A recent US study provides evidence of an autoimmune cause of epilepsy, leading researchers to suggest that individuals diagnosed with either an autoimmune condition or epilepsy should be screened for the other.
The researchers were given access to data from more than 2.5 million insurance clients registered with a US National Health Insurance agency. The researchers assessed the association between epilepsy and 12 autoimmune conditions: type 1 diabetes mellitus, psoriasis, rheumatoid arthritis, Graves' disease, Hashimoto's thyroiditis, Crohn's disease, ulcerative colitis, systemic lupus erythematosus, antiphospholipid syndrome, Sjögren syndrome, myasthenia gravis, and celiac disease.
The risk for epilepsy was raised nearly four times in individuals with an autoimmune condition and was particularly high in children. This heightened risk was evident across all 12 autoimmune conditions.
The researchers determined the following from the study:
- 17.5% of individuals with epilepsy had an autoimmune condition
- 30% of participants had epilepsy before being diagnosed with an autoimmune condition
- 1-2 years was the timeframe within which seizures tendered to occur after a diagnosis of an autoimmune condition
- 70% of individuals with both an autoimmune condition and epilepsy were not on antiepileptic drugs for at least 2 years before a diagnosis of an autoimmune condition.
The researchers recommend that because epilepsy and an autoimmune condition can often co-occur that individuals with either condition undergo investigation for the other.
"There are subtle signs of epilepsy that may suggest to an immunologist that a patient should be assessed by a neurologist," Mark Gorman, MD, study author and neurologist at Boston Children's Hospital, said in a statement. "Similarly, if you are a neurologist, a referral to an immunologist may be warranted if a patient shows subtle signs of autoimmunity."
The authors do admit that their study is limited because of the claims data, which does allow for an in-depth classification of epilepsy type.
Source: JAMA Neurol.
Published online March 31, 2014. doi:10.1001/jamaneurol.2014.188