PNES vs. Epileptic Seizures: Reading the Difference at the Bedside

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Updated July 2026 | More ICU clinical guides →

Few bedside events are as easy to misread as a convulsion. A patient shakes, the team floods the room, and benzodiazepines start flowing. Some of those events are epileptic seizures driven by abnormal cortical discharge. Others are psychogenic nonepileptic seizures (PNES) — now often called functional seizures — that look similar but arise from a different mechanism entirely and do not respond to antiseizure drugs. Telling them apart at the bedside is never certain without video EEG, but a nurse who knows the clinical patterns can guide the response, prevent needless intubation, and treat the patient with the dignity a functional disorder deserves. This guide walks through the features that lean one way or the other, why the distinction matters, and how to respond safely when you cannot be sure.

The short version: PNES are real, involuntary events — not faking — that stem from a psychological/functional mechanism rather than epileptic cortical discharge. Features that lean toward PNES include long duration with fluctuating course, side-to-side head shaking, out-of-phase or asynchronous limb movements, forward pelvic thrusting, closed and resisting eyes, preserved awareness during bilateral shaking, and rapid reorientation afterward. Features that lean toward epileptic include a stereotyped pattern, open eyes, tongue-biting on the side, incontinence, cyanosis, and a genuine postictal confusion. No single sign is proof — the gold standard is video EEG. When unsure, protect the airway, keep the patient safe, and avoid reflexive escalation.

Why this distinction matters

The stakes are not academic. Prolonged epileptic seizures are a true emergency — untreated status epilepticus causes neuronal injury and demands escalating drugs. But when a functional event is mistaken for refractory status, patients are given escalating benzodiazepines, loaded with antiseizure medications, sometimes intubated and paralyzed, and admitted to the ICU — a cascade of iatrogenic harm for a condition none of it treats. The reverse error is also dangerous: dismissing a true seizure as "just psychogenic" delays care that protects the brain. Because the same convulsion can be read either way, the nurse's structured observation is genuinely part of the diagnostic picture, not a side note.

Features that lean toward PNES

No feature is pathognomonic, but a cluster of these shifts the probability. Functional events tend to run longer than typical epileptic seizures (which usually self-limit within one to two minutes) and to wax and wane — pausing, then resuming — rather than following one stereotyped arc. The movements are often asynchronous or out of phase: arms and legs moving to different rhythms, side-to-side head shaking rather than a tonic turn, and sometimes forward pelvic thrusting. The eyes are frequently closed and actively resist opening, whereas epileptic seizures usually have open eyes. Awareness may be preserved during bilateral shaking, and patients often reorient quickly afterward without the deep, gradual postictal fog. Emotional triggers, crying or vocalizing with intelligible words during the event, and memory of the episode also point toward a functional mechanism.

Features that lean toward an epileptic seizure

Epileptic seizures tend to be brief and stereotyped — the same patient's events look alike each time. The classic accompaniments carry weight: lateral tongue-biting (the side of the tongue, not the tip), urinary incontinence, cyanosis from the apneic tonic phase, and a genuine postictal state of gradual, deepening confusion and drowsiness rather than quick recovery. Open eyes during the event, a preceding focal aura, and progression from focal to bilateral tonic-clonic activity all support an epileptic origin. Physiologic markers that follow — a lactate that rises after a true generalized convulsion, a transient prolactin elevation in the first 10 to 20 minutes — can support the picture, though they are imperfect and never delay treatment.

Feature	Leans PNES / functional	Leans epileptic
Duration	Often prolonged, fluctuating	Usually < 1–2 min, self-limited
Course	Waxes and wanes, pauses/resumes	Stereotyped, single arc
Movements	Asynchronous, side-to-side head, pelvic thrust	Synchronous, rhythmic, tonic then clonic
Eyes	Closed, resist opening	Open
Tongue	Tip bite (if any)	Lateral tongue-biting
Recovery	Rapid reorientation, memory often intact	True postictal fog, gradual
Other	Emotional trigger, vocalizing words	Incontinence, cyanosis, focal aura

No single sign confirms either diagnosis. All of these are probabilities, and epileptic seizures — especially those from the frontal lobe — can produce bizarre, thrashing, asynchronous movements that mimic PNES perfectly. Frontal seizures are brief and stereotyped but look "functional." The definitive test is video EEG capturing a typical event, which shows whether an ictal EEG correlate is present. Treat the bedside read as a working hypothesis, never a verdict.

Responding safely when you are not sure

Because you often cannot be certain in the moment, default to safety without escalating harm. Protect the patient from injury — pad rails, remove hazards, position to protect the airway. Do not force anything into the mouth. Monitor oxygenation and airway; true prolonged seizures compromise both, while functional events usually preserve them, which is itself informative. If the event has the hallmarks of a genuine prolonged convulsion, follow your status epilepticus protocol — timing and benzodiazepine dosing are what protect the brain. If the features strongly suggest a functional event and the patient is protecting their airway and stable, escalating antiseizure drugs may do more harm than good, and the team may choose to observe. Document precisely and objectively what you see — duration, movement pattern, eye state, responsiveness, incontinence — because that record is often what the epileptologist uses later.

Language matters and is part of the care. PNES is not faking, malingering, or attention-seeking. It is an involuntary functional neurological disorder, frequently linked to trauma or psychological stress, and it responds to psychological therapy rather than antiseizure drugs. Skeptical or dismissive language in front of the patient or family causes real harm and worsens outcomes. Describe events neutrally, avoid "pseudoseizure," and treat the person with the same respect you would extend to any patient with a serious diagnosis.

Where to go from here

Pair this with the status epilepticus guide for how to treat a true prolonged seizure, the nonconvulsive status and continuous EEG guide for the seizures you cannot see, the seizure precautions and postictal care guide for bedside safety, and the neuro checks and Glasgow Coma Scale guide for the assessment that frames every neuro event.