Ectopic ACTH secretion from a metastatic gastric carcinoma with neuroendocrine component.

An elderly gentleman was admitted to hospital with severe hypokalaemia of 1.75mmol/L. A background of a recently diagnosed metastatic gastric carcinoma with a neuroendocrine component pointed towards the diagnosis of ectopic ACTH secretion causing this dangerous electrolyte imbalance. He was treated with aggressive potassium supplementation and the adrenal steroid synthesis blocker metyrapone to acutely control his Cushing's syndrome. Chemotherapy consisting of carboplatin/etoposide combination was initiated but unfortunately the patients' health deteriorated, and he died three months after his initial diagnosis. This case highlights the accelerated presentation of hypercortisolism due to ectopic ACTH secretion. It discusses the classification of neuroendocrine tumours and their varied prognosis depending on the underlying tumour grade. It emphasises the importance of having a multidisciplinary team to be able to care for two underlying pathologies simultaneously: both the severe hypercortisolism and his metastatic gastric tumour.

Amiodarone-induced type 2 thyrotoxicosis.

The authors present a case of a 55-year-old gentleman with a medical history of atrial fibrillation on amiodarone who presented with weight loss, palpitations and exertional dyspnoea. Thyroid function tests revealed thyrotoxicosis with a free thyroxine (T4) of 117 pmol/L and a thyroid-stimulating hormone (TSH) of <0.008 mIU/L. Interleukin-6 level was low. The negative TSH-receptor antibody status, the presence of a small thyroid gland with heterogeneous echotexture and decreased internal vascularity on ultrasound together with the relatively quick drop in free T4 and free tri-iodothyronine (T3) levels once prednisolone therapy was added to carbimazole suggested that this was typical of amiodarone-induced thyrotoxicosis (AIT) type 2. Subsequently, carbimazole was discontinued and treatment with prednisolone was continued. This case highlights that AIT management may be challenging and it is of paramount importance to establish the type of AIT present as this will guide management and is key to improving prognosis.

Isolated second-phase diabetes insipidus post-transsphenoidal surgery.

A 57-year-old woman presented with severe lethargy, dizziness and nausea 1 week after transsphenoidal resection of a growth hormone secreting pituitary adenoma. She was found to have severe hyponatremia of 115 mmol/L. Importantly, she was neurologically intact and clinically euvolaemic. Her fluid intake was restricted and her sodium levels increased to 131 mmol/L over 4 days. She made a full recovery.She was diagnosed with isolated second-phase diabetes insipidus, a state of symptomatic hypoosmolar hyponatremia that usually occurs 7-10 days after transsphenoidal surgery. The sodium levels improve with fluid restriction.