Epilepsy

Notes
  • Epilepsy is a syndrome that is characterized by recurrent and unpredictable seizures.
  • An epileptic seizure occurs due to sudden imbalance between the excitatory and inhibitory forces within the network of cortical neurons.
  • Synaptic excitation of neurons is mediated by glutamate neurotransmitter that excites N-methyl-D-aspartate (NMDA) receptors while synaptic inhibition is mediated by gamma-Aminobutyric acid (GABA) neurotransmitter that stimulates GABA receptors.
  • Stimulation of NMDA receptors allows calcium ions (Ca++ ions) to enter the cells and excite the neuron.
  • Stimulation of GABA receptors allows the chloride ions (Cl-) to enter the cells and inhibit the signal. Inhibition can also occur when the GABA receptors are rendered dysfunctional by tumour, tissue damage or genetic predisposition.
Symptoms
  • Epileptic seizures may have four distinct phases: prodromal symptoms (that involve emotional signs such as irritability and mood changes as well as headache among others), aura (which is the beginning of the actual seizures that is manifested as biting of the tongue, blinking of the eyes, drooling etc.), ictal (seizure itself) and postictal stages.

 

Type of

Epilepsy

Symptoms

& signs

A. Partial (focal) Seizures (when only a small area of the brain is affected)

Simple partial

Seizure

*The patient remains conscious

*Jerking movements

*feeling of strange sensation

*Patient can remember the attack.

*It may lead to Jacksonian Seizure or generalized seizure

Complex partial seizure

*The level of consciouness is impaired

**Patient may NOT remember the attack.

*It may lead to Jacksonian Seizure or generalized seizure

 

B. Generalized Seizures (both hemispheres are affected). It can result from partial seizure (known as secondary  generalized  seizure)

Generalized tonic-clonic [grand Mal] seizure

*muscles are tonic (are contracting), stiff and flexed and patient falls backward. This is followed by alternate involuntary muscular contraction and relaxation in rapid succession (convulsions)

*This is the most common form of seizures.

Absence [Petit Mal] seizure

*Loss of consciousness over a short or long time.

moment

Atonic Seizure

*muscles lack tone (are relaxed)and patient falls forward.

Tonic Seizure

*muscles are tonic (contractions), stiff and flexed and patient falls backward.

myoclonic seizure.

*Short muscle twitches.

 

Infantile seizures[spasms] – this is more of epiletic syndrome.

*Sudden flexion (bending) of the arms, forward flexion of the trunk, extension of the legs.

*It affects infants and may subside at the age of 5yrs  or it may develop to other forms of seizures.

Status Epilepticus

*usually Grand mal occurring for a long time (5 minutes or above)

  • Other symptoms include:

*Confusion after seizure (Postictal confusion)

*Temporary paralysis of leg and arm of the same side of the body lasting 12-48hrs (Todd’s paralysis or Todd’s paresis).

Diagnosis
  • Patient’s history
  • Physical examination
  • Laboratory tests that include full hemogram, electolytes, urea, blood sugar and malaria
  • Skull X- ray (Any raised intracranial pressure or focal lesions?)
  • CT Scan (any tumour?)
  • MRI (any tumour?)
  • EEG
Management
  • During seizure: the seizure is allowed to complete its course, tight clothes (especially around the neck) are loosened, dentures are removed (in case they are worn) and the patient is placed on the left lateral position (with the head on the same side).
  • Surgical intervention in case of brain tumour.
  • Nerve stimulation to increase the release of neurotransmitters, especially that of vagus nerve.
  • Ketogenic diet
  • Start pharmacotherapy if there are 2 or more epileptic attacks per year and stop it in case of a seizure-free period of at least 2 yrs. The withdrawal of drugs and their dosages should be gradual.
  • It is advisable that pharmacotherapy is initiated with the first-line drug at the lowest recommeded dose that is gradually increased until either a satisfactory response is achieved or the upper limit of the drug is attained or the side effects become overwhelming. In case of the latter, a second drug is introduced at the lowest recommended dose that is also increased gradually. Depending on the response, the dose of the first drug may be reduced or removed altogether.
  • Pharmacological management that include the following:

NB: 1st line drugs are marked*

 

TYPE OF EPILEPSY

DRUGS USED

FOR TREATMENT

A. Partial Seizures

Simple partial

Seizure

Carbamazepine, phenytoin, phenobarbitone

Complex partial seizure

Carbamazepine, phenytoin, phenobarbitone

 

B. Generalized Seizures

Generalized tonic-clonic [grand Mal] seizure

Phenobarbitone, carbamazepine, phenytoin, valproate, primidone, oxcarbazepine.

Adjuvants: gabapentin, lamotrigine, topiramate.

Absence [Petit Mal] seizure

Phenytoin, ethosuximide, valproate, clonazepam, acetazolamide [in refractory cases]

 

Atonic Seizure

Phenobarbitone, carbamazepine, valproate [first line], ethosuximide, acetazolamide, clonazepam

Tonic Seizure

Phenobarbitone, carbamazepine, Phenytoin, valproate, primidone, oxcarbazepine.

Adjuvants: Gabapentin, lamotrigine, topiramate.

Clonic myoclonic seizure.

Clonazepam*, Valproate

 

Infantile [spasms] – this is more of epiletic syndrome.

Generally refractory to conventional anti-epiletics, clonazepam, ACTH, prednisolone.

Status Epilepticus

Diazepam, phenytoin, phenobarbitone, lorazepam.

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