A hitherto unrecognised case of progressive multifocal leukoencephalopathy.

A 65-year-old man presented with a 6-week history of increasing confusion with associated cognitive decline. Empirical antibiotic cover for a urinary tract infection was prescribed with no response. After exhaustive radiological and pathological investigations were carried out, a diagnosis of John Cunningham virus encephalopathy was made. This case report describes the varied clinical presentation of symptoms and their management options, along with the latest clinical opinions behind them.