Stroke: anterior hemisphere infarcts increased the risk of early seizure.

Clinical bottom line (level 4)

  1. A sixteenth of patients with a first cerebral infarction had early seizures.
  2. Patients were at an increased risk of early seizure after first cerebral infarction if their infarct was in the anterior hemisphere.
  3. A sixteenth of patients with first cerebral infarction had late seizures within 5.5 years.
  4. Patients were at an increased risk of late seizures/epilepsy if they had an early seizure or recurrent stroke.
So et al: Neurology 1996; 46: 350-355
Expires December 2002

The study

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

Setting: population-based, USA

535 patients (aged range 8 to 99 years; mean 71, 52% male) first cerebral infarction occurring while residing in the community between 1960 and 1969

Excluded if
  • prior history of haemorrhagic stroke
  • prior history of unprovoked seizures



    • Factors studied:
  • early seizures, initial late seizures and epilepsy
  • anterior hemisphere location of infarct
  • early seizure
  • recurrent stroke
  • early seizure
  • recurrent stroke




    • Multivariate analysis was used to adjust for confounding factors.

    100% followed for mean 5.5 years
    Outcomes studied:
  • early seizures occurring within one week after cerebral infarction and were considered to be acutely provoked by stroke events
  • initial late seizures developed > one week after infarction
  • epilepsy as defined by the ILAE

    • The evidence

    outcome time to outcome number of patients/total number %
    (95% CI)
    early seizures mean 5.5 years 33/535 6.17%
    (4.13% to 8.21%)
    initial late seizures mean 5.5 years 27/436 6.19%
    (3.93% to 8.46%)
    epilepsy mean 5.5 years 18/436 4.13%
    (2.26% to 6.00%)

    prognostic factor for
    early seizures     		time to outcome control rate (%) adjusted OR
    (95% CI)    		 NNF+
    (95% CI)
    anterior hemisphere location of infarct 5.5 years 3/147
    (2.04%)     		4.00
    (1.20 to 13.7)     		18
    (5 to 251)

    prognostic factor for
    initial late seizures     		time to outcome control rate (%) adjusted OR
    (95% CI)
    early seizure ? 7.80
    (2.80 to 21.7)
    recurrent stroke ? 3.10
    (1.20 to 8.30)

    prognostic factor for
    epilepsy     		time to outcome control rate (%) adjusted OR
    (95% CI)
    early seizure ? 16.4
    (5.50 to 49.2)
    recurrent stroke ? 3.50
    (1.20 to 10.5)

    Comments

    1. Control rates were not given for initial late seizure and epilepsy factors, so NNF+ could not be calculated.

    Citation

    1. So EL, Annegers JF, Hauser WA, et al: Population-based study of seizure disorders after cerebral infarction. Neurology 1996; 46: 350-355
    Contributor: Clare Wotton and Bob Phillips, December 1999
    Reviewer: Martin Mueller

    Clinical Question.
    Patient cerebral infarction
    Intervention or Exposure presence of prognostic factors
    Comparison absence of prognostic factors
    Outcome risk of seizure disorders