skip to main content

Triphasic Waves – Metabolic Encephalopathy — SCE Neurology MCQ

Instant feedback + full explanation. One question, done properly.

HardClinical NeurophysiologyTriphasic Waves – Metabolic EncephalopathySCE Neurology

In septic encephalopathy, EEG shows generalised periodic discharges with triphasic morphology. What is the most accurate interpretation?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — They support diffuse toxic-metabolic cerebral dysfunction but are not specific for hepatic encephalopathy and may lie on the ictal–interictal continuum

The best answer is “They support diffuse toxic-metabolic cerebral dysfunction but are not specific for hepatic encephalopathy and may lie on the ictal–interictal continuum”. Triphasic morphology is an EEG descriptor rather than a single diagnosis; clinical state, evolution and response to intervention determine ictal significance. “They confirm non-convulsive status epilepticus in every case” is a credible alternative elsewhere, but it fails the decisive discriminator in this case. “They are pathognomonic for sporadic CJD” is a credible alternative elsewhere, but it fails the decisive discriminator in this case. “They establish death by neurological criteria” is a credible alternative elsewhere, but it fails the decisive discriminator in this case. “They are a normal ageing variant requiring no clinical correlation” is a credible alternative elsewhere, but it fails the decisive discriminator in this case.

Reference: American Clinical Neurophysiology Society critical-care EEG terminology: https://pubmed.ncbi.nlm.nih.gov/33475321/