23-01-2013, 12:57 PM
EPILEPSY (MECHANICAL, CHEMICAL AND GENETIC CAUSES)
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INTRODUCTION
Epilepsy occurs when permanent changes in the brain tissues causes the brain to be too excitable, leading to an unexpected and reoccurring seizures. The term seizure refers to a transient alteration of behaviour due to abnormal, synchronized, and repetitive burst firing of neuronal populations in the central nervous system (CNS).
Epilepsy can develop in any person at any age, 1% of persons will develop epilepsy during their life time. Out of 60,000 persons 500 will have epilepsy . The duration, severity and interval of seizure differ from individual to individual depending on the extent to which the brain is damaged.
Cases of Epilepsy
New cases of epilepsy are common among children especially during their first year. The rate gradually decline until about 10years of age, after age 60 the rate increases again
CAUSES OF EPILEPSY
Brain injuries and tumors
Any thing that injures the brain can lead to abnormality in brain wiring and imbalances in neuronal signaling.
Chemical Imbalances
Abnormally high level of excitatory neurotransmitter. Examples are acetylcholine, glutamate.
Abnormally low level of inhibitory neurotransmitter. Examples are Gamma-aminobutyric acid(GABA), Serotonin.
Genetic Factors
Genetic defect in the code for a protein called cystatinB which regulates enzymes that help to breakdown other proteins (myoclonic epilepsy).
Defect in gene that help to breakdown carbohydrate (lafora’s disease).
Mutations in several genes that code for protein subunits of voltage-gated and ligand-gated ion channels. Examples are defective sodium channels, mutations in some non-ion channel genes .
Changes in the non-neuronal brain cells called glia. These cells regulates concentrations of chemicals in the brain that can affect neuronal signalling.
CLINICAL BIOCHEMISTRY OF EPILEPSY
In generalised epilepsy serum glucose and cholesterol concentrations tend to be low especially just before the seizure
Electrolyte balance is disturbed and epileptics tend towards alkalosis
Serum sodium ion is unaffected, but potassium ion is normally low between attacks and increases after.
Chloride ion is high before seizure.
Epileptics are usually mildly hypocalcemic especially in periods before the seizure, this is due to a high serum citrate resulting in hypo-ionic calcemia A.
Stress which releases epinephrine and corticotropin results in high serum citrate.
Apparently the dynamic system that controls glucose and lipid metabolism, and thus electrolyte balance through the hormones epinephrine, corticotropin, insulin, glucagon, calcitonin, and parathromone is abnormal in the epileptic.
WHO IS REALLY AT RISK?
Parents with epilepsy wonder whether their children will have epilepsy. In most cases they won't, but they do have a higher risk than others. If the mother has a generalized type of epilepsy, then the child's chance of having epilepsy may be as high as 5‐20%. But if a parent has epilepsy due to a brain injury, the child's chance of having epilepsy is only about 5%.
CONCLUSION
Today, the aetiology of seizures in most cases remains idiopathic, fortunately doctors do not have to know the cause to treat the seizure. It is sad to know that no known cure has been found for epilepsy but to a great extent this disease can be managed. Due to the increasing case of epileptic seizures world wide, scientist are seeking a better way to cure the disease with less side effect.
Recently, scientist have thought that it would be very important to test if embryonic stem cell transplant might be effective to repair damages caused by epilepsy.