Postictal, ictal and interictal phase
Postictal state refers to the altered state of consciousness that an individual enters after a seizure. Usually, it lasts for fifteen to thirty minutes but it may occur longer in the case of severe seizures. It may cause hypertension, headache, confusion, nausea, drowsiness, and other symptoms. It may also be accompanied by amnesia and other memory problems. During this period, the brain actively tries to recover from the trauma caused by the seizure.
The postictal, ictal and interictal phase
In medical terms, the postictal state refers to an abnormal condition that may occur between the end of epileptic seizures and the return to an individual’s baseline condition. Applying this definition can be difficult, especially in the case of partial seizures, where sensorimotor and cognitive impairments may merge imperceptibly into the postictal state. Most patients are also unaware of having had an epileptic seizure. Sometimes, electroencephalography can help distinguish postictal from ictal periods, but it may also demonstrate focal slowing during and after the seizure.
Changes in electroencephalogram do not necessarily correspond to changes in behavior, especially when it comes to scalp recordings. The postictal state will then end at the interictal phase, but this shift can be ambiguous as well. Interictal spikes as well as spike waves may also be associated with behavioral and cognitive impairments, suggesting that both represent fragments of ictal episodes. However, when the boundaries are clear, it is still best to describe the sequence of electroencephalographic changes and behaviors without labeling stages as being postictal or ictal.
Symptoms of postictal period
Some scientists define the postictal state as manifestations of seizure-induced alterations in a wide range of neuronal functions. After a seizure, parents commonly experience both physical and mental exhaustion that may last for a day or two. The common complaints of patients after a seizure include the incapacity to think clearly, characterized by poor concentration and memory, decreased interactive and verbal skills, and other cognitive defects. The collection of these symptoms was recognized as the postictal state, even though the word postictal means nothing more than after a seizure.
During the postictal state, patients suffering from epilepsy also complain about migraines. A possible cause of this symptom is the high intracranial pressure due to the postictal cerebral edema. Sometimes, patients may also be unaware that they experience a seizure, with the characteristic migraine remaining as their only clue. Depression is also a common concern after seizures. Other symptoms associated with seizures also include Todd’s paresis, a temporary loss of function in whatever region experienced the seizure.
Patients who experience Todd’s paresis during the postictal state may also experience temporary blindness, deafness, or numbness. Anterograde amnesia may also emerge if the seizure affected the bilateral hippocampi or aphasia if it began in the brains language-dominant hemisphere. Symptoms may last for 15 to 16 hours but physicians may need to resolve the loss of motor function caused by ischemia or Todd’s paresis.
What is postictal psychosis?
Postictal psychosis refers to a rare but severe complication that occurs after seizures. It is characterized by visual or auditory hallucinations, paranoia, delusions, and even aggression. Immediately following the end of the seizure, patients feel the usual lethargy and confusion caused by the postictal state and then gradually recovers to the baseline state that is called the lucid phase. Patients who experience postictal psychosis may also experience the lucid phase two hours a week even before the psychosis sets in.
A study that involved seizure patients also revealed that 12-50% of them may experience a period of psychosis for 12 hours to three months. Postictal psychosis is a reversible condition that may be treated with regular antipsychotic drugs. It also stops when patients no longer experience seizures. Postictal bliss, a highly blissful feeling associated with the emergence from temporary amnesia, may also follow the state of psychosis. All of these symptoms may be present for a few hours or even an entire day. Lack of responsiveness after seizures is also expected if patients fail to exhibit these symptoms after a seizure.
On the other hand, false seizures are known for having a psychogenic origin. Hence, the postictal state is actually useful for physicians who are trying to determine the origin of the seizure. Decreased verbal or short-term memory indicates that the seizure happened in the dominant hemisphere. On the other hand, seizures originating from the non-dominant hemisphere tend to manifest themselves with decreased visual memory. For example, the inability to read suggests seizures in the speech-dominant hemisphere.
What causes the postictal phase?
Although neurons may seem exhausted after the constant firing associated with seizures, the incapability of neurons to carry action potential after a seizure remains the same. The neurons of the brain still fire normally when subjected to stimulation, even after long periods of seizures. So instead of saying that exhausted neurons cause the postictal phase, it is actually appropriate to assume that cerebral blood flow changes, neurotransmitter depletion, and active inhibition are responsible for the occurrence of the postictal period.
During active inhibition, seizures may cease spontaneously but changes in the brain may still produce inhibitory signals that can slow down the activity of overactive neurons and put an end to the seizure. In fact, opioid peptides seem to be involved in the postictal state so they are sometimes anticonvulsive as well. Adenosine also seems to be involved in terminating epileptic seizures. Evidence of active inhibition actually lies in the postictal refractory period, which may last for a few weeks or even months after a series of seizures.
Changes in the flow of blood to the cerebrum may also cause the postictal period. While cerebral auto-regulation ensures that an adequate amount of blood is transmitted to various regions of the brain, seizures may cause the cerebral blood flow to become inadequate for metabolism. Although changes in blood flow will not change the state of the hippocampus, higher glucose uptake is observed during the early postictal periods. It is possible that problems in cerebral auto-regulation cause changes in blood flow after a seizure or it may be another factor involved in ceasing seizures.
Although there are few explanations as to what factors cause the long-lasting symptoms of postictal confusion or hypnosis, the mind-altering symptoms related to this condition is clear. However, it is still possible for a small number of patients that have experienced memory loss for weeks or months after a seizure to experience structural changes that may cause postictal symptoms to eventually disappear.
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