Epilepsy Flashcards
(35 cards)
What is a seizure?
A seizure is the transient occurrence of signs or symptoms due to abnormal excessive or synchronous neuronal activity in the brain
Seizures can manifest as a disturbance of consciousness, behaviour, cognition, emotion, motor function, or sensation
An isolated seizure can be caused by toxic, metabolic, structural, and infectious factors and should not be confused with epilepsy
What is epilepsy?
Epilepsy is a neurological disorder in which a person experiences recurring seizures
The International League Against Epilepsy describes epilepsy as a disease of the brain defined by any of the following conditions:
o At least two unprovoked seizures occurring more than 24 hours apart.
o One unprovoked seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years.
o Diagnosis of an epilepsy syndrome.
What is the aetiology of epilepsy?
A cause of epilepsy is only identified in about one third of people with the disorder:
- Structural — abnormalities visible on structural neuroimaging, for example stroke, trauma, or malformation of cortical development. The underlying basis for a structural abnormality can be genetic or acquired.
- Genetic — epilepsy resulting from a known or presumed genetic mutation (not necessarily inherited) in which seizures are a core symptom of the disorder, for example Dravet syndrome.
- Infectious — epilepsy results from a known infection in which seizures are a core symptom of the disorder (rather than seizures due to acute infection such as meningitis). Examples include tuberculosis, cerebral malaria, HIV, and congenital infection such as Zika virus.
- Metabolic — epilepsy results from a known or presumed metabolic disorder in which seizures are a core symptom of the disorder (which may occur as a result of a genetic defect). Examples include porphyria, amino-acidopathies, or pyridoxine deficiency.
- Immune — epilepsy that results directly from an immune disorder (where there is evidence of auto-immune mediated central nervous system inflammation) in which seizures are a core symptom of the disorder. Examples include anti-NMDA receptor encephalitis and anti-LG11 encephalitis.
What is the classification of epilepsy?
Focal seizures Generalised tonic-clonic seizures Myoclonic seizures Absence seizures Tonic seizures
What is a focal seizure?
Focal seizures (focal is now preferred to partial): originate within networks limited to one hemisphere, discretely localised or more widely distributed.
What is the classification of focal seizures?
They may be divided into simple focal (motor or sensory) with retained awareness or focal dyscognitive seizures (impaired awareness). Focal seizures may progress into generalised seizures.
Simple focal seizures (no loss of consciousness).
Focal dyscognitive seizures:
o With impairment of consciousness at onset.
o Simple focal onset followed by impairment of consciousness.
Focal seizure evolving to generalised tonic-clonic (GTC) convulsions.
o II. Generalised seizures (convulsive or non-convulsive with bilateral discharges involving subcortical structures); associated with impairment of consciousness and distortion of the electrical activity of the whole or a large part of both sides of the brain.
o May be tonic-clonic (the term generalised tonic-clonic is now preferred to ‘grand mal’), isolated tonic or clonic, myoclonic (brief, shock-like muscle contractions) or absence (‘petit mal’).
o Unclassified epileptic seizures (usually used when an adequate description is not available).
What are the risk factors for epilepsy?
Premature birth.
Complicated febrile seizures.
A genetic condition that is known to be associated with epilepsy, such as tuberous sclerosis or neurofibromatosis.
Brain development malformations – usually associated with epilepsy developing before adulthood.
A family history of epilepsy or neurologic illness.
Head trauma, infections (for example meningitis, encephalitis), or tumours — can occur at any age.
Comorbid conditions such as cerebrovascular disease or stroke — more common in older people.
Dementia and neurodegenerative disorders (people with Alzheimer’s disease are up to ten times more likely to develop epilepsy than the general population).
What is the presentation of GTC seizures?
Epilepsy may be difficult to diagnose in the early stages, especially in the absence of a witnessed account.
A clear history from the patient and an eyewitness to the attack provide the most important diagnostic information.
Generalised seizures cause a disturbance in consciousness. The classic GTC seizure progresses through tonic, clonic and postictal phases. The postictal phase is often associated with headache and drowsiness.
GTC seizures are often associated with tongue-biting and incontinence. Whatever the cause, the patient may have amnesia for both the event and its exact circumstances.
What is the presentation of absence seizures?
Absence seizures cause an interruption to mental activity for less than 30 seconds. They rarely persist into adulthood.
Blank spells
What features suggest genetic generalised epilepsies?
Childhood or teenage onset.
Triggered by sleep deprivation and alcohol.
Early morning tonic-clonic seizures or myoclonic jerks.
Short absence seizures photoparoxysmal response on electroencephalography (EEG).
Generalised 3 per second spike and wave or polyspike and wave on EEG.
What features suggest focal seizures?
History of potential cause.
Aura.
Focal motor activity during seizure.
Automatisms.
What features suggest complex focal seizures?
Motor: automatism, lip-smacking, plucking at clothes, hair.
Sensory: transient paraesthesiae.
Autonomic: odd epigastric sensation, nausea, abnormal taste or smell.
Psychiatric: unreality, déjà vu, fear.
What are the symptoms and signs of epilepsy?
There may be a clear precipitating cause - eg, inadequate sleep, alcohol abuse or medications such as tricyclic antidepressants, which lower the seizure threshold.
It is common for seizure frequency to vary throughout the menstrual cycle. In ovulatory cycles, peaks occur around the time of ovulation and in the few days before menstruation. In anovulatory cycles, there is an increase in seizures during the second half of the menstrual cycle.
Possible seizure-related symptoms include:
Sudden falls.
Involuntary jerky movements of limbs whilst awake.
Blank spells.
Unexplained incontinence of urine with loss of awareness, or in sleep.
Odd events occurring in sleep - eg, fall from bed, jerky movements, automatisms.
Episodes of confused behaviour with impaired awareness.
Possible simple focal seizures.
Epigastric fullness sensation.
Déjà vu.
Premonition.
Fear.
Elation, depression.
Depersonalisation, derealisation.
Inability to understand or express language (written or spoken).
Loss of memory, disorientation.
Olfactory, gustatory, visual, auditory hallucinations.
Focal motor or somatosensory deficit, or positive symptoms (jerking, tingling).
Signs
o Examination is usually unremarkable.
o Check for any neurological or cerebrovascular signs.
o Skin examination may reveal café-au-lait spots (neurofibromatosis), port-wine stain (Sturge-Weber syndrome) or adenoma sebaceum (tuberous sclerosis).
What is sudden unexpected death?
Sudden unexpected death in epilepsy (SUDEP) is defined as sudden, unexpected, unwitnessed, non-traumatic, non-drowning death of a person with epilepsy, with or without a seizure, excluding documented status epilepticus, and in whom post-mortem examination does not reveal a structural or toxicological cause of death.
The risk of SUDEP can be minimised by optimising seizure control and being aware of the potential consequences of nocturnal seizures.
What are the main risk factors for SUDEP?
Seizure type and frequency: GTC seizures are the principal risk factor for SUDEP. Early identification of treatment-resistant epilepsy and referral for assessment for epilepsy surgery to reduce seizure frequency may reduce incidence of SUDEP.
SUDEP is the most common cause of death directly related to epilepsy and most frequently occurs in people with chronic epilepsy.
Information provided to people with epilepsy and carers should take account of the small but definite risk of SUDEP .
When does SUDEP usually occur?
SUDEP seems to occur more commonly during sleep and more often affects young adults with medically intractable epilepsy (especially tonic-clonic seizures), those with neurological comorbidity and patients receiving AED polytherapy.
What are the differentials for epilepsy?
Misdiagnosis of epilepsy is common.
The conditions most frequently confused with epilepsy include vasovagal syncope, cardiac syncope and non-epileptic attack disorder.
Conditions that may mimic seizures include migraine, parasomnias, movement disorders, metabolic disturbances and panic disorder.
Syncope. Cardiac arrhythmias. Transient ischaemic attack. Migraine. Paroxysmal vertigo. Metabolic disorders, hypoglycaemia. Acute encephalopathy. Drop attacks. Sleep disorders: narcolepsy, sleep apnoea, parasomnias. Hyperventilation. Transient global amnesia. Involuntary movement disorder. Panic attacks. Hysterical fugue. Aggressive outbursts – e.g., related to learning disability. Non-epileptic seizures.
What are the investigations for epilepsy?
Appropriate blood tests (eg, glucose, electrolytes, calcium, renal function, liver function, and urine biochemistry) to identify potential causes and/or to identify any significant comorbidity should be considered.
EEG
Neuroimaging
Short-term video-EEG, preferably with suggestion, should be available for the investigation and diagnosis of suspected epilepsy and non-epileptic attack disorder. Inpatient video-EEG monitoring may be useful for patients who present diagnostic difficulties.
Polysomnography may be used to confirm a diagnosis of sleep-related epilepsy.
Handheld video: asking family members or friends to video record events should be considered in patients with uncertain diagnosis. Consent from the patient should always be sought in advance.
Electrocardiography (ECG) should be carried out in the assessment of all patients with altered consciousness, particularly those in older age groups, when disorders of cardiac rhythm may simulate epilepsy. 24-hour ambulatory ECG and other cardiovascular tests (including implantable loop devices) may also be helpful.
When should an EEG be performed?
An EEG should be performed only to support a diagnosis of epilepsy when the clinical history suggests that the seizure is likely to be epileptic in origin. The EEG should not be used in isolation to make a diagnosis of epilepsy.
If an EEG is considered necessary, it should be performed after the second epileptic seizure but may, in certain circumstances, as evaluated by the specialist, be considered after a first epileptic seizure. Following a first unprovoked seizure, unequivocal epileptiform activity shown on EEG can be used to assess the risk of seizure recurrence.
Photic stimulation and hyperventilation should remain part of standard EEG assessment but the patient should be made aware that such activation procedures may induce a seizure.
An EEG should not be performed in the case of probable syncope because of the possibility of a false positive result.
An EEG may be used to help to determine seizure type and epilepsy syndrome.
Repeated standard EEGs may be helpful when the diagnosis of the epilepsy or the syndrome is unclear. However, if the diagnosis has been established, repeat EEGs are not likely to be helpful. Repeated standard EEGs should not be used in preference to sleep or sleep-deprived EEGs.
When a standard EEG has not contributed to diagnosis or classification, a sleep EEG should be performed.
Long-term video or ambulatory EEG may be used in the assessment when there are diagnostic difficulties after clinical assessment and standard EEG.
Which neuroimaging is involved in the investigation of epilepsy?
Neuroimaging should be used to identify structural abnormalities that cause certain epilepsies. MRI is the imaging investigation of choice. MRI is particularly important in those:
Who have any suggestion of a focal onset on history, examination or EEG (unless clear evidence of benign focal epilepsy).
In whom seizures continue in spite of first-line medication.
Neuroimaging should not be routinely requested when a diagnosis of idiopathic generalised epilepsy has been made.
CT should be used to identify underlying gross pathology if MRI is not available or is contra-indicated. CT may be used to determine whether a seizure has been caused by an acute neurological lesion or illness.
What is the management of epilepsy?
All adults with epilepsy should have a comprehensive care plan, which should include lifestyle issues as well as medical issues.
Epilepsy specialist nurses (ESNs) should be an integral part of the network of care.
People with epilepsy, particularly those with a genetic epilepsy, should be advised that sleep deprivation may precipitate seizures and be provided with advice to obtain sufficient sleep with a regular sleep pattern
The decision whether or not to start AED treatment must be based on the relative risks of recurrent seizures and the commitment to long-term medication with potential adverse effects. AEDs should not be given until the diagnosis of epilepsy has been confirmed
What is the management of provoked seizures?
Provoked seizures are defined as occurring within seven days of an acute condition such as encephalitis, head injury, cerebral infarction, craniotomy and cerebral haemorrhage.
Seizures can be provoked by:
- Acute metabolic disturbances, treatment with certain drugs and drug withdrawal (eg, alcohol, benzodiazepines, barbiturates).
- Drug misuse (alcohol, heroin, cocaine, methadone, amfetamine, ecstasy).
The risk of recurrence of such provoked seizures can be reduced by correction or withdrawal of the provocative factor.
Following an acute brain insult, AEDs used to treat the provoked seizures should be withdrawn (unless unprovoked seizures occur later). Longer-term AED treatment is only indicated if unprovoked seizures occur.
Patients with seizures provoked by alcohol or substance misuse may benefit from referral to addiction services and other support agencies.
What is the principle of drug treatment in epilepsy?
Use monotherapy whenever possible
Treatment is associated with a small risk of suicidal thoughts and behaviour.
Therapy initiated by a specialist.
Treatment with AED therapy is generally recommended after a second epileptic seizure
Do not offer sodium valproate to women or girls of childbearing potential (including young girls who are likely to need treatment into their childbearing years), unless other options are ineffective or not tolerated and the pregnancy prevention programme is in place.
Adherence to treatment can be optimised with the following:
- Educating patients and their families and/or carers in the understanding of their condition and the rationale of treatment.
- Reducing the stigma associated with the condition.
- Using simple medication regimens.
- Positive relationships between healthcare professionals, the adult with epilepsy and their family and/or carers.
The risks and benefits of continuing or withdrawing AED therapy should be discussed when the person with epilepsy has been seizure-free for at least two years.
Withdrawal of AED treatment should be carried out slowly (at least 2-3 months) and one drug should be withdrawn at a time.
Particular care should be taken when withdrawing benzodiazepines and barbiturates (may take up to six months or longer) because of the possibility of drug-related withdrawal symptoms and/or seizure recurrence.
There should be an agreed plan that if seizures recur, the last dose reduction is reversed and medical advice is sought.
What is the management of GTC seizures?
First-line treatment: offer sodium valproate as first-line treatment.
Offer lamotrigine if sodium valproate is unsuitable. If the person has myoclonic seizures or is suspected of having juvenile myoclonic epilepsy (JME), be aware that lamotrigine may exacerbate myoclonic seizures.
