Non-epileptic seizures

Synonyms: non-epileptic attack disorder (NEAD); the use of the terms 'hysterical seizures' or 'pseudoseizures' is now considered to be inappropriate

Non-epileptic seizures (NES) is a descriptive term for a diverse group of disorders which refers to paroxysmal events that can be mistaken for epilepsy but are not due to an epileptic disorder. There are two subcategories of NES¹ :

• Organic: includes a broad spectrum of disorders - eg, syncope, paroxysms of acute neurological insults, paroxysmal toxic phenomena, non-toxic organic hallucinosis, non-epileptic myoclonus, sleep disorders, paroxysmal movement disorders, paroxysmal endocrine disturbances and transient ischaemic attacks (TIAs).

• Psychogenic seizures include different types:
  

  • Dissociative seizures are involuntary and happen unconsciously. This is the most common type of NES and the person has no control over the seizures.

  • Associated with psychiatric conditions that cause seizures - eg, panic attacks.

  • Factitious seizures - eg, Münchhausen's syndrome, fabricated or induced illness by carers.

Epidemiology

• Psychogenic non-epileptic seizures (PNES) are the most common paroxysmal event misdiagnosed as epilepsy. They significantly affect the person's quality of life² .

• The true prevalence is unknown. PNES are more common in females.

• PNES are diagnosed in at least 10-40% of the patients seen for long-term monitoring of epilepsy. Patients with PNES are often treated for epilepsy³ .

• Any psychological stress exceeding an individual's coping capacity often precedes PNES⁴ .

Presentation

• It can be difficult to differentiate NES from epilepsy, especially as the two disorders may co-exist.

• Epileptic and non-epileptic seizures can look the same and have the same features¹ :
  

  • They can happen suddenly and without warning.

  • They can include a loss of awareness or the person becoming unresponsive, making strange or repeated movements, or convulsing.

  • They can both cause injury and urinary incontinence.

  • They can both happen when awake and during sleep.

• It is essential to make a thorough assessment and ensure no further harm is caused by inappropriate diagnosis and treatment.

• Features suggesting NES include: duration over two minutes, gradual onset, fluctuating course, violent thrashing movements, side-to-side head movement, asynchronous movements, eyes closed and recall for period of unresponsiveness.

• Features suggesting epilepsy include automatisms, incontinence and biting the tongue.

Differential diagnosis of epilepsy

NES are one of the most common differential diagnoses of epilepsy⁵ . The differentiation between epileptic and non-epileptic seizures can be difficult⁶ .

• Medical causes of transient neurological dysfunction (with or without loss of consciousness):
  

  • Syncope: vasovagal, cardiogenic.

  • Neurological: cerebrovascular, migraine, vertigo, cataplexy, parasomnias, movement disorders, startle-induced phenomena.

  • Endocrine and metabolic: hypoglycaemia, hypocalcaemia, hereditary fructose intolerance.

  • Drugs and alcohol.

• Psychiatric disorders that may be mistaken for epilepsy: panic disorder, psychosis, attention deficit hyperactivity disorder.

• Dissociative seizures.

• Factitious disorder.

Investigations

Video-electroencephalogram is widely considered to be the gold standard for diagnosing NES⁶ .

• Investigations will depend on the specific presentation of each patient. Investigations include:
  

  • A full assessment for the presence of any underlying physical cause for epilepsy - eg, electroencephalograph (EEG), MRI brain scan.

  • The EEG should not be used to exclude a diagnosis of epilepsy in a child, young person or adult in whom the clinical presentation supports a diagnosis of a non-epileptic event. Provocation by suggestion may be used in the evaluation of non-epileptic attack disorder. However, it has a limited role and may lead to false-positive results in some people.⁷ .

  • Investigations for physical causes of NES - eg, fasting glucose, electrolytes, ECG, echocardiogram.

  • A full psychiatric assessment.

• Serum prolactin rises in over 90% of patients after a tonic-clonic seizure and 60% of patients after a complex focal seizure (previously called a complex partial seizure). However, an increased postictal prolactin is nonspecific.

Associated diseases

A significant number of patients have mixed epileptic and non-epileptic seizure disorders. PNES are often associated with mental health problems (eg, anxiety and depression) and also personality disorders⁹ .

Management

Where NES are suspected, suitable referral should be made to psychological or psychiatric services for further investigation and treatment⁷ .

• Management is directed at treatment of the underlying cause.

• It is essential that patients fully understand the diagnosis of non-epileptic seizures and the likely underlying causes/contributory factors. A poor reaction to the diagnosis and lack of understanding with regard to the condition and precipitating factors may lead to a poor prognosis.

• Various treatments have been tried with variable success for PNES. Treatment regimes for NES include non-psychological (eg, anti-anxiety and antidepressant medication) and psychological therapies (including cognitive behavioural therapy, hypnotherapy and paradoxical injunction therapy). With paradoxical injunction therapy, the therapist imposes a directive that places the client in a therapeutic double bind that promotes change regardless of the client's compliance with the directive.

• There is currently no reliable evidence to support the use of any treatment, including hypnosis or paradoxical injunction therapy, in the treatment of NES¹⁰ .

Prognosis³

• The prognosis of organic NES will depend on the underlying cause.

• There is no strong evidence for the long-term outcome of PNES. Factors that seem to predict better outcome include relatively benign psychiatric history, more recent onset of PNES, no co-existent epilepsy, and an identifiable trauma that precedes the onset of PNES. Prognosis may also depend on the psychological aetiology of the PNES, personality characteristics of the patient, and willingness to accept the diagnosis and receive treatment.