This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
New-onset refractory status epilepticus (NORSE) occurs when a person without a previous history of seizures, experiences status epilepticus (SE) without a clear cause. SE describes a state in which a person has one prolonged seizure, or a cluster of seizures without recovery time in between. The symptoms of NORSE typically begin with a mild fever and general symptoms of illness. People with NORSE may also experience behavioral and cognitive symptoms. SE associated with NORSE can last days, weeks, or months and may lead to a comatose state. A likely cause is identified in about half of all people with NORSE. The most common causes of NORSE include autoimmune disorders, paraneoplastic disorders, and viral encephalitis. Studies indicate that changes in certain genes, including the SCN2A and IL1RN gene(s) may increase the risk to develop NORSE. When the cause cannot be found, cryptogenic NORSE is diagnosed. Most people with cryptogenic NORSE experience a fever prior to seizure development. These cases are classified as a sub-type of NORSE, called Febrile Infection-Related Epilepsy Syndrome (FIRES).
A diagnosis of NORSE is suspected in people who develop SE that does not respond to typical treatment and that does not have an obvious cause. A diagnostic work-up may include brain imaging, cerebrospinal fluid studies, and blood tests. Electroencephalography (EEG) is used to monitor seizures throughout the illness. There is no standard treatment for NORSE. If an underlying cause of NORSE is known, it should be treated appropriately. SE associated with NORSE does not respond to at least two typical lines of anti-seizure treatment. Additional treatment with other anti-seizure medications and/or medically inducing a coma using anesthesia may be suggested.
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