Elsevier

World Neurosurgery

Volume 112, April 2018, Pages e385-e392
World Neurosurgery

Original Article
Seizures After Intracerebral Hemorrhage: Incidence, Risk Factors, and Impact on Mortality and Morbidity

https://doi.org/10.1016/j.wneu.2018.01.052Get rights and content

Highlights

  • Intracerebral hemorrhage is a frequent cause of epilepsy.

  • Risk factors and impact on mortality/morbidity for these seizures are poorly understood.

  • Incidence of seizures after intracerebral hemorrhage in the Nationwide Inpatient Sample from 1999 to 2011 (N = 220,075) was 11.87%.

  • High van Walraven score, encephalopathy, alcohol abuse, solid tumor, and prior stroke were linked to seizure.

  • Seizures were associated with a decreased risk of in-hospital mortality/morbidity.

Objective

Spontaneous intracerebral hemorrhage (ICH) is one of the most frequent causes of epilepsy in the United States. However, reported risk factors for seizure after are inconsistent, and their impact on inpatient morbidity and mortality is unclear. We aimed to study the incidence, risk factors, and impact of seizures after ICH in a nationwide patient sample.

Methods

We queried the Nationwide Inpatient Sample for patients admitted to the hospital with a primary diagnosis of ICH between the years 1999 and 2011. Patients were subsequently dichotomized into groups of those with a diagnosis consistent with seizure and those without. Multivariate logistic regression was used to assess risk factors for seizure in this patient sample, and the association between seizures and mortality and morbidity. Logistic regression was then used for trend analysis of incidence of seizure diagnoses over time.

Results

We identified 220,075 patients admitted with a primary diagnosis of ICH. Of these, 11.87% had a diagnosis consistent with seizure. Factors associated with increased risk of seizure after ICH included higher categorical van Walraven score, encephalopathy, alcohol abuse, solid tumor, and prior stroke. Seizure was independently associated with decreased odds of morbidity (odds ratio [OR], 0.89; 95% confidence interval [CI], 0.86–0.92) and mortality (OR, 0.75; 95% CI, 0.72–0.77) in multivariate models controlling for existing comorbidities.

Conclusions

Seizures after were associated with decreased mortality and morbidity despite attempts to correct for existing comorbidities. Continuous monitoring of these patients for seizures may not be necessary in all circumstances, despite their frequency.

Introduction

Seizures secondary to stroke are thought to be one of the most common causes of epilepsy among adults, with stroke estimated to antecede 11% of all adult epilepsies,1 and 45% of epilepsies diagnosed in patients above age 60 years.2 Seizures after spontaneous intracerebral hemorrhage (ICH) have a reported global incidence of up to 33%,3 but the true incidence is still unknown because of the difficulty of detecting nonconvulsive seizures.4, 5 By some estimates, 50% of seizures after ICH are electrographic only, with limited to no convulsive behavior.3, 4 To detect these seizures, intensivists have increasingly turned to the use of continuous electroencephalography (cEEG) monitoring.6 Unfortunately, because of the resource intensity of cEEG, its use is far from universal in critically ill patients.7

Although postischemic stroke seizures have been repeatedly shown to adversely impact outcome,4, 8, 9 the evidence relating to ICH has been significantly more mixed.3, 10, 11, 12 Furthermore, the use of prophylactic anticonvulsants in this patient population is of questionable efficacy, and may be associated with poor outcome.13, 14, 15 However, the impact of seizures subsequent to ICH has yet to be evaluated in a large patient sample, or across multiple sites.

Therefore, the primary aim of this study is to evaluate the reported incidence and risk factors of seizure after ICH in a national patient sample, including an assessment of whether the incidence of seizure diagnoses has changed over time. The secondary aim of this study is to evaluate the impact of these seizures on morbidity and mortality in this patient sample. We hope that the results of this study will emphasize the need for new diagnostic and management strategies that facilitate more effective detection and treatment of seizures after ICH.

Section snippets

Methods

Our retrospective cohort analysis was conducted according to the standards and guidelines of our institution. It was institutional review board exempt because data from the Nationwide Inpatient Sample (NIS) are deidentified and publicly available.

Results

Our query of the NIS yielded 220,075 patients with a primary diagnosis of ICH between 1999 and 2011 after excluding patients with other forms of acute brain injury or ischemic stroke. Demographic and clinical characteristics of patients in this sample are presented in Table 2. Overall, 50.2% of patients in our sample were women, with a mean age of 67.6 ± 0.15 years. Of those with a reported race, 67.6% were white, 15.5% were black, 9.2% were Hispanic, 4.3% were Asian, 0.4% were Native American,

Discussion

Contrary to our expectations, this study found that seizure secondary to ICH was associated with significantly reduced odds of both mortality and morbidity. We further found that higher vWR, encephalopathy, alcohol abuse, solid tumors, and prior stroke were independently associated with increased rates of seizures after ICH. Meanwhile, age, uncomplicated diabetes mellitus, renal failure, and fluid and electrolyte disorders were associated with decreased odds of seizure. Finally, we found that

Conclusions

Seizure secondary to ICH is a relatively common and likely underdiagnosed event that may have little impact on in-hospital mortality and morbidity. Further studies are necessary to determine the role that cEEG monitoring and antiepileptic drugs should play in managing this patient population.

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    Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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