Seizures Flashcards
Seizure : Definition
sudden and abnormal electrical discharge in the brain
Results in a temporary disturbance of normal brain function
Epilepsy : Definition
Epilepsy is a chronic neurological disorder characterized by recurrent, unprovoked seizures.
It is a condition in which the brain is predisposed to produce seizures.
Epilepsy : Types
- Generalised tonic-clonic seizures
- Partial seizures (or focal seizures)
- Myoclonic seizures
- Tonic seizures
- Atonic seizures
Generalised seziures : Definition
Generalized seizures involve
* Widespread electrical discharges that affect both hemispheres of the brain simultaneously from the onset.
* Rapid onset
* Associated with a loss of consciousness
Subtypes of Generalised epilepsy
1. Tonic-Clonic Seizures (Formerly Grand Mal):
2. Absence Seizures (Formerly Petit Mal):
3. Atonic Seizures:
4. *Myoclonic
Generalised tonic-clonic seizures : Clinical features
- Complete loss of Consciousness
- Prior to seizure : aura, an abnormal sensation that gives a warning that a seizure will occur.
-
Seizure activity
Typically, the tonic phase comes before the clonic phase
- tonic phase : muscle tensing
- clonic : muscle jerking
- Associated symptoms
* tongue biting, * incontinence, irregular breathing - Post-ictal phase
* Prolonged - confusion, tiredness
Tonic seizures : Clinical features
Tonic seizures
1. Sudden onset of increased muscle tone
* entire body stiffens.
* Results in a fall if the patient is standing
Time : They last only a few seconds, or at most a few minutes.
Atonic seizures : Clinical features
- Sudden loss of muscle tone - may result in fall
- Begin in childhood.
- No loss of awareness
Absence seizures : Clinical features
- Blank, stares into space, and then abruptly returns to normal.
- Loss of awareness
- These typically last 10 to 20 seconds.
Most patients stop having absence seizures as they get older.
Focal Seziures : Clinical features
Definition:
* originate in a specific area of the brain
- may involve only one hemisphere initially.
Subtypes:
- Simple Focal Seizures: Involving a specific area of the brain
- without loss of consciousness. - Complex Focal Seizures: Associated with altered consciousness or awareness.
- Secondary Generalization:
- Focal seizures may evolve from a localised area of the brain
-Electrical activity then spreads to other hemispheres
-Resulting in
generalized seizures
Manifestations:
* Depending on the area of the brain affected,
- Motor cortex :
jerking movements
sensory symptoms - Temporal lobe;
emotions or cognitive changes
- Déjà vu
- Strange smells, tastes, sight or sound 3. Paresthesia/ Abnormal sensation
- Autonomic symptoms;
* Changes in HR
* GI symptoms
Epilepsy : Management strategies
- Anti epileptics normally indicated
* Following 2nd seizure
Can be started following first seizure if ;
1. neurological deficit
2. brain imaging shows a structural abnormality
3. the EEG shows unequivocal epileptic activity
4. Further seizures will cause very high risk
Epilepsy : Mx of Generalised seizures
Generalised epilepsy with motor symptoms
1. Generalised tonic-clonic seizures
2. Myoclonic seizures
3. Tonic or atonic seizures
Mx
Males :
* Sodium valporate
Females :
* Lamotrigine
* Levetiracetam
Absence seizures
Mx
* first line: ethosuximide
* second line:
* male: sodium valproate
* female: lamotrigine or levetiracetam
* carbamazepine may exacerbate absence seizures
Epilepsy in pregnancy : Risks of AEDs
Increased risk of congenital heart defects if taking anti epileptics
- Sodium valproate: Neural tube defects
- Not to be used in pregnancy
- Phenytoin : cleft palate
- Lamotrigine:
* Lowest rate of congenital malformation
* Dose may need to be increased in pregnancy
_Breast feeding is generally considered safe for mothers taking antiepileptics _
Carbamazepine : MOA
Mechanism of action
* binds to sodium channels increases their refractory period
Carbamazepine : SE
- P450 enzyme inducer
- leucopenia and agranulocytosis
- hyponatraemia secondary to syndrome of inappropriate ADH secretion
