Leptospirosis is a common zoonosis worldwide. Leptospires are water borne spirochaetes which cause widespread immune-mediated capillary endothelial damage. A biphasic illness occurs with an acute infection followed by a secondary immune phase. We report the case of a 34 year old man who developed serologically confirmed leptospirosis during a fishing trip in France. This led to Weil's disease with hepatorenal dysfunction. After 3 weeks of antibiotic treatment, he was making a sustained recovery when he developed a rapid onset of headache without meningism, altered mental function, bilateral cortical visual impairment and focal seizures. At the onset of his symptoms there was a small rise in blood pressure from 170/90 to 161/111 millimeters of mercury. Renal and hepatic function were improving. He had started to pass urine. The seizures resolved with phenytoin. No other treatment changes were made. MRI with diffusion weighting revealed nonhaemorrhagic subcortical white matter lesions maximal in the occipital lobes. The patient's symptoms rapidly improved over days and this was paralleled by resolution of the white matter lesions. We postulate that secondary immune-mediated capillary endothelial damage, a common mechanism underlying PRES, may have been a factor in producing vasogenic oedema in the while matter in this patient. Metabolic dysfunction and hypertension may have contributed. Early imaging facilitated conservative management with full recovery.