Non-Convulsive Status Epilepticus

There are two types of status epilepticus. One is the status epilepticus that most people think about, convulsive status epilepticus, in which the person is having prolonged tonic-clonic (convulsive) seizures which would be treated as a medical emergency. A separate type, non-convulsive status epilepticus (formerly referred to as “minor motor status”), is an episode when a person has prolonged absence and atypical absence events, lasting a half-hour, an hour, or days. This non-convulsive status (NCSE) is not life-threatening or brain-damaging but should be recognized and treated.

Fortunately, convulsive status epilepticus is not commonly associated with Doose syndrome. There is, however, a peculiar and rare type of non-convulsive status epilepticus common in Doose syndrome patients which may continue for hours or days if not interrupted by adequate measures without major consequences. NCSE is debilitating for the child and awful to witness as a parent but be reassured that it is not harmful.

Although many myths and fears persist about status epilepticus and non-convulsive status-epilepticus, with early recognition and appropriate treatment, children who experience episodes of status should return to their previous function and have no residual effects.

There is no evidence that spike-wave stupor seen with NCSE causes permanent damage to the brain, even when it goes on for hours or days. However, it disrupts the child’s level of function.

What happens?

By definition, NCSE is a long-lasting on/off absence seizure. Whereas an absence seizure lasts under a minute, episodes of NCSE can continue for a long time – thirty minutes, an hour, a day, or longer. Just like other generalized seizures, NCSE can start suddenly and without warning but the shift in consciousness may be so subtle that it may be very difficult for an observer to detect.

As is the case with all generalized seizures, the child doesn’t know what is happening during episodes of NCSE. Even though the child may be somewhat responsive and aware of the surroundings, he/she may only recall “snippets” of what happened or nothing at all. There is a lot of subclinical seizure activity occurring in the brain, constantly interrupting the child’s ability to process and function. As one child has described, things feel “fuzzy in the head”.

With non-convulsive status in MAE, the typical clinical picture is of a drowsy, stuporous (ataxic, or as if in a drunk state) child with subtle, barely detectable, myoclonic seizures often involving the face or extremities such as fingers. The child is unresponsive, drools has slurred speech or is non-verbal, and even immobile. This condition is termed by Doose syndrome parents as “full-blown NCSE”. If this situation continues for a long period it can be serious because it usually means that the child is immobile and non-verbal but, more importantly, unable to swallow. In this state, it is very difficult to keep fluids up regularly and take medication so if the NCSE cannot be stopped by adequate measures, hospitalization may be required. Fortunately, such a deterioration of conditions in Doose syndrome is rare.

Non-convulsive status in Doose syndrome can also be subtle and very difficult to detect without an EEG. Only a very careful history of an unexplained change in function or behavior can lead a treating doctor to suspect NCSE and to obtain an EEG. When dealing with MAE, parents, carers, and treating doctors should maintain a high index of suspicion that such changes in behavior may be an episode of NCSE especially if these events occur at a regular time every day. This milder condition is termed by Doose syndrome parents as “high-functioning NCSE”. Even “with a head full of seizures”, in this milder state of NCSE, parents are constantly amazed at what the child is capable of doing.

During an episode of “high-functioning NCSE”, as a parent, you might think that something is not quite right but not be able to put your finger on it. You may notice behavior that is out of character. These are some of the behaviors you might observe:

  • somewhat unresponsive
  • slurred or labored speech
  • delayed actions (slow motion)
  • decreased ability to “compute” (process/function) compared to normal
  • grasping only “snippets” of his/her surroundings
  • dream-like, sleepwalking state
  • easily confused or agitated, or finds simpler tasks challenging
  • subtle facial twitches or eye blinking, (a clue that seizure activity might be occurring)
  • drooling which is out-of-character

You may suspect NCSE but the only way to know with certainty is to obtain an EEG during such an episode.