Temporal Lobe Epilepsy And Psychogenic Epilepsy Flashcards
What is temporal lobe epilepsy?
Temporal lobe epilepsy (TLE) may be simple focal seizures without loss of awareness (with or without aura) or focal dyscognitive seizures (with loss of awareness). Loss of awareness occurs during a focal dyscognitive seizure when the seizure spreads to involve both temporal lobes.
What is the presentation of TLE?
Aura occurs in the majority of temporal lobe seizures. Most auras and automatisms last a very short period - seconds or 1 to 2 minutes. Auras may cause sensory, autonomic or psychic symptoms:
Somatosensory and special sensory phenomena:
o Olfactory, auditory and gustatory illusions and hallucinations may occur.
o Patients may report distortions of shape, size and distance of objects.
o These visual illusions differ from the visual hallucinations associated with occipital lobe seizure in that there is no formed visual image.
o Objects may appear smaller or larger than usual.
o Vertigo may occur with seizures in the posterior superior temporal gyrus.
Psychic phenomena:
o Feeling of déjà vu (familiarity) or jamais vu (unfamiliarity).
o Depersonalisation (ie feeling of detachment from oneself) or derealisation (surroundings appear unreal).
o Fear or anxiety.
o May describe seeing their own body from outside.
Autonomic phenomena: changes in heart rate and sweating. Patients may experience an epigastric fullness sensation or nausea.
Following the aura, a temporal lobe focal dyscognitive seizure begins with a wide-eyed, motionless stare, dilated pupils and behavioural arrest.
• Lip-smacking, chewing and swallowing may be noted.
• Manual automatisms or unilateral dystonic posturing of a limb may also occur.
• A focal dyscognitive seizure may evolve to a generalised tonic-clonic (GTC) seizure.
• Patients usually experience a postictal period of confusion. The postictal phase may last for several minutes.
• Amnesia occurs during a focal dyscognitive seizure because of bilateral hemispheric involvement.
What are the causes of TLE?
Past infections – e.g., herpes encephalitis or bacterial meningitis.
Head injury producing contusion or haemorrhage that results in encephalomalacia or cortical scarring.
Hamartomas.
Gliomas.
Vascular malformations (i.e. arteriovenous malformation, cavernous angioma).
Cryptogenic: a cause is presumed but has not been identified.
Idiopathic (rare).
Hippocampal sclerosis produces a clinical syndrome called mesial temporal lobe epilepsy, which begins in late childhood, then remits but reappears in adolescence or early adulthood in a refractory form.
Febrile seizures: some children with complex febrile convulsions appear to be at risk of developing TLE in later life.
What are the differentials of TLE?
Absence seizures: have an abrupt onset with no aura, usually last for less than 30 seconds, have no postictal confusion and are not associated with complex automatisms. Focal dyscognitive seizures are usually preceded by a distinct aura, last longer than a minute, and have a period of postictal confusion.
Frontal lobe focal dyscognitive seizures appear in clusters of brief seizures with abrupt onset and ending. There is minimal postictal state. May cause behavioural changes with vocalisations and complex motor and sexual automatisms. In differentiating from TLE, may need electroencephalograph (EEG) localisation.
Excessive daytime somnolence - eg, due to a sleep apnoea or narcolepsy.
Periodic limb movement disorder.
Tardive dyskinesia.
Panic attacks.
Occipital lobe epilepsy: may spread to the temporal lobe and be clinically indistinguishable from a temporal lobe seizure.
Psychogenic seizures: patients with psychogenic seizures may also have epileptic seizures.
What is the management of TLE?
Same as focal seizures.
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Vagus nerve stimulation (VNS) with a high-frequency stimulation rate may be effective in reducing seizure frequency. A battery-operated stimulator device is implanted in the left vagus nerve in the neck.
Anteromedial temporal resection is the most frequently performed operation for medial TLE.
What are non-epileptic seizures?
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.
What are the types of NES?
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
What are the types of psychogenic seizures?
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.
What is the presentation of NES?
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 features:
o They can happen suddenly and without warning.
o They can include a loss of awareness or the person becoming unresponsive, making strange or repeated movements, or convulsing.
o They can both cause injury and urinary incontinence.
o 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.
What are the investigations for NES?
Video-electroencephalogram is widely considered to be the gold standard for diagnosing NES.
Investigations will depend on the specific presentation of each patient. Investigations include:
o A full assessment for the presence of any underlying physical cause for epilepsy – e.g., electroencephalograph (EEG), MRI brain scan.
o 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.
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.
What is the management of NES?
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.
What is the DVLA guide for group 1 drivers with epilepsy?
Group 1 car and motorcycle:
o Must not drive and must notify the DVLA.
o Provided the licence holder or applicant satisfies the regulations, a review licence will usually be issued.
o If there have been no seizures for 5 years (with medication if necessary), and no other disqualifying condition, a ‘til 70 licence is usually restored.
First unprovoked seizure:
- Driving will be prohibited for 6 months from the date of the seizure.
- Clinical factors that indicate that there may be an increased risk of seizures require the DVLA not to consider licensing until after 12 months from the date of the first seizure.
What is the DVLA guide for group 2 drivers with epilepsy?
Group 2 bus and lorry:
o Must not drive and must notify the DVLA.
o The person with epilepsy must remain seizure-free for 10 years (without epilepsy medication) before licensing may be considered.
First unprovoked seizure:
- Driving will be prohibited for 5 years from the date of the seizure.
- If, after 5 years, a neurologist has made a recent assessment and clinical factors or investigation results (for example, EEG or brain scan) indicate no annual risk greater than 2% of a further seizure, the licence may then be restored.
- Such licensing also requires that there has been no need for epilepsy medication throughout the 5 years up to the date of the licence being restored.
