Subacute Sclerosing Panencephalitis

A seven-year-old boy presented with inattentiveness in class for 6 months. His class teacher noted that his scholastic performance was gradually deteriorating. Over the next 2 months his grades dropped. Over the next 2 months, his parents noted that he became withdrawn, had reduced interaction, and did not show any interest in playing with his younger sister. Three months into the illness, he developed recurrent unprovoked falls. He had had an exanthematous fever at around 1 year of age. He was not immunized. At the time of evaluation, he was conscious with fluctuating alertness. Cranial nerve examination was normal. He had mild hypotonia of limbs. The striking feature was the presence of “slow” myoclonus resulting in extension of trunk and abduction of shoulders along with transient loss of “luster” in the eyes. His brain MRI was unremarkable. His EEG showed periodic complexes. He was diagnosed as having subacute sclerosing panencephalitis.