Autoimmune limbic encephalitis causing fits, rapidly progressive confusion and hyponatraemia.

A 78-year-old woman presented with a short history of confusion and seizures and was found to be hyponatraemic. Routine investigations failed to find a cause. Magnetic resonance imaging showed encephalitic changes in the temporal lobes, and voltage-gated potassium-channel antibodies were found in her blood in high titre. Although rare, this condition is important because it may respond to immunosuppression.