Catecholamines - Urine

General Information

Catecholamines are biogenic amines that serve as neuronal or hormonal signals in a wide range of physiological processes. Dopamine and noradrenaline function as neurotransmitters in the brain and peripheral sympathetic nerves while adrenaline functions as a hormone released by the adrenal medulla. Catecholamines are critical in maintaining the body's homeostatis and in responding to acute and chronic stress.

A phaeochromocytoma is a rare (0.1-1.0 % of hypertensive population), catecholamine-secreting tumor derived from chromaffin cells. When such tumors arise outside of the adrenal gland, they are termed extra-adrenal phaeochromocytomas, or paragangliomas. Because of excessive catecholamine secretion, phaeochromocytomas may precipitate life-threatening hypertension or cardiac arrhythmias. If the diagnosis of a phaeochromocytoma is overlooked, the consequences can be disastrous, even fatal; however, if a pheochromocytoma is found, it is potentially curable. Phaeochromocytomas are often associated with other endocrine tumours.

Symptoms of phaeochromocytoma are due to catecholamine excess and include:

• Sustained or paroxysomal hypertension
• Weight loss
• Sweating
• Headache
• Palpitations
• Anxiety

Since the secretion of the catecholamines, and hence the symptoms, from a phaeochromocytoma may be paroxysmal (i.e. short and frequent) it is recommended that 3 successive 24 hour urine collections are performed to 'catch' the catecholamine secretion and hence ensure the correct diagnosis.

Measurement of urinary metadrenaline and normetadrenaline will also be performed on all samples.