Management of water and electrolyte disorders post-pituitary adenoma surgery: experience with Tolvaptan 7.5 mg at a tertiary care centre.

BACKGROUND

Water and electrolyte disorders (WED) are common after pituitary surgery, increasing morbidity and hospital stay. We report our single-centre experience, with emphasis on tolvaptan use for syndrome of inappropriate antidiuresis (SIAD).

METHODS

This retrospective study analysed 82 patients with WED following pituitary adenoma surgery. Demographics, tumour features, and WED onset, duration, and management were reviewed.

RESULTS

The median age at surgery was 30 years, with female predominance (69.5%) and majority had macro adenoma (62.1%). Cushing's disease was the most common etiology (54.8%). Isolated arginine vasopressin deficiency (AVP-D) was the most frequent WED (40.2%), followed by isolated SIAD (39%), biphasic response (18.2%), triphasic response (1.2%), and cerebral salt wasting (1.2%). Median onset of AVP-D and SIAD was post-operative day 1 and 4, respectively. There was an inverse correlation (r=-0.43, 0.002) between the day of SIAD onset and its duration. Thirteen patients received 25 doses of oral tolvaptan 7.5 mg. The median baseline serum sodium at tolvaptan initiation was 127 (125-130) mEq/L with a 24-hour increment of 5 (2-9) mEq/L. Serum sodium correction did not correlate with baseline sodium at which tolvaptan was administered (r=-0.29, p = 0.15), but a trend toward higher correction with later postoperative use was observed (r = 0.34, p = 0.09). Overcorrection (> 10 mEq/L/24 h) occurred in 2 patients (15.3%), and none developed osmotic demyelination.

CONCLUSION

Tolvaptan 7.5 mg may serve as an effective alternative treatment modality in moderate-to-severe SIAD patients.