EPILEPSY AND SEIZURES Flashcards
What is epilepsy?
A condition where there is a propensity to have recurrent and unprovoked seizures.
What is an epileptic seizure?
A paroxysmal, synchronous and excessive discharge of neurons in the cerebral cortex manisfesting as a stereotyped disturbance of consciousness, behaviour, emotion, motor function or sensation. It is usually sudden in onset, lasts seconds to minutes and usually ceases spontaneously.
What is status epilecticus?
A state of continued or recurrent seizures, with failure to regain consciousness between seizures over 30 minutes. It is a medical emergency and has a mortality rate of 50%.
What is prodrome with regard to epilepsy?
Changes in mood or behaviour which come before a seizure. They may precede the attack by several hours.
What is aura with regard to epilepsy?
Subjective sensation or phenomenon which may precede and mark the onset of the seizure. It can localise the seizure within the brain if being monitored at the time.
What is the ictus with regard to epilepsy?
The attack or seizure itself.
What is the postictal period?
The time after the ictus (seizure) during which the patient may be drowsy, confused and disorientated.
In terms of epidemiology of epilepsy, when are the two age peaks in the incidence of grand mal seizures?
In children and adolescents, where there is often no cause found.
Then in patients in their fifties and sixties, where the disease is probably due to ischaemic changes as a result of hypertension.
What are the known causes and risk factors for epilepsy or epileptic seizures?
Alcohol abuse Vascular disease (such as stroke) Cerebral tumours Head injury Degenerative diseases Family history (especially in absence seizures) Antenatal factors (such as rubella infections, maternal drug abuse and irradiation) Perinatal factors (such as anoxia) Drugs Photosensitivity Sleep deprivation
Which medications are known to either cause epilepsy or increase the likelihood of experiencing a seizure?
Phenothiazines Monoamine oxidase inhibitors Tricyclic antidepressants Amphetamines Lidocaine and lignocaine Nalidixic acid Withdrawal from benzodiazepines
Which toxic agents are known to either cause epilepsy or increase the likelihood of experiencing seizures?
Alcohol
Carbon monoxide
Lead
Mercury
Other than epilepsy, what might cause seizures in a patient?
Metabolic causes: Hyponatraemia Hypernatraemia Hypocalcaemia Hypomagnesaemia Hypoglycaemia
Infectious and inflammatory causes: Encephalitis Meningitis Cerebral abscess Neurosyphilis
What is a partial seizure?
A seizure that arises from a localised area of cerebral cortex.
Where do most partial seizures arise from?
The temporal lobes
Where do partial seizure that do not arise from the temporal lobes most often arise from?
The frontal lobes
What are the features of the aura associated with a temporal lobe seizure?
Epigastric sensation
Olfactory or gustatory hallucinations
Autonomic symptoms (eg change in pulse or BP, facial flushing)
Affective symptoms (eg fear, depersonalization)
Deja vu
What are the clinical features of a seizure that originates in either temporal lobe?
Motor arrest
Absence
Automatism (eg lip smacking, chewing, fidgeting, walking)
Automatic speech
Contralateral dystonia
The seizure is slow to evolve (1-2 minutes)
What are the postictal features of a temporal lobe seizure?
Confusion Postictal dysphasia (if dominant hemisphere is affected)
What are the features of the aura associated with frontal lobe seizures?
Abrupt onset
Forced thinking
Ideational or emotional manisfestations
What are the clinical features of a seizure that originates in either frontal lobe?
Vocalisation / shrill cry Violent or bizarre automatism Cycling movements of the legs Ictal posturing Tonic spasms Head and eyes move away from affected side 'Fencing' posture - Extension and abduction of one arm with rotation of head to same side, whilst flexing other arm Sexual automatisms with pelvic thrusting Obscene gestures Genital manipulation Usually very brief (30 seconds)
What are the postictal features of a frontal lobe seizure?
Brief confusion
Rapid recovery
What are clinical features of a seizure that originates in either parietal lobe?
Somatosensory symptoms (eg pain, tingling, numbness, prickling, vertigo, distortions of space) Automatisms may occur
What are the clinical features of a seizure that originates in either occipital lobe?
Visual hallucinations (eg seeing flashes of light or geometrical figures; rarely complex hallucinations of figures)
Eyelids flutter
Automatisms
What is a simple partial seizure?
Seizures in which consciousness is not impaired, and in which the discharge remains localised. They are brief and involve focal symptoms.
What is a complex partial seizure?
Similar features to simple partial seizures but by definition consciousness is impaired. Patient often remains standing despite losing consciousness. They typically last 2-3 minutes but can continue for several hours as part of non-convulsive status epilepticus.
What is a secondary generalised seizure?
Partial seizure in which epileptic discharge spreads to both cerebral hemispheres resulting in a generalised seizure. The spread may be so rapid that no localised features are detected.
What is a generalised seizure?
Seizure involving both hemispheres at the onset of the seizure. Patients lose consciousness at onset, so there is often no warning.
What is a generalised tonic-clonic seizure?
A generalised seizure where there are two distinct phases once the patient has lost consciousness. The tonic phase and the clonic phase.
What happens in the tonic phase of a generalised tonic-clonic seizure?
The tonic phase lasts about 10 seconds and involves stiffening of the body, flexion of the elbows and extension of the legs. The patient will also stop breathing and may turn cyanotic.
What happens in the clonic phase of a generalised tonic-clonic seizure?
The clonic phase last about 1-2 minutes and involves violent generalised rhythmical shaking. The patients eyes will be open and will roll back, the tongue may be bitten. Tachycardia is common, as is fecal and urinary incontinence. The frequency of the clonic movements will gradually decrease.
What are the postictal features of a tonic-clonic seizure?
The patient often cannot be roused for several minutes Confusion Headache Myalgia Retrograde amnesia Patient may fall asleep
What is an absence seizure?
Seizure which involves sudden vacancy stare. There may be eye blinking and myoclonic jerks. Attacks usually last 5-15 seconds. The typical patient will be a 4-12 year old child with a history of complaints about inattentiveness and poor academic performance.
What does the EEG of an ongoing absence seizure show?
3-4 Hz generalised spike and wave discharge
What might absence seizures with an atypical EEG presentation be indicative of?
More severe epilepsy syndromes such as Lennox-Gastaut syndrome. The seizures will usually involve more eye-blinking and myoclonic jerking.
What is a myoclonic seizure?
Abrupt, brief involuntary movements that can involve the whole body. Not all myoclonus is epileptic. Epileptic seizures will be cortical rather than brainstem or spinal cord in origin.
What is an atonic seizure?
A generalised seizure involving the sudden loss of tone in postural muscles, causing a patient to fall.
What is a tonic seizure?
A generalised seizure involving the sudden increase in muscle tone, causing a patient to become rigid and fall.
In what cases is brain imaging quite important?
Late onset (post 25) Partial seizures Refractory to treatment Persisting abnormal clinical signs Status epilepticus
What are some of the extracerebral clinical features of any seizure?
Pupil dilatation
Increased BP
Tachycardia
Central and peripheral cyanosis
What might the ABG of someone who has come in having suffered an epileptic seizure show?
Low pH
Low pO2
What might blood tests of someone who has come in having suffered an epileptic seizure reveal?
Elevated creatinine phosphokinase
Elevated creatine kinase
Elevated serum prolactin
How do you differentiate between a pseudo epileptic seizure from an epileptic seizure?
Pseudoseizures are more common in young women with a psychiatric history
Pseudo seizures are refractory to all drugs
Pupils, BP, heart rate, pO2 and pH remain unchanged
Plantar reflex is flexor
Serum prolactin levels are normal
EEG shows no seizure activity during episode and no postictal slowing
When should anti-epiletic drugs normally be considered?
After the second unprovoked seizure.
When might you consider starting a patient on anti-convulsant medication after a single seizure attack?
If there is a clear EEG abnormality
Patients with neurological deficits present since birth
Seizures associated with a progressive neurological disorder
What are the first line drugs for an epileptic patient with primary generalised tonic-clonic seizures?
Sodium valproate
Lamotrigine if sodium valproate is unsuitable
What type of seizures might Lamotrigine exacerbate?
Myoclonic seizures, including juvenile myoclonic epilepsy
What are the first line drugs for an epileptic patient with absence seizures?
Ethosuximide
Sodium valproate
(Lamotrigine if ethosuximide and sodium valproate are unsuitable)
Which anti-convulsant drugs are known to exacerbate absence seizures?
Carbamazepine Gabapentin Oxcarbazepine Phenytoin Pregabalin Tiagabine Vigabatrin
What are the first line drugs for an epileptic patient with myoclonic seizures?
Sodium valproate
Levetiracetam or topiramate if sodium valproate is not suitable
Which anti-convulsant drugs are known to exacerbate myoclonic seizures?
Lamotrigine Carbamazepine Oxcarbazepine Phenytoin Gabapentin Pregabalin Tiagabine Vigabatrin
What are the first line drugs for an epileptic patient with atonic or tonic seizures?
Sodium valproate
What are the first line drugs for an epileptic patient with partial seizures?
Carbamazepine
Lamotrigine
What the main side effects of sodium valproate?
P450 inhibitor Nausea Increased appetite and weight gain Alopecia: regrowth may be curly Ataxia Tremor Hepatitis Pancreatitis Thromobcytopaenia Teratogenic in pregnant women Hyponatraemia Hyerammonaemia
What are the acute side effects of phenytoin?
Dizziness Diplopia Nystagmus Slurred speech Ataxia Confusion Seizures
What are the more chronic side effects of phenytoin?
Gingival hyperplasia (secondary to increased expression of platelet derived growth factor, PDGF)
Hirsutism
Coarsening of facial features
Drowsiness
Megaloblastic anaemia (secondary to altered folate metabolism)
Peripheral neuropathy
Enhanced vitamin D metabolism causing osteomalacia
Lymphadenopathy
Dyskinesia
What are the idiosyncratic side effects of phenytoin?
Fever Rashes (including severe reactions such as toxic epidermal necrolysis) Hepatitis Dupuytren's contracture* Aplastic anaemia Drug-induced lupus Teratogenic
What are the adverse effects of carbamazepine?
P450 enzyme inducer
Dizziness
Ataxia (coordination) Vestibulo-cerebellar
Drowsiness
Headache
Visual disturbances (especially diplopia)
Steven-Johnson syndrome (toxic epidermal necrolysis)
Leucopenia and agranulocytosis
Syndrome of inappropriate ADH secretion
When should an epileptic patient be considered for drug withdrawal?
After two years without a seizure. Withdrawal must be very gradual.
Which two anti-convulsants can be excreted as part of breast milk and are therefore contraindicated in breast feeding women?
Phenobarbital
Ethosuximide
At what point during a single seizure do you start to treat it as status epilepticus?
5 minutes
What is the drug treatment management of a patient in the premonitory stage (0-10 mins) of status epilepticus?
Lorazepam, diazepam, midazolam or paraldehyde can be used.
What is the drug treatment management of a patient in the early stage (10-30 mins) of status epilepticus?
A dose of fast acting intravenous benzodiazepines such as lorazepam. Can be repeated once if the seizure does not terminate.
What is the drug treatment management of a patient in the established stage (30-60 mins) of status epilepticus?
Phenobarbital or phenytoin intravenous loading dose
What is the drug treatment management of a patient in the refractory stage (after 60 mins) of status epilepticus?
Anaesthesia is required at this stage, with ventilation and intensive care. Agents most commonly used are thiopental or propofol. Neuromuscular blocks should be avoided as this can mask a recurrence of the seizure if initially terminated.
What are the indications for neurosurgery as a treatment for epilepsy?
Identification of localised site of onset
Epilepsy that is intractable to medical therapy (at least two first line drugs)
What part of the brain is more often removed in neurosurgery as a treatment for epilepsy?
Some part of the temporal lobe
Less common: hemispherectomies and corpus callosotomies
How long must an epileptic patient who has had a seizure wait before driving?
1 year after a single seizure
How long must a patient who only has nocturnal seizures be free of daytime seizures to be allowed to drive?
3 years
How long must a patient without a history of epilepsy or previous seizures who has had an unprovoked seizure wait before driving?
6 months
What are the side effects of Lamotrigine?
P450 inducer Neurotoxicity Ataxia Dizziness Headache Steven-Johnsons rash
