First and foremost is high level of clinical suspicion especially in young adults showing abnormal behavior as well as autonomic instability. The person may have alteration in level of alertness and seizures as well during early stage of the illness. Clinical examination may further reveal delusions and hallucinations. The initial investigation usually consists of clinical examination, MRI of the brain, an EEG and a lumbar puncture for CSF analysis. MRI of the brain may show abnormalities in the temporal and frontal lobes, but do so in less than half of cases. A FDG-PET scan of the brain may show abnormalities in cases when the MRI scan is normal. EEG is abnormal in almost 90% of cases and typically shows general or focal slow wave activity. CSF analysis often show inflammatory changes with increased levels of white blood cells, total protein and the presence of oligoclonal bands.<unk><unk> <unk> bodies can be detected in serum and/or CSF. Whole body FDG-PET is usually performed as a part of tumor screening. Gynecological ultrasound or a pelvic MRI might be performed to search for an ovarian teratoma in women. Diagnostic criteria for probable and definite<unk>  have been proposed to facilitate diagnosis at an early stage of the disease and help initiate early treatment.
Anti-NMDA receptor encephalitis
Neuroleptic malignant syndrome
Anti-Hu associated encephalitis
Psychosis
Anti-VGKC-complex encephalitis
Viral encephalitis
Powassan encephalitis
Autoimmune encephalitis