Case 8-2018: A 55-Year-Old Woman with Shock and Labile Blood Pressure

The morphologic-functional correlative studies that we have carried out in the past 25 years with the various catecholamines have served as an example for analyzing myocardial reaction patterns and the reactions of the cardiac muscle cells to insult. These studies disclosed the unique nature of isoproterenol in producing 'infarct-like' myocardial necrosis. It appears that the pathogenesis of the catecholamine-induced myocardial necrosis is multifactorial. Our early studies suggested the role of relative hypoxia. Later studies by using extracellular fine structural protein tracers demonstrated the importance of microcirculatory effects as well as, in the norepinephrine model, that of early sarcolemmal membrane permeability alteration. The Ca2+ overload theory is supported not only by the experimental observations but also by its successful application in clinical cardiology. A new contribution is the recognition of catecholamine oxidation products in producing myocardial injury. Experimental data indicate that catecholamines play an important role in reperfusion and ischemic myocardial injuries. The sequence of events demonstrated by our studies with catecholamines might represent a common pathway in the evolution of myocardial changes in humans who develop myocardial lesions without narrowing or obstruction of coronary arteries. Investigation in the field of molecular and cellular cardiology has led to a better understanding of current clinical problems and helped to devise procedures for the prevention and management of human myocardial disorders. The isoproterenol-induced myocardial necrosis served as model to Professor A. Fleckenstein to formulate the Ca2+ overload theory of myocardial injury and develop a series of now widely used Ca2+ antagonistic drugs for the management and the prevention of human myocardial diseases.

Pheochromocytomas are rare catecholamine-secreting tumors with many clinical and imaging manifestations. They may produce overwhelming cardiovascular crises if the diagnosis is not made or if appropriate treatment is delayed. It is thus important to recognize both their characteristic and atypical imaging appearances. Pheochromocytomas are encountered, sometimes unexpectedly, across a range of imaging modalities. They are characteristically solid, hypervascular masses with high signal intensity on T2-weighted magnetic resonance (MR) images. A wide spectrum of imaging appearances is seen, however, and pheochromocytomas may mimic other adrenal lesions, both benign and malignant. They may be dark on T2-weighted MR images, in contrast to their more classic bright T2-weighted appearance. Other atypical features include fatty, hemorrhagic, cystic, and calcific changes. Pheochromocytomas may contain sufficient fat to be mistaken for an adenoma at computed tomography (CT) or MR imaging. They may also demonstrate rapid contrast material washout and be mistaken for an adenoma owing to their deenhancement profile; however, their washout pattern can be inconsistent. The appearance of pheochromocytomas at radionuclide imaging is also unpredictable. These characteristics at CT, MR imaging, and scintigraphy pose diagnostic challenges, since they allow pheochromocytomas to mimic many other adrenal masses. Pheochromocytoma is an important, often clinically occult neoplasm with devastating consequences if overlooked. Radiologists must be aware of the various forms that pheochromocytomas can assume at imaging. Copyright RSNA, 2004.

We compared the diagnostic efficacy of fractionated plasma metanephrine measurements to measurements of 24-h urinary total metanephrines and catecholamines in outpatients tested for pheochromocytoma at Mayo Clinic Rochester from January 1, 1999, until November 27, 2000. Catecholaminesecreting tumors were histologically proven. The sensitivity of fractionated plasma metanephrines was 97% (30 of 31 patients), compared with a sensitivity of 90% (28 of 31) for urinary total metanephrines and catecholamines (P = 0.63). The specificity of fractionated plasma metanephrines was 85% (221 of 261), compared with 98% (257 of 261; P < 0.001) for urinary measurements. The likelihood ratios for positive tests were 6.3 (95% confidence interval, 4.7 to 8.5) for fractionated plasma metanephrines and 58.9 (95% confidence interval, 22.1 to 156.9) for urinary total metanephrines and catecholamines. An adrenal pheochromocytoma was missed by urinary testing in two patients with familial syndromes and one asymptomatic patient with an incidentally discovered adrenal mass. An extra-adrenal paraganglioma was missed by plasma testing in one patient. In conclusion, measurements of 24-h urinary total metanephrines and catecholamines yield fewer false-positive results, an attribute preferred for testing low-risk patients, but fractionated plasma metanephrine measurements may be preferred in high-risk patients with familial endocrine syndromes.