Headaches and hormones: a potentially lethal combination

An 85 year old man presented to the emergency department with a five day history of headache, vomiting, and progressive visual loss in both eyes. He had no history of weight loss, seizures, or limb or facial weakness. He had hypertension, abdominal aortic aneurysm (under surveillance), hypothyroidism, and benign prostatic hypertrophy.

His blood pressure was 110/75 mm Hg, pulse 80 beats/min and regular, Glasgow coma score (GCS) 15. Peripheral neurological examination was normal. Cranial nerve examination showed bitemporal hemianopia with normal fundoscopy.

Initial investigations showed deranged biochemistry: sodium 126 mmol/L (reference range 135-145), potassium 3.6 mmol/L (3.5-5), urea 5.6 mmol/L (2.5-6.7), creatinine 101 µmol/L (70-150), C reactive protein 66 mg/L (<10). Full blood count and liver function tests were normal.

He was admitted to the acute medical unit after computed tomography of the head showed a mass arising from the pituitary fossa. Magnetic resonance imaging (MRI) showed a sellar mass compressing the optic chiasm and signal changes suggestive of haemorrhagic regions within the mass (fig 1⇓).