WHAT IS NORSE?
NORSE is the abbreviated term or acronym that stands for new onset refractory status epilepticus. In layman terms, it is a severe medical condition requiring emergency treatment that comes seemingly from out of the blue (new onset), without any known cause despite extensive medical testing (cryptogenic.) The seizures don't respond to the established medical treatments (refractory) and the disorder is characterized by abnormally prolonged seizures (status epilepticus.)
The consequences of NORSE vary from mortality (death), significant neurological deficits (morbidity) to very rare, full recovery. Most survivors develop epilepsy even though they never had a history of epilepsy prior to their experience of NORSE. Patients are typically placed in a coma with anesthetic drugs to protect the brain (often referred to as a medically-induced coma) in an attempt to reduce the seizures. At least two anti-epileptic drugs are administered and then the drugs are gradually reduced. The hope is that after this period of quiet, the seizures have gone away. Sometimes doctors refer to this process of slowly reducing the drugs as "weaning" the patient away from the anesthetics. A formal medical report for NORSE can be found here.
Listen to an interview of Dr. Nicolas Gaspard on the nuanced changes in the conceptualization of NORSE reflected in the newly-proposed consensus definitions. We are grateful to Dr. Joseph Sirven, Editor-in-Chief of the Epilepsy Foundation's website, epilepsy.com, for conducting this interview as part of his Hallway Conversations series.
I STILL DON'T UNDERSTAND
Physicians and research scientists are similarly still trying to understand NORSE. The term NORSE is a relatively new one. The first reference to NORSE in a medical journal was in 2005. Since then researchers have used various terms to describe this syndrome. It has sometimes also referred to as cryptogenic NORSE, super-refractory status epilepticus or presumed encephalitis with refractory status epilepticus.
Most of the information about NORSE is in scholarly publications that may be difficult for the layman to fully understand, but they are available to the public (in a summarized form at least) here. An annotated list of relevant publications is also available on the Medical Professionals segment of this website.
WHY DID THIS HAPPEN?
No one knows for certain why NORSE strikes some patients and not others. The exact cause of the disorder is similarly unknown and the best medical treatments for it are also not established. What is known is that NORSE is a rare disorder. At the same time, underreporting and misdiagnoses are likely since the term itself is new and not well established. There is no evidence that NORSE runs in the family; no reports of NORSE striking more than once in a family.
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Despite the fact that the patient never had epilepsy previously, if a diagnosis of NORSE has been given, the patient currently has a disorder that falls under the disease category of epilepsy. A readable description of epilepsy is here:
Epilepsy is characterized by seizures, but seizures are not all the same. Status epilepticus is not a disease in and of itself; it is an event, a symptom of any of a number of diseases or disorders. Status epilepticus is considered the most extreme form of seizure, marked by abnormally prolonged seizures that can have severe long-term neurological consequences including death. The knowledge about status epilepticus (sometimes shortened to "status" or "being in status") is evolving such that a revised definition of the term was issued in the fall of 2015 by the International League Against Epilepsy.
Patient outcome refers to the condition of the patient at the end of the disease process or medical treatment. Sometimes doctors will talk about short-term outcomes and long-term outcomes. Functional outcome refers to the specific activities the patient will be able to do at the end of the disease process or medical treatment. Since NORSE patients can experience a range of outcomes from mild to severe brain deficits, ongoing evaluation and discussion of the patient's estimated functional outcomes are vital. It should be noted, however, that doctors seldom can predict the arc of any disease with reliable accuracy. This is even more so in the cases of NORSE. There simply is not enough information about the disorder to form a broad basis of prediction for the way NORSE will proceed and how the patient will end up. So, if the doctors say they simply don't know what the patient outcomes are presently, understand they are probably being candid rather than evasive. Ask again at a later point in time.
"CRYPTOGENIC" NORSE & DELAY OF DIAGNOSIS
Doctors may not be able to make a diagnosis of NORSE for what may seem to be an extended period of time. NORSE can be viewed as a diagnosis of exclusion, meaning doctors cannot say with any certainty that a patient has NORSE until they exclude all other logical alternative diagnoses. Only after an extensive battery of tests (or panels) have been completed, and only when the results of those tests rule out all other known neurological disorders, can the tentative diagnosis of NORSE be made. It's often seen as a tentative diagnosis because doctors and scientists are aware that there may be one specific or several viral or bacterial agents or immunological disorders for which they have no established name or test that may be causing this disorder (or in very rare cases, a specific test was not included.) The term cryptogenic (meaning obscure or unknown) is sometimes attached to NORSE which only reiterates the message that the origin or cause of the disorder is not known.
Given the range of outcomes of NORSE, and the inability of doctors to reliably predict the specific outcome for a particular patient, ongoing communication between the doctors and the families is vital. The involvement of a palliative care team which consists of doctors, nurses, social workers and other health care specialists who help manage symptoms as well as communication can be very helpful. Patients can receive palliative care at any point in their treatment whatever their prognosis. Read more on the topic of palliative care here.
Sample questions to guide decisions are here.