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Environmental factors can cause epilepsy (types of causes of epilepsy (4…

- - - - (14) “Although
        seizures occur spontaneously, they may
        also be precipitated by various exogenous
        and endogeneus factors. The term ‘seizure
        precipitants' may include both seizure inducing
        and seizure-triggering factors.”p103
  - - - “As a result of
        these technologies, the genetic basis of almost all of the
        200 single gene disorders, which have epilepsy within
        their phenotype, has been identified. A few of these are
        rare familial ‘‘pure’’ epilepsies. The immediate challenge
        now is to unravel the epistatic and epigenetic mechanisms
        of developmental epilepsy, and the elucidation of postgenomic
        mechanisms.”
    - - (6) Labs can then pinpoint where epilepsy is coming form, and with more precise surgical procedures, possibly remove problematic segments of the brain
  - - - (9) • Epilepsy Common?
        o 1 in 133 people have it in some capacity
        o 120,000 new cases each year in USA
        o Can affect anyone, mostly under 20 and over 60 though
        o More common in developing country because of brain infections, problems in childbirth, and poor nutrition…. all ENVIRONMENTAL FACTORS
- - - - (3) Lower-level tumors, surprisingly, cause more aggressive epilepsy and stronger seizures (DNETs), gangliogliomas, and other low grade gangliogliomas).////more aggressive tumors have generally a lower incidence of epilepsy
      - DNET
        
        (4) “Dysembrioplastic Neuroepithelial Tumor
        (DNET) is a congenital, benign tumor due to a developmental
        abnormality of certain embryonic cells
        of the brain, frequently associated with epilepsy.”
        
        • (4) DNET definition, see quote -- Dysembrioplastic Neuroepithelial Tumor
        o Lesions of these tumors typicall cause complex partial seizures before the age of 20 in individuals who re otherwise neurological normal.
        o At least 80% of patients are deemed seizure-free after such a tumor is removed
      - (9)  Head injuries – brain damage may lead to epilepsy as electrical connections and neurons in brain are damaged – “The brain tries to repair itself after an injury, but sometimes mixes up wiring, making odd connection between neurons in the brain. This can cause the unusual electrical messages that occur in the brain during seizures.” P26
      - (14)
        o More likely in adults, either secondary (carried by blood from another site to the brain) or primary (originally in brain)
      - (14) o Primary tumors that cause epilepsy don’t originate in nerve cells of brain, but in supporting cells between nerve cells and the covering membranes of the brain
         These tumors called gliomas and meningioma’s
         Affect epilepsy because disturbs connections between brain cells, (storms of electricity) that cause epileptic seizures
    - - (3)Head trauma and post-trauma siezures DO NOT always mean epilepsy. These “spells” might just be associated with PTSD
      - (3) The risk of developing post traumatic epilepsy increases at age 65 or older, presence of a brain contusion, linear depressed skull fracture, and if subject has lost consciousness for more than 24 hours
      - Without a doubt, the risk of epilepsy is increased when traumatic brain injusry is involved. (see quote)
        
        “The increased risk, however, is
        limited to those who are diagnosed with moderate or severe
        civilian traumatic brain injury, which comprises almost 5% of
        all cases of head trauma. In people who are under the age of
        35, traumatic brain injury increases the risk for both generalized
        tonic–clonic seizures and complex partial seizures” p233
      - Risk of developing epilepsy post-trauma is greatest in the first two years after incident
      - (15) damage to cerebral nerve cells
    - - So these tumors, trauma, etc, therefore constitue lesional epilepsy as they damage brain tissue resulting in the causation of eoplepsy
      - (16) Lesional epilepsy is when epilepsy develops because of a structural lesion in brain tissue
      - (16) This “might include malformation of blood vessels, a tumor in the brain, or an area of abnormal brain tissue”
      - (16) Sometimes, if the lesion or damage is in a non-vital area of brain tissue, it can be completely removed
- - - - (2)• Predisposing vs exciting causes
        o Innate predisposition, predisposing cause - inherited
        o Precipitating, exciting cause - determining
    - - (8) o Mutations in genes put certain people at higher risk of developing epilepsy, often in genes that control brain function and the “excitability” of neurons in brain
      - (8) o Usually not just genetic cause, often linked to environmental conditions
      - (8)o 30-40% of epilepsies cause by genetic predisposition
      - (8) inherited predisposition to epilepsy
  - - - (1) “In any individual case, the epilepsy is often (perhaps almost always) the result of both genetic and acquired influences and also influenced by provoking factors (and many epilepsies clearly have both exciting and predisposing causes, to reintroduce an old concept).”
- - - - ---“One type is benign familial neonatal convulsions (bfnc), a
        dominantly inherited disorder of newborns kcnq2 and kcnq3 are two homologous k+ channel
        subunits that can combine to form heterothermic channels. Loss-of-function mutations in
        kcnq2 and kcnq3 potassium channel genes can lead to benign familial neonatal convulsions
        (bfnc)” p35 ----mutations of these channels often cause generalized epilepsy
    - - The main etiologies, or causes, of acquired epilepsy’s might act through these abnormal ion channels as a common pathway (this is a quote)p35