Retrospective analysis of abnormal 24-h urinary free catecholamine concentration in screening for phaeochromocytoma

Ann Clin Biochem. 2003 May;40(Pt 3):283-5. doi: 10.1258/000456303321610628.

Abstract

Background: Patients with hypertension often have increased 24-h excretion of urinary free catecholamines (UFCA) compared with normotensive patients, but the extent to which beta-blockade and other antihypertensive agents affect 24-h UFCA concentrations remains unclear. Consequently, many patients with slightly elevated 24-h UFCA concentrations are not adequately investigated for the presence of phaeochromocytoma.

Method: We undertook a retrospective study on patients with at least one abnormal 24-h urinary collection of adrenaline (Adr), noradrenaline (NA) or dopamine (DA) between July 1997 and December 1999 to assess these issues.

Results: Of the 168 patients identified with raised 24-h UFCA concentrations, 106 with hospital notes were audited. Of the 46 patients whose values were more than twice the upper reference limit, 24 had their result confirmed with a repeat sample and only 10 underwent computed tomography or m-iodobenzylguanidine scanning. Two patients of these 10 had a phaeochromocytoma. We observed that hypertension correlated with significantly increased NA excretion compared with normotensive patients (median value 490+/-222 nmol per 24 h versus 304+/-229 nmol per 24 h, P<0.005). Patients on beta-blockers showed a trend towards significantly increased NA excretion (P=0.08).

Conclusions: Many patients with abnormal 24-h UFCA excretion are not thoroughly investigated for the presence of phaeochromocytoma. NA concentration is significantly raised above the reference limit for patients with hypertension, and the use of beta-blockers showed a trend towards a further elevation in NA concentrations. Care must therefore be taken when interpreting abnormal NA concentrations in patients with hypertension or in those taking beta-blockers.

MeSH terms

  • Adrenal Gland Neoplasms / complications
  • Adrenal Gland Neoplasms / diagnosis*
  • Adrenal Gland Neoplasms / urine
  • Analysis of Variance
  • Antihypertensive Agents / therapeutic use
  • Biological Clocks
  • Calcium Channel Blockers / therapeutic use
  • Catecholamines / urine*
  • Dopamine / urine
  • Epinephrine / urine
  • Humans
  • Hypertension / complications
  • Hypertension / drug therapy*
  • Hypertension / urine
  • Norepinephrine / urine
  • Pheochromocytoma / complications
  • Pheochromocytoma / diagnosis*
  • Pheochromocytoma / urine
  • Retrospective Studies

Substances

  • Antihypertensive Agents
  • Calcium Channel Blockers
  • Catecholamines
  • Dopamine
  • Norepinephrine
  • Epinephrine