Pheochromocytomas, although a rare cause of hypertension, are dangerous tumors that require consideration among large numbers of patients. The subsequent low prevalence of the tumor among those tested and inadequacies of commonly used biochemical tests make excluding or confirming the tumor an often difficult and time consuming task. Recognition that catecholamines are metabolized to free metan...

A24-year-old man presented with 2 years of treatmentresistant hypertension, headaches, palpitations, and sweats. One year earlier at an outside hospital, he was found to have elevated urine metanephrines, although an abdominal computed tomography scan and I-metaiodobenzylguanidine scintigraphy were unrevealing. He was lost to medical follow-up until he presented to this clinic with similar symp...

BACKGROUND Pheochromocytoma is a rare cause of hypertension resulting from increased catecholamine secretion. We aimed to develop a method to measure unconjugated plasma normetanephrine (NMN) and metanephrine (MN) without interference from acetaminophen, a widely prescribed drug for headaches. METHODS Plasma samples were obtained from 48 subjects (23 males, 25 females; mean age, 49 +/- 14 yea...

We report a case of elderly Chinese lady with neurofibromatosis type-1 presenting with longstanding palpitation, paroxysmal hypertension and osteoporosis. Biochemical testing showed mild hypercalcaemia with non-suppressed parathyroid hormone level suggestive of primary hyperparathyroidism, and mildly elevated urinary fractionated normetanephrine and plasma-free normetanephrine pointing to a cat...

A 61-year old female presented with paroxysmal hypertension and a 4.5cm left adrenal mass on CT scan. Repeated measurements of 24-hour urinary fractionated metanephrines, total catecholamines and vanillylmandelic acid (VMA) were within normal range. A further scintigraphic study with (131)I -metaiodobenzylguanidine ((131)I-MIBG) revealed selective concentration of the radiotracer, corresponding...

Pheochromocytomas are rare chromaffin cell tumors that nevertheless must be excluded in large numbers of patients who develop sustained or episodic hypertension as well as in many others with suggestive symptoms or with a familial history of pheochromocytoma. Diagnosis of pheochromocytoma depends importantly on biochemical evidence of excess catecholamine production by a tumor. Imperfect sensit...

BACKGROUND Urinary catecholamines and metanephrines have been proposed as a diagnostic tool for identifying canine pheochromocytomas, but the effects of critical illness on urine concentrations of catecholamines and metanephrines currently are unknown. OBJECTIVES To examine the effects of illness on urine concentrations of catecholamines and metanephrines in dogs. ANIMALS Twenty-five critic...

BACKGROUND Determination of urinary free catecholamine and total (i. e., free plus conjugated) metanephrine excretion is considered the most clinically sensitive biochemical test for pheochromocytoma. In this study, we evaluated new immunoassay methods for the measurement of these analytes for potential drug-based interference. METHODS Urine samples collected from patients on a variety of med...