Epilepsy causes

Dedek K, Kunath B, Kananura C et al. (2001) Myokemia and neonatal epilepsy caused by a mutation in the voltage sensor of the KCNQ2 K+ Channel. Proc Nat Acad Sci USA 98(21) 12272-12277... 

Cendes, E, Andermann, E, and Carpenter, S. 1995. Temporal lobe epilepsy caused by domoic acid intoxication evidence for glutamate receptor-mediated excitotoxicity in humans. Annals Neurology 37, 123-126. 

A seizure is an abnormal behavioral (often motoric) activity caused by abnormal electrical activity of the brain. Seizures can be the symptom of a chronic neurological malfunction, i.e. epilepsy, or can appear as single events, e.g. during fever in infants. 

Epilepsy may be defined as a permanent, recurrent seizure disorder. Examples of the known causes of epilepsy include brain injury at birth, head injuries, and inborn errors of metabolism, hi some patients, the cause of epilepsy is never determined. 

All such animal procedures suffer from the obvious and basic problem that laboratory animals do not behave like humans and that humans cannot reliably interpret their reactions and behaviour. Thus we know that Parkinson s disease is caused by a degeneration of the dopaminergic nigrostriatal tract but its lesion in animals does not produce any condition which resembles human Parkinsonism, except in primates, even though there are functional tests (e.g. rotational movements) which readily establish that loss of dopamine function and also respond to its augmentation (Chapter 15). By contrast, there are many ways, e.g. electrical stimulation and the administration of certain chemicals, to induce convulsions in animals and a number of effective antiepileptic drugs have been introduced as a result of their ability to control such activity. Indeed there are some tests, as well as animals with varied spontaneous seizures, that are even predictive of particular forms of epilepsy. But then convulsions are a very basic form of activity common to most species and epileptic seizures that are characterised by behavioural rather than motor symptoms are more difficult to reproduce in animals. 

Irrespective of the cause of epilepsy, the spread of seizure activity will be attenuated by either decreasing the excitation or increasing the inhibition of neurons. This may be achieved in a number of ways, either directly by... 

For nearly 80% of patients with epilepsy, the underlying etiology is unknown.8 The most common recognized causes of epilepsy are head trauma and stroke. Developmental and genetic defects are the cause of about 5% of cases of epilepsy. Central nervous system (CNS) tumors, central nervous system infections, and neurodegen-erative diseases are other common causes. Other important causes of epilepsy are human immunodeficiency virus infection or neuro-cysticercosis infection, primarily occurring in Latin America. 

Isolated seizures that are not epilepsy can be caused by stroke, central nervous system trauma, central nervous system infections, metabolic disturbances (e.g., hyponatremia and hypoglycemia), and hypoxia. If these underlying causes of seizures are not corrected, they may lead to the development of recurrent seizures I or epilepsy. Medications can also cause seizures. Some drugs that are commonly associated with seizures include tramadol, bupropion, theophylline, some antidepressants, some antipsy-chotics, amphetamines, cocaine, imipenem, lithium, excessive doses of penicillins or cephalosporins, and sympathomimetics or stimulants. 

In some patients, epilepsy worsens over time, with the seizures becoming more frequent as patients grow older. This does not occur in most patients with epilepsy. In those so affected, it is possible that the seizures themselves may cause some damage to the cortex loss of neurons, especially inhibitory neurons, has been demonstrated in tissue from seizure foci. Other changes occur in brain areas affected by seizures reorganization of connections between groups of neurons may strengthen excitatory connections and weaken... 

Symptomatic epilepsies There is an identifiable cause for the seizures, such as trauma or hypoxia. 

Patients with epilepsy may have completely normal findings in these assessments. Many of the tests are done to rule out other causes of seizures (e.g., infection or electrolyte imbalance). Often the EEG appears normal between seizures.20 Several manipulations can be done in an attempt to capture seizure or seizure-like activity on the EEG. These include sleep deprivation, photic stimulation, prolonged (greater than 20 minutes) EEG recording, and 24-hour EEG monitoring with video correlation. 

Additionally, the risk of a subsequent seizure must be determined. If there is an underlying treatable cause, such as hyponatremia or a CNS infection, the risks of another seizure and the development of epilepsy are very small. In these cases, the only pharmacotherapy that is necessary is to correct the underlying problem and possibly short-term use of an AED. Risk factors for repeated seizures in patients without an underlying disorder include ... 

Interestingly, many forms of partial epilepsy are characterized by a seizure-free interval lasting months to years between the occurrence of the causative insult and the emergence of epilepsy termed the latent period , this provides a valuable window of opportunity during which pharmacologic intervention might be implemented in high-risk individuals so that development of epilepsy could be prevented. 

Tables 37-3 and 37-4 list the genes responsible for idiopathic and symptomatic epilepsies in humans, respectively. Table 37-5 lists genes identified as causing epilepsy...

Kalachikov, S., Evgrafov, O., Ross, B. et al. Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditory features. Nat. Genet. 30 335-341, 2002. 

A broad variety of diseases may cause neuropathic pain. The majority of diseases associated with neuropathic pain involve the peripheral nervous system. These diseases include traumatic injuries hereditary, metabolic, inflammatory or paraneoplastic neuropathies and infections. However, neuropathic pain can also be caused by injuries or disorders affecting the spinal cord or the brain (central neuropathic pain) tumors stroke epilepsy and neurodegenerative disorders [20]. Genetic factors appear to contribute to inter-individual differences in the susceptibility to neuropathic pain. 

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