Initial and postoperative hyponatremia associated with pituitary adenoma: a case report

Recurrent Hyponatremia as Presenting Manifestation of Pituitary Macroadenoma

Hyponatremia is commonly seen electrolyte disturbance clinically. It is potentially life-threatening and requires prompt diagnosis and treatment. Non-functioning pituitary macroadenoma generally presents with a headache, visual disturbances, and the diagnosis is often delayed because of nonspecific nature of symptoms. Hyponatremia being initial manifestation before other common symptoms of pituitary macroadenoma is rare. We present a case of 55-year-old male with recurrent episodes of hyponatremia who was found to non-functioning pituitary macroadenoma along with panhypopituitarism. He was managed with hormone replacements. Our case highlights the importance of correct diagnosis of hyponatremia, measurement of the thyroid, adrenal and pituitary function in cases of hyponatremia.

Hyponatremia Associated with Hepatocellular Carcinoma

Hyponatremia is the most common electrolyte abnormality in clinical practice, and a differential diagnosis of the etiologic disorders is crucial because hyponatremia is associated with many different disease states including malignancies. Although only a few cases of hyponatremia with hepatocellular carcinoma (HCC) have been previously reported, the abnormal expression of arginine vasopressin (AVP) in tumor cells has not been demonstrated. We herein present a rare case of hyponatremia associated with the aberrant expression of AVP in tumor cells of HCC. This case suggests that an extensive diagnostic work-up is needed in patients with hyponatremia because hyponatremia may provide diagnostic clues for the presence of other underlying disorders.

Rathke's cleft cyst presenting with hyponatremia and transient central diabetes insipidus

We describe an 18-year-old female who complained of general weakness, nausea, vomiting, headache, and lightheadedness. On physical examination, she was euvolemic without visual or neurological deficits. The striking biochemical abnormality was hyponatremia (125 mmol/l). This hyponatremia met the laboratory diagnostic criteria for the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Two litres of normal saline were given per day for 4 days and this did not correct her hyponatremia. A spontaneous diuresis (6.6 l) developed in 1 day, causing a rise in her PNa of 26 mmol and a final PNa of 152 mmol/l. Magnetic resonance imaging revealed a dumbell-shaped intrasellar and suprasellar cyst. During transsphenoidal surgery, a Rathke's cleft cyst (RCC) lined with columnar epithelium containing mucoid material was resected. We speculate that the growing RCC may have produced critical compression over the stalk, thus contributing to the transition from SIADH with hyponatremia to transient central diabetes insipidus with hypernatremia.