Meningoencephalitis in a Royal Marine after skinning reindeer in Norway.

Meningoencephalitis presenting in service personnel overseas may present a diagnostic challenge due to the broad range of potential differential diagnosis as well as the requirement for rapid assessment and treatment. A 25-year-old Royal Marine was evacuated to the Royal Centre for Defence Medicine in Birmingham, UK, with a history of rash consistent with erythema chronicum migrans, a seizure, and lymphocytic pleocytosis after skinning reindeer in Norway. Neuroborreliosis was suspected and empirical antibiotics were administered. Despite subsequent negative serology for Borrelia burgdorferi , given the clinical features and lymphocytic pleocytosis, an atypical presentation of neuroborreliosis remains a possible diagnosis in this scenario. This case serves to illustrate that British military personnel on exercise are potentially at risk of contracting borreliosis both in the UK and abroad, serological tests can be unreliable, and the differential diagnosis of meningoencephalitis can be broad with specialist input often required.