<prompt> A young male develops fever, followed by headache, confusional state, focal seizures and a right hemiparesis. The MRI performed shows bilateral frontotemporal hyperintense lesion. The most likely diagnosis is:Acute pyogenic meningitisHerpes simplex encephalitisNeurocysticercosisCarcinomatous meningitis  <response>: Herpes simplex encephalitis Herpes simplex encephalitis HSE HSV 2 in neonates, HSV 1 in children, adults usually activation of latent infection in Gasserion ganglion Most common viral encephalitis Fulminant, necrotizing, hemorrhagic viral infection Predilection for limbic system temporal lobes, cingulate gyri, subfrontal region, in older children, adults CT: Often normal early in the disease. Low-density lesions in temporal lobes with mild mass effect are common initially. Hemorrhage is highly suggestive of HSE and is seen later in the disease course. CECT shows the ill-defined patchy or gyriform enhancement in neonatal HSE. It shows strikingly increased density of coical gray matter and diffuse low attenuation in white matter MR: Gyral edema Hemorrhage in late stages. Temporal lobe hyperintense on T2 WI - enhancement in early stage. 