Seizures and Epilepsy

Dr. Adnan Hamawandi

Definitions

Seizure: abnormal neural discharge in the cerebral cortex that result in abnormal function, the nature of clinical manifestations depend on the region(s) of the brain affected.

Epilepsy: recurrent seizures unrelated to fever or acute cerebral insult.

Etiology

Idiopathic. Symptomatic.

A. Acute symptomatic. 1. metabolic (hypoxia, hypoglycemia,.. 2. Intoxication( Cocaine, Antidepressants,.. 3. Fever. 4. Head injury. 5. CNS infections. 6. Vascular accidents.

Cont. Etiology

B. Chronic Symptomatic. 1. Cerebral malformations. 2. Acquired cerebral injuries. 3. Neurocutaneous syndromes. 4. Tumors. 5. Inborn errors of metabolism.

Classification

Partial seizures: arise from localized portions of the cerebral cortex. Simple partial (consciousness retained) Sensory Motor Autonomic Psychotic Complex partial (consciousness impaired) Partial seizures-secondary generalization.

Cont. Classification

Generalized seizures: arise simultaneously from both cerebral hemispheres. Absence seizures (petit mal) Tonic clonic ( Grand mal) Myoclonic Atonic Infantile spasm

Unclassified seizures.

Epileptic / seizure syndromes

Describes a particular type or types of seizures associated with typical EEG findings and patient characteristics , which is useful diagnostically, helps in choosing appropriate antiepileptic therapy, and allows for accurate prognostic statements to be made.

Benign focal epilepsy of childhood

Age of onset 4 – 10 years. The typical seizure while the patient is awake

is a focal one involving the face, pharynx and possibly the arm. The patient is conscious but unable to speak and may drool. Nocturnal seizures may be generalized with focal onset and pharyngeal muscle involvement where gagging is common.

Cont. Rolandic seizures

EEG; shows abnormal discharge in one or both pre-rolandic gyrus. The discharge may be limited to the sleep portion of recording.

Treatment: Carbamazepine or Phenytoin . Prognosis: is good with high remission rate,

about 99% resolution by 16 years of age.

Complex Partial seizures

There are sensory and motor phenomena. Consciousness is clouded The motor manifestations are complex and

semipurposful, e.g. picking at clothes or walking in a circle ”Automatism”.

There is a period of confusion or exhaustion after the seizure “ postictal state”

EEG: Temporal lobe spikes, or sharp waves. Treatment: Carbamazepine or phenytoin are good

first choice drugs. Tiagabine can be added for refractory cases.

Absence seizures

Are characterized by staring and loss of awareness of the environment. There is no warning.

Seizures are brief, last less than 30 seconds and terminate abruptly without postictal state.

Hyperventilation for 3-4 minutes routinely produce an absence seizure.

EEG: Typical spike and wave discharge 3/second. epilepsy1.pdf.

Treatment: Ethosuximide or valproate are first choice clonazepam is useful as a second choice.

Tonic - Clonic seizures

Are common and may follow partial seizures or occur de novo. The presence of aura always indicate a focal onset of the seizure.

The patient suddenly loses consciousness, eyes roll back, and the entire body muscles undergo tonic contractions, apnea cause cyanosis. The clonic phase is heralded by rhythmic contractions alternating with relaxation of all muscle groups. The clonic phase slows towards the end of the seizures and the patient sigh as the seizure stops abruptly.

Cont. Grand mal seizures

Postictally children are initially semicomatose and remain asleep for 30-120 minutes. The postictal phase is often associated with vomiting and intense bifrontal headache.

EEG :shows generalized spikes and waves. Treatment: Valproate is the drug of choice.

Carbamazepine and phenytoin are suitable alternatives.

Infantile spasms

May be idiopathic or symptomatic e.g. tuberous sclerosis.

Onset is usually at 4 - 8 months of age. Characterized by brief symmetric contractions of the

neck, trunk, and extremities occurring in clusters of seizures persisting for minutes with brief intervals between each spasm.

EEG: shows chaotic pattern of high voltage, bilaterally asynchronous, slow wave activity called “Hypsarryhtmia”. epilepsy2.pdf

Cont. Salam attacks

Treatment: ACTH is the most effective drug. Clonazepam and valproate are helpful as secondary agents to control the seizures.

Prognosis: Idiopathic Infantile spasms are more likely to respond to aggressive treatment. Prognosis for symptomatic infantile spasms is poor and reflects the severity of the underlying disease.

Febrile seizures

Typical age affected is 6month – 6years. Peak age of onset is 14 – 18months. Incidence: 3 - 4% of young children. Genetic predisposition had been proved. In the context of a febrile illness often an URT

infection, roseola, or otitis media, the convulsion is associated with rapidly rising temperature usually develops when core temperature reaches 39ºC or greater. The classic seizure is brief generalized tonic - clonic lasting less than 5 minutes.

Cont. Febrile convulsions

The interictal EEG is normal. The child must be carefully examined for serious

infection like meningitis and if any doubt exist lumbar puncture is indicated.

The risk of recurrence is 30%. Treatment consist of fever control, careful search for

the cause of fever. Oral diazepam at the onset of each febrile illness and for the duration of the illness is effective and safe in reducing recurrences.

The Diagnosis of seizure

Description of the event. An eye witness. Physical and neurological examination may provide

a clue in patients with symptomatic epilepsy. Electroencephalography (EEG): During a seizure the

brain generates high voltage chaotic activity that peaks rapidly giving the appearance of Spikes or Sharp Waves. Between the clinical seizures shorter discharges may be recorded. Provocative modalities increases the chance of recording an abnormality, like photostimulation, hyperventilation, and recording during sleep.

Cont. Diagnosis

EEG with simultaneous closed circuit video recording can provide an invaluable method for recording ictal seizure events that are rarely recorded during routine EEG.

CT scan or MRI are indicated in case of partial seizure or when the neurological examination is positive.

Prognosis

Anticonvulsant therapy can control about 50% of patients. Adequate control is less likely when 1.seizures begin early in life. 2. occur frequently. 3. are of mixed type. 4. associated with mental retardation. 5. associated with abnormal neurological findings.

If the patient is seizure free for at least 2 years discontinuing medications should be considered.

Status Epilepticus

A prolonged continuous seizure lasting more than 30 minutes or a series of seizures without return of consciousness for more than 30 minutes.

Prolonged febrile seizures is the most common form in children less than 3 years.

Withdrawal of antiepileptic drugs suddenly can result in status epilepticus.

Symptomatic status can be due to encephalitis, drug intoxication, electrolyte abnormalities, malformations of the brain, inborn errors of metabolism,brain tumor, encephalopathy, and intracranial hemorrhage.

Treatment of Status epilepticus

Admit to intensive care unit, if possible. Secure airway patency, gentle suction of oral

secretions. Give oxygen through properly fitting face mask.

Record vital signs, set in IV line and place nasogastric tube.

Measure blood glucose by dextrostix and take blood sample for CBC, electrolytes, glucose, creatinine, lactate, anticonvulsant level, and if indicated blood and urine samples for toxicology.

Cont. Treatment

A rapid physical and neurological assessment for evidence of trauma, papilledema, bulging fontanel, lateralizing neurological signs, manifestations of meningitis or sepsis, retinal hemorrhage, acidotic breathing, dehydration and pupil size.

A complete examination is done after seizure had been controlled.

Diazepam 0.2 – 0.3 mg./Kg. IV slowly is used initially followed by Phenobarbital 10 – 20 mg./Kg. loading dose.

Cont. Treatment

If seizures are not controlled, continuous infusion of Diazepam or Midazolam has been effective in most cases.

If the patient does not respond, he should be put on a ventilator and given general anesthesia by thiopental, halothane, or isoflurane.

IV valproic acid is a promising drug for status epilepticus.