Session: MON 37-82-Pheochromocytoma & Paraganglioma
Poster Board MON-51
A 24 hour urine collection was done which revealed elevated levels of catecholamines. The elevated levels of dopamine 5022 mcg/day (normal range: 60-440 mcg/day) were felt to be due to her L-dopa treatment but she also had concurrent elevations of norepinephrine 1726 mcg/day (0-100 mcg/day), epinephrine 225 mcg/day (0-25 mcg/day), metanephrine 93440 nmol/day (152-1775 nmol/d) and normetanephrine 189216 nmol/d (273-3548 nmol/d).
Pre operative management could not include phenoxybenzamine as patient had significant orthostatic hypotension. Alternatively, nicardepine was used. Her intra and post operative course was uneventful. Following surgery, despite ongoing L-dopa treatment, her 24 urine demonstrated normal catecholamines excretion except elevated dopamine level. Her symptoms resolved.
Discussion: The coexistence of Parkinson’s disease being treated with dopaminergic medications in a patient, being evaluated for phaeochromocytoma confounds the interpretation of biochemical tests. This unusual case provided the opportunity to analyze the combined effects of L-dopa therapy and phaeochromocytoma secretion on urinary-excreted catecholamines and their metabolites. Literature review has shown significant increase in urinary dopamine levels in patients treated with L-dopa, with severity of elevation related to drug dose. It has been demonstrated that therapeutic doses of L-dopa does not result in abnormally elevated excretion of vanillyl mandelic acid,5-hyroxyindoleacetic acid, noradrenaline or adrenaline or exhibits a correlation with the daily dose of L-dopa.
Conclusion: Physicians should be aware of the effect of L-dopa on urinary catecholamines as a confounder in the evaluation of pheochromocytoma.
Nothing to Disclose: HK, REI
*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm
See more of: Abstracts - Orals, Featured Poster Presentations, and Posters