Differentiating Pseudoseizure from True Seizure in a Code Situation
In a code situation, you cannot definitively distinguish pseudoseizure from true seizure without EEG monitoring, so you must treat all convulsive episodes as true seizures until proven otherwise. 1
Immediate Management Approach
The critical reality is that during an active code or emergency situation, clinical features alone are unreliable for distinguishing these entities, and the consequences of undertreating true status epilepticus (mortality 5-22%, up to 65% if refractory) far outweigh the risks of treating a pseudoseizure. 1
Treat First, Diagnose Later
- Administer benzodiazepines immediately for any convulsive activity lasting >5 minutes or recurrent seizures without return to consciousness, regardless of suspected etiology 2, 3
- The American College of Emergency Physicians emphasizes that various conditions can mimic seizures (syncope with brief jerking, rigors, psychogenic events), but diagnostic certainty is often impossible even after thorough ED evaluation 1
- Do not withhold treatment based on clinical suspicion of pseudoseizure during the acute event 1
When EEG Becomes Essential
Consider emergent EEG in the following scenarios where pseudoseizure differentiation becomes clinically relevant: 1
- Persistent altered consciousness after apparent seizure termination (may indicate nonconvulsive status epilepticus vs. pseudoseizure)
- Refractory "status epilepticus" not responding to appropriate benzodiazepine and second-line agents
- Patients who received paralytics (cannot assess clinical response)
- Drug-induced coma where ongoing seizure activity must be excluded
The ACC/AHA/HRS guidelines note that simultaneous EEG and hemodynamic monitoring during tilt-table testing can distinguish among syncope, pseudosyncope, and epilepsy, but this is obviously not applicable during acute code situations. 1
Clinical Clues (Use Cautiously)
While these features may suggest pseudoseizure, they are not reliable enough to withhold treatment during active convulsions: 4, 5
- Prolonged duration (>2-3 minutes) with waxing/waning intensity
- Pelvic thrusting or side-to-side head movements (rare in true seizures)
- Eye closure during the event (epileptic seizures typically have eyes open)
- Resistance to eye opening when attempted by examiner
- Lack of postictal confusion (though absence seizures also lack this) 6
- Normal post-ictal EEG if obtained immediately after event 7
However, these features overlap significantly, and 20-30% of patients with pseudoseizures also have true epilepsy, making clinical distinction even more treacherous. 5, 7
Critical Pitfalls to Avoid
- Never assume pseudoseizure in a code situation - the mortality risk of untreated status epilepticus is too high 1
- Do not rely on "atypical" features - true seizures can present atypically, and pseudoseizures can mimic typical seizures convincingly 1, 5
- Recognize that 25% of patients with treated generalized convulsive status epilepticus continue to have electrical seizures on EEG despite cessation of motor activity 1
- Avoid anticonvulsant toxicity in known pseudoseizure patients, but this determination requires prior video-EEG confirmation, not acute clinical judgment 7
Post-Resuscitation Evaluation
After stabilization, if pseudoseizure is suspected based on atypical features or treatment resistance:
- Obtain neurology consultation before pursuing EEG, as interpretation requires specialized expertise 1
- Video-EEG monitoring is the gold standard for definitive diagnosis 7
- Tilt-table testing with simultaneous EEG can be useful for selected patients with recurrent episodes 1
- Consider psychiatric evaluation for conversion disorder, dissociative disorder, or panic disorder once pseudoseizure is confirmed 5
The ACC/AHA/HRS guidelines specifically state that tilt-table testing is reasonable to distinguish convulsive syncope from epilepsy and to establish a diagnosis of pseudosyncope, but these are outpatient diagnostic tools, not acute interventions. 1