A 58-year-old lady who had waxing and waning nonspecific symptoms including fatigue and unsteadiness for 15 months became acutely confused 12 h prior to presentation. Her travel history prior to presentation consisted of visits to Argentina, Chile and the Outer Hebrides. On admission to a district hospital she was pyrexial and unresponsive. CT was normal, she had a lymphocytic pleocytosis of 500, protein of 1 g, a low glucose ratio and type 2 oligoclonal bands, CSF cytology and HSV were negative. Baseline blood tests, tumour markers, autoimmune screening including paraneoplastic antibodies and voltage-gated potassium channel antibodies were also negative. Magnetic resonance imaging revealed multiple abnormal areas of high signal on T2 FLAIR sequencing within the cerebellum, temporal lobes, and periventricular areas. Western blotting of serum and CSF for Borrelia burgdoferi were both positive. She was treated with cefuroxime and acyclovir and within 24 h she was alert and responsive. She received 4 weeks of cefuroxime in total and made a good recovery. Lyme disease should be considered in patients with acute meningoencephalitis preceded by nonspecific waxing and waning symptoms even if a tick bite or erythema is not recalled.