Large Population-Based Study Links Epilepsy to Other Autoimmune Disorders

Sing Ong M, Kohane IS, Cai T, et al.Population-Level Evidence for an Autoimmune Etiology of Epilepsy.JAMA Neurol. (2014) March 31. doi:10.1001/jamaneurol.2014.188

Another strong argument for prompt treatment of autoimmune disease (AD.) Epilepsy is often comorbid with AD, and treating the latter can stop seizures. This study found that AD increased the odds ratio of epilepsy by 3.8 in non-elderly patients, and by 5.2 in children.

A retrospective population-based study that screened more than 2.5 million beneficiaries of an insurance plan in the United States has confirmed a strong relationship between epilepsy and 12 autoimmune diseases:  rheumatoid arthritis, systemic lupus erythematosus (SLE), antiphospholipid syndrome, Sjögren syndrome, psoriasis, Graves disease, Hashimoto thyroiditis, Crohn disease, ulcerative colitis, type 1 diabetes mellitus, myasthenia gravis, and celiac disease. Higher epilepsy risk was consistently associated with all 12 diseases, echoing results of previously published studies.

Patients with antiphospholipid syndrome had the highest increased risk, at 9-fold. Patients with SLE had a 7-fold increased risk. The prevalence of epilepsy was 7.3% among SLE patients younger than age 19, a 22-fold increased risk. Children and teenagers with celiac disease had a 17-fold increased risk, and 5.7% had epilepsy. This is consistent with published studies.

Two possible mechanisms associated with AD may cause epilepsy: Neuroinflammation and cerebrovascular complications. For example, SLE is associated with inflammation in the brain, and antiphospholipid syndrome is associated with cerebral ischemia.

AD drugs did not seem to increase the risk of epilepsy, and some AD drugs (aminosaicylates, NSAIDs, and biologics) appear to reduce it. Conversely, anti-epilepsy drugs did not seem to increase the risk of AD, and some anti-epilepsy drugs, such as valporate and carbamazepine, are anti-inflammatory.

Earlier treatment of AD is more effective than delayed treatment at preventing epilepsy, according to this data. However, the study was not designed to assess the effects of AD medications on epilepsy, so any of these associations need explicit confirmation.