Abstracts

Rationale: Systematic analyses of patients with epilepsy referred to tertiary care are infrequent. We explored clinical features, epilepsy risk factors, seizure triggers and psychiatric comorbidity, in a large self contained newly referred population. Methods: The University of Calgary Division of Neurology is the main tertiary referral centre for adults with epilepsy, serving 1.3 million people. We prospectively captured data on all consecutive 1st encounters in our outpatient epilepsy program, using a validated data capture and verification system, excluding patients with single seizures and children. We analyzed demographics, causes of epilepsy, syndrome and seizure type, seizure triggers, and psychiatric comorbidity and its treatment. Results: In 687 consecutive patients (52% women), mean age and duration of epilepsy was 40 and 12 years, respectively, 23% had an abnormal neurological exam, 83% were on AEDs, and 21% were seizure free in the last year. The majority of patients had focal epilepsy (64%), while 23% had idiopathic generalized epilepsy and 10% had non-epilepsy diagnoses (syncope, psychogenic, others). Primary or secondary generalized tonic clonic (GTC) seizures occurred in 67%. Focal seizures occurred in 55%. The probability of having at least monthly seizures was 70% for simple partial, 54% for complex partial, 56% for GTC and 60% for absences. The probability of having daily seizures was highest for absence (31%), tonic (47%), atonic (40%), myoclonic (39%) and psychogenic (36%) seizures. The most common risk factors for epilepsy were head injury (40%) and family history of seizures (30%), followed by developmental disorders (13%), perinatal factors (7%), stroke (6%), and brain tumor (6%). The most commonly described seizure triggers were stress (82%) and sleep deprivation (70%), followed by non-adherence to AEDs (18%), alcohol (17%) and menses (17%). Psychiatric comorbidity was present at the time of the 1st visit in 28%, and in the past in 23%. The three most common self-reported past psychiatric comorbidities were depression (16%), alcohol/drug dependence (7%), and anxiety disorder (4%). The two most common comorbidities at the time of the 1st visit were depression (14%) and anxiety (7%). Treatment for psychiatric comorbidity was received only by 65% of patients with past comorbidities and by 55% of those with current comorbidities. 7% of patients reported a learning disorder and 30% reported other significant medical conditions. Conclusions: This consecutive sample provides a good approximation to a population based cohort receiving care at a tertiary care epilepsy program. The general clinical features are similar to other reported series, but GTCs were more frequent. Head injuries and family history were the most important risk factors in this adult population. Factors requiring further exploration include psychiatric comorbidity which was frequent and often untreated, stress as a common and treatable seizure trigger and the lack of AED therapy in 20% of patients.