How are nonepileptic seizures differentiated from status epilepticus (SE)?

Updated: Feb 13, 2018
  • Author: Julie L Roth, MD; Chief Editor: Stephen A Berman, MD, PhD, MBA  more...
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Answer

Recognition of status epilepticus (SE) may be easy or difficult. SE in the patient with sequential, generalized major motor convulsions is obvious; the patient with nonconvulsive or subtle SE presents a diagnostic dilemma.

Nonepileptic seizures (NES), formerly called psychogenic seizures, may at times be indistinguishable from generalized convulsive SE. The risk in such cases is that the physician may immediately assume that a neurologic emergency was present and embark on an aggressive course of pharmacotherapy, neglecting physical examination and historical information. [54] A brief period of observation for atypical features (see Physical Examination) may lead to the conclusion that the patient has nonepileptic seizures and does not need anticonvulsant therapy.

In one study, unresponsiveness without movement was the most common presentation of psychogenic SE. [54] Other reviews of psychogenic SE note other frequently seen presentations, including asynchronous extremity movement, forward pelvic thrusting, and geotropic eye movements (a physical finding that indicates the eyes deviating toward the ground in a nonphysiologic manner whether the head is turned left or right). [55]

A retrospective study from one institution noted that patients with psychogenic nonepileptic SE were younger, had implanted port devices for intravenous medication administration, had lower creatine kinase levels, and received higher doses of benzodiazepines compared with patients with generalized convulsive SE epilepticus. [56]

NES is associated with several behavioral characteristics that help distinguish it from a nonepileptic event. Motor activity during an NES often is punctuated by brief periods of rest, whereas epileptic convulsions are usually sustained without pause until the end of each individual seizure.

When seizure activity spreads during an epileptic seizure, it usually follows the organization of the homunculus. NES may fail to show this stereotypical and predictable evolution of behavior.

Behaviors such as pelvic thrusting, head turning from side to side, and bizarre vocalizations are usually not seen in epileptic seizures. The exception to this rule is seizure of frontal-lobe onset.

Although clinical features are usually helpful, the ultimate test to differentiate between epileptic seizures and NES is EEG.


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