Magnetic resonance imaging patterns of subacute sclerosing panencephalitis may mimic metabolic disorders: clinical, electroencephalographic and imaging features of six cases.

Subacute sclerosing panencephalitis is a rare, devastating neurodegenerative encephalitis whose diagnosis and therapy are still in question. Atypical clinical presentation and heterogeneity of neuroimaging findings that have been initially confused with metabolic disorders have hampered early diagnosis. To describe a series of patients with subacute sclerosing panencephalitis with imaging findings mimicking metabolic disorders. A total of six patients with subacute sclerosing panencephalitis were diagnosed from January 2012 to December 2016 in whom a metabolic disorder was suspected on initial clinical and MRI findings. Detailed laboratory investigation was performed in all patients. All patients presented with atypical neurologic manifestations, including dystonia, syncopal attacks, involuntary limb movements, meaningless speech and ataxia. Magnetic resonance imaging abnormalities included bilateral putaminal, bilateral posterior periventricular white matter and diffuse or splenial corpus callosum involvement which are particularly unusual in SSPE and mostly observed in metabolic disorders. All patients had elevated cerebrospinal fluid Ig G measles antibodies. The diagnosis of subacute sclerosing panencephalitis through clinical and imaging features can be considerably challenging. It is crucial to differentiate it from metabolic disorders, since the management and clinical outcome are different.