CASE PRESENTATION: 26 year old G1P0 female presented at 36 weeks gestation with increasing confusion and changes in her personality and speech for a few weeks. Brain MRI showed extensive T2 flair hyperintensities in the white matter of the left parietal and both occipital lobes. CSF was significant for 5 WBCs, 12% lymphocytes, normal protein and glucose. EEG showed diffuse cerebral dysfunction with intermittent bursts of delta waves. The patient developed increasing lethargy, incomprehensible speech and progressive motor deficits, prompting an urgent C-section. Her serum ANA was positive, but all other autoimmune serologies were negative. A CSF autoimmune panel, paraneoplastic panel, and anti-NMDA receptor antibodies were negative. Since she had measles at the age of 11 months, measles serologies were checked - her serum IgG was positive at 12.98, and serum IgM was negative. CSF rubeola IgG was positive at 1:128 and IgM was 1:1. Therefore, the patient was diagnosed with SSPE. Despite initiation of isoprinosine, her neurologic status progressed to a persistent vegetative state within 3 weeks.