A seizure is defined as a sudden change in consciousness, behaviour or movement of the body, due to electrical hypersynchronization of neuronal networks in the cerebral cortex. This sudden change tends to be transient, and is characterized mainly by motor symptoms (eg. shaking) and non-motor symptoms (e.g., language, vision and sensory changes, confusion, or alterations of awareness).
Elements of a seizure
| Element | Description | Features |
|---|---|---|
| Prodrome | Precedes the seizure and last hours to days. | Changes in mood or behavior |
| Aura | A sensory experience that correlates to the epileptic event | Rising epigastric sensation, gustatory/olfactory hallucination, visual changes, headache, paresthesia, or psychiatric phenomena (deja vu, jamais vu) |
| Post-ictal states | Follows the seizure | Headache, somnolence, aggression, confusion, cognitive impairment, temporary paralysis (Todd’s paralysis following a focal seizure in the motor cortex), or dysphasia (focal seizure in the temporal lobe) |
Classification based on seizure type
| Classification | Description |
|---|---|
| Focal onset seizuress | Focal onset seizures involve one part of the brain. The patient may not lose consciousness, but may have altered awareness. |
| Generalised onset seizures | Generalised seizures arise from both cerebral hemispheres. |
| Unkown onset seizures | This is when the onset of a seizure has not observed. It can later be reclassified into focal or generalised when more information is available. |
Types of focal onset siezures
| Focal seizure | Description |
|---|---|
| Focal aware seizures | Previously known as simple partial seizure. The patient is aware and recalls events during the seizure. It can involve sensory, motor, psychiatric, or autonomic symptoms |
| Focal impaired awareness seizure | Previously known as complex partial seizure. The patient has altered awareness, appearing dazed or confused. The symptoms are similar to simple focal seizures |
| Focal to bilateral tonic-clonic seizures | These begin in one hemisphere then spread to involve both, producing a tonic-clonic seizure |
Localising features of focal seizures
| Location | Features |
|---|---|
| Temporal lobe | Automatisms, dysphasia, deja vu, jamais vu, emotional disturbance, elation, derealization, hallucination, delusions, and bizarre associations |
| Frontal lobe | Motor features, Jacksonian march, motor arrest, subtle behavior disturbances, dysphasia or speech arrest, or post-ictal drowsiness |
| Parietal lobe | Sensory disturbance, or motor symptoms if it spreads to the pre-central gyrus |
| Occipital lobe | Visual phenomena – spots, lines, and flashes |
Types of generialised onset seizures
| Type | Description | Features |
|---|---|---|
| Absence (petit mal) seizure | Loss of consciousness. Non-motor. Classically seen in children. The child looks out into space for a few seconds and snaps back into reality | Blank stare < 10 seconds that starts and ends abruptly, Automatisms (lip smacking, hand wringing, motor tics), 3 Hz spike and wave on EEG |
| Tonic-clonic (grand mal) seizure | Loss of consciousness with stiffening and jerking of all limbs. There may be one without the other, i.e., stiffening only = tonic seizure, repetitive jerking only = clonic seizure | Loud moan (air coming out of closed epiglottis) followed by stiffening and jerking (involving all four limbs). Tongue biting(look for tongue laceration esp. in patients who live by themselves) and Urinary incontinence. There may be post-ictal confusion and drowsiness |
| Myoclonic seizure | No loss of consciousness. There is a sudden jerk of a limb, face, or trunk. “My flying-saucer epilepsy” | Sudden jerk of part of the body (arm or leg). They may fall over suddenly or have a violently disobedient limb |
| Atonic seizure | Sudden loss of muscle tone causing a fall. | Sudden loss of muscle tone < 15 seconds, falls over. To differentiate this from syncope, an atonic seizures has haziness and confusion after loss of consciousness, while in syncope the patient will be generally OK after recovering. |
Common causes of seizures
| Age group | Common causes |
|---|---|
| Neonates and infants (< 1 year) | Genetic, congenital structural maldevelopment, perinatal injury, perinatal/postnatal infection (meningitis), metabolic disorder (hypoglycemia, hypocalcemia), and West syndrome |
| Young children (<10 y) | Febrile, genetic causes, infection, traumatic Brain Injury, congenital brain malformation, metabolic disorders, and accidental poisoning |
| Adolescents (10-18 years) | Traumatic brain injury, encephalitis, genetic disorders, and illicit substance abuse |
| Adults (18-60y) | Alcohol withdrawal, traumatic brain injury, illicit substance use, neoplasm, infection, and metabolic acidosis |
| Older adults (60+ years) | Traumatic brain injury, cerebrovascular disease, neoplasm, abscess, and neurodegenerative disease |
- Common triggers
- Anti-epileptic drug non-compliance OR new drug that interferes with medication (break-through seizures)
- Sleep deprivation
- Stress
- Alcohol use and alcohol withdrawal
- Hypoglycemia
- Patient History
- What is the frequency and duration of seizures?
- What happened before/after the event? (pre-ictal phase and post-ictal phase)
- Was there a preciding aura?
- Was there residual weakness or confusion post-ictal?
- Are there any automatisms? (Gives a clue as to the focus of origin)
- Was there tongue-biting?
- Was there incontinence?
- Has there been trauma OR drug/alcohol use? (triggers)
- Is there a Family History?
- Differentials (VITAMIN D)
- Vascular malformation
- Infection, Inherited conditions
- Trauma
- Alzheimer’s
- Metabolic derangement
- Hypocalcemia
- Hyponatremia
- Hypernatremia
- Hypermagnesemia
- Hypomagnesemia
- Hyperglycemia
- Hypoglycemia
- Idiopathic
- Neoplasms
- Drugs
- Fluoroquinolones
- Bupropion
- Imipramine
- Meperidine
- Metronidazole
- Isoniazid
- Investigations
- Random blood sugar to exclude extreme hypoglycemia or hyperglycemia
- Complete blood count to rule out systemic or CNS infections
- U/E/Cs to rule out hyponatremia, hypernatremia, hypocalcemia and uremia
- Urine toxicology screen to rule out cocaine, amphetamines, heroin, PCP, or GHB
- Blood Alcohol Concentration
- 0.06 after binge drinking
- Alcohol withdrawal
- Head CT or MRI for ****space occupying lesions. An MRI is the imaging modality of choice for structural lesions since it has superior resolution compared to a CT.
- Electroencephalogram (EEG) for unprovoked first seizure
- Treatment
- Seizure precautions
- DO NOT put anything in the patient’s mouth to prevent tongue biting
- DO NOT restrain the patient
- Gently lean the patient on their side with the head turned to the same side to prevent aspiration
- Cushion the patients head to prevent head injury
- Loosen or remove tight or dangerous clothing around the head and neck such as necklaces, and glasses
- Remove dentures
- Call for help immediately
- Establish IV access
- Abort the seizure using anti-epileptic drugs (see status epilepticus)
- If the convulsion lasts more than 3 – 5 minutes consider status epilepticus or psychogenic non-epileptic seizure
- Seizure precautions