Utility of plasma free metanephrines in diagnosis of factitious pheochromocytoma.
OBJECTIVE
To report a case of epinephrine-induced factitious pheochromocytoma in a young woman with a past medical history of Conn's syndrome.


METHODS
We present a case report with clinical and laboratory details, review related reports in the literature, and demonstrate the usefulness of plasma free metanephrine levels in facilitating the diagnosis of factitious pheochromocytoma.


RESULTS
A 34-year-old woman was admitted to our hospital for confirmation and localization of an occult pheochromocytoma. After thorough investigation, we discovered that the patient was surreptitiously injecting epinephrine in order to induce symptoms and signs consistent with a pheochromocytoma. Analysis of the patient's biochemical profile during and between her catecholaminergic crises revealed plasma epinephrine and free metanephrine levels that would be highly unusual for a patient with a pheochromocytoma.


CONCLUSIONS
This case illustrates the utility of implementing the ratio of plasma epinephrine to free metanephrine levels in distinguishing factitious from organic pheochromocytoma.
Chidakel
Aaron R
AR
Division of Intramural Research, National Institute of Diabetes and Digestive and Kidney Diseases, W. G. Magnuson Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
Pacak
Karel
K
Eisenhofer
Graeme
G
Lawrence
Jennifer E
JE
Ayala
Alejandro R
AR
D000328:Adult; D003937:Diagnosis, Differential; D004837:Epinephrine / Q000008:administration & dosage / Q000652:urine; D005162:Factitious Disorders / Q000097:blood / Q000139:chemically induced*; D005260:Female; D006801:Humans; D008676:Metanephrine / Q000097:blood* / Q000652:urine; D009638:Norepinephrine / Q000097:blood; D009647:Normetanephrine / Q000097:blood; D010673:Pheochromocytoma / Q000097:blood / Q000175:diagnosis*
D009647:Normetanephrine; D008676:Metanephrine; D009638:Norepinephrine; D004837:Epinephrine