common endocrine conditions in older dogs. Caused by excess cortisol production, it causes a characteristic constellation of signs that significantly impair quality of life if untreated.
Dogs with uncontrolled Cushing's syndrome experience progressive weakness from muscle catabolism, excessive thirst causing constant urination that disrupts sleep, thinning skin prone to infection and injury, and pot-bellied discomfort. Panting and restlessness from excess cortisol affect sleep quality and resting behaviour. Pulmonary thromboembolism — a serious complication of hyperadrenocorticism — causes sudden breathlessness and is life-threatening. Trilostane treatment normalises cortisol within weeks in responsive cases, improving quality of life markedly. Welfare monitoring requires regular ACTH stimulation testing to ensure trilostane dosing is appropriate — under-treatment leaves dogs symptomatic while over-treatment causes adrenocortical insufficiency.