|
Test Name: Diagnosis of Cushing’s Disease (Differentiation between Adrenal and Pituitary Forms)
Species: Dog
Material Required: 1 ml morning urine
Duration: 1–2 weeks
Parameters Measured: Cortisol, Creatinine
Execution Protocol
- Day 1: Collect morning urine (Sample 1)
- Day 2:
- Collect morning urine (Sample 2)
- Administer dexamethasone orally: 3 doses of 0.1 mg/kg body weight throughout the day
- Day 3: Collect morning urine (Sample 3)
Assessment Criteria
Ratio of Day 1 to Day 2:
- < 40: Normoadrenocorticism — Cushing’s disease unlikely
- 40–60: Questionable result
- > 60: Hyperadrenocorticism possible; recommend confirmation via low-dose dexamethasone suppression test
Ratio of Day 3 (Prerequisite: elevated ratios on Day 1 and Day 2):
- > 50% of the average value of Day 1 and Day 2: Suggests cortisol-producing adrenocortical tumour; nonsuppressible pituitary Cushing’s disease also possible
- < 50% of the average value of Day 1 and Day 2: Indicates pituitary-dependent Cushing’s disease or other causes of elevated cortisol (e.g. diabetes, stress, gastrointestinal disease, protein-losing conditions)
|
