It’s all in your head, literally! – Seizures versus Psychogenic Non-epileptic Seizures

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It’s all in your head, literally! – Seizures versus Psychogenic Non-epileptic Seizures

Resident Clinical Pearl (RCP) May 2019

Allyson Cornelis – PGY2 FMEM Dalhousie University, Saint John NB

Copyedited by Renee Amiro

Reviewed by Dr. David Lewis

 

 

 

Background

When patients present with seizure like activity it can be difficult to distinguish true seizure/epilepsy from psychogenic non- epileptic seizures (PNES; also known as pseudoseizures). This task is made more difficult by the fact that 10-30% of patients with PNES can have true epilepsy as well4. The risks associated with diagnosing a psychogenic non-epileptic seizure as true seizure are mainly associated with administration of anti-epileptic drugs during both acute episodes and chronically, with the potential for associated side effects3-4,6. The most severe of these include sedation and even intubation if large enough doses are administered during an acute seizure episode. Additionally, there is added cost to both the patient and the healthcare system for continued use of medications and hospital admissions/investigations.

The underlying mechanism for PNES is believed to be psychiatric in origin, often attributed to conversion disorders, and patients are often not aware of their seizure like behaviours.

 

Risk factors for PNES include:

  1. childhood trauma
  2. PTSD
  3. depression
  4. anxiety
  5. personality disorders
  6. female gender

The challenge remains distinguishing between true seizures and PNES. There are various historical features and seizure characteristics that can assist in differentiating the two, though no one feature is confirmatory for seizure.

 

Distinguishing between PNES and true seizure3-8

Sign/symptom Seizure PNES
Eyes *open Closed, resist forced opening by examiner

 

*Fluttering
Seizure onset *abrupt Gradual
Awareness during seizure Not aware * awareness during episode
Influence of the presence of others Does not change seizure *May intensify or alleviate

 

activity may only occur/be triggered by the presence of others
Seizure activity Generalized tonic clonic

 

Synchronous

 

Stereotyped (first stiff and in extension, then develops synchronous clonic activity)

 May be asynchronous, asymmetrical, waxing and waning

Thrashing/violent

Pelvic thrusting
Post ictal *Confusion May recall events during their apparent unresponsive event
head One sided Side to side head turning during event
**incontinence common occasional
***Tongue biting Common, may be severe, usually on SIDE of tongue Occasional, rare to be severe, may be on tip of tongue or the lip
Post ictal corneal reflex impaired normal
Post ictal babinksi upgoing downgoing
Hand drop test negative Positive (patient moves hand away from face)
Response to sternal rub/nail bed pressure Usually nonresponsive May stop seizing, withdraw from stimuli
****Vital signs Desaturation more likely

Ictal apnea

Ictal bradycardia

  

 

 

*represents elements found to be most useful in distinguishing PNES and ES8

** incontinence has little utility in distinguishing between PNES and true seizure5

*** lateral tongue biting was 100% specific for true seizure vs 38% sensitivity and 75% specificity for any type of tongue bite5

****prospective trial7

 

Lab Values

No lab value has proven consistently useful for confirming seizure versus PNES.

A note on Prolactin:

The American Academy of Neurology released guidelines in 2005 recommending the use of prolactin following a seizure event2.

  1. Best when drawn 10-20 minutes after the event and can be used to differentiate between PNES and true seizure
  2. If >6 hours later prolactin should be at baseline levels
  3. Cannot be used to differentiate seizure from syncope
  4. Not applicable in status epilepticus or repetitive seizures

 

Bottom Line: 

  1. Challenging to differentiate between PES and true seizure and some patients can have both!
  2. No definitive distinguishing measure but eye opening, abrupt seizure onset, and confused post-ictal state can help point toward true seizure.
  3. A normal prolactin is more helpful in ruling out seizure while an elevation is non-specific and cannot be used to confirm seizure.

 

References

  1. Abubakr A, Wambacq I. Diagnostic value of serum prolactin levels in PNES in the epilepsy monitoring unit. Neurol Clin Pract. 2016 Apr; 6(2): 116–119.
  2. Graham L. AAN releases guidelines for the use of serum prolactin assays in diagnosing epileptic seizures. Am Fam Physician. 2006. Apr; 73(7): 1284.
  3. Huff JS, Murr N. Seizure, Pseudoseizures. [Updated 2018 Oct 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2018 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441871/
  4. Mellers JDC. The approach to patients with “non-epileptic seizures.” Postgrad Med J. 2005 Aug;81(958):498-504.
  5. Nowacki T, Jirsch JD. Evaluation of the first seizure patient: Key points in the history and physical examination. 2017 Jul;49:54-63. doi: 10.1016/j.seizure.2016.12.002. Epub 2016 Dec 8.
  6. Panayiotopoulos CP. The Epilepsies: Seizures, Syndromes and Management. Oxfordshire (UK): Bladon Medical Publishing; 2005. Chapter 1, Clinical Aspects of the Diagnosis of Epileptic Seizures and Epileptic Syndromes. Available from: https://www.ncbi.nlm.nih.gov/books/NBK2609/
  7. Pavlova M, Abdennadher M, Singh K, Katz E, Llewellyn N, Zarowsly M, et al. Advantages of respiratory monitoring during video- EEG evaluation to differentiate epileptic seizures from other events. Epilepsy Behav. 2014 Mar; 32: 142–144.
  8. Syed Tu, LaFrance WC Jr, Kahriman ES, Hasan SN, Rajasekaran V, Gulati D, et al. Can semiology predict psychogenic nonepileptic seizures? A prospective Ann Neurol.2011 Jun;69(6):997-1004
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