[Clinical and immunological profile of limbic encephalitis associated with voltage-gated potassium channel antibodies].

OBJECTIVE

Limbic encephalitis (LE) associated with antibodies to voltage-gated potassium channels (VGKC-Ab) have recently been reported as an immunotherapy responsive encephalitis typically not associated with cancer. In the present study, we report the clinical, radiological and evolution features of LE associated with VGKC-Ab in our area.

METHODS

Retrospective analysis of clinical, radiological and evolution variables in a series of LE associated with VGKC-Ab without onconeuronal antibodies.

RESULTS

Thirteen patients were detected during a 10-years period; 77% were male and the median age was 67 years (50-75 years). The median time of presentation was 10 weeks (1-24 weeks). All patients had episodic memory impairment, 77% had epileptic seizures and 77% had confusion or behaviour disturbances. A REM-behaviour disorder (RBD) was detected in all asked patients. MRI was abnormal in the 84.6%, EEG in the 91%, CSF in 60% and hyponatraemia was detected in the 83% of cases. All cases were treated with IGIV and/or costicosteroids and 61.5% remained asymptomatic or with minimal symptoms. After a median follow-up of 24 months (3-108 months) no patient developed cancer.

CONCLUSIONS

Demographic and clinical characteristics of our series are similar to those previously reported, confirming its immunotherapy-responsive condition. Chronic presentation or normal MRI does not exclude the syndromic diagnoses, and the coexistence of RBD, hyponatraemia or inflammatory CSF are especially useful to make the diagnoses in these cases.