Limbic Encephalitis - Two Case Reports

Limbic encephalitis was initially described as a rare paraneoplastic syndrome characterized by rapid progression, anterograde amnesia, mood disturbances, psychiatric symptoms and temporal lobe epilepsy. In the last decade, the concept of limbic encephalitis has expanded - apart from any paraneoplastic aetiology, it may occur as an infectious or autoimmune disorder (that may or may not be associated with antineuronal antibodies). Due to its various non-specific symptoms, early diagnosis of limbic encephalitis is frequently difficult. The first reported case, a 53-year-old female, presented with short-term memory loss, and was treated initially for Alzheimer's disease, later developing typical symptoms of limbic encephalitis with rapid alteration of consciousness, accompanied by seizures and discrete temporal lobe signal change on MRI. The second case was a 38-year-old male with rapidly progressing amnesia and behavioural disturbances. Development of epileptic seizures, typical medial temporal lobe signal change on MRI and abnormal increase of antibodies against voltage-gated potassium channels confirmed a diagnosis of limbic encephalitis. Both cases improved after corticosteroid therapy. No paraneoplastic origin was found in either case. We discuss the most usual signs and symptoms of limbic encephalitis, focusing on recent classification, diagnostics and treatment of this often under-diagnosed disorder.