Status Epilepticus: increased mortality with seizures lasting > 1 hour or anoxia.

Clinical bottom line (level 2b)

  1. Few patients with status epilepticus died.
  2. Patients were at increased risk if
    • Seizures lasted > 1 hour (NNH = 7 at 1 months)
    • The patient was anoxic (NNH = 20 at 1 months)
    • The patient was older (NNH = 130 at 1 months)
  3. The commonest causes of status epilepticus were failure to take any-epilepsy medication, stroke and alcohol withdrawal.
Towne et al: Epilepsia 1994; 35 (1): 27-34
Expires September 2003

The study

Retrospective cohort study with objective outcomes, adjusted for confounding factors, not validated in an independent set of patients.

Setting: University Hospital, USA 1982-1986

253 patients (aged 16 to 96, mean 57, 57% male) status epilepticus defined as
  • seizure lasting at least 30 minutes, or
  • intermittent seizures > 30 minutes from which patient did not regain consciousness


Excluded if
  • age < 16


    • Cases: 5 patients (58% male, mean age 57): died
    Controls: 248 patients (58% male, mean age 57): recovered


    Outcomes studied:
  • mortality

    • patients were identified using a computerised discharge database, reviewing emergency department records and all EEG reports during the study period.

    The evidence

    Patient expected event rate for mortality: 2.0%
    risk factor for
    mortality     		adjusted OR
    (95% CI)    		 NNH
    (95% CI)
    Seizure duration > 1 hour 9.97
    (2.14 to 44.9)     		7
    (2 to 46)
    Anoxia 3.66
    (1.47 to 9.09)     		20
    (7 to 110)
    Age (% 10) 1.39
    (65 to 860)     		130
    (65 to 860)

    • Aetiology of risk factors
      • Stopped anti-epileptic medication 22.5 %
      • Stroke 22.5 %
      • Alcohol withdrawal 14.2 %
      • anoxia 11.9 %
      • metabolism 11.5 %
      • Haemorrhage 5.1 %
      • Infection 5.1 %
      • Tumour 4.4 %
      • Trauma 4.0 %
      • Drugs 2.4 %

    Citation

    1. Towne AR, Pellock JM, Ko D, et al: Determiners of mortality is status epilepticus. Epilepsia 1994; 35 (1): 27-34
    Contributor: Chris Ball and Musab Hayatli, October 2000
    Reviewer:

    Clinical Question.
    Patient status epilepticus
    Intervention or Exposure poor prognostic factors
    Outcome mortality