Source: Rogers SJ, Cavazos
JE. Epilepsy. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells
BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic
Approach. 8th ed. http://www.accesspharmacy.com/content.aspx?aid=7985219.
Accessed July 18, 2012.
- Occurrence of at least two unprovoked seizures with or
without convulsions separated by at least 24 hours.
- Genetic predisposition.
- Seizure onset in elderly may be associated with strokes, neurodegenerative
disorders (e.g., Alzheimer's disease), and other conditions.
- Unprovoked seizures without identifiable cause are called
idiopathic or cryptogenic epilepsy.
- Seizure results from excessive discharge of cortical neurons.
- Mechanisms contributing to neuronal hyperexcitability may
- Alterations of ion channels in neuronal
- Biochemical modifications of receptors
- Modulation of second messaging systems and gene expression
- Changes in extracellular ion concentrations
- Alterations in neurotransmitter uptake and metabolism in glial
- Modification in ratio and function of inhibitory circuits
- Local imbalances between main neurotransmitters (e.g., glutamate, γ-aminobutyric
acid [GABA]) and neuromodulators (e.g., acetylcholine,
norepinephrine, and serotonin)
- Incidence: 44 per 100,000 person-years.
- Approximately 125,000 new epilepsy cases occur in United States
- Only 30% in people younger than
18 years at time of diagnosis.
- Bimodal distribution in occurrence of first seizure, with
one peak in newborn and young children and second peak in patients
older than 65 years.
- Patients with mental retardation, cerebral palsy, head
injury, or strokes at an increased risk for seizures and epilepsy.
- Seizures can be precipitated by:
- Sleep deprivation
- Sensory stimuli
- Emotional stress
- Hormonal changes with menses, puberty, or pregnancy
- Drugs that may provoke seizures include:
- Antidepressants (especially maprotiline or bupropion)
- Street drugs
- Perinatal injuries and small birth weight are risk factors
for partial-onset seizures.
- Obtaining accurate history and description of event (including
time course) from third party important because clinician often
not in a position to witness seizures.
- Symptoms depend on seizure type. Seizures can vary among
patients but tend to be fixed within individual.
partial seizures may include somatosensory or focal motor features
and are associated with altered consciousness.
- Absence seizures have only very brief (seconds) periods of
- Generalized tonic-clonic (GTC) seizures may be preceded by
premonitory symptoms (aura).
- Tonic-clonic seizures
begin with short tonic muscle contraction followed by period of
rigidity and clonic movements.
- The patient may lose sphincter control, bite tongue, or become
- Episode may be followed by unconsciousness, and patient frequently
goes into deep sleep.
- Usually no objective signs of epilepsy between seizure episodes.
Means of Confirmation
- Ask patient and family to characterize seizures for:
- Precipitating factors
- Time of occurrence
- Presence of aura
- Ictal activity
- Postictal state
- Physical exam may help identify underlying causes.
- Laboratory tests to rule out treatable causes of seizures
- Serum glucose
- Complete blood count (CBC), serum creatinine, and liver function
tests may also be obtained.
- Serum prolactin level obtained within 10–20 minutes
of tonic-clonic seizure may be elevated, which can help differentiate
seizure activity from ...