Abstracts

Rationale: Patients with epilepsy are exposed to a variety of potential risk factors and comorbidities that could theoretically increase their probability to develop peripheral neuromuscular diseases (PNMDs). These may include the use of antiepileptic drugs (AEDs), traumatic injuries, or other comorbid conditions. On the other hand, the use of antiepileptic drugs (AEDs) may potentially mask early neuropathic symptoms and delay diagnosis. In this study, we aimed to determine the types and relative prevalence of PNMDs and their risk factors in patients with history of seizures who were referred for nerve conduction (NCV) studies. To partially adjust for the impact of stress and concurrent use of AEDs, results were compared with those from patients with history of headaches who were referred for NCV studies. Methods: We conducted a retrospective review of the records and electrodiagnostic studies of 74 patients with a history of seizures and 136 patients with history of headaches who were referred for evaluation and NCV studies. Demographics, reason for referral, past medical history, medications, and social history were compared as risk factors using logistic regression. Results: Among the patients with seizures who were referred for NCV studies, peripheral polyneuropathies (PN) were diagnosed in 39.2%, entrapments in 25.7%, radiculopathies in 17.6%, and myopathies in 1.3%. In contrast, in the referral subpopulation with history of headaches, PN were diagnosed in 8%, entrapments in 42.6%, and radiculopathies in 23.5%. Age older than 45 years increased the risk of PN only among patients with seizures (odds ratio, OR 8.2; 95% confidence interval, CI 1.7-38.9) but not in the headache population. Female gender increased the risk of entrapments in the seizure population only (OR 2.7; CI 1.4-5.5) but decreased the risk of PN in the headache population (OR 0.3; CI 0.08-0.96). Diabetes mellitus increased the risk of PN only in the headache population (OR 5.4; CI 1.4-21.1). Use of antiepileptic drugs, prior trauma, smoking or alcohol abuse did not alter the prevalence of PN or entrapments. Conclusions: Among patients referred for NCV studies, PN was more commonly found in patients with seizures whereas entrapments in patients with headaches. Risk factors for PN and entrapments also differed in each referral population. These suggest that factors inherently associated with the expression of seizures or headaches may differentially influence the type, prevalence, and natural course of PNMDs. Prospective studies are needed to further clarify the impact of seizures, headaches, and their comorbid conditions or therapies on PNMDs.