Seizures Patho

Question 1

Definition
Seizures

Answer 1

• burst of electrical activity
• neurons are hyper excitable (lower seizure threshold)
• increased freuqency and synchronicity of discharge

Question 2

Provoked Seizure
Etiology & Treatment

Answer 2

Seizure is secondary to a known cause
*This is NOT epilepsy
Treatment: Treat cause

1. Drugs and drug withdrawal
   - CNS Depressants: Alcohol, barbiturates, benzodiazepine withdrawal
   - CNS stimulants: Cocaine, amphetamines
2. Infection
   - meningitis
3. Cerebrovascular event and diseases
   - hemorrhage, stroke, ischemia, AVM
   - multiple scelerosis
4. Traumatic brain injury
5. Metabolic disorders
   - Hyperaemia
   - hypoglycemia
   - electrolyte imbalances
   - Acid-base imbalances
   - Dehydration
6. Idiopathic

Question 3

Two types of Seizures

Answer 3

1. Unprovoked (primary, epilepsy)
2. Provoked (secondary)

Question 4

Epilepsy
Diagnostic Definition

Answer 4

1. Two unprovoked seizures within 24 hours
2. 1 unprovoked seizure with > 60% re-occurance rate in 10 years
3. epilepsy syndrome

Question 5

Epileptogenic Focus
Pathophysiology

Answer 5

Group of hyper-excitable neurons
Depolarization shift, lower threshold for action Potential generation

Fire
1. more frequently
2. greater amplitude

Cortical excitation and spreading
-neighbour neurons recruited
- fire more easily
- seizure generalizes

Question 6

Brain Regions
Tonic vs. Clonic

Answer 6

Tonic: Muscles rigid
Brain: brainstem, sub cortex, thalamus

Clonic: rhythmic contract-relaxation
Brain: basal ganglia, thalamus, cortex

Question 7

Seizures
Oxygen Consumption

Answer 7

Seizures = increased BMR
- increase oxygen demand
- increase cerebral blood flow
- increase glucose consumption

Status
Risk: anaerobic glycolysis, acidosis, brain damage

Question 8

Seizures
Mirror Focus

Answer 8

Mirror focus
- contralateral side of brain
- mirror epileptogenic focus
- learns to seize

Question 9

Focal Seizure

Answer 9

• Discrete area of brain
• One hemisphere
• clinical symptoms = brain area activated

Question 10

Generalized seizure

Answer 10

1. primary generalized
   - onset generalized
   - both hemispheres
   - loss of consciousness
2. secondary generalized
   - cortical spreading from focal seizure
   - loss of conscousness
   - both hemispheres

Question 11

3 phases of a Seizure

Answer 11

1. Pre-ictal
2. Ictal
3. POst-ictal

Pre-ictal
- Prodrome: HA, tired, depressed, mental clouding (days, hours)
- aura: sensory warning (partial seizure)

Ictal
- Tonic: muscle rigidity (brainstem)
- Clonic: rhythmic relaxation and contraction (basal ganglia)

Post-ictal
- immediately following seizure (hours, days)
- HA, confusion, dysphasia, paralysis (Atodd’s paresis)
- neurons exhausted

Question 12

Status Epilepticus
Definition

Answer 12

1. Seizure duration > 5 minutes
2. 3 seizures in 30 minutes

Risk
- mirror focus
- irreversible brain damage: anaerobic glycolysis, acidosis

Question 13

International League of Epilepsy
Seizure Levels

Answer 13

1. Seizure type
   - focal
   - generalized
   - unknown
2. Epilepsy type (*EEG required)
   - focal
   - generalized
   - combined
   - uknonwn
3. Epilepsy syndrome

Question 14

ILAE
Focal Seizure
Characterization

Answer 14

1. Level of awareness (aware vs. not aware)
2. Level of motor involvement ( motor vs. non-motor)
3. Level of generalization (focal –> bilateral)

Examples:
Focal, aware, motor involvement
Focal, aware, non-motor involvement
Focal, unaware, motor involvement
Focal, unaware, non-motor involvement

Question 15

Focal aware seizure

Answer 15

Focal
- discrete area of brain

Aware
- one hemisphere

Also known as “simple partial seizure)

Question 16

Focal unaware seizure

Answer 16

Focal
- discrete area of brain
- usually starts prodrome: aura (simple partial seizure)

Unaware
- generalized to both hemispheres

Also known as “complex partial seizure”

Question 17

ILAE
Focal Seizure
Motor Onset
Examples

Answer 17

• Automatism: lip smacking
• Atonic: loss of motor
• Clonic: rhythmic relax-contract
• Spasm: fencing position
• Hyperkinetic: bicycling
• myoclonic: jerk
• tonic: stiff

Question 18

ILAE
Focal Seizure
Non Motor Onset
Examples

Answer 18

• Autonomic: ANS, SNS ex. flushing
• Behavioural arrests: stop, staring
• cognitive: language deficit
• emotional: fear, laugh, cry
• sensory: gustatory, numbness, tingling

Question 19

ILAE
Generalized Onset Seizure
Definition

Answer 19

Generalized
- both hemispheres
- loss of consciousness right away (unaware)

Motor vs. Nonmotor

Ex. Absence seizure
Generalized, non-motor, unaware
Sudden cessation of activity

Question 20

ILAE Generalize Seizure
Nonmotor onset

Answer 20

Nonmotor onset
- typical: sudden stop activity, blank stare
- Ayptical: tone is pronounced
- myoclonic: eyes jerk upwards

Question 21

ILAE Generalized Seizure
Motor onset

Answer 21

Motor onset
- tonic
- clonic
- myoclonic
- atonic (drop seizures)
- *mixture of the above

Question 22

Differential Diagnosis
Psychogenic seizure

Answer 22

• Eyes closed
• Asynchronous movements
• bicycling, pelvic thrusting
• can talk
• wax and wane
• 10 to 30 minutes
• history trauma, abuse

Question 23

Differential diagnosis
Fainting

Answer 23

• Eyes roll back in head
• twitch after they lose consciousness
• pale
• low blood pressure, low heart rate

Question 24

Diagnostic work up
Seizure

Answer 24

1. Seizure onset
   - focal? generalized?
   - aware? unaware?
   - motor? non-motor?
   - first time? new?
2. R/O metabolic causes (ABCDEFG)
   - Vital sign extremes
   - labs: electrolytes (Na, K, Mg, Ca), acid-base balance, toxicology screen, glucose level
   - eclampsia (8 weeks post party)
3. Labs for seizure complications
   - Cardiac: troponin, ECG (MI)
   - Metabolic acidosis: lactate, creatinine kinase (rhabdomyolysis)
   - hypoglycaemia: glucose
   - electrolytes: dehydration
4. Imaging
   - CT (10-15% positive secondary cause)
5. Loading dose Keppra
   1500mg PO
   D/C home if stable, someone watching
   10% re-occurance within 24 hours
   referral neurology
   EEG urgent (first time seizure, status, don’t D/C)