Health Questions and Answers

SEIZURES

What is an epileptic seizure?
An epileptic seizure is the abnormal discharge of a neuron or group of neurons that leads to excessive electrical activity in the brain, causing disruption of brain function sufficient to produce clinical symptoms such as staring spells or jerking of muscles.

What are the main kinds of epileptic seizures?

Generalized seizures Partial seizures
Generalized tonic-clonic (grand mal) Partial simple (focal)
Generalized absence (petit mal) Partial complex (psychomotor)

Describe the clinical features of partial simple seizures.
Most partial simple seizures encountered in a medical setting consist of the focal jerking or twitching of an arm or leg on one side of the body. This is usually due to a structural lesion in the brain (such as a stroke, abscess, or tumor) that leads to local irritation and an epileptic discharge. If this discharge spreads, the focal seizure also spreads, sometimes involving the other side of the brain and causing twitching or jerking of both arms and legs (generalized tonic-clonic or grand mal seizure). Occasionally, metabolic lesions, especially hyperglycemia and hyperosmolar states, can cause focal lesions and focal partial seizures.

Describe the clinical features of partial complex seizures.
Partial complex seizures may be preceded by an aura of abnormal smells or tastes, visual sensations, or mental phenomena, such as deja-vu. The seizure itself may consist of an episode of staring, lip smacking, and automatic, semipurposeful movements, such as picking at clothes. Often there is no jerking of muscles, no loss of tone, and no falling down. Patients, however, are in a state of significantly altered mental status and often completely unresponsive. After a minute or two, the seizure passes, leaving a postictal state of confusion and lethargy.

Which group is most likely to develop generalized absence seizures?
Generalized absence seizures, sometimes referred to as petit mal, are seen almost exclusively in children. These seizures usually do not have a significant aura or postictal state but may consist of just a few seconds of staring and altered mental status. This may be so brief as to escape detection by untrained observers. At other times, children are thought to be daydreaming rather than experiencing a seizure.

How do generalized tonic-clonic seizures present?
Generalized tonic-clonic seizures, the so-called grand mal seizures, consist of the sudden onset, often without any preceding aura, of jerking tonic and clonic activity of both arms and both legs, with a generalized increase in muscle tone and loss of consciousness. There may be tongue biting or incontinence. Seizures usually last a minute or two and then resolve, often with a period of postictal lethargy and confusion.

How do the identifiable causes of seizures vary by age?

COMMON CAUSES OF SEIZURES BY AGE

Neonate to 3 Yr 3-20 Years 20-60 Years >60 Years
Prenatal injury Genetic predispositions Brain tumors Vascular disease
Perinatal injury Infections Trauma Brain tumors, esp. metastatic tumors
Metabolic Defects Trauma Vascular Disease
Congenital malformations Congenital malformations INfections Trauma
CNS Infections Metabolic defects Systemic metabolic derangements
Postnatal trauma Infections

What are the most common causes of seizures seen in the emergency department or on the medical ward?
Anticonvulsant withdrawal. Most patients seen here are known epileptics who have been taking medicine and, for one reason or another, are noncompliant with their drugs. Alcohol withdrawal, drug overdose, and metabolic derangements such as hyponatremia are other common causes. Structural brain disease, including stroke and meningitis, is a less common cause of seizures.

How do alcohol withdrawal seizures present?
Such seizures generally occur 12-48 hours after cessation or abrupt reduction in the intake of alcohol. These seizures are always generalized tonic-clonic seizures, without focality. They are often single, isolated seizures, but sometimes patients may have two or more over a span < 6 hours. Status epilepticus is rare after alcohol withdrawal but does occasionally occur. Alcohol withdrawal seizures seldom persist and are self-limited.

What are the most important principles of seizure management?
Most seizures can be controlled completely, or nearly so, by following three basic principles:

  1. Pick the most appropriate anticonvulsant for the type of seizure that the patient is experiencing.
  2. Steadily increase the dose of that drug, guided by serum anticonvulsant levels, until seizures are controlled. If drug toxicity develops before the seizures stop, the drug is not the appropriate one; try a different one. Obviously, increase the new anticonvulsant to therapeutic levels before tapering of the old drug.
  3. Monotherapy is preferable. Good therapeutic levels of one drug are preferable to subtherapeutic levels of multiple drugs.

How is status epilepticus treated?

  • Rapid history and physical examination, including airway, breathing, circulation.
  • Start IV and draw blood for complete blood count (CBC), electrolytes, anticonvulsant levels. Administer thiamine and glucose.
  • Infuse fosphenytoin by slow IV push at 50 mg/min to a dose of ∼20 mg/kg (1500 mg). To break a continuous seizure, give diazepam up to 20 mg or lorazepam up to 8 mg.
  • Infuse IV phenobarbital, 100 mg/min up to 600 mg.
  • Institute general anesthesia.

When should you intubate a patients with status epilepticus?
Experts disagree about when to intubate that patient. Some do it in step 2; others wait until step 4. You should always be prepared to immediately intubate any patient in status epilepticus.

References
WEB SITES
www.neuroguide.com
www.aan.com (American Academy of Neurology)
www.medmatrix.org
www.internets.com/mednets/sneurolo.htm
www.medwebplus.com/subject/Neurology.html

BIBLIOGRAPHY

  • Treiman DM: Convulsive status epilepticus. Curr Treat Options Neurol 1:359-369, 1999.
  • Aminoff M: Neurology and General Medicine, 3rd ed. Philadelphia, Churchill-Livingstone, 2001.
  • Bradley WG, Daroff RB, Fenichel GM, Jankovic J: Neurology in Clinical Practice, 4th ed. Philadelphia, Butterworth-Heinemann, 2004.
  • Caplan LR: Stroke: A Clinical Approach, 3rd ed. New York, Butterworth-Heinemann, 2000.
  • Samuels MA, Feske S (eds): Office Practice of Neurology, 2nd ed. Boston, Churchill-Livingstone, 2003.
  • Johnson RT, Griffin JW: Current Therapy in Neurologic Disease, 6th ed. St. Louis, Mosby, 2002.
  • Victor M, Ropper AH: Prinicples of Neurology, 7th ed. New York, McGraw-Hill, 2001.
  • Wyllie E: The Treatment of Epilepsy: Principles and Practice, 3rd ed. Philadelphia, Lea & Febiger, 2002.

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