Epilepsy (Seizure Disorder)

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Epilepsy is a brain disorder characterized by an enduring predisposition to generate epileptic seizures, the consequences of this condition and the occurrence of at least one seizure. Seizures can be classified as being partial-onset seizures and generalized-onset seizures.


Presentation

The symptoms of epilepsy usually vary on the basis of underlying pathology. Seizure is the only symptom which is present in all types of epilepsy. However, the associated symptoms may differ on the type of seizures.

Impairment or loss of consciousness is usually a feature of complex partial seizures. The level of consciousness is not affected in simple partial seizures. Atonic and tonic seizures often make the patient fall down.

Workup

Before the diagnosis of epilepsy is made, the following investigations are used to rule out infections or metabolic causes of seizures.

  • Blood Chemistry Panel
  • Serum urea, creatinine and electrolytes
  • Random blood sugar
  • Serum calcium and magnesium
  • Liver function tests
  • Lumbar puncture

Other investigations that will help diagnose epilepsy include the following.

  • Electroencephalography: Electroencephalography may help establish and characterize the type of epilepsy by demonstrating abnormal electrical activity in the brain.
  • Compuerized Tomography (CT) or Magnetic Resonance Imaging (MRI) scan: CT or MRI brain scanning is often useful in defining or excluding structural causes for seizures e.g. tumors and infections.
  • Position Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT): PET and SPECT are also used to evaluate certain patients of seizures who do not respond to medical therapy.

Treatment

Immediate care of seizures:

Little can be done for a person having a major seizure. Supportive treatment includes first aid, maintenance of airway, provision of oxygen and administration of intravenous anticonvulsants.

Anti-convulsant drug therapy:

If the cause of epilepsy is treatable promptly, drug therapy is not necessary. Drug therapy is required when the cause is not immediately treatable and and the patient is at a risk of having further seizures. There are various anticonvulsant drugs with different mechanism of actions. They can be divided into the following large groups [6]. 

  • Sodium channels e.g. phenytoin, carbamazepine etc
  • GABA-A receptor enhancers e.g. phenobarbital
  • T-calcium channel blockers e.g. valproate
  • Carbonic anhydrase inhibitors e.g. zonisamide
  • Blockers of unique binding sites e.g. gabapentin

Surgical choices

The type of epilepsy surgery depends on the location in the brain causing the seizures. Anterior temporal lobectomy is the most common surgical choice in adults [7]. In children, the surgical choices include corpus callosotomy and hemispherectomy [8] [9].

Prognosis

If epilepsy is properly controlled via medications, the lifespan of the patients is completely normal.

Even without treatment, sudden death in the patients suffering from epilepsy is very uncommon. Those suffering from tonic-clonic seizures may suffer from accidents and traumas. Mortality is also higher in the patients whose seizures are associated with loss of consciousness.

Etiology

The etiology of epilepsy varies with age group.

In neonates, developmental insufficiency or brain injury are the most common causes for the development of epilepsy.

In the infantile age group, the principal congenital malformations, perinatal injury and metabolic disorders are the principal causes of epilepsy.

In children and adolescents, epilepsy usually results from genetic causes.

In adults, in addition to genetic causes, cerebral neoplasms, drugs, alcohol withdrawal, brain trauma, stroke, infection and surgery are the predisposing conditions that lead to the development of epilepsy.

The genetic syndromes that cause seizures include Angelman syndrome, Rett syndrome, Pitt Hopkin’s syndrome, tuberous sclerosis, Prader Willi syndrome and Struge Weber syndrome [1][2].

Epidemiology

The annual incidence of epilepsy in Minnesota was demonstrated by a study to be around a 100 cases per 100,000 persons aged between 0 to 1 years; 40 cases per 100,000 persons aged 38 to 40 years and 140 cases per 100,000 persons aged 79-80 years.

Overall, the total incidence of epilepsy is 3400 per 100,000 men (3.4%) and 2800 per 100,000 women (2.8%) by the age of 75 years [3].

Sex distribution
Age distribution

Pathophysiology

Seizures result from a sudden imbalance between the excitatory and inhibitory mechanisms in the brain [4].

Partial seizures are those in which the seizure activity is restricted to one part of the cerebrum; i.e. the focus of increased electrical activity is in one hemisphere.

On the other hand, in generalized seizures, diffuse regions of both the hemispheres are involved simultaneously and sunchronously.

If any seizure remains for 60 minutes, irreversible brain damage occurs. Cell death occurs from excessively increased metabolic demands of the continuously discharging neurons.

Prevention

Since the cause of epilepsy is not exactly known, it is not possible to prevent it. However, head injury being the most important cause, if avoided can prevent the development of epilepsy [10]. Wearing seat belts, following traffic rules and avoiding accidents is helpful in reducing the risk of head trauma.
Epileptics sensitive to alcohol must prevent alcohol intake.

Summary

A seizure or convulsion is a paroxysmal involuntary disturbance of brain function that may be manifested as an impairment or loss of consciousness, abnormal motor activity, behavioral abnormalities, sensory disturbances or autonomic dysfunction.
Epilepsy is defined as a brain disorder that is characterized by recurrent seizures unrelated to fever or to an acute cerebral etiology.

Patient Information

Epilepsy is a group of disorders characterized by seizures in association with loss of consciousness and psychic abnormalities. The patients of epilepsy may belong to any age group. Early diagnosis and proper management of the disease improves the outcome. Treatment may be done through anti-seizure drugs or brain surgery.

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References

  1. Steffenburg U, Hagberg G, Hagberg B. Epilepsy in a representative series of Rett syndrome. Acta paediatrica. Jan 2001;90(1):34-39.
  2. Whalen S, Heron D, Gaillon T, et al. Novel comprehensive diagnostic strategy in Pitt-Hopkins syndrome: clinical score and further delineation of the TCF4 mutational spectrum. Human mutation. Jan 2012;33(1):64-72.
  3. Hauser WA, Annegers JF, Rocca WA. Descriptive epidemiology of epilepsy: contributions of population-based studies from Rochester, Minnesota. Mayo Clinic proceedings. Jun 1996;71(6):576-586.
  4. Engelborghs S, D'Hooge R, De Deyn PP. Pathophysiology of epilepsy. Acta neurologica Belgica. Dec 2000;100(4):201-213.
  5. Tharyan P. Prolactin levels in epilepsy. The Journal of the Association of Physicians of India. Jun 1991;39(6):505-506.
  6. Goldenberg MM. Overview of drugs used for epilepsy and seizures: etiology, diagnosis, and treatment. P & T : a peer-reviewed journal for formulary management. Jul 2010;35(7):392-415.
  7. Matsuura M. Indication for anterior temporal lobectomy in patients with temporal lobe epilepsy and psychopathology. Epilepsia. 2000;41 Suppl 9:39-42.
  8. Gonzalez-Martinez JA, Gupta A, Kotagal P, et al. Hemispherectomy for catastrophic epilepsy in infants. Epilepsia. Sep 2005;46(9):1518-1525.
  9. Rahimi SY, Park YD, Witcher MR, Lee KH, Marrufo M, Lee MR. Corpus callosotomy for treatment of pediatric epilepsy in the modern era. Pediatric neurosurgery. 2007;43(3):202-208.
  10. Pitkanen A, Bolkvadze T. Head Trauma and Epilepsy. In: Noebels JL, Avoli M, Rogawski MA, Olsen RW, Delgado-Escueta AV, eds. Jasper's Basic Mechanisms of the Epilepsies. 4th ed. Bethesda (MD)2012.

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