LPDs (lateralized periodic discharges, formerly PLEDs) on EEG

Lateralized periodic discharges (formerly PLEDs) · Periodic · ICU

Periodic sharp waves about once a second over the left hemisphere; the right is spared. Simulated trace, longitudinal bipolar channels. Open in the interactive viewer

What it looks like

Sharp discharges of similar shape recurring at nearly regular intervals, usually 0.5–2 Hz, over one hemisphere. They reflect an acute or subacute destructive lesion: stroke, herpes simplex encephalitis, tumour, haemorrhage, or the aftermath of seizures. ¹

What it means at the bedside

Of all the periodic and rhythmic patterns, LPDs carry the strongest association with seizures, more so when faster than about 1.5 Hz or with superimposed fast or rhythmic activity ("plus"). ²⁵ Fever, confusion and temporal LPDs: treat for herpes simplex encephalitis while you confirm it. ¹⁷

PeriodicLateralizedHigh seizure risk

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Sources

Hirsch LJ, et al. American Clinical Neurophysiology Society's Standardized Critical Care EEG Terminology: 2021 version. J Clin Neurophysiol 2021;38:1–29. doi.org/10.1097/WNP.0000000000000806
Tunkel AR, et al. The management of encephalitis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis 2008;47:303–327. doi.org/10.1086/589747
Rodriguez Ruiz A, et al. Association of periodic and rhythmic electroencephalographic patterns with seizures in critically ill patients. JAMA Neurol 2017;74:181–188. doi.org/10.1001/jamaneurol.2016.4990

LPDs (lateralized periodic discharges, formerly PLEDs) on EEG

What it looks like

What it means at the bedside

Sources

Related patterns