Acute headache and visual field defect

A 79 year old woman developed a sudden onset severe bifrontal headache accompanied by an acute loss of peripheral vision, which she described as tunnel vision, and a subsequent transient reduction in her level of consciousness six days after an elective right total hip arthroplasty. Postoperatively she had experienced mild generalised headaches and erratic blood pressure control, with a tendency to marked hypertension.

Her medical history included type 2 diabetes, poorly controlled hypertension, and osteoarthritis, for which she regularly took co-codamol 30/500, metformin, and bisoprolol; no recent changes had been made to these drugs.

On initial examination, her blood pressure was 105/68 mm Hg, pulse 85 beats/min, and temperature 37.8°C. Her Glasgow coma scale score was 10/15 (E3, M5, V2) but rapidly improved to 14/15 (E4, M6, V4) over about 15 minutes. Further neurological examination showed visual acuities of 6/9 bilaterally and a marked bitemporal hemianopia, which was confirmed on formal visual fields assessment. Notably, fundoscopy was normal and she had no signs of meningism.

Initial blood tests showed hyponatraemia (119 mmol/L), with otherwise normal biochemistry and random glucose of 10.2 mmol/L. Calcium profile, full blood count, and coagulation screen were normal. Serum and urine osmolalities were 274 mosmol/kg and 581 mosmol/kg, respectively. Magnetic resonance imaging (MRI) was performed (figs 1⇓ and 2⇓).