Epilepsy
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Introduction
Epilepsy is a cluster of symptoms characterized by recurrent, spontaneous, unprovoked seizures. It affects 0.5-1.0% of the population.
Generalized epilepsy tends to begin in children and adults, though 10-20% of cases begin after age 20.
People can have a number of different seizures as a part of their epilepsy, though tend to have either partial or generalized.
Epilepsy syndromes show the presence of some seizures, along with other findings, but do not meet the criteria for epilepsy.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.
Causes and Risk Factors
- any insult to cortex can cause seizures, often years later
- over 50% of cases have no known cause
- danage to four neurons can start a seizure
- can be caused by any pathology affecting the cortex
- genetic
- infectious, especially certain types of meningitis; postinfectious
- postinfectious, neoplastic, traumatic, vascular, degenerative
- hyponatremia
- alcohol withdrawal
- developmental brain problems: arterio-venous malformations
- with traumatic injury, there is often a lag of a few years between the trauma and the onset of seizures
Pathophysiology
seizure is a "sudden excessive discharge of gray matter"
- clinical feature depends on where seizure begins and propogates to
- seizures can arise from the spread of improper electrical activity from a seizure focus
- clinical manifestations of the seizure depend on the location
- frontal and temporal lobes are very eleptogenic; parietal and occipital lobes are much more resistant
- possible mechanisms include excess 'excitation', diminished inhibition (ie GABA), hypersynchrony
- http://content.nejm.org/cgi/content/full/349/13/1257
Signs and Symptoms
- history
- physical exam
History
neurologic history is very important from both patient and witness
Todd's paresis: if during the postictal phase they can't speak, it suggests the language centre is the area of focus
EEG can be used to localize seizure foci. Interictal (non-clinical) waves can sometimes be seen
neuroimaging for aetiology
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
Diagnostic Imaging
Differential Diagnosis
distingush from:
- syncope (which only occur when standing)
- pseudoseizures (events of non-epileptic origin)
- can be malingering, subconscious
- more of a mental health condition
- suggestibility (this tuning fork may trigger your seizure...)
- pelvic thrusting
- bilateral shaking
- migraine aura
Benign Rolandic epilepsy
onset from ages 4-10
focal seizure, related to sleep
appears to be inherited in an AD fasion, with very incomplete penetrance
EEG has characteristic findings
always outgrown
Treatments
Treatments are first to prevent injury and preserve life.
They also have a substantial psychosocial role: people want to know their seizures are being managed.
ketogenic diet - high fat, low sugar = no fun
First Aid for a Seizure
- remove dangerous objects
- cover person with blanket to protect dignity
- when seizure is finished, place person in recovery position
Stopping a Seizure
- benzodiazepines such as diazepam can be used to end seizures
Prophylactic Medications
- there are 12-15 anticonvulsant drugs
- ONE drug at a time, with as low a dose at a time
- there are no drugs that prevent the development of seizure foci, ie following trauma
Surgery
cortical resection of focus, corpus callostomy (for atonic seizures), hemisperectomy (but only really for kids who have serious seizures
vagal nerve stimulation
Consequences and Course
Resources and References
Topic Development
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