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Neurological seizures- types,pathogenesis,mechanism,first aid

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"Seizures"[MeSH Terms] AND classification

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seizure first aid official guidance do not restrain recovery position emergency 5 minutes

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Neurological seizures

A seizure is a temporary episode of signs or symptoms caused by abnormal, excessive, synchronized electrical activity of neurons in the brain. The manifestations depend on where the abnormal discharge begins and how far it spreads. Epilepsy is a tendency to recurrent unprovoked seizures, not simply a single seizure. Harrison’s Principles of Internal Medicine, p. 3452.

1. Types of seizures

The modern clinical classification is based mainly on onset.
TypeMain features
Focal onsetBegins in one cerebral hemisphere or local network.
Focal aware seizureAwareness is retained. May cause tingling, visual/smell sensations, jerking of one limb, autonomic symptoms, or déjà vu.
Focal impaired-awareness seizureAwareness and response are impaired. May include staring, lip smacking, picking movements, or confusion afterward.
Focal to bilateral tonic-clonic seizureStarts focally, then spreads to both sides of the brain, producing bilateral convulsions.
Generalized onsetInvolves both cerebral hemispheres rapidly from onset.
Generalized tonic-clonicLoss of consciousness, stiffening phase (tonic), then rhythmic jerking (clonic), followed by postictal sleepiness/confusion.
Absence seizureBrief staring and behavioral arrest, often lasting seconds, with rapid recovery and little or no postictal confusion.
Myoclonic seizureVery brief, shock-like muscle jerks.
Tonic seizureSustained muscle stiffening.
Atonic seizureSudden loss of muscle tone, causing head drop or sudden fall.
Clonic seizureRepetitive rhythmic jerking.
Epileptic spasmsSudden flexion or extension movements, usually occurring in clusters in infancy.
Unknown onsetUsed when the beginning was not observed or cannot be determined.
Focal seizures can evolve into bilateral tonic-clonic seizures. Guyton and Hall Textbook of Medical Physiology, section “Seizures and Epilepsy.”

2. Pathogenesis and mechanism

Basic mechanism

Normal brain function depends on a balance between:
  • Excitation, mainly through glutamate-mediated neurotransmission
  • Inhibition, mainly through GABA-mediated neurotransmission
A seizure occurs when this balance shifts toward excessive excitation or inadequate inhibition in a neuronal network. Neurons then fire excessively and synchronously, producing an abnormal electrical discharge that may remain localized or spread through the brain. Guyton and Hall Textbook of Medical Physiology, section “Seizures and Epilepsy.”

How seizures develop

  1. Hyperexcitable focus or network develops because of altered neurons, synapses, ion channels, or brain structure.
  2. Excitatory activity exceeds inhibitory control.
  3. Neurons fire in synchronized bursts.
  4. The discharge may:
    • remain in one area, causing focal symptoms, or
    • spread across both hemispheres, causing generalized manifestations and loss of consciousness.
  5. After the discharge, the brain may enter a suppressed recovery phase, producing the postictal state: confusion, drowsiness, headache, weakness, or speech difficulty.

Causes and risk factors

Seizures can be:
  • Acute symptomatic (provoked): hypoglycemia, low sodium or calcium, alcohol/drug withdrawal or toxicity, fever in children, meningitis/encephalitis, eclampsia, renal or liver failure, hypertensive encephalopathy.
  • Structural: head trauma, stroke, brain tumor, scar tissue, congenital brain malformation.
  • Genetic or channel-related: inherited susceptibility affecting ion channels or synaptic signaling.
  • Infectious or immune-mediated: CNS infections, autoimmune encephalitis.
  • Unknown cause: common in epilepsy.
Brain injury from trauma, stroke, or infection may lead to epilepsy months or years later because neuronal networks can reorganize and become persistently hyperexcitable. Guyton and Hall Textbook of Medical Physiology, section “Seizures and Epilepsy.”

3. First aid during a convulsive seizure

Do:
  1. Stay calm and note the time the seizure starts.
  2. Protect from injury: move sharp or hard objects away.
  3. If the person falls, place something soft under the head.
  4. Loosen tight clothing around the neck.
  5. After jerking stops, if they are not fully awake, place them on their side in the recovery position to help keep the airway clear.
  6. Stay with them until they are awake, breathing normally, and aware of their surroundings.
  7. Reassure them during recovery. Confusion and sleepiness may occur after a seizure.
Do not:
  • Do not restrain the person or try to stop their movements.
  • Do not put anything in their mouth. They cannot swallow their tongue, and objects can injure teeth, mouth, or airway.
  • Do not give food, water, or medicines by mouth until they are fully alert.
  • Do not move them unless there is immediate danger.
These steps align with Epilepsy Foundation seizure first-aid guidance.

4. Call emergency services immediately if

  • The seizure lasts more than 5 minutes
  • Another seizure begins before recovery of consciousness
  • It is a first seizure
  • Breathing is difficult or does not return to normal
  • The person is injured
  • The seizure occurs in water
  • The person is pregnant, has diabetes, or you are worried about their condition
  • The person does not return to their usual level of consciousness afterward
A prolonged or repeated seizure without recovery is status epilepticus, a medical emergency that needs urgent treatment to prevent brain injury.
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