Endocrine Abstracts

Introduction: Hyponatremia in patients with pituitary tumours are common due to many reasons including secondary hypoadrenalism and secondary hypothyroidism. When these causes are treated with the background of hyponatremia, serum sodium should be regularly monitored as it could get corrected too rapidly leading to ODS.

Case report: 34 Year old patient presented to a tertiary care hospital with headache. His MRI brain revealed a large suprasellar lesion suggestive of a craniopharyngioma. He was discharged with outpatient endocrinology referral. Several weeks later, before his endocrinology review, he presented with nausea, vomiting and postural symptoms. His blood results showed serum Na of 108 mmol/l. He was managed in the acute medical ward with 3% saline followed by normal saline. Although his sodium improved to 148 mmol/l, his symptoms persisted. He was referred to the endocrine team. Adrenal crises was suspected and he was commenced on intravenous hydrocortisone and intra venous 0.9% saline. Biochemistry revealed panhypopituitarism (0900 h cortisol 81 nmol/, TSH 1.7 mIU/l, FT4-4.65 pmol/l). His symptoms improved rapidly. Day 3 after hydrocortisone commencement he developed slurring of speech, spastic quadriparesis with upgoing plantars. Retrospectively, His blood results showed rise of Na (day 1–134, day 3–141) with associated polyuria unmasking diabetes insipidus. With the given clinical background, the diagnosis of osmotic demyelinating syndrome (ODS) was made. We aimed at reducing the Na level to 126 mmol/l based on 18 mmmol correction in 48 h. He was managed with 5% dextrose and subcutaneous vasopressin. His Na results were as follows: day 3 evening-137, day 4–135, 129, 128, day 5–119, day 6–126, day 7–126 130, day 8–133. He gradually improved from his ODS from day 4. He completely recovered from the illness by day 8. He underwent transcranial surgery and had an uneventful recovery except for a side 3rd nerve palsy. His histology revealed craniopharyngioma.

Conclusion: Thus, when hyponatremia and hormonal deficiency is corrected in pituitary base tumours, Na should be carefully monitored to prevent a rapid correction and should use desmopressin if needed. If ODS develops we should bring the Na down based on the calculation with the help of hypotonic fluids and desmopressin.