What is Postictal Seizure State?
The postictal state is a period that occurs after a seizure and lasts until the patient returns to their normal state. Identifying the end of a seizure and the start of the postictal state can be simple in some cases, but challenging in others. The complexity of identifying these stages can depend on the type of seizure a person has experienced.
For example, it’s usually easier to determine the end of a seizure and the start of the postictal state in cases of generalized tonic-clonic or generalized tonic seizures. These are seizures that involve a loss of consciousness and violent muscle contractions, or sudden stiffening of the muscles, respectively.
However, distinguishing between the actual seizure and the postictal state can be more difficult in cases of absence seizures (brief episodes of staring or daydreaming), focal seizures with impaired awareness (seizures that affect one area of the brain and can cause confusion or a lack of awareness), and myoclonic seizures (brief, jerky spasms of a muscle or muscle group).
The importance of understanding the postictal state lies in determining when it’s safe for the patient to get back to normal activities without posing a risk to themselves or others. It might also help identify where in the brain the seizure started. For example, if someone stops speaking during a seizure but starts speaking again right after it ends, this could indicate that the seizure began in the non-dominant hemisphere (side) of their brain. Similarly, if someone experiences weakness on one side of their body after a seizure, it could suggest that the seizure started in the opposite side of their brain.
What Causes Postictal Seizure State?
It’s believed that the period after a seizure, known as the postictal state, is due to neurons, a type of cell in the brain, becoming overly tired and overly restrained.
Risk Factors and Frequency for Postictal Seizure State
There isn’t a lot of specific information about how often the postictal state (a period of confusion or disorientation that can happen after a seizure) occurs in people with epilepsy. However, a study found that a significant portion of those with epilepsy, about 72%, said that they experienced behavioral problems during this post-seizure period.
Signs and Symptoms of Postictal Seizure State
The postictal period, which is the time after a seizure, affects various brain functions, including speech, motor function, and memory. For example, patients with seizures originating in the left side of the brain often have a pronounced verbal memory deficit during this period, while those with seizures beginning in the right side of the brain may experience a visual memory deficit. Another interesting factor is that memory is so impacted that 30% of patients cannot remember the seizure at all, and only 25% remember all of their seizures. Postictal motor weakness, also known as Todd’s paresis, can indicate that the seizure started in the opposite hemisphere of the brain. Other symptoms one might see during and after the seizure include repetitive unconscious gestures and movements and other symptoms such as coughing, spitting, and abnormal salivation.
How long the postictal state lasts depends on a variety of factors. For example, someone who has had a focal seizure (a seizure that starts on one side of the brain) with impaired awareness might take 1 to 2 hours to recover. However, Todd’s paresis could take up to 1 to 2 days to resolve. Certain patients may even experience changes in cognitive abilities, their mood, and energy levels that could last several days.
Testing for Postictal Seizure State
Deciding whether or not to take action during the period immediately after a seizure, known as the postictal state, depends on the symptoms following the seizure and previous history of the person’s epilepsy. Understanding previous seizures and postictal events is very important. If for example, a person consistently gets a headache after a seizure, they don’t need urgent brain imaging.
However, if there is a new symptom such as weakness on one side of the body after a seizure, then brain imaging is needed to rule out other possible causes like a stroke. Also, when a person has their first seizure and they show prolonged mental status changes afterwards, a more detailed examination is needed, which could include analyzing the fluid that surrounds the brain and spinal cord to look for the cause of the seizure.
Nonconvulsive status epilepticus—where a person has ongoing seizure activity in their brain but doesn’t show the usual outward signs of a seizure—should be considered if a person is confused for an extended period after a seizure. Figuring out when a seizure ends and the postictal state begins can be challenging. An electroencephalogram (EEG), which records the electrical activity of the brain, can help identify these two phases.
Brain imaging may detect changes in the postictal brain, but at this point, it is mostly a tool researchers use—not a tool that has been proven helpful in regular clinical practice.
EEG
EEGs can display the transition from seizure activity to the postictal state, and this can be classified by its rhythm or location. Some seizures end suddenly, and others slow down gradually. In terms of location, some seizures stop all at once throughout the brain, while others cease activity in different parts of the brain at different times.
Postictal EEG typically shows a reduction or slowing (usually in delta frequency range) or both. As recovery proceeds, the EEG reads slow wave frequencies, which then transitions to faster frequencies before returning to normal. Some people may fall asleep during recovery. The EEG changes are usually more noticeable with longer seizures. A study found that the average time for an EEG to read normal again was 120 minutes, with a maximum of 420 minutes in adults. The EEG reading postictally was found to match the site of surgery in 96% of cases in people with seizures in the temporal lobe.
Neuroimaging
Positron emission tomography (PET) scans of the brain can study how the postictal state changes neurotransmitters and receptors. One study found that opioid receptors increased after a seizure in a person with temporal lobe epilepsy on the side where the seizure took place. PET scans also showed that receptors for a type of drug used for induced relaxation (benzodiazepines) change with the duration of the postictal period—the shorter the postictal period, the lower the level of benzodiazepine receptors.
Perfusion magnetic resonance imaging (MRI) measures changes in blood flow in the brain after a seizure. One study revealed that blood flow to the side of the brain responsible for the seizure doubles within 5 minutes of a seizure and falls below average after 1 hour. Diffusion-weighted imaging also shows restrictions to diffusion postictally.
Treatment Options for Postictal Seizure State
Postictal deficits are problems that can happen after a person has a seizure, things like confusion or memory loss. Once a doctor has made sure these symptoms aren’t due to some other health issue, the patient usually just needs careful observation and comforting care. Postictal delirium, a type of confusion that can happen after a seizure, usually lasts a few hours but may go on for one to two days. Usually, this makes the patient less active, but in some cases, the patient may become more active than usual. Just providing a calming and supportive environment is typically all that’s needed unless the patient becomes overly agitated. In those cases, medication might be necessary to help calm the patient down.
What else can Postictal Seizure State be?
The following are some factors or conditions that could potentially cause central nervous system (CNS) problems or other systemic issues:
- Central Nervous System Secondary Causes such as a stroke
- Continuous seizures
- Systemic causes which can include:
- Use of certain drugs or exposure to toxins
- Infections
- Metabolic disorders