Euvolaemic hyponatraemia as a rare first presentation of chronic hypopituitarism.

A man in his late 40s with no significant medical history presented with 2 weeks of lethargy, nausea and dizziness, alongside worsening headaches. Initial assessment revealed severe hyponatraemia and secondary hypothyroidism; urgent MRI pituitary was requested with a clinical suspicion of pituitary apoplexy. This demonstrated a likely cystic pituitary adenoma, with further testing revealing pituitary gland suppression, leading to a diagnosis of chronic secondary hypopituitarism. Initiating hormone replacement allowed substantial reported improvements in this patient's quality of life.A review of the patient's work-up revealed areas in which best practice was not followed. Cortisol measurements and paired urinary and serum osmolalities were initially not sent, nor results appropriately chased. A subsequent literature review identified that conformation with national and local guidelines on hyponatraemia management is poor. This patient's case, when combined with the literature review, provides evidence to support methods to increase educational awareness of an appropriate work-up of hyponatraemia among clinicians.

Parathyroid carcinoma presenting as severe hypercalcaemia responding to steroids.

A man in his 50s was referred with profound, symptomatic hypercalcaemia. He was diagnosed with primary hyperparathyroidism, confirmed on 99mTc-sestamibi scan. He was treated for the hypercalcaemia and referred to ear, nose and throat (ENT) surgeons for parathyroidectomy, which was delayed due to the COVID-19 pandemic. In the ensuing 18 months, he had five hospital admissions with severe hypercalcaemia requiring intravenous fluids and bisphosphonate infusions. During the last admission, hypercalcaemia was resistant to maximal medical management. Emergency parathyroidectomy was planned, but delayed due to intervening COVID-19 infection. Due to persistent severe hypercalcaemia (serum calcium: 4.23 mmol/L), he was commenced on intravenous steroids, following which serum calcium normalised. Subsequently, he underwent emergency parathyroidectomy, which normalised his serum parathyroid and calcium levels. On histopathological examination, a diagnosis of parathyroid carcinoma was made. On follow-up, patient remained well and normocalcaemic. In patients with primary hyperparathyroidism unresponsive to standard therapy, but responsive to steroids, underlying parathyroid malignancy should be considered.