Neurological syndromes and the traveller: An approach to differential diagnosis

In 2001 there were 58 million overseas trips made by UK residents, and over 22 million people visited the UK from abroad. As the relative cost of air travel falls, holidays in exotic destinations have become easier and therefore more common. Travel to such places can be associated with particular health risks, not only through exposure to indigenous pathogens but also through changes in behaviour when released from one's normal day to day schedule-for example, use of alcohol and illicit drugs, "adventure holidays", transport, and sex. This article will focus on infectious agents that a neurologist may need to consider when asked to see an adult who has recently arrived from abroad. The emphasis will be on developing a logical approach to establishing a differential diagnosis rather than on an exhaustive list of all the potential weird and wonderful infectious agents or on the detailed specifics of treatment.