Periodic discharges in portable EEG of critically ill patients with altered mentation; an alerting and alarming phenomena with helpful clues.

INTRODUCTION

Periodic discharges (PDs) in critically ill patients with altered mental status (CIPAMS) have important implications. This study aimed to describe different characteristics of PDs in CIPAMS using routine electroencephalogram.

METHODS

This retrospective study was carried out at King Fahd University Hospital. The EEG recordings of CIPAMS reporting PDs were reviewed. All patients had at least 30 min of portable EEG recording (pEEG). Patients were dichotomized into two groups according to PDs. Clinical and radiological variables between the two groups were compared using Chi-square tests and Odds ratio. P value < 0.05 was considered statistically significant.

RESULTS

The electronic charts of 295 consecutive CIPAMS were reviewed. PDs, detected in 21% of the patients, were significantly more frequent in women as compared to men (OR = 1.71,CI = 1.09-2.67,P = 0.01). The mean (SD) age of the patients was significantly higher in the group having PDs than without (P = 0.01). LPDs were detected in 41, and GPDs in 17 patients. Chronic neurological illness, encephalitis, and brain tumor had a significant association with LPDs, whereas metabolic derangement and Creutzfeldt-Jakob disease with GPDs. The frequency and peri-ictal features were important determinants of non-convulsive seizure (NCS). Overall, PDs were associated with an increased likelihood of unfavorable outcomes and mortality.