Endocrine Abstracts

Introduction: Hyponatremia is one of the possible complications of pituitary surgery. Mild, asymptomatic hyponatremia can be managed with fluid restriction and oral supplementation, however more profound hyponatremia, especially when symptomatic, can be a reason for hospital readmission and often needs to be treated with saline infusion in ICU.

Aims: To estimate prevalence of hyponatremia and provide clinical characteristics in the cohort of patients who underwent surgery for tumour in sellar region at our centre.

Method: Single centre retrospective analysis of cohort of patients undergoing pituitary surgery in the past 30 months. Data of patients who had surgery for pituitary adenoma or other sellar tumor were analysed retrospectively. Those who developed hyponatremia in the period of 30 days following surgery were selected for further analysis. Preoperative radiologic features, patterns of sodium level changes, and endocrinological characteristics were noted.

Results: In the selected period, 313 pituitary surgeries have been performed at our centre. 23 cases of hyponatremia were identified of which 16 were women. Average age was 49 years (27–75 y). Pituitary adenoma was histologically confirmed in 15 cases of which 13 were macroadenoma. Four were hormonally active (one prolactinoma and three GH secreting adenoma). Other types of tumours involved 4 cystic lesions a 3 meningiomas. Suprasellar extension was present in 14 cases and parasellar extension in 12 cases. Six patients had early postoperative complication (four cases of CSF leakage and two haemorrhagic complications). Four patients developed early postoperative polyuria but in only one case diabetes insipidus reappeared after recovery from hyponatremia however it lasted only temporarily and the treatment with desmopressin was withdrawn subsequently.

In most of the cases hyponatremia was diagnosed on day 7 (39%, 9 cases, range 3–10 day). The lowest sodium on presentation was 118.9 mmol/l and during the treatment period the sodium nadir level observed was 113 mmol/l. Hyponatremia was symptomatic in 10 patients. Seven patients presented with neurological symptoms (seizures, vertigo, headache or confusion), three patients had gastrointestinal symptoms (nausea, vomiting). Thirteen patients were treated with 3% saline infusion while in the remaining cases treatment with oral salt tablets and fluid restriction was sufficient. Only two patients were treated as outpatient while the rest were readmitted and 9 of them were treated in the ICU. Only two patient developed diabetes insipidus after recovery from hyponatremia.

Conclusion: Hyponatremia was present in 7.3% cases while in only 2.8% hyponatremia was clinically and biochemically severe requiring admission to ICU.