Endocrine Abstracts

Background: Hyponatremia is the most common electrolyte disorder in clinical practice, whereas severe hyponatremia can be life-threatening if not diagnosed and managed appropriately. Severe hyponatremia can be the only presentation of several endocrine and non-endocrine diseases, and investigation for underlying causes and its appropriate management can be potentially life-saving. Severe hyponatremia is frequently overlooked as the presenting manifestation hypopituitarism. Herein, we describe a case of delayed diagnosis of hypopituitarism due to empty sella.

Case report: A 61-year-old patient was treated in a hospital for pneumonia, hyponatremia, when he developed seizure and coma. After two weeks of treatment, the patient was discharged, but on the next day his condition worsened with fatigue, dizziness, nausea, progressive somnolence, and was re-hospitalized in our emergency department. Upon admission, BMI=16.3 kg/m², BP=125/80 mm/Hg, HR=79, RR=19. Laboratory tests revealed severe hyponatremia (Na=109 mmol/l), with normal potassium and glucose levels. IV infusion of 3.0%NaCL was initiated instantly with increase in sodium levels ≈6 mmol/l per 24h in order to avoid further neurological complications. Further tests: serum osmolality 227 mOsm/kg, urine osmolality 493 mOsm/kg H<inf>2</info>O, urine sodium 118 mmol/l, serum cortisol 1.62 µg/dl (5,27-22.45), ACTH 12.10 pg/mL (0.1–46.0), FT4 0.43 ng/dl (0.89–1.76), FT3 0.9 pg/ml (3.1-6.8), TSH 1.91 µIU/mL (0.35–5.5). Other investigations unremarkable. He had been diagnosed with hypothyroidism (unknown etiology) 40 years ago, and was on levothyroxine 50 µg since then. According to the clinical and laboratory findings, he was diagnosed with hypopituitarism—secondary adrenal insufficiency, central hypothyroidism. Pituitary MRI revealed empty sella syndrome. Patient was started on IV hydrocortisone instantly and levothyroxine dose was increased in a few days. After hydrocortisone initiation, patient’s symptoms resolved with complete biochemical and clinical improvement. He was discharged on 20 mg hydrocortisone and 100 µg levothyroxine daily without any worsening during follow-up visits.

Conclusion: Our case demonstrates the importance of management of severe hyponatremia along with comprehensive workup to establish the cause of hyponatremia and appropriate management. Adequate treatment of hyponatremia in our patient led to a complete recovery without consequences.