English researchers used the entire population of England to create the largest study on this topic to date.
These researchers found a significantly greater risk of developing epilepsy in patients with MS.
This study also showed that patients who exhibited epileptic symptoms first had a greater chance of being diagnosed with MS within 10 years.
"Discuss any changes in your MS symptoms with your doctor."
This study was conceived of and led by Alexander N. Allen of the University of Oxford, Brasenose College, Radcliffe Square, Oxford, UK.
The researchers analyzed two sets of data consisting of hospital admission records from the Oxford Record Linkage Study (ORLS), collected between 1963 and 1998, along with data covering all of England from 1999 through 2011.
Epilepsy and MS are fairly common conditions and would have a reasonable chance of occurring in the same person. This study was conceived to see if the two occurred more often together than expected by chance.
The research team looked for occurrences of hospital admissions for epilepsy in people after a previous admission for multiple sclerosis (MS). This data was compared with a control group of more than 85,000 MS patients.
The researchers found a strong link between MS hospital admissions and admission for epilepsy within 10 years. The risk increased by 4.7 times in the ORLS group and 3.9 times in the all-England group.
This study also looked at admissions for epilepsy followed by admission for MS and found a 2.5 times greater risk in the ORLS group and 1.9 times greater risk in the all-England group.
These researchers concluded that MS and epilepsy may occur together more often possibly because the lesions associated with MS act as a focus of an epileptic seizure.
"This is an interesting article because it closely reflects the neurological concept of permissive comorbidities in conditions that had long been completely disjointed," said Sadat Shamim, MD, Director of Inpatient Neurology and Neurophysiology at the Baylor University Medical Center in Dallas.
"In the past epilepsy had been thought to be a largely cortical gray matter disease (originating in the surface layers of the brain) and multiple sclerosis (MS) had been thought to be mostly a subcortical or white matter disease and never the twains shall meet. However, it has been shown that epilepsy can be perpetuated by subcortical circuits and that MS can cause cortical changes," explained Dr. Shamim, who was not involved in this research.
"This study describes MS to have a permissive role in development of epilepsy with a greater occurrence of epilepsy in patients with MS than seen in the general population. Although there may be an increased risk of developing MS in patients with epilepsy, this finding was not as robust as the reverse," said Dr. Shamim.
This study suggested that doctors should be aware of the connection between MS and epilepsy. The findings may also help researchers come up with additional theories related to the two diseases.
This study only looked at people who had a hospital admission or sought care from their doctor for both conditions. It did not have the ability to follow up on patients who moved out of either the Oxford area or England.
This study was published on December 4 in BMC Neurology.
No conflicts were reported by the researchers.
This study was supported by the English National Institute for Health Research.