Epilepsy
Epilepsy is a brain disorder
characterized by convulsive seizures or loss of consciousness or both.
Convulsion and
Convulsive Seizure
Convulsion refers to uncontrolled
involuntary muscular contractions. Convulsive seizure means sudden attack of
uncontrolled involuntary muscular contractions. It occurs due to paroxysmal
(sudden and usually recurring periodically) uncontrolled
discharge of impulses from neurons of brain, particularly cerebral cortex.
Epileptic
Patient affected by epilepsy
is called epileptic. The person with epilepsy remains normal in between
seizures. Epileptic attack develops only when excitability of the neuron is
increased, causing excessive neuronal discharge.
TYPES OF EPILEPSY
Epilepsy is divided into
two categories:
1. Generalized epilepsy
2. Localized epilepsy.
GENERALIZED EPILEPSY
Generalized epilepsy is the
type of epilepsy that occurs due to excessive discharge of impulses from all
parts of the brain. It is also called general onset seizure or general onset
epilepsy.
Generalized epilepsy is
subdivided into three types:
1. Grand mal
2. Petit mal
3. Psychomotor epilepsy.
GRAND MAL
Grand mal is characterized
by sudden loss of consciousness, followed by convulsion. Just before the onset
of convulsions, the person feels the warning sensation in the form of some hallucination.
It is called epileptic aura.
Convulsions occur in two
stages:
a. Tonic stage
b. Clonic stage.
Tonic Stage
Initially, seizure is
characterized by tonic contractions of muscle leading to spasm. Spasm
causes twisting facial features, flexion of arm and
extension of lower limbs.
Clonic Stage
Clonic
convulsions develop after the tonic stage. This stage is characterized by
violent jerky movements of limbs and face due to alternate severe contraction
and relaxation of muscles.
At the end of attack,
alternative tonic and clonic convulsions are seen. During the entire period of
seizure, tongue may be
bitten. Electroencephalogram (EEG) shows fast waves with a frequency of 15 to
30 per second during tonic stage. Slow and large waves appear during clonic
phase. After
the attack, slow waves are
recorded for some time. In between seizures, EEG shows delta waves in all types
of epileptics.
Causes of Grand Mal
Cause of grand mal
epilepsy is the excess neural activity in all parts of brain. Cause for
stoppage of
attack is neuronal fatigue.
Factors which accelerate the neural activity resulting in grand mal epilepsy
are:
i. Strong emotional
stimuli
ii. Hyperventilation and
alkalosis
iii. Effects of some drugs
iv. Uncontrolled high
fever
v. Loud noises or bright
light
vi. Traumatic lesions in
any part of brain.
PETIT MAL
In this type of epilepsy,
the person becomes unconscious suddenly without any warning. The
unconsciousness lasts for a very short period of 3 to 30 seconds. Convulsions
do not occur. However, the muscles of face show
twitchlike contractions and there is blinking of eyes.
Afterwards, the person recovers automatically and
becomes normal. Frequency of attack may be once in
many months or many attacks may appear in rapid
series. It usually occurs in late childhood and disappears completely
at the age of 30 or above. EEG recording shows slow and
large waves during the attack. Each wave is followed by a sharp spike. This
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