Misdiagnosis of epilepsy: Many seizure-like attacks have a cardiovascular cause

OBJECTIVES We sought to investigate the value of cardiovascular tests to di agnose convulsive syncope in patients with apparent treatment-resistant epi lepsy. BACKGROUND As many as 20%, to 30% of epileptics may have been misdiagnosed. Many of these patients may have cardiovascular syncope, with abnormal move ments due to cerebral hypoxia, which may be difficult to differentiate from epilepsy on clinical grounds. METHODS Seventy-four patients (33 men, mean age 38.9 +/- 18 years [range 16 to 77]) who were previously diagnosed with epilepsy were studied. Inclusio n criteria included continued attacks despite adequate anticonvulsant drug treatment (n = 36) or uncertainty about the diagnosis of epilepsy, on the b asis of the clinical description of the seizures (n = 38). Each patient und erwent a head-up tilt test and carotid sinus massage during continuous elec trocardiography, electroencephalography and blood pressure monitoring. Ten patients subsequently underwent long-term electrocardiographic (ECG) monito ring with an implantable loop recorder. RESULTS In total, an alternative diagnosis was found in 31 patients (41.9%) , including 13 (36.1%) of 36 patients taking an anticonvulsant medication. Nineteen patients (25.7%) developed profound hypotension or bradycardia dur ing the head-up tilt test, confirming the diagnosis of vasovagal syncope. O ne other patient had a typical vasovagal reaction during intravenous cannul ation. Two patients developed psychogenic symptoms during the head-up tilt test. Seven patients (9.5%) had significant ECG pauses during carotid sinus massage. In two patients, episodes of prolonged bradycardia correlated pre cisely with seizures according to the insertable ECG recorder. CONCLUSIONS A simple, noninvasive cardiovascular evaluation may identify an alternative diagnosis in many patients with apparent epilepsy and should b e considered early in the management of patients with convulsive blackouts. (C) 2000 by the American College of Cardiology.