Written by Jen Rogers (with opinion from Dr Neil Archibald)
4th year medical student
Epilepsy, syncope and non-epileptic attacks
A huge number of disorders can mimic epilepsy, leading to an incorrect diagnosis of epilepsy in up to 20% of cases. It useful to think about how to clinically distinguish between the most common ‘mimics’ so patients are given the optimal treatment from an early stage.
Syncope
Syncope is a sudden loss of consciousness, often accompanied by myoclonic jerks (sudden muscle contractions) from which recovery rapidly occurs. It is important to note that people giving collateral histories will often overestimate how long the jerking lasts .
There is often a situational element to syncope, such as exposure to blood or a situation or place that makes the person fearful, such as an aeroplane.
Syncope may be preceded by autonomic and hypoperfusion symptoms such as blurring of vision, nausea, sweating, pallor, light-headedness, palpitations and blacking of vision. Syncope often occurs from an upright position.
During syncope, most people are flaccid with myoclonic jerking occurring only after the person has fallen down (this is different to epileptic seizures), with jerking lasting up to around 15 seconds.
Watch this video and then take a moment to reflect on how amazingly like a seizure some cases of syncope can appear. This is why you need to be very, very careful when taking a witness account.
People will try and tell you that urinary incontinence is suggestive of a seizure - ignore them. They are deluded. Urinary incontinence can easily occur in syncope. While we're on the subject, tongue biting is also common in syncope and non-epileptic attacks.
Treatment of syncope very much depends on the cause, with the most common causes being vasovagal syncope and cardiac syncope.
Seizure
Seizures are a transient (hopefully) electrical disturbance in cortical activity which may, or may not, lead to loss of consciousness – it all depends on where the seizure starts and where it ends up.
If the seizure generalises quickly, then there is no warning. If the seizure is focal in onset, then, depending on where in the brain it comes from, patients can experience an “aura”. This can progress to a generalised seizure (tonic-clonic) or remain focal (partial).
Partial seizures can disturb awareness, and the patient can appear “vacant’ or “absent”. This is not an “absence”, which lasts seconds, and does not typically present in adulthood.
Recovery time is prolonged, even if the electrical seizure itself is brief (less than 2 minutes usually).
A witness account is very helpful, but only if you ask the right question.
Non-epileptic attacks
Non-epileptic attack disorder (NEAD) or ‘dissociative attacks’ can appear to be treatment-resistant epilepsy and are often diagnosed as such. The cause of the disorder is psychogenic, but the person does not have control over the seizures: they are not factitious.
There are some predisposing factors:
- Traumatic events, past or present, including injury or disease
- Female gender – 75% of those with NEAD are female
- Being a young adult
- The presence of other psychiatric conditions
During discussion, the patient will often avoid focusing on the symptoms of their seizures, and may avoid using the word ‘seizure’.
The attacks can be prolonged, and are often associated with hyperventilation and closed eyes. The ictal phase can differ from epilepsy in that the head may move side-to-side, the course may fluctuate, the onset of symptoms can be gradual, and the person may be able to recall the period during which they were unresponsive. The patient can injure himself/herself and become incontinent of urine, as in epilepsy.
Up to 20% of people who have NEAD also have epilepsy.
Treatment for NEAD focuses on psychological support. Current treatments include CBT, psychotherapy (there is thought to be a link to childhood abuse), and reducing antiepileptics. Antidepressants may also be of use.
Table 1
| Epilepsy | Non-epileptic attacks | Syncope | |
| Prodrome | Partial sometimes have aura | May begin as panic | Autonomic/hypoperfusion symptoms |
| Duration | Usually <2 minutes | Often >2 minutes | <30 seconds |
| Eyes | Usually open | Usually closed | Open |
| Crying during attack | Rare | Relatively common | Never |
| Talking during attack | Rare | Relatively common | Never |
| Tongue biting | Side of tongue | Front of tongue | Very rare |
| Side-to-side head movement | Rare | Relatively common | N/A |
| Urinary incontinence | Not uncommon | Not uncommon | Relatively common |
| Night symptoms | Common, but often begin while awake | Can occur | |
| EEG | Abnormal | Normal* | Abnormal** |
| Post-ictal | Usually 5-30 minutes, fatigue, often headache | Fatigue, no headache, may remember ictal period | Fatigue, but rapid recovery |
* 10% of healthy people have ‘non-specific’ abnormalities on their EEG.
** But different to seizures
Bibliography
Smith PEM. Epilepsy: mimics, borderland and chameleons. Practical Neurology 2012;12:299-307. doi:10.1136/practneurol-2012-000304 (accessed 5 August 2015).
Wieling W et al. Symptomsand signs of syncope: a review of the link between physiology and clinical cues. Brain 2009;132;2630-2642. doi:10.1093/brain/awp179 (accessed 6 August 2015).
Smith PEM. Epilepsy. Practical Neurology 2008;8:195-202. doi:10.1136/pn.2007.134031 (accessed 5 August 2015).