LIMBIC ENCEPHALITIS OCCURRING IN ASSOCIATION WITH ALZHEIMERS-DISEASE

Paraneoplastic limbic encephalitis is a rare cause of subacute dementi a. A patient with limbic encephalitis and small-cell lung carcinoma is reported in whom the onset of subacute cognitive impairment was obscu red by concurrent Alzheimer's disease. MRI revealed increased T2 signa l in medial temporal lobes which corresponded to inflammatory patholog y demonstrated at necropsy. High titres of antineuronal antibody (type II, anti-Hu) were present at death. Direct immunofluorescent staining of necropsy tissue revealed IgG bound to most remaining neurons in th e temporal lobe. Antineuronal antibody screening and MRI are important in detecting limbic encephalitis.