History

An 83-year-old man presented as an emergency with rapidly emerging confusion and visual hallucinations. His family had noted mild cognitive symptoms for a year or two, but he was living independently, and had recently enjoyed a family celebration.

He was in good health and his medical history included angina and a cholecystectomy and transurethral prostatectomy. Eight years previously, his General Practitioner had noted an isolated episode when he awoke confused, making ‘out of context’ comments about money to his wife. A CT scan of head was reported as mildly atrophic for age, and he was referred to a psychogeriatrician, but he was never assessed as he recovered fully after this isolated episode. He was on no regular medication at the time of this admission.

On assessment, his Abbreviated Mental Test was 9/10 with a normal neurological examination. The following day he appeared more confused and agitated, and was treated with lorazepam and haloperidol. Two days later he was transferred for rehabilitation, with a diagnosis of delirium, possibly due to infection (see table 1 for a summary of investigations).

On the rehabilitation ward, he was ‘drowsy and disorientated in time and place’. He had two falls over the next few days. On the fifth day of his admission, he became hypotensive with atrial fibrillation and a rapid ventricular rate. A neurologist saw him the following day, noting dysarthria with slurred, nasal speech. His conscious level and degree of confusion fluctuated, and on day 9 there were some myoclonic jerks. Later that day he was transferred to the regional Neurosciences unit for further assessment, including MR scan of brain. Imaging was postponed, however, as his airway was unsafe and soon after transfer, his airway safety deteriorated further, and he was intubated and ventilated (it was reasoned that although his …