Endocrine Abstracts

Background: Postoperative severe polyuria is a rare condition after adrenal pheochromocytoma resection. We presented this case due to its rarity.

Case: A 50-year-old women admitted to emergency service with malaise and fatigue complaint. The patient was using triple antihypertensive combination that started 10 years ago. Her medical history included cerebrovascular event due to hypertension 5 years ago. In physical examination her BMI was 20 kg/m², her pulse was 110 beats/min, her blood pressure was 160/100 mm Hg, Left upper and lower extremity were plegic. Laboratory evaluation revealed low potassium level (2 mEq/l). Patient was hospitalized to investigate the causes of hypertension and hypokalemia. After potassium normalization PAC:PRA ratio were normal. Urine metanephrine and normetanephrine levels were 7269.7 μg/day (52–341 μg/day) and 689.76 μg/day (88–444 μg/day) respectively. MRI revealed 34×33×32 mm mass in right adrenal gland and 57×52×45 mm mass in left adrenal gland, both mass had hyperintens in T2weighted images. Preoperatively doxazosin, amlodipin and metoprolol were started. Intravenous fluid was replaced as well. Left adrenolectomy was performed to patient for pheochromocytoma and pathologic result was pheochromocytoma. Metanephrin and normetanephrin levels 1 week after left adrenolectomy were 129 and 11 742 μg/day respectively. After these results, under the umbrella of steroid right adrenalectomy was performed as well. Pathologic result of right adrenalectomy was also pheochromocytoma. In postoperative first day urine output was 12 l/day and urine density, blood urea nitrogen were 1002 and 25 mg/dl (6–20 mg/dl) respectively but blood osmolarity and other electrolyte values were normal. ADH levels and other biochemical values were normal as well. Oral and parenteral fluid was replaced due to central venous pressure. Polyuria was continued for 5 days and after 6th day urine output decreased and urine density was improved.

Discussion: After adrenalectomy postoperative change of atrial natriuretic peptide, brain natriuretic peptide, adrenomedullin, ADH and urinary β2 microglobuline levels were thought to be responsible from polyuria. In our case the patient was suffered from a transient severe polyuria after bilateral adrenalectomy due to pheochromocytoma. We suggest that pheochromocytoma patients should be evaluated in terms of polyuria postoperatively.