Pituitary-Dependent Hyperadrenocorticism Surgery in Dogs

Transsphenoidal hypophysectomy — surgical removal of a pituitary tumour — offers the possibility of cure for pituitary-dependent Cushing's disease in dogs, with welfare implications distinct from lifelong medical management.

Key Facts

Pituitary-dependent hyperadrenocorticism (PDH) accounts for approximately 85% of canine Cushing's disease cases
Trilostane and mitotane are the primary medical management options; they control signs but do not address the underlying tumour
Transsphenoidal hypophysectomy is performed at specialist referral centres and offers cure rates of approximately 85% in experienced hands
The surgery requires sophisticated neurosurgical expertise, fluoroscopy guidance, and intensive post-operative care
Post-surgical dogs require cortisone supplementation until the adrenal glands recover function — a period of several months
Diabetes insipidus requiring desmopressin supplementation is a common post-surgical complication requiring ongoing management
Dogs successfully treated surgically show resolution of polydipsia, polyphagia, hair regrowth, and muscle strengthening
Large pituitary macroadenomas have lower surgical cure rates and higher complication risks than microadenomas

Welfare Considerations

The welfare comparison between lifelong medical management and surgical cure of PDH is nuanced. Medical management with trilostane effectively controls signs but requires daily medication, regular monitoring, and does not prevent tumour growth — dogs with macroadenomas may develop neurological signs from tumour expansion. Successful hypophysectomy achieves true cure, eliminating the need for ongoing adrenocortical suppressant medication and allowing full return to normal adrenal physiology. The surgical risk is real and requires an honest informed consent discussion. For dogs with microadenomas and appropriate surgical candidacy, the welfare benefit of cure versus indefinite medical management can be substantial. Access to specialist centres capable of performing this surgery is limited, making referral pathways an important welfare infrastructure issue.

What You Can Do

Discuss all treatment options including surgical referral with your veterinarian when Cushing's disease is diagnosed
Research specialist centres offering transsphenoidal hypophysectomy if your dog is a potential surgical candidate
Ensure regular monitoring (LDDS tests, clinical assessment) for dogs on medical management to detect disease progression
Learn the signs of hypoadrenocorticism in post-surgical dogs — cortisone supplementation must not be stopped abruptly
Support veterinary neurology and endocrinology research that improves outcomes for dogs with pituitary disease