Usefulness of the head-upright tilt test for distinguishing syncope and epilepsy in children.

Summary:  Purpose: Episodic loss of consciousness in children, whether or not associated with hypertonia or short-duration clonic movements, presents a diagnostic challenge to the pediatrician and child neurologist. We provide some evidence of the usefulness of the head-upright tilt test for investigating the causes of transient loss of consciousness in children, and for distinguishing between syncope, convulsive syncope, and epilepsy. Methods: We studied nine children previously diagnosed as epileptic on the basis of compatible clinical events and epileptiform findings in routine EEGs who were treated over the long term with antiepileptic drugs, but whose clinical records suggested syncope or convulsive syncope rather than epilepsy on reevaluation. All subjects underwent head-upright tilt testing. Results: The tilt-test result was positive in all nine cases, with the patients reporting the same symptoms as in the previously considered epileptic attacks. Conclusions: Inadequate histories and misuse/overinterpretation of EEG results often lead to misdiagnosis of epilepsy in children. The head-upright tilt test is a useful and reliable diagnostic technique, allowing syncopal events to be induced and evaluated under controlled conditions. In a subset of patients, it may help to distinguish epilepsy from simple or convulsive syncope.