Reversible focal splenium lesion--MRS study of a different etiology

A 36-year-old man with staphylococcal meningitis had similar symptoms and MRI characteristics as reversible splenium lesion syndrome described in the literature-hyperdensity on DWI and T2WI/FLAIR, hypodensity on ADC, iso-intensity on T1WI, and no contrast enhancement on midline splenium. The splenium lesion on MRI disappeared as the symptoms improved. The etiology of staphylococcal meningitis was different from other reported cases, and the MRS study showed relatively elevated lactate and myo-inositol of splenium as compared to other selective regions in the brain (both white matter and gray matter), which implies increased anaerobic glycolysis and hyperosmolar state on the splenium. The ratios of NAA/Cr, NAA/Cho, and Cho/Cr were abnormal in all selected regions, indicating that the pathologic change involved the whole brain. More series MRS and other advanced exams to correlate intracranial environment (ex. cerebral blood flow, osmolality, inflammatory process, metabolites distribution, and neurotransmitter changes) are needed to confirm the mechanisms of different etiologies with reversible splenium lesion syndrome.