Epilepsy

Shan Ellawela

‘Epileptic seizure’

“……Transient occurrence of signs and/or symptoms due to abnormal , excessive or synchronous neuronal activity in the brain…..”

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Generalised tonic clonic seizures• Pre ictal Phase• Ictal Phase Loss of consciousness 1) Stiffening (“tonic phase”)

2)Jerking (“clonic phase”) Sometimes (lateral)tongue-biting, incontinence

• Post ictal phase Slow recovery, headache, sleepiness

? Types

• Generalised

• Focal

Generalised seizuresTonic-clonic (in any combination)

Absence - Typical - Atypical - Absence with special features

Myoclonic absence Eyelid myoclonia

Myoclonic - Myoclonic- Myoclonic atonic- Myoclonic tonic

Clonic

Tonic

Atonic

Focal seizures• Without impairment of consciousness or awareness– Previous term: simple partial– With observable motor or autonomic components• eg. focal clonic, autonomic, hemiconvulsive

– With subjective sensory or psychic phenomena• Aura - specific types

• Where alteration of cognition is major feature– Previous term: complex partial– Dyscognitive

Semiological classification (Luders et al.)

• 1. Auras a. Somatosensory auras b. Visual auras c. Auditory auras d. Gustatory auras e. Olfactory auras f. Autonomic auras g. Abdominal auras h. Psychic auras

• 2. Autonomic Seizures • 3. Dialeptic Seizures• 4. Motor Seizures a. Simple Motor Seizures

i. Myoclonic seizures ii. Clonic Seizures iii. Tonic Seizures iv. Versive Seizures v. Tonic-Clonic Seizures vi. Epiletic Spasms

b. Complex Motor Seizures i. Automotor seizures ii. Hypermotor seizures iii. Gelastic Seizures

• 5. Special Seizures a. Atonic seizures b. Akinetic seizures c. Astatic seizures d. Negative myoclonic seizures e. Hypomotor seizures f. Aphasic seizures

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Syncope

• Precipitating factor apparent• Warning/aura beforehand• Multifocal arrhythmic jerks in up to 90%• Head turns, oral automatisms in 70%• Initial upward deviation of eyes common• Consciousness may be partially preserved• Short duration, rapid recovery

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Dissociative seizures• Tend to wax and wane• Nature/frequency/amplitude of the movements• Longer duration and build up• Often quick recovery• ?Thrashing, ?flailing, pelvic-thrusting,

opisthotonus• May be distracted• May cause injury• ‘absences’• May or may not be obvious precipitants

Differential diagnosis• Syncope

• Dissociative seizures

• Cardiac dysrhythmias

• Concussive syncope

• Panic attacks• Breath-holding attacks• Migraine

• Transient global amnesia

• Transient ischaemic attacks

• Hypoglycaemia

Diagnosis• Clinical

• Clinical

• Clinical

• Detailed description:• Precipitating factors• Onset of seizure• Frequency of attacks• Duration of attacks• State of consciousness

• Age at onset• Previous febrile seizures• Perinatal and developmental history• History of CNS infections or head trauma• Family history of epilepsy

Aids to diagnosis….• EEG

• MRI

• Others.. ECG,Echo,24 Hr or longer monitoring Tilt test….

EEG

• An EEG should be performed only to support a diagnosis of epilepsy in adults in whom the clinical history suggests that the seizure is likely to be epileptic in origin.

• An EEG should be performed only to support a diagnosis of epilepsy in children and young people. 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.

• An EEG should not be performed in the case of probable syncope because of the possibility of a false-positive result.

• 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.

• The EEG should not be used in isolation to make a diagnosis of epilepsy. • An EEG may be used to help determine seizure type and epilepsy syndrome in

children, young people and adults in whom epilepsy is suspected. This enables them to be given the correct prognosis.

• In children, young people and adults presenting with a first unprovoked seizure, unequivocal epileptiform activity shown on EEG can be used to assess the risk of seizure recurrence.

Neuroimaging

• Neuroimaging should be used to identify structural abnormalities that cause certain epilepsies.

• MRI should be the imaging investigation of choice in children, young people and adults with epilepsy.

• MRI is particularly important in those: who develop epilepsy before the age of 2 years or in adulthood 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.

• Children, young people and adults requiring MRI should have the test performed soon.

• Neuroimaging should not be routinely requested when a diagnosis of idiopathic generalised epilepsy has been made.

? Epilepsy

‘Conceptual’ definition

“…Enduring predisposition to generate epileptic seizures………….”

Practical clinical definitions

“ two unprovoked seizures occurring at least 24 hours apart…..”

‘Unprovoked’: Absence of a temporary or a reversible factor lowering the seizure threshold

‘Provoked’: Transient factor acting on an otherwise normal brain to temporarily lower the seizure threshold

Current practical definition• At least two unprovoked (or reflex) seizures

occurring greater than 24 hours apart.• One unprovoked (or reflex) 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.

• Diagnosis of an epilepsy syndrome

Epilepsy is considered to be resolved for individuals who had an age-dependent epilepsy syndrome but are now past the applicable age or those who have remained seizure-free for the last 10 years, with no seizure medicines for the last 5 years

• What is the chance it can happen again?• How long does it take to know it won’t happen

again?• How effective is treatment?• If treatment is delayed does it change my

chances of getting seizure control?

Risk of recurrence after first seizure In prospective series….• Meta-analysis by Berg and Shinnar 1991 36% by 2 years (Treated and untreated)

• FIRST Trial (Italy) 1993 51% in 2 years in untreated

• MESS Trial (MRC UK) 2005 39% in 2 years in the deferred treatment group

Treatment• Sure of diagnosis?• Risk of recurrence• Severity of seizures• Patient’s wishes• Driving/employment• Other factors eg pregnancy

AED

• 47% of patients become seizure-free on 1st antiepileptic drug

• 14% of patients become seizure-free on 2nd or 3rd antiepileptic drug

• Chance of becoming seizure-free after this ?4%

Kwan and Brodie(2000 NEJM)

Refractory Epilepsy

• Epilepsy surgery• VNS

• Others…

Implications of diagnosis

•Legal restrictions eg driving•Loss of independence•Effect on work/loss of job•Injuries •Responsibilities eg childcare•Anxiety/depression•Underlying cause of seizures

…Lot more to talk about!

Thank you !