Canine Cushing's Disease: Long-term Quality of Life Management

Cushing's disease (hyperadrenocorticism) causes widespread physiological changes in dogs that significantly affect quality of life, requiring careful long-term medical management.

Key Facts

Cushing's disease results from excess cortisol, most commonly from a pituitary tumour (PDH, ~85%) or adrenal tumour (~15%).
Classic signs include pot-bellied appearance, hair loss, increased drinking and urination, skin thinning, and lethargy.
Affected dogs are at increased risk of diabetes, hypertension, pulmonary thromboembolism, and urinary infections.
Diagnosis requires ACTH stimulation testing, low-dose dexamethasone suppression test, and abdominal ultrasound.
Trilostane is the most widely used medical treatment, inhibiting cortisol synthesis with once or twice daily dosing.
Mitotane (o,p'DDD) is an alternative with a different mechanism and monitoring requirements.
Medical therapy requires lifelong treatment and monitoring — adrenal crisis from overdose can be life-threatening.
Pituitary-dependent Cushing's has a median survival of approximately 2 years with appropriate treatment.

Welfare Considerations

Untreated Cushing's disease causes progressive, multi-system welfare compromise. Chronic cortisol excess causes muscle wasting, abdominal enlargement that impairs comfortable lying, skin fragility with chronic infections, panting from metabolic heat, and the fatigue and weakness of ongoing endocrine dysfunction. Dogs are often miserable for months before diagnosis because owners attribute the signs to normal aging. Treatment with trilostane produces significant quality of life improvements — most owners report their dog "comes back to life" within weeks of starting treatment. However, the risk of adrenal crisis from treatment requires careful monitoring and owner education about signs requiring emergency care.

What You Can Do

Investigate unexplained pot-belly, hair loss, increased thirst, or recurrent skin infections in middle-aged dogs.
Request ACTH stimulation testing rather than relying on clinical signs alone for diagnosis.
Start trilostane at conservative doses with mandatory recheck at 10-14 days after initiation or dose change.
Educate yourself on signs of Addisonian crisis (weakness, vomiting, collapse) requiring emergency care.
Monitor drinking and urination at home as a proxy for cortisol control between veterinary rechecks.
Assess your dog's quality of life holistically — hair regrowth, improved energy, and reduced panting are positive indicators.