Limbic encephalitis represents a group of autoimmune conditions characterized by inflammation of the limbic system and other parts of the brain. The cardinal sign of limbic encephalitis is a severe impairment of short-term memory; however, symptoms may also include confusion, psychiatric symptoms, and seizures. The symptoms typically develop over a few weeks or months, but they may evolve over a few days. Limbic encephalitis is often associated with an underlying neoplasm (paraneoplastic limbic encephalitis); however some cases never have a neoplasm identified (non-paraneoplastic limbic encephalitis). Delayed diagnosis is common, but improvements are being made to assist in early detection. Various tests including imaging studies (MRI, PET) laboratory tests (CSF analysis), and tests that measure the electrical activity of the brain (EEG) may be utilized to confirm a diagnosis. Treatment includes removal of the neoplasm (if identified) and immunotherapy.

• Infection (herpes simplex virus, cytomegalovirus, adenovirus, HIV)
• Acute disseminating encephalomyelitis (ADEM)
• Degenerative diseases (Creutzfeldt-Jakob disease, rapidly progressing Alzheimer disease)
• Nutritional deficiencies (thiamine deficiency)
• Recreational drugs/alcohol
• Metabolic disturbances
• Connective tissue disorders (systemic lupus erythematosus)
• Primary or secondary tumor of the central nervous system