A 25-year-old woman presented with a 6-month history of extreme lethargy and difficulty in concentration following a flu-like illness. She was unable to work as a physiotherapist and experienced considerable stress as a result of having to give up work. Clinical examination was unremarkable with the exception of globally reduced muscle strength; the rest of the neurological examination was normal. She was assessed by several specialists with no explanation being found for her extreme lethargy. A diagnosis of chronic fatigue syndrome (CFS) of unknown aetiology was made and a programme of graded exercises was recommended. Over the next 2 years she improved steadily enabling her to resume employment.
