Unusual Case of Pheochromocytoma With a Surprising Response to the Intravenous Administration of Norepinephrine
A 34-year-old woman with a 1-year history of hypertension was admitted to the internal department of the catchment hospital on March 31, 2000, with dyspnea, chest discomfort, and vomiting. On April 11, cephalea with paroxysmal hypertension appeared. An ultrasonographic examination showed a suspected right adrenal pheochromocytoma. On April 18, the patient was transferred to our hospital, and a right adrenal tumor was diagnosed by CT scan. After her admission to the coronary unit, periodic fluctuations of blood pressure (and heart rate) were found. The blood pressure ranged between 65/40 and 270/150 mm Hg, with a 10-minute periodicity. During hypertension, pallor was present, accompanied by cephalea and sinus bradycardia, which was changing into sinus tachycardia during hypotension. Therefore, we cannulated the left radial artery and measured the blood pressure invasively. The patient was treated with intravenous phentolamine; a total dose of 20 mg was given, but with no effect. After this ineffective treatment, we started treatment with clonidine given intravenously at a dose of 0.06 mg/h. Three hours after the onset of this therapy, temporary unconsciousness occurred during hypotensive periods. Therefore, the administration of clonidine was discontinued. We inserted 2 luminal central venous catheters with the idea of transient administration of norepinephrine during the hypotensive periods and the administration of sodium nitroprusside during the hypertensive periods (Figures 1 and 2⇓). Infusion of norepinephrine at a dose of 2.8 mg/h was given during the decrease of the systolic blood pressure from the peak value of 280 mm Hg to the value of 100 mm Hg to prevent hypotension. After the administration of this infusion, the systolic blood pressure decreased to as low as to 85 mm Hg and immediately increased up to 120 mm Hg, with a surprising immediate cessation of blood-pressure and heart-rate fluctuation (Figure 3). The dosage of a norepinephrine infusion was gradually reduced and completely discontinued after 18 hours. Simultaneously with an infusion of norepinephrine, a saline infusion (100 mL/h) was administered. Plasma catecholamine levels were not measured because of the exogenous norepinephrine therapy. On April 20, a right adrenalectomy was performed. The tumor was well circumscribed on cross section, with areas of hemorrhage and in the central part, cystic degeneration (Figures 4–7⇓⇓⇓). The diagnosis of pheochromocytoma was confirmed histologically. The patient was discharged on May 5, and no symptoms of tumor recurrence have been shown since then.