Status epilepticus (SE), or status seizure, is a medical condition characterized by a refractory period of seizure activity without a complete return to normal. It is a medical emergency that can lead to irreversible brain injury (due to excitotoxicity) if untreated. Convulsive status epilepticus, the most dangerous and life-threatening type, is characterized by seizures of the tonic–clonic type, with a regular pattern of contraction and extension of the arms and legs, lasting at least 5 minutes without return to normal (time point 1). Early treatment is essential to minimize damage to the brain, which starts to particularly accrue after 30 minutes (time point 2). Status epilepticus may also be non-convulsive, manifesting in the form of absence seizures or complex partial seizures. For other seizure types, the time points may vary. Previous definitions used a 30-minute time limit irrespective of type of seizure. Risk factors for status epilepticus include a history of epilepsy or other brain problems. These brain problems may include trauma, infections, or strokes, among others. Diagnosis often involves checking the blood sugar, imaging of the head, a number of blood tests, and an electroencephalogram. Psychogenic nonepileptic seizures may present similarly to status epilepticus. Other conditions that can mimic status epilepticus include low blood sugar, movement disorders, meningitis (including tuberculous meningitis), and delirium, among others. Benzodiazepines are the preferred initial treatment, after which typically phenytoin is given. Possible benzodiazepines include intravenous lorazepam as well as intramuscular injections of midazolam. A number of other medications may be used if these are not effective, such as phenobarbital, propofol, or ketamine. After initial treatment with benzodiazepines, typical antiseizure drugs are given, including valproate, fosphenytoin, levetiracetam, or similar substances. Intubation may be required to help maintain the person's airway. Between 10% and 30% of people who have status epilepticus die within 30 days. The underlying cause, the person's age, and the length of the seizure are important factors in the prognosis. Status epilepticus occurs in up to 40 per 100,000 people per year. Those with status epilepticus make up about 1% of people who visit the emergency department.
Signs and symptoms Status epilepticus can be divided into two categories: convulsive and nonconvulsive (NCSE).
Convulsive Convulsive status epilepticus presents an urgent neurological condition, which is characterized by an elongated and uncontrollable onset of seizures in which a regular pattern of contraction and extension of the arms and legs will be observed from the patient. The symptoms can be managed by initially introducing a seizure suppressing medication as the first stage of the treatment, which optimally works only for that stage because any delay will reduce the efficacy of those medications. Convulsive status epilepticus commonly affects the elderly and young children, with a mortality rate of up to 20–30% of elderly patients and 0–3% of young children. Patients who survive initial onset are often left with cognitive and neurological defects. Epilepsia partialis continua is a variant involving hour-, day-, or even week-long jerking. It is a consequence of vascular disease, tumors, or encephalitis, and is drug-resistant. Generalized myoclonus is commonly seen in comatose people following cardiopulmonary resuscitation (CPR) and is seen by some as an indication of catastrophic damage to the neocortex; myoclonus status in this situation can usually (but not always) be considered an agonal phenomenon. Refractory status epilepticus is defined as status epilepticus that continues despite treatment with benzodiazepines and one antiepileptic drug. Super-refractory status epilepticus is defined as status epilepticus that continues or recurs 24 hours or more after the onset of anaesthetic therapy, including those cases where status epilepticus recurs on the reduction or withdrawal of anesthesia.
Nonconvulsive Nonconvulsive status epilepticus is a relatively long duration change in a person's level of consciousness without large-scale bending and extension of the limbs due to seizure activity. It is of two main types with either prolonged complex partial seizures or absence seizures. Up to a quarter of cases of status epilepticus are nonconvulsive. In the case of complex partial status epilepticus, the seizure is confined to a small area of the brain, normally the temporal lobe. Absence status epilepticus is marked by a generalized seizure affecting the whole brain. An electroencephalogram (EEG) is needed to differentiate between the two conditions. The cases of nonconvulsive status epilepticus are characterized by a long-lasting stupor, staring, and unresponsiveness. Recent studies indicated 50% of cases involve patients that are semi-conscious in a way that they can respond but are confused spontaneously. Only 6% have shown a decelerated thought process. About 44% of cases of nonconvulsive status epilepticus are marked by a prolonged or fragmentary coma.
Causes
Only 25% of people who experience seizures or status epilepticus have epilepsy. The following is a list of possible causes:
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