Pheochromocytoma: Serial studies during pregnancy

Cardiovascular and catecholamine responses to adrenergic stimulation and blockade were studied in a patient with pheochromocytoma during pregnancy, crisis, premature delivery, and tumor resection. The degree of cardiovascular response to phentolamine was influenced by the level of circulating catecholamines and the degree of hypovolemia. Administration by microinfusion appeared to be a safe procedure in conducting phentolamine tests and an effective method for controlling blood pressure during hypertensive crisis, labor, and operation. The hypertensive and catecholamine responses to tyramine administration were absent immediately after removal of the tumor. The weight loss during the second trimester of pregnancy, failure to expand the intravascular volume, and a severely growth-retarded fetoplacental unit may be a consequence of chronically elevated catecholamines in this patient.