A Case of Hyperventilation Syndrome Mimicking Complex Partial Seizure: Usefulness of EEG Monitoring in Emergency Department

Acute hyperventilation syndrome not only can be clinically misdiagnosed as epileptic seizures, but also complex partial seizures may involve hyperventilation as a part of aura. Although electrography (EEG) monitoring is one of the most important procedure to differentiate these conditions, it could not be widely used in emergency department. Variety forms of epileptic attack, mainly idiopathic generalized epilepsy, are provoked by voluntary hyperventilation. In contrast, it is not clear whether hyperventilation can activate the partial seizures. We reported a case of acute hyperventilation syndrome (HSV) mimicking first onset complex partial seizure, impending non-convulsive status epilepticus, which was diagnosed by EEG in the emergency department. The electrographic seizure was provoked again by voluntary hyperventilation after clinical improvement.