A 35 year male came with history of mild to moderate fever from 3 days, headache from 2 Days and altered sensorium since morning. By occupation PVC factory worker. CBC, chest x-rays NCCT with Contrast CT normal and Viral marker negative.

PS for MP negative BUN,S.Cr; Normal, ECG ; show U wave Na-139,k+- 2.9, SGOT ;56,SGPT; 83 ; GGT S.ALP ; normal CSF routine, India ink and HSV PCR; Normal S.amonia; Normal EEG showed diffuse encephalopathy ABG; normal. What could be the most probable diagnosis?