Epilepsy

IM

Epilepsy

Professor Salih Bin Salih

Epilepsy Syndrome

Epilepsy syndromes may be classified according to:

• Whether the associated seizures are partial or generalized
• Whether the etiology is idiopathic or symptomatic/cryptogenic
• Several important pediatric syndromes can further be grouped according to age of onset and prognosis

• EEG is helpful in making the diagnosis

• Children with particular syndromes show signs of slow development and learning difficulties from an early age

Three most common epilepsy syndromes

1. Benign childhood epilepsy
2. Childhood absence epilepsy
3. Juvenile myoclonic epilepsy

Three devastating catastrophic epileptic syndromes

1. West syndrome
2. Lennox-Gastaut syndrome
3. Landau Kleffner Syndrome

Diagnosis in Epilepsy

Aims:

• Differentiate between events mimicking epilepsy (syncope, vertigo, migraine, psychogenic non-epileptic seizures)Z

• Confirm the diagnosis of seizure (or possibly associated syndrome) and the underlying etiology

Differential DiagnosisZ

• Syncope attacks
• Cardiac arrhythmias
• Migraine
• Hypoglycemia
• Narcolepsy (sudden attack of sleep)
• Panic attacks
• PSEUDOSEIZURES

Diagnosis in Epilepsy

Approach:

• History (from patient and witness)
• Physical examination
• Investigations

History

* Event
○ Localization
○ Temporal relationship
○ Factors
○ Nature
○ Associated features
* Past medical history
* Developmental history
* Drug and immunization history
* Family history
* Social history

Physical Examination

• General ○ esp. syndrome or non-syndromal dysmorphic features, neurocutaneous features
• Neurological
• Other system as indicated ○ E.g. Febrile convulsion, infantile spasm

InvestigationZ

• Routine investigation: Haematology, biochemistry chest X-ray and toxicology

• Electroencephalography (EEG). Neuroimaging (CT/MRI) should be performed in all persons aged 25 or more presenting with first seizure and in those pts. with focal epilepsy irrespective of age.

• Specialised neurophysiological investigations: Sleep deprived EEG, video-EEG monitoring.

• Advanced investigations: Semi Invasive or invasive EEG recordings, MR Spectroscopy, Positron emission tomography (PET) and ictal Single photon emission computed tomography (SPECT)

International 10-20 System of Electrode Placement in EEG

Neuroimaging

• Structural neuroimaging

• Functional neuroimaging

Venn Diagram

Anticonvulsants

Suppress repetitive action potentials in epileptic foci in the brain

• Sodium channel blockade
• GABA-related targets
• Calcium channel blockade
• Others: neuronal membrane hyperpolarisation

AnticonvulsantsZ

Adverse EffectsZ

• Teratogenicity ■ Neural tube defects ■ Fetal hydantoin syndrome
• Over dosage toxicity
• Life-threatening toxicity ■ Hepatotoxicity ■ Stevens-Johnson syndrome
• Abrupt withdrawal ⇒ seziure

Medical Intractability

• No known universal definition
• Risk factors ■ High seizure frequency ■ Early seizure onset ■ Organic brain damage
• Established after adequate drug trials
• Operability

Pediatrics

Epilepsy

• The tendency to have recurrent, unprovoked (reflex) seizures.
• At least two unprovoked (reflex) seizures occurring >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.

Reflex Epilepsies

Evoked by specific external sensory stimuli (e.g., photosensitive epilepsies), internal cognitive and emotional processes, or activity of the patient (e.g., reading). - (not a medical cause in stress)

An Epilepsy Syndrome

Represents a complex of signs and symptoms that together define a distinctive clinical seizure disorder, e.g., West syndrome or Lennox-Gastaut syndrome.

Incidence/Prevalence

• Incidence rates of epilepsy in childhood range from 0.5 to 8 per 1,000 person-years.
• An estimated 1% of children and adolescents in the United States will experience at least one unprovoked seizure by age 14 years.
• In Saudi Arabia, 6.54 per 1000 population have active epilepsy.

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SurgeryZ

• Curative (Resection)
• Palliative ■ Vagal nerve stimulation

Aetiology of Status EpilepticusZ

○ Idiopathic status epilepticus ■ Non-compliance to anticonvulsants ■ Sudden withdrawal of anticonvulsants ■ Sleep deprivation ■ Intercurrent infection

○ Symptomatic status epilepticus ■ Anoxic encephalopathy ■ Encephalitis, meningitis ■ Congenital malformations of the brain ■ Electrolyte disturbances, drug/lead intoxication, extreme hyperpyrexia, brain tumour

Status Epilepticus

• A condition when consciousness does not return between seizures for more than 30 min. This state may be life-threatening with the development of pyrexia, deepening coma and circulatory collapse. Death occurs in 5-10%.
• Treatment: AEDs intravenously ASAP, event. general anesthesia with propofol or thiopentone should be commenced immediately.

Medication Used in Status Epilepticus

• Stop Seizure Benzodiazepine

• Prevent Recurrence Epanutin, Valproate and Levetiracetam