Cluster seizures (or seizure clustering) are a series of seizures that occur in the following patterns: two to four seizures over 48 hours, three seizures in 24 hours or, per Epilepsy.com, "two generalized tonic–clonic seizures or three complex partial seizures in four hours." For an epileptic, one seizure is frightening enough; cluster seizures are worse, causing them to miss school, work or social events, and posing the risk of "status epilepticus," a perpetual state of seizure, according to the Epilepsy Foundation.
The National Institute of Neurological Disorders and Stroke defines epilepsy as "a brain disorder in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally." The abnormal signals disrupt the brain's natural neuronal activity and results in seizure activity such as convulsions, muscle spasms and fainting. Normally, an epileptic seizure lasts only a few minutes; however, if the seizure is prolonged, or the epileptic person experiences multiple seizures in a short period of time, they are suffering from cluster seizures.
There are two different classifications of seizures according to Mayo Clinic: partial or generalized. Partial seizures come in two forms: simple and complex. Generalized seizure activity has four common types: absence (petit mal), myoclonic, atonic and tonic-clonic (grand mal) seizures. Cluster seizures can be one, or any combination of the six types of seizure activities.
Signs of a simple partial seizure include changes in emotions or sensory interpretation and involuntary muscle spasms. Complex partial seizures block awareness--the epileptic may stare into space or walk in circles as if in a trance. Both absence and tonic-clonic seizures result in loss of consciousness, although the tonic-clonic (grand mal) has far greater convulsive activity than the absence (petit mal) seizure. Myoclonic seizures primarily cause a twitching of the arms and legs. If the epileptic suddenly collapses and falls down, they are suffering from an atonic seizure.
The Epilepsy Foundation estimates that 42,000 annual deaths result from status epilepticus, or uncontrolled cluster seizure activity. Deaths are commonly caused by an underlying brain injury, repeated stress from tonic-clonic seizing or constant electrical discharge in the brain. If the patient is fortunate enough to live through cluster seizing, brain damage is another unfortunate occurrence in numerous cases. The Epilepsy Foundation cautions that 15 percent of epileptics will eventually experience status epilepticus. Young children and seniors are the most susceptible to cluster seizures.
In 1999, Boston's Beth Israel Deaconess Medical Center released a report detailing U.S. Food and Drug Administration-approved treatments for cluster seizures. Treatments include doses of diazepam, phenytoin and valproate sodium solution administered intravenously in the hospital; diazepam administered rectally in the home; and, perhaps most importantly, health education for the epileptic and their family members to understand the alternate forms of treatment and ensure they are effective against cluster seizure activity.
- Epilepsy Professionals: Seizure Clusters
- Epilepsy Foundation: Prolonged or Serial Seizures (Status Epilepticus)
- National Institute of Neurological Disorders and Stroke: NINDS Epilepsy Information Page
- Mayo Clinic: Epilepsy
- Pub Med: New Therapies in the Management of Acute or Cluster Seizures and Seizure Emergencies