Adult Seizure Disorders Flashcards
What is a seizure?
Episode of abnormally synchronized and high frequency firing of neurons resulting in abnormal behavior or experience
What is epilepsy?
Chronic brain disorder of various etiologies characterized by recurrent, unprovoked seizures.
Not all seizures are epileptic seizures. Only seizures that are recurrent and are clearly unprovoked can be considered to be epileptic in etiology.
What are some provoking factors that could precipitate a seizure (remember if there’s a provoking factor then its not epilepsy)?
fever, acute head trauma, metabolic disorders such as hypo and hyperglycemia, and electrolyte disturbances such as hyponatremia.
What are epilepsy syndromes?
Grouping of similar epileptic patients according to seizure type, EEG age of onset, prognosis and clinical signs
A well known example of an epileptic syndrome is the syndrome of Juvenile myoclonic epilepsy (JME).
How common are epileptic seizures?
The prevalence of epileptic seizures is roughly 0.5% world wide, and can be as high as 5% in countries where some communities have inadequate access to primary health care facilities.
The increase in patients over age 60 is partly the result of increased rate of Strokes in that age group. Strokes may predispose to epileptic seizures.
Note the incidence peaks in children and in the elderly.
What are some common causes of adult-onset epileptic seizures?
Cerebrovascular disease
Trauma
Tumors
Infections
Cerebral degeneration
Describe the ILAE classicifcation of epileptic seizures
ILAE is the International League Against Epilepsy.
Partial seizures are focal onset seizures that emanate from a specific cortical head region, and may sometimes spread to become secondarily generalized. Generalized seizures refer to Primarily Generalized seizures with no focal onset, thought to emanate from the brainstem structures; with spread to both hemispheres at the same time.
What is often a key to distinguishing between simple partial seizures, complex partial seizuresm, and partial seizures with secondary generalization?
The level of consciousness
Describe simple partial seizures
Signs/symptoms depend on the nidus (motor, somatosensory, autonomic, psychic)
Simple partial seizures emanating from the motor cortex may demonstrate a classic “Jacksonian march”, with focal seizure starting from the hand, for instance and “marching” up to involve the arm and face on the same side.
Somatosensory partial seizures have a focus in the sensory cortex and present with tingling and numbness of an extremity or side of face.
Autonomic seizures may present with rising epigastric sensations, nausea, while psychic seizure presentations may include sensations of fear, Déjà vu, or Jamais vu phenomena.
T or F. Consciousness is intact in a simple partial seizure
T. And an EEG may appear normal
What are Auras?
Auras are brief, simple partial seizures with no overt behavioral manifestations.
Describe the presentation of complex partial seizures
Impaired consciousness
Lasts about 1 min.
Blank stare
Oral / ipsilateral hand automatisms (Include chewing and lip-smacking movements.Typical hand automatisms are hand rubbing and picking movements)
Contralateral dystonic posturing
Amnesia for ictal event and confusion
Focal abnormality on routine EEG
Where do complex partial seizures arise from?
the temporal or frontal lobes
What causes the Contralateral dystonic posturing seen in complex partial seizures?
results from spread of seizure activity from the temporal lobe to the ipsilateral basal ganglia..
What are the types of primary generalized seizures
Absence (Petit Mal)
Tonic-Clonic
Clonic
Tonic
Myoclonic
Atonic
Describe the presentation of absence seizures
There is a brief (10-20sec) loss of consciousness, associated with a staring spell, subtle myoclonic movements, eyelid flutter, but no post-ictal confusion
No baseline neurologic deficits
How does an EEG for an absence seizure present?
may show generalized 3Hz spike-wave discharges
How does a tonic-clonic seizure (aka “Grand Mal” seizures) present?
Cry, loss of consciousness
Muscular rigidity (tonic)
Patient may fall
Rhythmic jerking (clonic) and/or Tongue-biting/injury common Bladder/bowel incontinence
Post-ictal confusion / sleep
How do myoclonic seizures present?
- Brief, shock-like muscle contractions that are sually bilaterally symmetrical: Head/ Upper extremities common
- Consciousness preserved
- May progress into tonic-clonic seizures
What causes myoclonic seizures
Precipitated by awakening or falling asleep
NOTE: Juvenile myoclonic epilepsy commonly presents with myoclonic seizures.
Describe the presentation of atonic seizures
- Impaired consciousness (Brief duration (few seconds))
- Loss of muscle tone
- Head drop
- Fall (Injury common)
How are seizures diagnosed?
Eyewitness description of seizures are very helpful.
Neurological examinations are usually normal in the patients with epileptic seizures.
Metabolic panels (CBC, CMP) help to detect abnormalities like hypoglycemia or hyponatremia which may have provoked seizure..
Serum levels of antiepileptic drugs (AED) that the patient may be taking helps to detect non-compliance or inadequate dosing of AED.
wInitial EEG detects an epileptiform discharge in __-__% of patients.
29-55. While Serial EEGs reveal epileptiform discharges in 80-90% of patients.
Repeat studies, with sleep deprivation and extended recording times, helps increase chances of detecting epileptiform discharges in patients with epilepsy
This EEG indicates that the seizure focus is in the left anterior temporal head region.
Sharp waves, spikes, and sharp-and slow wave discharges are examples of epileptiform abnormalities which are sometimes seen in the EEGs of patients with epileptic seizures.
This EEG demonstrates a bilateral burst of epileptiform spike and slow wave discharges (starting at red arrow and continuing to the right). which is typical for primary generalized seizures such as in Juvenile myoclonic epilepsy. The discharge occurs simultaneously and symmetrically in both hemispheres.
Bilateral and symmetrical spike and wave activity occurring at a frequency of 3 per second (3 Hz) is classic for petit mal absence seizure, a primary generalized seizure type..
Recent-onset epilepsy in adults requires imaging sequences, including gadolinium-DPTA enhanced sequences to find primary or secondary tumors, infection or inflammation
Coronal MRI showing an atrophic and sclerotic hippocampus (arrow).
What might be the effect of using CYP450 inducing AEDs?
lead to failure of oral contraceptives
cause osteopenia, osteoporosis, fractures
increase metabolism of androgens and estrogens
Note: The older AEDs cause malformations in 4-8% of children (twice the normal rate) with risk increasing with higher AED dose and polytherapy.
The older AEDs are category D drugs, while the newer AEDs are category C
How does vagus nerve stimulation work?
An electrical pulse generator is implanted subQ in the chest, and a lead is attached to the left vagus nerve (MOA unknown, but about 40-50% have 50+% seizure reduction, but rarely seizure free)
