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Absence Seizure

Last updated March 10, 2018

Approved by: Krish Tangella MD, MBA, FCAP

DoveMed suggests an informative video about the generalized absence seizure, or petit mal seizure, by Steve Wolf, MD and Patty McGoldrick, NP.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Absence Epilepsy
  • Absence Seizure Disorder
  • Akinetic Petit Mal

What is Absence Seizure? (Definition/Background Information)

  • Seizures are conditions caused by abnormal or disturbed electrical activities of the brain
  • There are several types of seizures, and Absence Seizure is one such disorder that occurs:
    • Either due to the presence of other neurological conditions/disorders affecting the body (classified as symptomatic generalized epilepsies)
    • Or the cause may be entirely unknown (classified as idiopathic generalized epilepsies)
  • Absence Seizures, commonly seen in children, are characterized by a sudden and brief absence of consciousness lasting up to 20 seconds, with intense neuroelectrical activities in the brain, called spike-and-slow wave discharges on the EEG (electroencephalography)
  • They are generally mild and do not cause a collapse of the human body. But, they may occur abruptly and hence, can pose a serious threat to the individual, depending on the activity being performed (like swimming, driving, working with machines,etc.) at that specific instance

Absence Seizures, also referred to as Petit Mal Epilepsy, are sub-divided into two categories: Typical Absence Seizure and Atypical Absence Seizure

  • Typical Absence Seizures begin abruptly, last 10-30 seconds, and resolve by themselves, without any complications. The individuals seems to simply stop in their tracks (and/or in a mid-sentence), and enters a staring, trance-like state during which they are unresponsive and unaware of the surroundings
  • Atypical Absence Seizures are similar to typical seizures, except they tend to begin more slowly, last longer (up to a few minutes), and can include slumping or falling down

Who gets Absence Seizure? (Age and Sex Distribution)

  • Absence Seizures generally affect children and young adolescents, more than the adult population
  • Girls are more affected than boys (on a 2:1 ratio)
  • Any racial or ethnic predilection is not observed with the disorder

What are the Risk Factors for Absence Seizure? (Predisposing Factors)

Absence Seizure risk factors include:

  • Those with a family history of idiopathic epilepsies show an increased risk; a genetic predisposition seems to be apparent
  • Among children, females are at a higher risk than males
  • Hyperventilation (a respiratory disorder) is known to trigger Absence Seizure
  • Individuals with porphyria (a rare group of blood disorders) may have a higher risk
  • Certain medications (even alcohol and cocaine) have a tendency to lower the body’s threshold to any seizures, increasing the risk associated with it

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Absence Seizure? (Etiology)

  • Absence Seizures due to generalized idiopathic epilepsies have no established cause
  • But, symptomatic epilepsies are due to many reasons that result in various types of brain damage (which have an origin in the initial stages of brain development)
  • EEG in all cases show unusual and intense neural activities; neurotransmission (communication within the nerve cells) that take place due to electrical and chemical signals being transmitted and received, indicate abnormalities

What are the Signs and Symptoms of Absence Seizure?

Absence Seizure signs and symptoms mainly relate to involuntary expressions and other abrupt physical motions that take place many times a day. These appear suddenly and spontaneously for brief intervals affecting the normal activity an individual is in the midst of (such as eating, walking, speaking), and they disappear within a very short span of time (usually a minute) with complete recovery.

These include:

  • Lack of consciousness for a very short period of time
  • Staring briefly into vacant space, from time to time
  • Facial expressions include chewing action, smacking of lips, fluttering eyelids, rotation of eyes
  • Head, hand/arm (jerky) movements, dropping objects due to handgrip relaxation
  • Slow, interrupted speech
  • Individual does not respond to sounds or voice calls
  • Occasionally, sweating, pupil dilation, urine incontinence
  • Inattentiveness at school
  • Shortage of sleep may aggravate the seizure effects

How is Absence Seizure Diagnosed?

Diagnosis of Absence Seizures in children may be difficult, because the symptoms last only for some seconds and the children are not subsequently aware of them, after recovery. A declining performance in academic activities due to learning disabilities and lack of concentration may be among the first indicators of this disorder.

A physician would examine the physical, neurological condition, and medical history of the individual; including a family history of such disorders, medications, and vitamin supplements being taken, if any. Some other tests would include:

  • Blood tests, to eliminate other causes of the seizures
  • EEG tests to measure the electrical activities of the brain (a conclusive test)
  • MRI scan of brain
  • The underlying conditions may interfere with diagnostic studies conducted on those with symptomatic generalized epilepsies; hence, differential diagnosis may be necessary

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Absence Seizure?

Absence Seizures may be existent throughout life in some individuals, while most kids outgrow and overcome them, some within a few months.

  • It may cause learning difficulties and affect the child’s performance at school
  • The convulsions may develop progressively to last longer periods, called grand mal seizures
  • Behavioral patterns, such as confusion, lack of awareness while eating, drinking, moving, etc. for prolonged periods may be symptomatic of a condition called Absence Status Epilepticus. In such cases, speedy medical attention is required
  • If any seizure lasts for over five minutes, then appropriate and immediate medical care has to be provided

How is Absence Seizure Treated?

Treatment of Absence Seizures would involve:

  • Properly scheduled and administered anti-epileptic drugs (AEDs, usually sodium valproate or ethosuximade) of the right dosage are effective against Absence Seizures
  • Such anti-epileptic medications are normally discontinued after two years of non-seizure period
  • Pregnant women and those planning to conceive, with Absence Seizures, may require more careful planning and treatment, considering side effects of the drugs and the potential harm it could pose to the babies
  • Many anti-seizure drugs have proven to be contraindicated for idiopathic epileptic conditions producing adverse reactions. Hence, administering drugs under such conditions require extreme caution
  • Under certain conditions, specialized diets (called MCT diets with high fat, low carbohydrate, acceptable protein levels) have shown to be beneficial for children

How can Absence Seizure be Prevented?

  • Absence Seizures cannot be prevented, since its occurrence depends on many factors, some unknown
  • If seizures appear at an early age and the individuals respond well to treatment, and if a treatable etiology (cause) is identified, then the prognosis is excellent

What is the Prognosis of Absence Seizure? (Outcomes/Resolutions)

  • A high number of patients respond well to treatment and no recurrence is observed after a certain period of time. The medications may be stopped after no seizures are recorded, for a long time (usually two years)
  • In some cases of juvenile epilepsy, the remission rate is very high, hence medications and healthcare support are required for life
  • Absence Seizures are not fatal; however, they could cause fatal accidents due to the activity the individual is performing, like swimming, driving, or operating electrically-driven machinery (or equipment with moving parts), etc.
  • Death in children with seizures, may occur from secondary epilepsies, such as those caused by other neurological defects
  • Children with such epilepsies should not be restricted in their regular physical activities. But, when they perform certain activities that may be risky, like cycling, swimming, etc. it should not be permitted without proper supervision
  • Adults should refrain from driving or operating heavy machinery that may be potentially dangerous
  • Children or adults under AEDs, should be closely monitored for any adverse reactions and side effects

Additional and Relevant Useful Information for Absence Seizure:

  • The efficacy (with respect to the dosage, duration, and right combination) and safety of drugs administered is still under medical research
  • There are support groups that provide help and understanding to the families of patients with Epilepsy

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Dec. 12, 2013
Last updated: March 10, 2018