Neuro: Seizures Flashcards
A paroxysmal event due to abnormal excessive or synchronous neuronal activity in the brain
Seizures
A condition in which a person has recurrent seizures due to a chronic, underlying process
Epilepsy
Recurrent seizures from an infection or avoidable cause. Is this epilepsy?
No
Definition of epilepsy
2 or more UNPROVOKED seizures
Classifications of seziures
Focal
Generalized
Unclear
Motor, sensory, autonomic, cognitive seizures are what classification?
Focal
Absence, tonic clonic, atonic, and myoclonic seizures are what classification?
General
Seizure that arises from a neuronal network within one hemisphere
Focal seizures
What determines the difference between a simple and complex focal seizure?
Simple –> No LOC
Complex –> Alteration in consciousness
What would you expect an EEG to look like between seizures?
normal
may show brief discharges (epileptiform spikes)
In focal seizures WITHOUT dyscongitive features (simple), movement is typically (clonic, tonic)
clonic
Focal seizures accompanied by transient impairment of the patient’s ability to maintain normal cognition
Focal seizures WITH dyscognitive features (complex)
Pt can’t respond appropriately to visual or verbal commands during seizure and usually doesn’t remember it
Thought to arise at some point in the brain but immediately and rapidly engage neuronal networks in both cerebral hemispheres
Generalized seizures
Characterized by sudden, brief lapses of consciousness without the loss of postural control. Seizure lasts for a few seconds and consciousness returns as suddenly as it was lost. No postictal confusion
Typical absence seizures (generalized seizure)
Electrophysiologic hallmark of typical absence seizure
generalized, symmetric, 3 hz spike-and-wave discharge that begins and ends suddenly. Seen on EEG
Absence seizure with longer lapse of consciousness, associated with diffuse or multifocal structural abnormalities of the brain.
Atypical absence seizures
You give anticonvulsants to a pt with a typical absence seizure and a pt with atypical absence seizure. Who will respond better?
Typical
Most common seizure type resulting from metabolic derangements
Generalized, tonic-clonic seizures
How does tonic-clonic seizure begin?
abrupt without warning. Some pts have vague premonitory symptoms minutes to seconds before seizure
Characteristics of tonic-clonic seizures
initial phase: tonic contractions
Respirations are impaired, secretions pool in oropharynx and cyanosis develops
Contraction of jaw muscles causes biting of the tongue
When observing a pt undergoing a tonic-clonic seizure, what might you see?
cyanosis, increased HR, BP, pupils dilate
After 10-20 seconds, clonic phase begins
How long do typical tonic-clonic seizures last? How long is dangerous?
Typical - 1 minute
Dangerous - more than 5 minutes
Describe the postictal phase of tonic-clonic seizures
unresponsiveness Muscular flaccidity Excessive salivation Bowel/bladder incontinence Confusion
Sudden loss of postural muscle tone lasting 1-2 seconds.
Atonic seizures
“drop attacks”
Sudden, brief muscle contraction. Normal, physiologic form is sudden jerking when falling asleep.
Myoclonic seizures
Associated with metabolic disorders, degenerative CNS dz, anoxic brain injury. caused by cortical dysfunction
Myoclonic seizures
What are the three types of epilepsy syndromes?
Juvenile Myoclonic Epilepsy (JME)
Lennox-Gastaut Sydrome (LGS)
Mesial Temporal Lobe Epilepsy
Characterized by bilateral jerks, single or repetitive. More common in the morning, provoked by lack of sleep. 1/3 have absence seizures, many can experience tonic-clonic seizures
Juvenile Myoclonic Epilepsy
Treatment of choice for JME
Valproate (Depakote)
Remission is relatively uncommon, but responds well to anticonvulsants
Occurs in children, associated with developmental abnormalities, perinatal hypoxia, trauma, and infection
Lennox-Gastaut Syndrome
LGS triad
- Multiple seizure types (tonic and atonic seizures)
- EEG showing spike-and-wave discharges/abnormalities
- Impaired cognitive function in most cases
Prognosis of LGS
Poor, results in poorly controlled epilepsy
Most common syndrome associated with focal seizures with dyscognitive features
mesial temporal lobe epilepsy
Mixture of different feelings, emotions, thoughts, and experiences, which may be familiar or completely foreign
Mesial temporal lobe epilepsy
MRI findings on mesial temporal lobe epilepsy
Hippocampal sclerosis
What causes seizures?
Shift in the normal balance of excitation and inhibition within the CNS
What are the three clinical observations that can cause seizures?
- Endogenous factor (factor within ourselves that makes seizures more likely)
- Epileptogenic factor (something that transforms normal CNS that makes it more excitable)
- Precipitating factors (induce seizures)
An otherwise normal child gets a fever and has a seizure. This is an example of what factor?
Endogenous
Following penetrating trauma to the head, the pt has seizures. This is an example of what factor?
Epileptogenic
Pt doesn’t get enough sleep and has a seizure. This is an example of what factor?
Precipitating factor
What is an important factor in determining both incidence and likely causes of seizures/epilepsy?
AGE
Causes of seizures in neonates/early infancy
Encephalopathy Trauma Infection Congenital Metabolic D/O Drugs Hypoglycemia (CHIME TD)
Causes of seizures in late infancy/early childhood
Febrile seizures (most common) occurs during rising phase of fever. 1/3 have recurrence
Simple vs complex febrile seizurse
Simple: single event, brief, no risk of developing epilepsy
Complex: repeated events, >15 minutes, Do have a risk of developing epilepsy)
Causes of seizures in childhood
Idiopathic
Trauma
Infection
Tumor
Causes of seizures in adolescents
Acquired CNS lesion predominant, idiopathic less common Trauma genetic d/o infection, tumor illicit drug use
Causes of seizures in young adults
Alcohol withdrawal
Trauama
Illicit drugs
Brain tumor
Result of alcohol withdrawal, symptoms like shakiness, irritability, change in MS, seizure
Delirium tremens
Causes of seizures in older adults
Cerebrovascular disease Tumor Alcohol withdrawal Metabolic disorders AD/Degenerative CNS dz Just being old
Initiation phase of seizures is characterized by two concurrent events:
- High frequency bursts of action potentials
2. Hypersynchronization
Pathophys of burst
problem with the neuron itself. Allows an influx of calcium that causes Na channels to open up, increasing action potential. Causes spike discharge on EEG. After burst, hyperpolarizing occurs mediated by GABA or K channels
What causes the spike discharge on EEG?
Synchronized bursts from a sufficient number of neurons
What normally prevents burst activity from spreading?
hyperpolarization and inhibitory neurons
Transformation of a normal neuronal network into one that is chronically hyperrexcitable.
Epileptogenesis
What are the new findings in genetic causes of epilepsy?
Ion channel mutations and
Chromosomal microdeletions
May be the cause of epilepsy in some patients
You are taking history from someone who had their first seizure. What 3 things do you want to establish?
- Actual seizure or just a paroxysmal event?
- Cause? (RF, precipitating events)
- Is Anticonvulsant therapy required?
You are taking history from someone with prior seizurse. What 2 things is the evaluation directed toward?
- Identify cause and precipitating factors
2. Determine if their current treatment therapy is enough
What specifics are you looking for on PE in someone who had a seizure?
Signs of infection, trauma, drug/alcohol use, metabolic d/o (jaundice), neuro exam deficits
What labs do you order on someone who had a seizure?
Glucose!!
CMP, urine and blood tox screen, LP if suspect meningitis
What imaging do you order on someone with new-onset seizure?
MRI is better than CT
CT used if assessing for infection/bleed/mass
EEG can confirm electrical activity, classify seizure, and locate focus
Someone with a suspected seizure d/o has a normal EEG. Now what?
doesn’t rule out epilepsy. Repeat EEG or do long term monitoring
If this is your first seizure and it is left untreated, how many will have recurrence? How many will have recurrence if the seizure is treated?
Half if untreated
25% if treated
What lab test can tell you if someone is having a pseudoseizure?
Their prolactin level will be normal
Seizures and driving
PA state law is to suspend driver’s license for 6 months. Must report seizure of LOC to PENDOT
Who should perform seizure management? What are the main goals of management?
Neurologist Goals: 1. control seizures 2. Avoid tx side effects 3. maintain quality of life
When is Antiepileptic Drug Therapy started?
After 2+ unprovoked seizures (above 50% chance of recurrence)
How many patients will be seizure free when using AED?
Half with new dx of epilepsy will be seizure free with first AED prescribed
What type of AEDs are the most problematic with interactions with warfarin and oral contraceptive therapy? (as well as anti-cancer and anti-infective drugs)
Enzyme-inducing AED's: Phenytoin (dilantin) Carbamazepine (Tegretol) Phenobarbital Oxycarbazepine (Trileptal) Topiramate (Topamax)
How do you add another AED if the first one does not control epilepsy?
- Second med is increased to therapeutic levels before first agent is reduced
- Second med is titrated up slowly
- Temporary increase in side effects during overlap period until first AED is tapered off
Prognosis for patients who have failure of initial AED therapy
Fewer patients will have successful drug trial
What do you need to watch for in AED therapy?
- Increased risk of suicide
- Stevens-Johnson syndrome
- Toxic epidermal necrolysis
- Drug rash with eosinophilia and systemic symptoms
When is the period of highest risk of developing severe complications with AED?
First 2 months
Mainly used for focal seizures and neuropathic pain. SE: diplopia, hyponatremia
Carbamazepine (Tegretol)
SE of Phenytoin (Dilantin)
nystagmus, slurred speech, ataxia, drowsiness
signs of toxicity from phenytoin
gum hyperplasia
hirsuitism
Folate deficiency
(monitor LFTs and CBC)
Widely effective treatment for all seizures, also used for migraine prophylaxis. Elevated LFTs common as well as weight gain, alopecia, and tremor.
Valproic Acid (Depakene)/Divalproex (Depakote)
Rash and dizziness common. Most effective drug for focal seizures. 1:1000 get SJS.
Lamotrigine (Lamictal)
Used for general or focal seizures and has NO interactions with other drugs! May cause decrease in WBC and anger issues
Levetiracetam (Keppra)
AED that causes weight loss. Often used for focal seizures, pain syndromes, migraines.
Topiramate (Topamax)
Who should not get topamax?
If pregnant or hx of kidney stones
What classifies someone as being in remission of seizures?
Seizure-free for 2-5 years
Predictors of relapse of epilpesy after remission
- Abnormal EEG before/during withdrawal of AED
- Abnormal neuro exam
- Mental retardation
A seizure lasting >30 minutes or multiple seizures without regaining consciousness. More than half have no prior seizure history.
Status Epilepticus
Most common cause of status epilepticus
Low AED blood level
Treatment of status epilepticus
ABCs
Check Glucose
Benzos, phenytoin, or keppra IV
General anesthesia is a last resort
Surgical option used for refractory epilepsy
Vagal nerve stimulation
Reduces seizures by 40% in up to half of those with refractory epilepsy
Most common surgical excision of brain lesion in refractory epilepsy
Resect mesial temporal lobe sclerotic lesions
What % of those who do not get seizure control in the first year ever reach remission?
60%