CHAPTER TWO
2.0 LITERATURE REVIEW
Epilepsy in Nigeria - a review of etiology, epidemiology Although there is general agreement that genetic factors are important in generalized seizure disorders, partial seizures have been attributable mainly to acquired causes such as asphyxia, infection, trauma, tumor and haemorrhage1,18,36. Some workers had, however, reported the interaction of environmental and hereditary influences in partial seizures. Rimoin and Metrakos reported that patients who suffered brain insults and did not have seizures had a lower familial predisposition to seizures than those who did have seizures. Furthermore, 15% of siblings of children with complex partial seizures were reported to have had seizures. The literature concerning the genetics of febrile seizures is voluminous and controversial. It is however generally agreed that there is an increased incidence of febrile seizures among the relatives of children with febrile seizures. A positive family history for febrile seizures can be elicited in 25 to 40% of patients with afebrile seizures 16. There is scanty information available on genetic epidemiology of epilepsy in Nigerians, but there are reports of tuberous sclerosis among Nigerians with epilepsy. Infections the commonest cause of symptomatic epilepsy remains central nervous system infections, mainly bacterial and viral meningitis, encephalitis, neurosyphilis, brain abscess and tuberculosis. These infections accounted for 10% to 20% of cases of epilepsy reported in Africa. Most of the acute presentations of seizures in the tropics, where health facilities are lacking, especially in the rural and suburban communities, are due to CNS infections. Incidentally, Human immunodeficiency virus infection (HIV) is increasing steadily in Africa, with the recent WHO report stating that `11.3 million cases out of 17 million worldwide are found in Africa with South Africa, Uganda, Kenya and Nigeria leading other African Countries'38. It is now clear that HIV infection will be, or already is, a much greater problem in developing tropical countries. It may lead to epilepsy by direct invasion of the brain, as in HIV encephalopathy, or as a consequence of opportunistic infections, as in toxoplasmosis. Although there is a high incidence of parasitic infections in Nigeria, there is little evidence that these parasites commonly cause epilepsy locally. [1][2][3]
2.1 CAUSES OF EPILEPSY;
Becoming obvious,
 Trauma
 Hereditary
 Anoxia (lack of oxygen in the brain)
 Idiopathic
 Vascular lesions account for 6 - 20%2 in Africa but lower incidence rate of 3.3%21 and 1.3%28 were obtained among Nigerian PWE
 Seizures occur in 15% of patients with cerebral infarction and become chronic in less than 5%
 Inflammatory vasculitis (e.g. polyarteritis nodosa, lupus erythematosus), subdural hematoma,
 Arteriovenous malformation and intracerebral hemorrhage can present as seizures.
 Metabolic derangements, such as pyridoxine deficiency which is associated with increased glutamic acid and reduced gamma amino butyric acid (GABA) levels in the brain, may result in seizures.
Other metabolic causes of epilepsy include
 Aminoaciduria,
 Hypoglycemia,
 Hypocalcaemia,
 Hypomagnesaemia,
 Uremia,
 Alkalosis and
 Water intoxication.
2.2 TYPES OF EPILEPSY;
 Focal epilepsy (jacksomia) epilepsy
 Temporal lobe or psychonotic epilepsy
 Grandmal (major epilepsy)
 Petimal (minor) epilepsy
 Talsomia epilepsy, etc.
2.3 SIGN AND SYMPTOMS
 Convulsion
 Fitting
 Twisting of the eye lid
 Excessive salivation in children
 Loss of consciousness
