Abstracts

Rationale: Ictal apnea and hypoxia can be seen in around 1/3 of patients with intractable focal epilepsy and has been implicated as a mechanism of sudden unexpected death in epilepsy (SUDEP). However, an epidemiologic link between ictal hypoxia and subsequent SUDEP has not been established. We wish to report a patient with new-onset temporal lobe epilepsy and severe central apnea and hypoxia during video EEG monitoring who subsequently passed away at home from autopsy confirmed SUDEP. Methods: 30-year old right handed female with no prior medical history and no known epilepsy risk factors who presented in status epilepticus to an outside hospital with seizures arising from both temporal lobes, > 100 within the first 4 days. An extensive workup yielded an elevated thyroid-peroxidase antibodies of 354.4 and lymphocytic pleocytosis on CSF. She was in the intensive care unit for several weeks and discharged on carbamazepine and phenobarbital and a short course of steroids. She continued to have weekly complex partial seizures often with noticeable pallor. Nine months after disease onset, she was found dead by family members in the morning in prone position. The family was not alerted by the auditory alarm system in her room or by sleeping next room with open doors. Results: Video EEG monitoring 4 months before her death was reviewed. She had been on long term video EEG with concurrent monitoring of EKG and respiratory parameters (chest and abdominal wall excursion, airflow, end-tidal CO2, O2 saturation, see figure 1). Her interictal EEG was noteworthy for intermittent generalized slowing and bitemporal sharp waves. Several seizures while monitored arising from the left temporal lobe associated with ictal apnea and oxygen desaturation below 70% were recorded, associated with staring and subtle bilateral tonic movements. Figure 1: EEG seizure onset precedes the clinical onset by 50 seconds. A broadly distributed left hemispheric sharp wave maximum temporal followed by a low amplitude rhythmical activity is seen at onset (see insert). The ictal pattern spreads to the contralateral temporal lobe approximately 1 minute after clinical seizure onset. Patient s baseline EKG shows a normal sinus rhythm at 60 beats per minutes (bpm) during sleep which doubles during the event. Patient s baseline O2 saturation was measured at 93% and her ETCO2 was 46-47 mm Hg. Approximately 40 seconds after EEG seizure onset, she was noted to have central apnea with absent chest and abdominal excursion for over 1 minute associated with a maximum O2 desaturation of 68 %. Conclusions: We present a patient with temporal lobe epilepsy associated with central ictal apnea and severe oxygen desaturation who subsequently died of SUDEP. The case strongly suggests that ictal apnea may be a risk factor for SUDEP. It also demonstrates that standard video EEG monitoring with EKG is insufficient to detect ictal apnea. Desaturation and SUDEP can occur in partial seizures even without noticeable convulsive activity. Oxygen monitoring and hypoxia triggered alarm systems may improve the safety of patients during seizure recording and if technically feasible also at home.