Phaeochromocytoma in dogs: episodic signs and diagnosis
11-year-old crossbreed dog with episodes of intense panting, restlessness, weakness and tachycardia that last minutes and resolve spontaneously. In the clinic systolic pressure is 210 mmHg on one reading and 150 mmHg on another. Ultrasound shows a right adrenal mass.
Which test is most useful to confirm the suspected phaeochromocytoma?
chevron_right Show answer and explanation
A. Measure adrenaline and noradrenaline in a single plasma sample in the clinic
Catecholamines are released episodically and have a very short half-life; clinic stress also raises them. A single sample is unreliable.
B. Perform a low-dose dexamethasone suppression test
It assesses hypercortisolism, not catecholamine secretion. Phaeochromocytoma is not diagnosed with cortisol axis tests.
C. Measure urinary normetanephrine (ratio to creatinine, collected at home) or plasma free normetanephrine
Correct. Metanephrines are metabolites produced continuously by the tumour and are more stable than catecholamines. A markedly raised normetanephrine strongly supports phaeochromocytoma; collecting urine at home avoids the effect of stress.
D. Perform an ultrasound-guided aspirate of the mass for cytology
Aspirating a possible phaeochromocytoma can trigger a hypertensive crisis, arrhythmias or haemorrhage, and cytology does not reliably determine the origin of the mass.
lightbulb Key takeaway
Suspect phaeochromocytoma with episodic signs (panting, tachycardia, collapse, intermittent hypertension) and an adrenal mass. Confirm with urinary or plasma normetanephrine, do not aspirate the mass, and prepare for surgery with alpha-blockade (phenoxybenzamine).
Test yourself with 10 random questions
Endocrinology · 100 questions, a different test every time
Related questions
Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.