Cryptogenic Epilepsy: An Infectious Etiology?

Summary: Purpose: Cryptogenic epilepsy, the group of epilepsy syndromes for which an etiology is unknown, comprises ∼20% of all epilepsy syndromes. We selected patients in this subgroup of epilepsy and tested them for evidence of Toxoplasma gondii IgG antibodies by the enzyme-linked immunosorbent assay. T. gondii is found in up to 20% of the U.S. population forming dormant brain cysts in the latent bradyzoite form. We investigated the hypothesis that dormant T. gondii infection might be associated with cryptogenic epilepsy.

Methods: We selected patients with cryptogenic epilepsies and tested them for evidence of T. gondii IgG antibodies by the enzyme-linked immunosorbent assay. A control group was also tested for comparison.

Results: We have found a statistically-significant elevation of T. gondii antibodies among cryptogenic epilepsy patients as compared to controls [59% increase in optical density (OD), p = 0.013]. This association persisted after adjustment for subjects' gender and age in a multiple logistic regression model; however, it was no longer as statistically significant.

Conclusions: Our results suggest that chronic T. gondii infection with brain cysts may be a cause of cryptogenic epilepsy.