How to differentiate and treat real vs false seizures, specifically psychogenic non-epileptic seizures (PNES)?

Differentiating Real Seizures from Psychogenic Non-Epileptic Seizures (PNES)

The most reliable method to distinguish true epileptic seizures from PNES is video-EEG monitoring, which demonstrates normal blood pressure, heart rate, and absence of epileptiform activity during apparent loss of consciousness in PNES patients. 1, 2

Key Clinical Features for Differentiation

Timing and Duration Characteristics

Seizure onset and movement patterns are critical distinguishing features:

• True epileptic seizures: Tonic-clonic movements begin at the exact moment of loss of consciousness and typically last <30 seconds (mean 74-90 seconds total) 1
• PNES: Movements begin after apparent loss of consciousness, with duration frequently >5 minutes and sometimes 10-30 minutes 1
• Convulsive syncope (often confused with both): Brief myoclonic jerks starting after loss of consciousness, lasting <15 seconds 1

Movement Quality and Pattern

The nature of movements provides strong diagnostic clues:

• Epileptic seizures: Symmetrical, synchronous tonic-clonic movements; hemilateral clonic movements; restricted to one limb or side 1
• PNES: Asymmetrical, asynchronous movements; pelvic thrusting; repeated waxing and waning in intensity; changes in movement nature during the event 1, 2
• Movement quantity: Few movements (~10) suggest syncope or epilepsy; many movements ("cannot count") suggest PNES or epilepsy 1

Eye Position During Event

Eye position is highly specific for PNES:

• Eyes closed during unconsciousness: Strongly suggests PNES or psychogenic pseudosyncope 1, 2
• Eyes open: Typical for epileptic seizures and most syncope 1

Post-Ictal Features

Recovery patterns differ significantly:

• Epileptic seizures: Prolonged confusion (often >5 minutes), muscle aching, headache, elevated creatinine kinase and prolactin 1
• PNES: Variable recovery, often with continued symptoms of psychopathology 3
• Syncope: Immediate or brief confusion, nausea, pallor 1

Tongue Biting Pattern

Location of tongue injury is diagnostically useful:

• Lateral tongue bite (uni- or bilateral): Strongly suggests epileptic seizure 1
• Tip of tongue bite: May occur in syncope 1
• Note: Tongue biting does not differentiate PNES from epilepsy reliably 1

Diagnostic Testing Algorithm

First-Line: Video-EEG Monitoring

Video-EEG is the gold standard for PNES diagnosis 4, 2:

• Captures typical events with continuous ECG, EEG, and blood pressure monitoring
• PNES findings: Apparent unconsciousness with normal vital signs and no epileptiform activity 1
• Epileptic seizure findings: Epileptiform discharges correlating with clinical event
• Accuracy is high when typical seizures are recorded 2

Tilt-Table Testing for Specific Scenarios

Tilt-table testing is reasonable when syncope vs. seizure differentiation is unclear 1:

• Useful for distinguishing convulsive syncope from epilepsy in drug-refractory cases (50% of questionable epilepsy cases show positive tilt-table tests) 1
• Can establish psychogenic pseudosyncope diagnosis: apparent unconsciousness with normal hemodynamics 1
• Key finding for pseudosyncope: Eye closure during event, prolonged apparent loss of consciousness, increased heart rate and blood pressure 1

Ancillary Testing

EEG and neuroimaging have limited utility for PNES diagnosis:

• Interictal EEG is normal in syncope and may be normal in epilepsy 1
• Brain imaging (CT/MRI) not indicated for uncomplicated syncope 1
• EEG useful only if recorded during a provoked attack to establish psychogenic pseudosyncope 1

Treatment Approach

For PNES

Psychotherapy is the primary treatment modality for PNES 5:

• Multidisciplinary approach with structured treatment programs improves outcomes 4
• Critical first step: Clear communication of PNES diagnosis to patient 3
• Antiepileptic drugs should be discontinued (PNES patients are often misdiagnosed and inappropriately treated with anticonvulsants) 4, 6
• Address psychiatric comorbidities: depression, anxiety, PTSD, dissociative disorders (present in 65-80% of cases) 3

For True Epileptic Seizures

Standard antiepileptic drug therapy based on seizure type 7:

• Correct identification of seizure type crucial for appropriate treatment selection 7
• For status epilepticus: benzodiazepines first-line, followed by fosphenytoin, levetiracetam, or valproic acid 8

Critical Pitfalls to Avoid

Dual diagnosis occurs in 10% of PNES patients who also have true epilepsy 6, 2:

• Do not assume all events are PNES in patients with confirmed epilepsy
• Video-EEG monitoring essential when pseudo-refractory epilepsy suspected (20-25% of "refractory epilepsy" cases are actually PNES) 6
• Overreliance on single clinical features leads to diagnostic errors 2
• No single feature is pathognomonic for PNES 2

Delayed diagnosis is common:

• Mean latency between symptom onset and PNES diagnosis is 7 years 3
• Misdiagnosis leads to inappropriate anticonvulsant escalation, unnecessary side effects, and reduced quality of life 6