seizure is a transient occurrence symptoms due to abnormal … · 2017. 2. 4. · seizure at age 6...
Transcript of seizure is a transient occurrence symptoms due to abnormal … · 2017. 2. 4. · seizure at age 6...
Provoked seizures, also called acute symptomatic seizures, are directly attributable to an acute, active insult to the central nervous system (CNS) or a systemic metabolic derangement (e.g., hypoglycemia). By definition, provoked seizures occur in close temporal proximity to the inciting event
Acute symptomatic seizures represent ~40% of all seizures (excluding febrile seizures in the pediatric population) and have an incidence of 29 to 39 per 100,000 person years.[2,3] Provoked seizures can occur at any age, but are most common in infants and the elderly.
In adults, the leading etiologies are cerebrovascular disease, drug and alcohol withdrawal,metabolic,.[2] Provoked seizures are usually isolated, nonrecurrent events. Treatment is aimed at the underlying cause, and long-term antiepileptic drug (AED) therapy is not indicated.
“unprovoked” implies absence of a temporary or
reversible factor lowering the threshold and producing a seizure
at that point in time.
Two seizures. A 25-year-old woman has two unprovoked
seizures, 1 year apart. Comment: This person has
epilepsy, according to both the old and new definitions.
Stroke and seizure. A 65-year-old man had a left
middle cerebral artery stroke 6 weeks ago and now
presented with an unprovoked seizure. Comment: With
a seizure in this time relation to a stroke (or brain
infection or brain trauma) the literature6 suggests a
high (>70%) risk of another unprovoked seizure.
Therefore, in the new (but not the old) definition, this
man would have epilepsy.
Photic seizures. A 6-year-old boy has had two seizures 3 days apart while playing a videogame involving flashing lights. There have been no other seizures. EEG shows an abnormal photoparoxysmal response. Comment: This boy has epilepsy according to the new definition (but not the old), even though the seizures are provoked by lights, since there is an abnormal enduring predisposition to have seizures with light flashes.
Benign Epilepsy with Centrotemporal Spikes (BECTS).
A 22-year-old man had seizures with face twitching
when falling asleep at ages 9, 10, and 14 years; he has
had none since. EEG at age 9 years demonstrated centrotemporal
spikes. Medications were discontinued at
age 16. Comment: For this young man, epilepsy is
resolved, because of passing the relevant age range of an
age-dependent syndrome. The old definition has no provision
for considering epilepsy to be resolved.
Two seizures long ago. An 85-year-old man had a focal
seizure at age 6 and another at age 8 years. EEG, MRI,
blood tests, and family history were all unrevealing. He
received antiseizure drugs from age 8 to age 10 years,
when they were discontinued. There have been no further
seizures. Comment: According to the new definition,
epilepsy is resolved, since he has been seizure-free
for >10 years and off seizure medication for at least the
last 5 years. This is not a guarantee against future
7. Long-interval seizures. A 70-year-old woman had
unprovoked seizures at ages 15 and 70. EEG, MRI, and
family history are unremarkable. Comment: Both old
and new definitions consider this woman to have epilepsy.
Despite the diagnosis, many clinicians would not
treat because of the low frequency of seizures. Should
investigations somehow show that the causes of the
two seizures were different, then epilepsy would not be
considered to be present.
The incidence of unprovoked seizures in the general population is 57 to 63 per 100,000 persons and the incidence of epilepsy is 46 to 48 per 100,000.[
An estimated 40 million individuals worldwide have epilepsy
indicates that 142,000 persons with epilepsy die annually, equating to 0.2% of all deaths worldwide
Approach:
History (from patient and witness)
Physical examination
Investigations
Event Localization
Temporal relationship
Factors
Nature
Associated features
Past medical history
Developmental history
Drug and immunization history
Family history
Social history
General
esp. syndromal or non-syndromal dysmorphic
features, neurocutaneous features
Neurological
Other system as indicated
E.g. Febrile convulsion, infantile spasm
I. Exclusion of differentials:
Bedside: urinalysis
Haematological: CBP
Biochemical: U&Es, Calcium, glucose, ABGs
Radiological: CXR, CT head
Toxicological: screen
Microbiological: LP
(Always used with justification)
Structural neuroimaging
Functional neuroimaging
Who should have a structural neuroimaging?
Status epilepticus or acute, severe epilepsy
Develop seizures when > 20 years old
Focal epilepsy (unless typical of benign focal epilepsy syndrome)
Refractory epilepsy
Evidence of neurocutaneous syndrome
Modalities available:
Magnetic Resonance Imaging (MRI)
Computerized Tomography (CT)
What sort of structural scan?
MRI better than CT
CT usually adequate if to exclude large tumor
MRI not involve ionizing radiation
I.e. not affect fetus in pregnant women (but nevertheless
avoided if possible)
Modalities available:
Positron Emission Tomography (PET)
Single Photon Emission Computerized Tomography
(SPECT)
Functional Magnetic Resonance Imaging (fMRI)
Mostly used in:
Planning epilepsy surgery
Identifying epileptogenic region
Localizing brain function