Involvement of the corpus callosum splenium in a case with SSPE: magnetic resonance spectroscopy findings

Subacute sclerosing panencephalitis (SSPE) is a fatal, incurable, inflammatory, and neurodegenerative disease. The parieto-occipital lobes are the most frequently and severely affected. The basal ganglia, cerebellum, spinal cord and corpus callosum are less frequently involved [1-4]. Because magnetic resonance spectroscopy (MRS) provides information regarding in vivo brain metabolism and neuronal function, it is a promising method that may illustrate the pathophysiological features of SSPE [5-8]. To our knowledge, this is the first report of MRS findings of corpus callosum in a case with SSPE. A 15-year-old, previously healthy boy was hospitalized because of 4-week history of muscle weakness, impaired vision, and gait imbalance. He had not been vaccinated. A neurological examination revealed symmetric muscular weakness, ataxia, sequential slow movement, decreased motor activity and deep tendon reflexes, and negative Babinski reflex. He had exhibited myoclonic jerks, intellectual deterioration and behavioral changes. The characteristic burst suppression pattern was seen on EEG. Cerebrospinal fluid investigation revealed oligoclonal IgG bands and elevated titers of the measles antibody. He was diagnosed as clinical stage II according to the Jabbour classification. Magnetic resonance imaging (MRI) demonstrated diffuse hyperintensity in the cortical gray and subcortical, deep and periventricular white matter of the parieto-occipital region with mass effect observed as sulcal effacement and hyperintensity in the splenium of the corpus callosum on T2 and FLAIR weighted images. MRS was performed (TE: 135 ms). Voxels were placed in the right parietooccipital region and splenium of the corpus callosum. MR spectrum obtained from right parietooccipital subcortical and deep white matter and splenium of the corpus callosum showed a significant decrease in N-acetylaspartate (NAA)/creatine (Cr) and increase in the ratio of choline (Cho)/Cr. Additionally, there were also inverted prominent lactate peaks (Figures 1 and 2). Subacute sclerosing panencephalitis is persistent and chronic encephalitis secondary to measles virus infection that causes widespread demyelination of the central nervous system. Since clinical profiles of the disease lead to various presentations, early diagnosis and true clinical staging are not always easy. Usually, MRI findings and the clinical stage of SSPE are Corresponding author: Alpay Alkan MD Department of Radiology School of Medicine Bezmialem Vakif University Vatan Street, Aksaray I . stanbul, Turkey Phone: 90 212 4531700 Fax: 90 212 6318551 E-mail: [email protected] Letter to the Editor