Epilepsy - Schwabe Flashcards
What is the definition of a seizure?
What is epilepsy?
Seizure: Stereotypic alteration of behavior (positive symptoms) that results from abnormal and excessive activity of a group of cerebral neurons.
Epilepsy: Tendency to have recurrent, unprovoked seizures.
On an EEG recording, what is referred to as “ictal”?
“Interictal”?
“Ictal” refers to activity recorded during a seizure.
“Interictal” refers to the periods of normal activity between seizures in a patient who suffers from seizures (e.g. epilepsy)
In patients with epilepsy, what abnormality can be noted on EEG during interictal periods?
Interictal spikes - small spikes in the EEG that signify a brief, subclinical (symptomless) seizure.
In terms of seizures, what are “ephatic effects”?
“Spilling over” of electrical activity of overexcited neurons to neighboring neurons. Propagation method of seizures.
What are the three major types of seizures?
- Partial (localized)
- Generalized (throughout both sides of the brain)
- Secondarily Generalized (starts localized and spreads to both sides)
What are the two types of parital seizures?
Simple
Complex
Not counting secondarily generalized, what are the five types of generalized seizures?
- Absence
- Tonic
- Atonic
- Generalized Tonic-Clonic (GTC)
- Myoclonic
What are some brain abnormalities that can lead to epilepsy?
Abnormalities include (likely low yield to memorize these):
- Neuronal network
- e.g. Aberrant excitatory connections
- Neuronal structure
- e.g. Aberrant dendrites and dendritic spines
- Neurotransmitter synthesis
- e.g. Decreased GABA
- NT inhibition
- Abnormal receptors
- NT excitation
- e.g. Activation of NMDA receptors by excess glycine
- Synaptic Development
- Channelopathies
What symptoms can be present in a **simple partial **seizure?
- Consciousness is not impaired
- Sxs depend on localization in brain, but can include:
- Clonic movements of face, arm, leg
- Somatosensory
- Autonomic
-
Psychic
- De’ja vu
- Hallucinations
- Illusions
What is the time frame of a simple partial seizure?
What post-ictal symptoms are there?
- Brief
- No post-ictal symptoms, except:
- Possibly Todd’s Paraylsis
- Transient weakness following a partial seizure
- Ranges from mild to complete paralysis
- Typically in the same area that clonic movements were occuring
- Possibly Todd’s Paraylsis
What are the symptoms of a complex partial seizure?
What about post-ictal symptoms?
- Ictal:
-
Impaired consciousness during seizure
- No recall afterwards
- Staring
-
Automatisms
- Facial grimacing, gestures, chewing, lip smacking, finger snapping, repetitie speech
- Fragmented but coordinated motor tasks
-
Impaired consciousness during seizure
- Post-Ictal Impairment
- Lethargy and/or confusion that lasts minutes to hours
- Possible headache and/or emesis
What two lobes of the brain are complex partial seizures known to originate from?
What types of symptoms are associated with each?
- Frontal
- Arrest of activity with few automatisms
-
Brief attacks that come in clusters
- Abrupt “on and off”
- Temporal
- Often preceeded by an aura
- Fear
- Stomach pain
- Light headedness
- Rising sensation
- Distortion of time or memory
- De’ja vu
- Autonomic symptoms
- Often preceeded by an aura
What is a generalized tonic-clonic (GTC) seizure? How does it present?
- Loss of consciousness + stiffening of limbs (tonic phase)
- Evolves to generalized muscle jerking (clonic phase)
- Deep sleep post-ictally
The majority of GTC seizures in childhood have what type of onset?
Focal onset
i.e., most childhood GTC seizures are of the secondarily generalized type
How does an absence seizure present?
-
Abrupt cessation of activity
- Head nodding or dropping of object
- Change in facial expression (blank stare)
- Typically:
- Less than 30 seconds
- No aura
- No significant post-ictal symptoms
- Clonic eye movements (blinking, nystagmus)
- Autonomic phenomena:
- Pupil dilation
- Pallor
- Flushing./Sweating
- Salivation
What pattern of eletrical activity is seen with a clonic seizure?
How does a clonic seizure present?
- Focal or multifocal onset
- Rarely is “truly” generalized (despite being under that category… sigh)
- Presents as clonic muscle movements, i.e., muscle jerking
- Clonic seizures alone are rare. Tonic-clonic seizures are much more common.
What seizure symptom can be a sign of metabolic or anoxic damage and should be investigated?
Migrating clonus
How does a tonic seizure present?
How long does it last?
- Sudden onset of increased extensor tone
- Impaired consciousness
- Brief - 60 seconds
How does an atonic seizure present?
- “Drop attack”
- Suddon loss of muscle tone
- Usually only a brief loss of consciousness
How does a myoclonic seizure present?
How is it differnet from a clonic seizure?
- Myoclonic:
- Extremely sudden & brief (<350ms)
- “Shock”-like
- Can be generalized or confined to face, trunk, etc.
- Can be seen prior to absence, tonic, or tonic-clonic seizures
- Sometimes a sign of diffuse brain injury
- Recall: clonic seizures last more than a second and so involve more repetitive jerking. Myoclonic seizures are so fast they can be mistaken for tremors or tics.
What is status epilepticus?
- 30 minutes of either:
- Sustained seizure activity
- 2+ seizures without full recovery of consciousness in between
- What type of imaging will most likely be used to work-up suspected focal seizures?
- What about primary generalized epilepsy?
- MRI
- EEG (sorry, I know this is more a “recording” than imaging)
What initial studies should be included in the evaluation of seizures?
-
First, all your basic stuff:
- glucose, electrolytes, BUN
- ABG
- Antiepileptic (and other) drug levels
- CBC
- Urinalysys
-
Secondary to those, as needed:
- Lumbar puncture
- Liver function
- Toxicology
- Metabolic testing
- EEG
- CT or MRI
What are some major side effects of antiepileptic medications?
Can you name a couple specific drugs known to cause each adverse effect?
- “Direct Toxicity” [how vague…]
- Dermatologic
- carbamazepine, lamotrigine
- Bone Marrow effects
- phenobarbital, ethosuximide, carbamazepine, phenytoin, valproic acid, zonisamide
- Hepatic Effects
- phenytoin, carbamaepine, valproic acid
What antiepileptic drug marks the earliest of the “new” or more “current” drugs?
When is this drug used?
Felbamate
Used as a last pharmaceutical resort in medically resistant epilepsy due to possibility of aplastic anemia and liver damage.
Which 8 anticonvulsant drugs (ACDs) are the most useful across the board of different seizure types?
(Yup. This is about as specific as the lecturer got.)
- Valproic acid
- Lamotrigine
- Topiramate
- Zonisamide
- Levetiracetam
- Felbatol
- Rufinamide
- Lacosamide
Which 3 ACD’s are most useful for treating absence seizures in particular?
- Ethosuximide
- Valproic acid
- Lamotrigine
What % of epilepsy patients repond to the first or second ACD prescribed?
After how long of being seizure free are ACDs typically withdrawn?
70-80% (aka, THE MAJORITY)
Withdrawn after 2 years of being seizure free
What treatments othan than medications can be used in the treatment of intractable epilepsy?
- Ketogenic (high fat) diet
- Surgery
- Vagal nerve stimulator implantation
- Epilepsy surgery
- aka removal of specific brain structures
