Epilepsy

last authored:

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.

"people are walking collections of molecules"

types of seizures
diagnosis

The Case of...

a simple case introducing clincial presentation and calling for a differential diagnosis. To get students thinking.

return to top

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

return to top

Pathophysiology

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

return to top

Signs and Symptoms

seizure is a "sudden excessive discharge of gray matter"

clinical feature depends on where seizure begins and propogates to

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

return to top

Investigations

lab investigations
diagnostic imaging

Lab Investigations

Diagnostic Imaging

return to top

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

return to top

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.

Partial seizures -

there are 12-15 anticonvulsant drugs
- don't use them for the rest of time
- ONE drug at a time, with as low a dose at a time
surgery: cortical resection of focus, corpus callostomy (for atonic seizures), hemisperectomy (but only really for kids who have serious seizures
vagal nerve stimulation -
ketogenic diet - high fat, low sugar = no fun
there are no drugs that prevent the development of seizure foci, ie following trauma