What is Status Epilepticus and SUDEP?

What is Status Epilepticus

Status epilepticus is a potentially life-threatening condition in which a person either has an abnormally prolonged seizure or does not fully regain consciousness between seizures. Most people agree that any seizure lasting longer than 5 minutes or if a second seizure occurs before recovery, should, for practical purposes, be treated as though it was status epilepticus. Status epilepticus affects about 195,000 people each year in the United States and results in about 50,000 deaths.

It is important to treat a person with status epilepticus as soon as possible. Doctors in a hospital setting can treat status epilepticus with several different drugs and can undertake emergency life-saving measures, such as administering oxygen, if necessary. People in status epilepticus do not always have severe convulsive seizures. Instead, they may have repeated or prolonged non convulsive seizures. This type of status epilepticus may appear as a sustained episode of confusion or agitation in someone who does not ordinarily have that kind of mental impairment.

What is SUDEP

Sudden Unexpected Death in Epilepsy is a mysterious, rare condition, better known as SUDEP, in which typically young or middle-aged people with epilepsy die without a clearly defined cause. By definition, (1) death is sudden and unexpected, (2) a clear cause of death must be absent, and (3) victims must have had epilepsy. Victims are often found in bed with or without signs of having had a convulsive seizure, but were otherwise in a reasonable state of health at the time of death. Although seizures are suspected to have occurred prior to death, there should be no evidence of seizure as the direct cause of death.

What causes SUDEP

Although the cause of death is unknown, some researchers suggest that a seizure causes an irregularity in the heart rhythm. More recent studies have suggested that a combination of impaired breathing (apnea), increased fluid in the lungs (impairing the exchange of oxygen and carbon dioxide), and being face down on the bed all combine to cause death due to impaired respiration. In many cases, death probably occurs after a seizure has ended.

How common is SUDEP

Various report information gathered shows the number of people with epilepsy who die of sudden unexpected death in epilepsy (SUDEP) to be rare. The incidence of SUDEP in the general epilepsy population has been reported to be 0.09–1.2/1,000 person-years. This incidence is higher, 1.1–5.9/1,000 person-years, in patients with medically refractory epilepsy and even higher, 6.3–9.3/1,000 person-years, in patients who have failed respective epilepsy surgery ({A} Tomson T, Nashef L, Ryvlin P, Sudden unexpected death in epilepsy: current knowledge and future directions, Lancet Neurol, 2008; (11):1021–31. {B} Devinsky O, Sudden, unexpected death in epilepsy, N Engl J Med, 2011;365(19):1801–11.)

One most recent study out from the Institute of Medicine 2012, entitled; Epilepsy Across the Spectrum: Promoting Health and Understanding sites “SUDEP numbers vary from 1 in 10,000 newly diagnosed people with epilepsy to 9 of every 1,000 candidates for epilepsy surgery.” It is clear that much more research and data collection is needed in order to get more accurate numbers.

Although the risk is highest in people with severe, intractable epilepsy that have frequent seizures and take large doses of many anti-epileptic drugs. A recent 40 year follow-up of children once diagnosed with epilepsy suggests that SUDEP may account for approximately 30% of all deaths in people with epilepsy (Sillanpää & Shinnar 2010). However, with poor case identification and inconsistencies in the investigation and recording of the deaths, these numbers could very well be an underestimate.

The lowest risk is seen among people with newly diagnosed Epilepsy. The risk is highest in young male adults (ages 20-40), with frequent convulsive seizures, taking several anti-epileptic medications. Combination therapy (poly-therapy) with anti-epileptic drugs had a 3 times higher risk compared with those on a single anti epileptic drug (mono therapy) in a recent combined ILAE analysis. There is no conclusive evidence of greater risks associated with the use of individual specific anti-epileptic drugs. On the other hand, SUDEP is rare in patients with new onset epilepsy, in patients without convulsive seizures as a seizure type, and in patients with well controlled seizures.

What are the risk factors for SUDEP
Major risk factors for SUDEP appear to relate to the severity of the epilepsy, as SUDEP is more common in people with:

  • Seizures that can’t be controlled
  • Treatment with multiple anti-convulsant drugs
  • Having long standing chronic epilepsy
  • Generalized tonic-clonic seizures
  • Seizures that happen at night (called nocturnal seizures)
  • Not taking anti convulsant medicine as prescribed
  • Stopping the use of anti convulsant medicine abruptly
  • Developmental delays
  • Onset of epilepsy at a young age

A few safety precautions can minimize the chances of SUDEP

  • Patients should make sure to take the medications prescribed for them.
  • Patients should visit with their doctor regularly, especially if convulsive seizures are not completely controlled.
  • Adult patients with a high likelihood of tonic-clonic seizures in sleep should be supervised whenever possible. (SUDEP is extremely rare in children with epilepsy and in other patients who are well monitored. In fact, supervision has emerged as a protective factor for SUDEP, independent of seizure control.)
  • Basic first aid should be provided during a seizure, including rolling the person onto one side, checking respiration and avoiding putting any object in the patient’s mouth.
  • Family members and/or caregivers of patients with uncontrolled convulsive seizures should learn cardiopulmonary resuscitation.

IOM Summary: Data seem to suggest that the mechanism of SUDEP may be dependent upon individual susceptibility to one or a combination of factors. These may include: seizure-related central apnea and/or lung edema with respiratory death; seizure-related hypoxia plus acute pulmonary changes and systemic acidosis leading to a fatal arrhythmia; an inherited cardiac ion channelopathy combined with acute seizure-related cardiac autonomic disruption leading to a fatal arrhythmia. Added to the mix is the unknown of acute psychological stress. The mechanism(s) of SUDEP remain a mystery, but with a growing interest in investigating the mechanistic variables, there is reason to be optimistic that eventually it will be solved.

I’m work to raise SUDEP awareness in part by teaching seizure recognition and first aid. The ultimate goal of all SUDEP research is to prevent deaths caused by seizures. This requires a better understanding of it, by comparing people who die from SUDEP to people living with epilepsy, and people with epilepsy who die of other causes.

 

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