Generalized tonic–clonic seizure

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Tonic-clonic seizure
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"Grand mal" redirects here. For other uses, see Grand Mal (disambiguation).

Generalized tonic–clonic seizure
Other namesGrand mal seizure, tonic–clonic seizure
electroencephalogram
SpecialtyNeurology

A generalized tonic–clonic seizure, commonly known as a grand mal seizure or GTCS,

seizure type most commonly associated with epilepsy and seizures in general and the most common seizure associated with metabolic imbalances.[2] It is a misconception that they are the sole type of seizure, as they are the main seizure type in approximately 10% of those with epilepsy.[2]

These seizures typically initiate abruptly with either a

generalized onset. A prodrome (a vague sense of impending seizure) may also be present before the seizure begins. The seizure itself includes both tonic and clonic contractions, with tonic contractions usually preceding clonic contractions. After these series of contractions, there is an extended postictal state where the person is unresponsive and commonly sleeping with loud snoring. There is usually pronounced confusion upon awakening.[3]

Causes

The vast majority of generalized seizures are

fluorescent lighting
, rapid motion or flight,
antihistamines and other factors.[6][7] Tonic–clonic seizures can also be induced deliberately with electroconvulsive therapy.[8]

In the case of symptomatic

MRI or other neuroimaging techniques showing that there is some degree of damage to a large number of neurons.[9]
The lesions (i.e., scar tissue) caused by the loss of these neurons can result in groups of neurons forming a seizure "focus" area with episodic abnormal firing that can cause seizures if the focus is not abolished or suppressed via anticonvulsant drugs.

Mechanism

Prodrome

Most generalized tonic–clonic seizures begin without warning and abruptly, but some epileptic patients describe a prodrome. The prodrome of a generalized tonic–clonic seizure is a sort of premonitory feeling hours before a seizure. This type of prodrome is distinct from stereotypic aura of focal seizures that become generalized seizures.

Phases

A tonic–clonic seizure comprises three phases: the

clonic phase and postictal
phase.

  • Tonic phase
The tonic phase is usually the first phase and consciousness will quickly be lost (though not all generalized tonic–clonic seizures involve a full loss of consciousness), and the skeletal muscles will suddenly tense, often causing the extremities to be pulled towards the body or rigidly pushed away from it, which will cause the patient to fall if standing or sitting. There may also be upward deviation of the eyes with the mouth open.
ictal cry." Starting in the tonic phase, there may also be bluing of the skin from respiration impairment as well as pooling of saliva in the back of the throat. Increased blood pressure, pupillary size and heart rate (sympathetic response) may also be noted with clenching of the jaw possibly resulting in biting the tongue.[3]
  • Clonic phase
The clonic phase is an evolution of the tonic phase and is caused by muscle relaxations superimposed on the tonic phase muscle contractions. This phase is longer than the tonic phase with the total ictal period usually lasting no longer than 1 min.[2] Skeletal muscles will start to contract and relax rapidly, causing convulsions. These may range from exaggerated twitches of the limbs to violent shaking or vibrating of the stiffened extremities. The patient may roll and stretch as the seizure spreads. Initially, these contractions may be high frequency and low amplitude, which will progress to decreased frequency and high amplitude. An eventual decrease in contraction amplitude just before seizure cessation is also typical.[2]
  • Postictal phase
The postictal phase causes are multifactorial to include alteration of cerebral blood flow and effects on multiple neurotransmitters.
stertorous breathing. Confusion and total amnesia upon regaining consciousness are also usually experienced and slowly wear off as the patient becomes gradually aware that a seizure occurred and remembers their identity and location. Impaired consciousness duration can last several hours after a seizure, especially with a compounding central nervous system condition or a prolonged seizure.[2] Occasionally the patient may vomit or burst into tears from the experienced mental trauma. An additional smaller seizure can also occur several minutes after the main seizure, particularly if the patient's seizure threshold has been brought unusually low by known factors or combinations of such. Examples include: severe hangovers, sleep deprivation, elevated estrogen at ovulation, prolonged physical tiredness, and drug use or abuse (including, but not limited to, stimulants, alcohol and caffeine).[11]

Diagnosis

Diagnosis can be made definitively by Electroencephalography (EEG), which records the electrical activity of the brain. This is typically done after a seizure episode in a clinical setting with an attempt to "capture" a seizure while it happens. According to "Harrisons Manual of Medicine," the EEG during the tonic phase will show a "progressive increase in low-voltage fast wave activity, followed by generalized high-amplitude, poly spike discharges."[2] The clonic phase EEG will show "high amplitude activity that is typically interrupted by slow waves to create a spike-and-slow-wave pattern."[2] Additionally, the postictal phase will show suppression of all brain activity, then slowing that gradually recovers as the patient awakens.

Management

For a person experiencing a tonic–clonic seizure, first-aid treatment includes rolling the person over into the

antiepileptic drugs, surgical therapy, diet therapy (ketogenic diet), vagus nerve stimulation, or radio surgery.[3]

Terminology

Generalized tonic–clonic seizures can have a focal onset (described above) that progresses into a generalized seizure or be a generalized seizure at onset. The term "Grand Mal" is nonspecific, referring to generalized tonic–clonic seizures with either a focal or generalized onset. Due to this lack of specificity in describing the onset of a seizure and being considered an archaic term, it is not typically used by medical professionals.[3]

See also

References

  1. ^ MayoClinic.org
  2. ^
    OCLC 956960804.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link
    )
  3. ^
    ISBN 9781437704341
  4. ^ David Y Ko (5 April 2007). "Tonic–Clonic Seizures". eMedicine. Retrieved 2008-03-19.
  5. ^ a b "2017 Revised Classification of Seizures". Epilepsy Foundation. Retrieved 2018-12-04.
  6. ^ "Seizure Mechanisms and Threshold". Epilepsy Foundation. Retrieved 2015-11-13.
  7. ^ "Triggers of Seizures". Epilepsy Foundation. Retrieved 2017-09-30.
  8. ^ "Electroconvulsive therapy-Electroshock (ECT)". Retrieved 25 November 2018.
  9. ^ Ruben Kuzniecky, M.D. (16 April 2004). "Looking at the Brain". epilepsy.com. Epilepsy Therapy Project. Archived from the original on 2007-10-12. Retrieved 2008-03-19.
  10. PMID 12609127
    .
  11. ^ "Triggers of Seizures". Epilepsy Foundation. Retrieved 2018-12-07.
  12. PMID 21109100
    .
  13. ^ "General First Aid Steps". Epilepsy Foundation. Retrieved 2018-12-14.

External links

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