Mild encephalopathy with reversible lesion of the splenium caused by infectious endocarditis

Mild encephalopathy with reversible lesion of the splenium of corpus callosum is a rare disease revealing mild neurological symptoms, such as disturbance, ataxia, vertigo and in some cases headache. Magnetic resonance signal alterations in the splenium of the corpus callosum can be found in patients suffering from different diseases, mostly viral infections, but also seizures, antiepileptic drug therapy, bacterial infections, hypoglycaemia, Wernicke encephalopathy, Marchiafava Bignami disease, hemolytic uremic syndrome, acute urinary retention, and acute axonal trauma. We report a 32-year old man admitted to our hospital with fever and vomiting. In the neurological examination he presented with mild dizziness and confusion. Until that time no cardiac symptoms had been reported. Due to the neurological symptoms an MR scan of the brain was performed visualizing an area of restricted diffusion with a diameter of 7 mm located in the central portion of the splenium of the corpus callosum being hyperintense on Fluid Attenuated Inversion Recovery (FLAIR) and T2-weighted turbo spin-echo images. Furthermore, multiple punctate lesions with similar appearance on diffusion weighted imaging were found in both hemispheres suspicious of embolic ischemic etiology. Consecutive transesophageal echocardiography revealed endocarditis of the mitral valve. Transient lesions of the splenium recovering within a month are not specific and there is a wide range of differential diagnoses. They may indicate severe disease despite of initially mild neurological symptoms. Pathophysiology of these lesions is not clearly understood yet, even if there exist some – however not proven – theories, such as rapidly resolving intramyelinic edema or influx of inflammatory cells associated with cytotoxic edema.