Status epilepticus: patients may have no clinical signs.

Clinical bottom line (level 5)

Mortality rate in adults with status epilepticus was approximately 20%.
Some patients with status epilepticus may have no clinical signs.
Patients with acute causes have a worse prognosis. Myoclonic status epilepticus after hypoxia carries an especially bad prognosis.

Lowenstein and Alldredge: New England Journal of Medicine 1998; 338 (14): 970-976

Expires December 2003

The study

Case series with ?objective ?blinded outcomes, not adjusted for confounding factors, not validated in an independent set of patients.

Setting: narrative review of the evidence (used mainly as a bibliographic resource).

0 patients status epilepticus, defined as a seizure that persists for a sufficient length of time or is repeated frequently enough that recovery between attacks does not occur.

Outcomes studied:

The study is a review article of some of the available data.

The evidence

Frequency of status epilepticus in the US is approximately 102,000 to 152,000 per year.
Overall mortality rate among adults is approximately 20%, and patients who have a first episode are at substantial risk for future episodes and the development of chronic epilepsy.
clinical features:
- when first seen: unresponsive and usually have clinically obvious seizures, such as tonic, clonic, or tonic-clonic movements of the extremities
- after some time: clinical manifestations become subtle. Patients only have small-amplitude twitching movements of face, hands or feet, nystagmoid jerking of the eyes.
- some patients have no observable, repetitive motor activity, and the detection of ongoing seizures requires EEG
Acute processes that cause status epilepticus include metabolic disturbances, CNS infection, stroke, head trauma, drug toxicity and hypoxia. Seizures in this category are often difficult to control and are associated with a higher mortality, especially those occurring after hypoxia and in older patients.
Myoclonic status epilepticus after hypoxia carries an especially bad prognosis.
Chronic processes that cause status epilepticus include preexisting epilepsy in which status epilepticus is due to breakthrough seizures or the discontinuation of antiepileptic drugs, seizures in the context of chronic ethanol abuse, and remote processes such as CNS tumours or strokes that lead to status after a latent period that may span weeks to years. Generally, patients with chronic processes respond well to treatment.

Citation

Lowenstein DH, and Alldredge BK: Status epilepticus. New England Journal of Medicine 1998; 338 (14): 970-976

Contributor: Clare Wotton, December 2000
Reviewer: Bob Phillips

_{Clinical Question.}

_Patient	_{status epilepticus}
_{Intervention or Exposure}
_Outcome	_{causes, outcomes, therapy}