1. Epilepsia partialis continua (EPC) of Kojevnikov
(a) Rasmussen syndrome
(b) Focal lesions
(c) Inborn errors of energy metabolism
2. Supplementary motor area status epilepticus
(a) Individual tonic motor seizures, without impairment of consciousness
(b) Tonic motor seizures which involve into generalized seizures, with impairment of consciousness
3. Aura continua
4. Dyscognitive focal status epilepticus
(a) Mesial temporal origin
(b) Neocortical origin
5. Tonic-clonic status epilepticus
6. Absence status epilepticus
(a) Typical and atypical absence status epilepticus
(i) Absence status epilepticus
(ii) Atypical absence status epilepticus
(iii) Absence status epilepticus with focal features
(iv) De novo absence status epilepticus in the elderly
(b) Myoclonic absence
7. Myoclonic status epilepticus
(a) Negative myoclonic status epilepticus
8. Tonic status epilepticus
9. Subtle status epilepticus
10. Nonconvulsive status epilepticus
11. Febrile status epilepticus
The 2010 ILAE terminology excludes some terms as they may lead to confusion and were not clearly defined. Some examples of such terms are idiopathic epilepsy, symptomatic epilepsy, and complex partial seizure. These have been replaced with terms that are meant to be more clearly defined. As the newer terms appear in the text, where there might be confusion, they will be concretely defined. In addition, the 2006 ILAE report on the classification of SE gives sparse details on some of the types of SE. When the details are so sparse as to be potentially misleading, additional details have been added, and they are identified as not appearing in the ILAE classification system.
Definition of Status Epilepticus
The definition of SE is an area of controversy. The 1993 ILAE guidelines for epidemiologic studies define SE as a seizure lasting more than 30 min or more than one epileptic seizure where function has not been regained for more than 30 min [4]. In certain animal models, 30 min is the time in which there is neuronal injury, so the 30-min time does make certain sense. Unfortunately, none of the American Academy of Neurology Class I trials on SE use the 30-min criteria for defining SE. The Veterans Affairs SE Cooperative Study, for example, used 10 min as the inclusion criteria. Others have suggested other times, such as 15 min, 5 min, etc. [5]. Moreover, another study found no significant differences between episodes of SE lasting more or less than 30 min [6]. An operational SE definition has been suggested in which SE is treated as if it were SE after 5 min, even if it cannot be formally diagnosed until 30 min.
Classification Scheme
The various types of SE that are recognized in the 2006 ILAE classification are discussed in the section below. As noted above, additional information is provided to add clarity where needed.
Epilepsia Partialis Continua
Epilepsia partialis continua (EPC) is a combination of focal seizures with ongoing twitching. The site of twitching represents the area of the motor cortex from where the seizure originates. There are three subtypes of EPC.
Rasmussen Syndrome
EPC with Rasmussen syndrome has focal myoclonus and focal seizures emanating from the same hemisphere. There is variability regarding the presence of an EEG correlate of the myoclonic jerks. The jerks persist during sleep. Over time, the EEG shows progressive background slowing of the affected hemisphere.
Focal Lesions
Focal lesions such as tumors and dysplastic cortex can lead to seizures and EPC. The jerking seen with EPC affects the same area as the focal seizures, but it does not persist in sleep. There is often an EEG correlate. It can last for days to months. This type of EPC is also seen with nonketotic hyperglycemia.
Inborn Errors of Metabolism
EPC with inborn errors of metabolism have uni- or bilateral rhythmic jerks that persist in sleep, and they typically have an EEG correlate. These inborn errors of metabolism are the ones affecting energy metabolism, like myoclonic epilepsy with ragged red fibers (MERRF) or Alpers syndrome.
Supplementary Motor Area
With Preserved Consciousness
In this type of supplementary motor area (SMA) SE, there are recurrent focal tonic seizures with preserved consciousness. The individual tonic seizures occur every few minutes during wakefulness and sleep.
With Impaired Consciousness
SMA SE can also result in secondarily generalized, bilateral, convulsive seizures. These can become repetitive asymmetric, tonic motor seizures with impairment of consciousness.
Aura Continua
Aura continua is an episode with symptoms that depend on localization wax and wane, often for hours, without impairment of consciousness. A full seizure with alteration of consciousness does not occur. Symptoms may include a motor component, dysesthesia, painful sensations, or visual changes. Perhaps the most common form is limbic aura continua, which may include fear, epigastric rising sensation, or other limbic features that recur every few minutes for hours or longer. EEG correlation is variable.
Dyscognitive Focal
Dyscognitive focal SE has recurrent focal seizures with impairment of consciousness or awareness leading to SE. There are two types.
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