Part of “CHAPTER 110 – ENDOCRINE DISEASE IN PREGNANCY“

Some patients with pheochromocytoma have such infrequent episodes that suspicion of the condition first arises with an increase in blood pressure during the induction of anesthesia, during labor, or during surgery. Failureto recognize this possibility may result in the death of the patient. Some pregnant patients with pheochromocytoma have sudden shock that appears spontaneously or is induced by anesthesia or by labor and delivery.132,133,134 and 135 Extraadrenal tumors, which constitute ˜10% of cases, may provoke paroxysmal symptoms after particular activities. A frequent site is the organ of Zuckerkandl, located at the bifurcation of the aorta. The enlarging uterus may cause pressure on a tumor at this site, with hypertensive episodes occurring with changes in position, uterine contractions, fetal movement, and execution of Valsalva maneuvers.136

The rate of maternal mortality from undiagnosed pheochro-mocytoma is ˜50%; the rate falls to 11% if the condition is diagnosed before delivery.133,134 and 135 The rate of fetal loss is similar, even if the diagnosis is made during pregnancy.133,134 and 135 Catechol-amines cross the placenta only minimally,133 and the fetus appears to be unaffected by the high maternal levels. However, some element of hypoxia, caused by vasoconstriction of the uterine vascular bed, may be present.135