Epilepsy, seizures Flashcards
What is the definition of a seizure?
A transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain
Per the International League Against Epilepsy (ILAE), what are the 2 main classifications of seizures now?
- Generalized. These can be tonic-clonic, absence, clonic, tonic, atonic, and myoclonic.
Generalized seizures are those that arise in and rapidly engage bilaterally distributed networks. - Focal. These are characterized by one or more features (aura, motor, autonomic, awareness/responsiveness-could be altered). Focal or localized seizures usually involve 1 hemisphere.
What is epilepsy?
Recurrent, unprovoked seizures, usually secondary to an underlying pathological condition. One does not have epilepsy if they have seizures from transient factors such as withdrawal from substance.
What could cause epilepsy?
There are acquired causes (trauma, neoplasm).
There are congenital causes (cortical dysplasia).
There are genetic causes.
Where is the most common site of pathology in adults with seizures?
The temporal lobe - particularly the hippocampus - is the most common site of pathology for those with seizures with alteration of consciousness or awareness (2/3 of cases). The most common pathology in adults is hippocampal sclerosis, which is characterized by neuronal loss (CA1 and CA3 subfields). The remaining neurons may become part of the “epileptogenic network” that is marked by synaptic reorganization. Sclerosis is indicated by atrophy on imaging and increased signal intensity on T2 weighted MRI and FLAIR
Beyond hippocampal sclerosis, what is another common cause/site of epilepsy?
Cortical malformations. These can be present anywhere in the cortex. Perhaps to a lesser extent, neurovascular disease, TBI, and tumors can precipitate seizures.
What is the incidence of epilepsy?
Incidence or number of new cases per year is estimated to be approx 50 per 100,000 individuals in US. Prevalence is 5-10 per 1,000 in US
Are individuals with epilepsy at increased risk of death?
Yes
What determines severity of epilepsy?
Severity increases with seizure recurrence and frequency. Seizure frequency is the most significant factor in determining severity of cognitive impairment. Younger age of seizure onset and number of AEDs also predict severity of cognitive impairment.
What are symptoms that go hand in hand with temporal lobe epilepsy with hippocampal sclerosis?
Auras are common. Involve GI symptoms (rising epigastric sensation or butterflies in stomach), feelings of deja vu. Usually patients have altered awareness and clouding of consciousness, but not LOC. During the sz, bx is disorganized and include repetitive movements of hands, tongue, mouth, and lips. Repetitive movements of the hand are seen typically ipsilateral to the side of sz onset. The other hand is typically forced in a tonic posture. The ability to continue speaking clearly is associated with non-language dominant temporal lobe onset in the majority of cases. Aphasic or dysnomic speech is typically observed following dominant TLE sz. Postictal confusion/fatigue are common for minutes to hours.
What are the possible risks of undergoing temporal lobectomy?
- Cognitive decline, particularly memory and language (if resection is done to the dominant temp lobe).
- Superior quadrantanopsia (pie shaped visual loss or blind spot in the upper peripheral visual field) due to the location and the path of the optic radiation (Meyer’s loop) in relation to temporal lobe.
Is lobectomy successful?
Yes up to 80% of ppl with medically refractory TLE become sz free after surgery with long term use of AEDs. Successful surgery is associated with improved QoL and reduced mood px
What is the association between IQ and epilepsy?
Many forms of epilepsy are associated with global cognitive impairments, of which one manifestation is low intelligence. Many ppl with epilepsy have normal IQ though. IQ usually serves as a proxy for outcome, disease severity, and extent of underlying pathology. Persons with less severe epilepsy and those with more focal seizure onset are more likely to have normal IQ. A risk factor for low IQ is age of seizure onset, with earlier onset associated with lower IQ.
What are other associations of cognitive domains with epilepsy?
More than a quarter of children with epilepsy have attention problems regardless of sz type. Processing speed deficits may have a structural basis or be related to side effects of AEDs used to treat epilepsy. AEDs tend to reduce hyperexciteability and neuronal transmission by increasing inhibitory action (GABA) or reducing availability and function of excitatory NTs (glutamate). Language deficits are commonly reported in children, onset of seizures during critical language development can disrupt important networks in language even if they arise from the R hemisphere. Adults with TLE particularly have deficits in word finding and semantic knowledge. Memory deficits may be material specific, and list learning measures tend to be most sensitive to dominant hem TLE. Executive dysfunction may be seen in frontal lobe epilepsy and to a lesser extent, TLE.
What are considerations to have in mind when seeing patients with epilepsy? (recommendations?)
1) Supervision may need to be increased if seizures are placing the individual at risk (and individual may need to refrain from certain activities).
2) Driving may not be permitted. Although not a law, 3 months of seizure freedom has been used by providers in state of Nebraska.
3) Work options are reduced for patients with epilepsy due to safety concerns.
4) Depression and anxiety are common in patients with epilepsy.
