Evaluation of the clonidine suppression test in the diagnosis of phaeochromocytoma

• Published in: Journal of human hypertension Vol. 25; no. 7; pp. 451 - 456
• Main Authors: MCHENRY, C. M, HUNTER, S. J, MCCORMICK, M. T, RUSSELL, C. F, SMYE, M. G, ATKINSON, A. B
• Format: Journal Article
• Language: English
• Published: Basingstoke Nature Publishing Group 01.07.2011
• Subjects: Adrenal Gland Neoplasms - blood; Adrenal Gland Neoplasms - diagnosis; Antihypertensive Agents; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Catecholamines; Catecholamines - blood; Clonidine; Computed tomography; Controlled conditions; Coronary heart disease; CT imaging; Diagnosis; Diagnostic Tests, Routine; Drug therapy; Epinephrine; Epinephrine - blood; Female; Health aspects; Heart; Humans; Hypertension; Liquid chromatography; Male; Medical sciences; Middle Aged; Neuroendocrine tumors; Norepinephrine; Norepinephrine - blood; Patients; Pheochromocytoma; Pheochromocytoma - blood; Pheochromocytoma - diagnosis; Plasma; Retrospective Studies; Sensitivity and Specificity; United Kingdom; Imidazoline receptor; α2-Adrenergic receptor; Hypertension; Imidazole derivatives; Agonist; Antihypertensive agent; Cardiovascular disease; α-Adrenergic receptor agonist; Clonidine; clonidine suppression testing; phaeochromocytoma; Diagnosis
• ISSN: 0950-9240; 1476-5527
• DOI: 10.1038/jhh.2010.78

The aim of this study is to review the experience of the clonidine suppression test in a regional endocrine centre and to compare the diagnostic sensitivity and specificity using various previous published criteria. The design used is retrospective study. The subjects include 56 patients in whom clonidine suppression tests had been performed from 1995 to 2000: 15 with phaeochromocytoma and 41 patients in whom the diagnosis was excluded using a combination of biochemical testing, abdominal computed tomography scanning and clinical follow-up. Plasma catecholamines were measured by high pressure liquid chromatography on basal samples and at hourly intervals for 3 h after the administration of clonidine 300 μg orally and the following diagnostic criteria were applied: plasma noradrenaline+adrenaline>2.96 nmol l(-1) at 3 h post-clonidine or a baseline plasma adrenaline plus noradrenaline>11.82 nmol l(-1); plasma noradrenaline>2.96 nmol l(-1) at 3 h post-clonidine and plasma noradrenaline>2.96 nmol l(-1) and <50% fall in noradrenaline at 3 h post-clonidine. The results obtained is that mean plasma noradrenaline plus adrenaline fell across the test in 40/41 patients in the non-phaeochromocytoma patients and was lowest at 3 h (basal 2.28 ± 0.14 vs 1.36 ± 0.11 nmol l(-1), P<0.001). In the phaeochromocytoma group, clonidine had a variable effect on adrenaline plus noradrenaline levels with increases in 7/15. Using an abnormal result as a 3 h level of noradrenaline plus adrenaline>2.96 mmol l(-1) gave a sensitivity of 93% and specificity of 95%. When a 3 h noradrenaline>2.96 mmol l(-1) was used, sensitivity was 87% and specificity 95%. Using the former criteria, noradrenaline plus adrenaline>2.96 mmol l(-1), 1/15 in the phaeochromocytoma group had a normal result after clonidine suppression testing. Two of 41 in the non-phaeochromocytoma group had a false-positive result. Under carefully controlled conditions, the clonidine suppression test is well tolerated, safe and accurate for use in the investigation of patients with suspected phaeochromocytoma.