Novel electroencephalographic delta brush pattern in typhoid encephalitis

Abstract

Extreme delta brush is a rare interictal electroencephalography (EEG) pattern first described in anti-N-methyl-D-aspartate receptor (NMDA) receptor encephalitis and initially considered pathognomonic for this autoimmune subtype. It has since been reported, rarely, in other forms of encephalitis. Typhoid encephalitis commonly presents with acute confusion and behavioral changes and may also cause severe neurologic complications, including seizures, coma, and cerebral edema. Typhoid toxins may increase blood–brain barrier permeability and contribute to neurologic dysfunction. We report this rare EEG finding in a 13-year-old girl with typhoid encephalitis. Our case highlights the diagnostic value of EEG in unexplained encephalopathy or suspected encephalitis. Although extreme delta brush is specific to anti-NMDAR encephalitis, its presence should prompt evaluation for other autoimmune or infectious encephalitis when the anti-NMDAR antibodies are negative.