Electrographic significance of Periodic Discharges and association with etiology and outcome in a tertiary care hospital, a retrospective cohort study

Abstract

Background and Objective:

Periodic discharges on electroencephalograms (EEGs) are rhythmic waveforms that may indicate acute or subacute brain injury. This aim of this study was to determine the frequency distribution of periodic discharge subtypes on EEG and to assess their association with underlying etiologies and clinical outcomes in a tertiary care hospital.

Methods:

This retrospective observational cohort study included neurological patients aged ≥18 years admitted to the medical ICU or ward of Aga Khan University Hospital between January 1, 2021, and January 1, 2023, with periodic discharges on EEG. Patients with prior traumatic brain injury were excluded. Data on demographics, clinical presentation, EEG subtype, neuroimaging findings, management, and outcomes were extracted from medical records. Statistical analysis was performed using SPSS version 22, with categorical variables presented as frequencies and percentages, continuous variables as mean ± standard deviation, and significance set at p ≤ 0.05.

Results:

 Out of f 41 patients, 51.2% were female, with a mean age of 58.5 years. Generalized tonic-clonic seizures were the most common presentation (48.8%), and ischemic stroke was the leading etiology (31.7%). Lateralized periodic discharges were the most frequent EEG subtype. Chronic imaging changes were present in 34%, most often encephalomalacia and gliosis. Most patients (87.8%) were discharged home, while mortality occurred in 12.2%, often linked to status epilepticus or metabolic encephalopathy.

Conclusion:

 Periodic discharge subtypes, particularly lateralized patterns, are often associated with ischemic stroke and severe neurological presentations. Their recognition and etiological correlation are essential for timely intervention and improved patient outcomes.