Endocrine Abstracts

A 44 years old lady with history of suspected psychogenic polydipsia (2021), presented with acute on chronic abdomen pain. She complained of lethargy, intermittent vomiting, abdomen pain, weight loss (four stones) over last six months associated with confusion and visual hallucination since two weeks. She mentioned feeling always thirsty and drinks around 4-5 litres of water per day. Her blood pressure was 87/61 mmHg, heart rate 74/min and U&Es were normal (serum sodium 140 mmol/l, potassium 3.7 mmol/l, urea 3.0 mmol/l and creatinine 76 umol/l). The CT abdomen was normal but the CT head showed new supra-sellar lesion (20x 14 mm) involving optic chiasm, pituitary stalk. The pituitary work up showed very low cortisol at 43 nmol/l, suppressed gonadal axis, with raised TSH at 9.19 mu/l, low FT4 of 5.0 pmol/l and raised prolactin at 3459 miu/l. She was started on injection hydrocortisone 100 mg qds and tab levothyroxine 100 mg was started after three days. The MRI head confirmed bright supra-sellar lesion (19x18x10 mm) inseparable from optic chiasm and pituitary stalk. After two days of receiving hydrocortisone injection she had clinical (had polyuria) and biochemical evidence of diabetes insipidus (serum osmolality 308 mosmol/kg, serum sodium 149 mmol/l, urine osmolality 287 mosmol/kg) hence tablet desmopressin 100 mg twice daily was started, following which polyuria resolved and serum sodium level improved.

Conclusion: • A high index of suspicion is required to identify adrenal crisis

• Patients with adrenal crisis along with diabetes insipidus may not have hyponatremia.

• Steroid replacement could unmask central diabetes insipidus, hence close input output monitoring and daily U&Es needed.

• Raised TSH and low FT4 in context of supra-sellar lesion, should still be considered as central hypothyroidism, as the raised TSH likely reflects the biologically inactive form.