Definition of epilepsy
Tendency to have recurrent seizures; transient derangement of nervous system 2/2 sudden, excessive, and disorderly discharge of cerebral neurons
What are the 3 major seizure types?
Describe the electrical discharges in generalized seizures
Bilateral, synchronous and symmetrical, involving BOTH cerebral hemispheres
Describe a tonic-clonic (grand mal) seizure
Tonic phase 10-15 sec (LOC, body stiffens, clench teeth, bite tongue, apnea, urinary incontinence)
Clonic phase 1-2 min (rhythmic muscle contractions)
Postictal phase (confusion and drowsiness)
What are the common types of generalized seizures?
Tonic-clonic (grand mal), absence (petit mal), myoclonic, tonic, atonic
What are the types of partial (focal) seizures?
Simple partial, complex partial
Describe an absence (petit mal) seizure
Brief LOC 5-10 sec with starring or blinking but only minimal motor involvement; consciousness regained with amnesia of event
EEG appearance of absence seizure
Bilateral synchronous 3-Hz spike and wave activity
What can provoke an absence seizure or its EEG abnormality?
Describe a myoclonic seizure
Brief, usually single, jerking of trunk +/- limbs
EEG appearance of myoclonic seizure
Bilateral synchronized spike and wave activity
What differentiates partial from generalized seizures?
Electrical activity of partial seizures starts in defined focus
Define simple partial vs. complex partial seizures
Simple partial - w/o impairment of consciousness
Complex partial - with impairment of consciousness
Where do most complex partial seizures arise from?
Temporal lobe (often begin with an aura - taste, smell, deja vu, fear)
What are automatisms?
Lip smacking, chewing movements, repetitive swallowing, upper limb movements
What happens when electrical discharge of a partial seizure generalizes?
Can have secondarily generalized tonic-clonic seizure
What are the 3 types of post-traumatic seizures?
Immediate, early, and late epilepsy
Describe immediate post-traumatic epilepsy
Occurs at the time of, or within minutes, of head injury; usually does not recur; good prognosis; does not predispose to late post-traumatic epilepsy
Describe early post-traumatic epilepsy
Occurs within 1 week of head injury; complicates injuries (e.g. intracranial hemorrhage, prolonged amnesia); predisposes to late post-traumatic seizures
Describe late post-traumatic epilepsy
Occurs after 1 week following head trauma (can be years later)
Factors predisposing to late post-traumatic epilepsy
Post-traumatic amnesia >24 hrs, intracranial hemorrhage, early seizures, depressed skull fracture
Tx of post-traumatic epilepsy
Phenytoin or carbamazepine
What is the incidence of seizures following craniotomy?
What is the drug of choice for postoperative seizure prophylaxis?
Phenytoin for 6 months
What is the relationship between the grade of malignancy of a glioma and the seizure risk?
Inverse! Lower grade a/w higher risk of seizure
DDx for seizures
Syncope (emotional, cardiac, postural, vasovagal), migraine (aura vs. partial seizure), pseudoseizures, movement disorders (Tourette's vs. myoclonic seizure)
What hormone is often elevated after seizures?
What is the chance of recurrence in a patient with first seizure?
78% in 3 years
Should you start an antiepileptic after 1st seizure?
Controversial; randomized studies say yes (esp. if structural lesion and early life onset)
AED after head injuries?
Decreases risk of early seizures (first 7 days) but not thereafter
Use phenytoin or carbamazepine