FIRST EPILEPTIC SEIZURE

COMMENCEMENT OF TREATMENT

DR Y. SASIKUMAR

An epileptic seizure - A clinical event presumed to result from an abnormal and excessive neuronal discharge. The clinical symptoms are paroxysmal and may include impaired consciousness and motor, sensory, autonomic, or psychic events perceived by the subject or an observer.

DEFINITIONS

Epilepsy - when 2 or more epileptic seizures occur unprovoked by any immediately identifiable cause.

The seizures must occur more than 24

hours apart.

Symptomatic seizure -A seizure caused by a previously known or suspected disorder of the CNS.

An acute symptomatic seizure - Occurs following a recent acute disorder such as a metabolic insult, toxic insult, CNS infection, stroke, brain trauma, cerebral hemorrhage, medication toxicity, alcohol withdrawal, or drug withdrawal.

That occurs within 1 week of a insult

A remote symptomatic seizure -A seizure that occurs longer than 1 week following a disorder that is known to increase the risk of developing epilepsy.

example - traumatic brain injury or stroke.

Provoked or unprovoked seizure .

1. Fever or signs suggestive of infection.

2. Prolonged seizure for more than 5 minutes.

3. Recurrent seizure .. Eg - 2 graand mal seizure in 24 hrs.

4. Incomplete recovery after a seizure.. Eg-drowsiness for >2 hrs.

5. Persistent post-ictall focal neurological deficit.

INDICATIONS OF HOSPITAL ADMISION FOR FIRST SEIZURE

Detailed history-1. Regarding seizure event.2. Past medical history- severe head injury. 3. Growth and developmental history -

cerebral palsy or mental retardation.4. Family history.5. Social history - exposure to lead or drugs of

abuse, as well to the practical impact on employment and lifestyle.

6. Review of systems may find other non-neurological signs or risk factors associated with seizures

EVALUATION

The physical examination –

Include both a general exam and a detailed age-appropriate neurological exam.

The general exam should focus on identifying systemic signs that may be associated with seizures ,such as the dysmorphic facial features of a chromosomal disorder or the skin lesions of tuberous sclerosis.

The neurological exam should look for any abnormalities that would help identify an underlying neurological disease

Reactive or systemic causes1. Reactive seizures triggered by sleep

deprivation, fever, drug withdrawal or toxycity

2. Systemic disease– infection,hypoglycemia,hypoxia,hypocalcemia

CNS insult1. Direct CNS insult– head injury,

stroke,encephalitis, brain neoplasm2. May be the manifestation of idiopathic

epilepsy

CAUSES OF SINGLE FIRST SEIZURE

MRI or CT brain

Metabolic screening– S/E, blood glucose, liver function,toxicology studies (alcohol,paracitomol,cocaine).

EEG

CSF analysis only if there is suspicion of intra cranial infection.

DIAGNOSTIC TESTS FOR SEIZURE EVALUATION

  In adolescents and young adults

1. Syncope

2. Psychological disorders

3. Sleep disorders

4. Paroxysmal movement disorders

5. Migraine

6. Miscellaneous neurologic events

In the elderly

1. Transient ischemic attack

2. Transient global amnesia

IMITATORS OF EPILEPSY

The risks versus benefits of giving antiepileptic drugs (AEDs) after a first seizure are controversial for patients of any age.

Several factors must be weighed in making a decision about prescribing medication:

Is the diagnosis correct? Are seizures likely to recur? Is treatment likely to be successful?

Does the risk of more seizures outweigh the negative aspects of treatment?

WHEN TO START AED THERAPY ?

 Antiepileptic drug (AED) therapy is generally reserved for patients who are at increased risk for recurrent seizures.

FINDINGS:

Number of seizures of all types at presentation, presence of a neurological disorder, and an abnormal EEG were significant factors in indicating future seizures.

Individuals with two or three seizures, a neurological disorder, or an abnormal EEG were identified as the medium-risk group

Multicentre trial for Early Epilepsy and Single Seizures (MESS)

Those with two of these features or more than three seizures as the high-risk group.

Those with a single seizure only as the low-risk group

INTERPRETATION: The model shows that there is little benefit to immediate treatment in patients at low risk of seizure recurrence, but potentially worthwhile benefits are seen in those at medium and high risk.

  Lancet Neurol. 2006;5(4):317

Pediatric Study: Prospective study of 407 children, with mean follow-up of 6.3 years (Shinnar et al. 1990, 1996).

Overall recurrence risk = 42% at 5 years.

5 risk factors for recurrence were identified:

1. Etiology: remote symptomatic (66%) vs. idiopathic (37%).

2. EEG: abnormal EEG (59%) vs normal EEG (32%).

3. Sleep state: seizure in sleep (53%) vs awake (36%).

4. Hx of febrile seizure: positive history (54%) vs negative (39%).

5. Status epilepticus did not increase recurrence risk,

Multiple seizures within 24 hours did not increase recurrence risk.

Minnesota Study: 208 primarily adult patients with mean follow-up of 4 years (Hauser et al. 1982)

Overall recurrence risk =34% at 4 years.

Risk factors: Etiology: remote symptomatic (48%) vs idiopathic

(29%). Among idiopathic cases, increased recurrence was

associated with positive FHx of epilepsy (46% vs 27%)

Abnormal EEG (58% vs 26%).

Hx of febrile/acute symptomatic seizure (39% vs 27%).

Other Studies (Annegers et al. 1986, Camfield et al. 1985, Hart et al. 1990) have found partial seizures and an abnormal neurological examination to have increased recurrence risk.

high risk features for seizure recurrence after a first unprovoked seizure

1. Epileptiform abnormalities on EEG.

2. Remote symptomatic cause, as identified by clinical history or neuroimaging (eg, brain tumor, brain malformation).

3. Abnormal neurologic examination, including focal findings and mental retardation.

AED treatment after a first seizure may be considered in any of these higher risk subgroups.

Other potential risk factors for seizure

Patients who have a first presentation with status epilepticus or with multiple seizures within a single day.

However, limited data suggest that these features, in the absence of other risk factors, do not increase the risk of seizure recurrence.

Whether a history of prior febrile seizures is associated with an increased risk of seizure recurrence after a first unprovoked seizure is uncertain.

Study results have conflicted as to whether a family history of epilepsy impacts recurrence risk.

Some observations suggest that a first seizure that occurs during sleep is associated with a greater risk of recurrence

Benefit of early versus deferred treatment 

Immediate AED treatment reduces the incidence of seizure recurrence in the short-term(30%-50%), studies suggest that it has little impact on long-term outcome.

However, the questionnaires demonstrated significant trade-offs between the adverse effects of seizures versus adverse effects of taking AEDs, suggesting that individual patient preferences should be considered.

REFERENCES

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