GRAPEVINE, TEX. – Convulsive status epilepticus is a medical emergency that requires quick thinking and quick action to protect the patient from both acute and long-term damage.
Convulsive seizures can be strong enough to break bones, Dr. David Likosky said at the annual meeting of the Society of Hospital Medicine. They can acutely endanger the patient and, if not controlled, pave the way for more frequent episodes.
Experts now recognize that repeated seizures can cause brain injury that increases the risk of more seizures, "kindling is the idea that the more seizures you have, the more likely you are to have them," said Dr. Likosky, a neurohospitalist and director of the stroke program at Evergreen Medical Center in Kirkland, Wash. "There is even some evidence that patients who have repeated convulsive status can develop areas of gliosis over time."
The definition of status epilepticus has changed somewhat recently, he said. "It used to be a seizure lasting more than 20-30 minutes or frequent seizures without a return to a normal level of consciousness in between. Now most neurologists will call any seizure that lasts more than 5 minutes status and treat [as if it is] status," according to Dr. Likosky, who has developed an algorhithm for treating convulsive status epilepticus in the emergency department.
These events are not rare, with more than 152,000 cases presenting each year, resulting in about 42,000 deaths. "The odds are that you are going to see one of these at some time, and you need to be able to treat it."
Status doesn’t occur only in patients with a known epilepsy diagnosis. Infections, tumors, brain abscess, traumatic brain injury, metabolic derangement, and drug overdose can all precipitate an event. For patients with an epilepsy diagnosis, a frequent cause is medication noncompliance.
"Convulsive status is a medical emergency," Dr. Likosky said. "The repeated seizures cause a huge amount of metabolic stress, which can even lead to a mycoardial infarction."
The rapid cycling between convulsive and nonconvulsive states can cause hypotension. Strong muscle contractions can result in hypoxia and metabolic acidosis and actually put enough torque on the bones to crack them. Patients can go into shock, and all of these things complicate an already-dire situation.
Dr. Likosky’s treatment algorithm is similar to one published this year in the journal Neurohospitalist. Dr. Edward Manno, a neurointensivist at the Cerebrovascular Center in Cleveland, created a decision tree outlining the treatment process step by step (Neurohospitalist 2011;1:23-31).
As in most emergency situations, the first step is to maintain an open airway, using pulse oximetry and cardiac monitoring to measure vitals. A quick glucose test is necessary because hypoglycemia can be at the root of a seizure storm.
Intravenous benzodiazepines are the first level of treatment. Lorazepam, diazepam, and midazolam are frequently employed. Although all are effective, a 2001 study found that lorazepam was more effective than diazepam in treating status epilepticus (N. Engl. J. Med. 2001;345:631-7).
"A new study is looking at the effectiveness of intramuscular midazolam that can be given by medics, or even at home," Dr. Likosky said. The results should be available later this year.
Sometimes patients in status require a fairly large drug dose to stop the seizures. "Since the underlying point is to treat aggressively and quickly, underdosing really hurts these patients. People vary, for example, in how much lorazepam to give. Some give 2 mg and some give 4 mg, but don’t be shy about increasing it to 6 or even 8, Dr. Likosky said."
If the patient doesn’t respond to initial benzodiazepine treatment, the next step is to administer fosphenytoin intravenously. "The key here is that one size does not fit all. You can’t just give 1 g. What you want is 18-20 mg/kg. The most important thing is to get [the patient] to a good level, and you may even give an additional dose on top of that," increasing to 30 mg/kg if necessary.
If this doesn’t arrest the seizure, phenobarbital or pentobarbital are in order. "Keep in mind that they cause respiratory suppression, especially when given in high doses to someone who has already had a benzodiazepine. If you haven’t intubated the patient before this, you have to do it now, prophylactically, in case breathing stops."
Other antiepileptic medications should be tried next. An intravenous loading dose of valproic acid (20-25 mg/kg) or levetiracetam (500-1,000 mg) are two possible choices.
Refractory status occurs when a patient fails benzodiazepine, phenytoin, and antiseizure medications. "This is when you start thinking about anesthetics. You need to titrate these according to the EEG." Propofol, midazolam infusion, pentobarbital, or ketamine are possibilities here.