Poststroke seizures as stroke mimics: Clinical assessment and management

Diagnosis and Treatment of Poststroke Epilepsy: Where Do We Stand?

Purpose of Review

Stroke is the most common cause of seizures and epilepsy in older adults. This educational paper aims to give an update on current clinical aspects of diagnosis and treatment of poststroke epilepsy.

Recent Findings

Regarding epileptic seizures related to stroke, it is important to distinguish between acute symptomatic seizures and unprovoked seizures as they differ in their risk for seizure recurrence. In fact, after a single unprovoked poststroke seizure, a diagnosis of epilepsy can be made because there is a greater than 60% risk for further seizures. Clinical models that can predict the development of epilepsy after a stroke have been successfully established. However, treatment with anti-seizure medications is advised only after a first unprovoked poststroke seizure, as current treatments are not known to be effective for primary prevention. The management of poststroke epilepsy requires consideration of aspects such as age, drug-drug interactions and secondary vascular prophylaxis, yet evidence for the use of anti-seizure medications specifically in poststroke epilepsy is limited.

Summary

This text reviews the epidemiology and risk factors for poststroke epilepsy, explains the role of EEG and neuroimaging in patients with stroke and seizures and provides an overview on the clinical management of stroke-related acute symptomatic seizures and poststroke epilepsy.

Stroke mimics: incidence, aetiology, clinical features and treatment

Mimics account for almost half of hospital admissions for suspected stroke. Stroke mimics may present as a functional (conversion) disorder or may be part of the symptomatology of a neurological or medical disorder. While many underlying conditions can be recognized rapidly by careful assessment, a significant proportion of patients unfortunately still receive thrombolysis and admission to a high-intensity stroke unit with inherent risks and unnecessary costs. Accurate diagnosis is important as recurrent presentations may be common in many disorders. A non-contrast CT is not sufficient to make a diagnosis of acute stroke as the test may be normal very early following an acute stroke. Multi-modal CT or magnetic resonance imaging (MRI) may be helpful to confirm an acute ischaemic stroke and are necessary if stroke mimics are suspected. Treatment in neurological and medical mimics results in prompt resolution of the symptoms. Treatment of functional disorders can be challenging and is often incomplete and requires early psychiatric intervention.

Microvascular changes associated with epilepsy: A narrative review

The blood-brain barrier (BBB) is dysfunctional in temporal lobe epilepsy (TLE). In this regard, microvascular changes are likely present. The aim of this review is to provide an overview of the current knowledge on microvascular changes in epilepsy, and includes clinical and preclinical evidence of seizure induced angiogenesis, barriergenesis and microcirculatory alterations. Anatomical studies show increased microvascular density in the hippocampus, amygdala, and neocortex accompanied by BBB leakage in various rodent epilepsy models. In human TLE, a decrease in afferent vessels, morphologically abnormal vessels, and an increase in endothelial basement membranes have been observed. Both clinical and experimental evidence suggests that basement membrane changes, such as string vessels and protrusions, indicate and visualize a misbalance between endothelial cell proliferation and barriergenesis. Vascular endothelial growth factor (VEGF) appears to play a crucial role. Following an altered vascular anatomy, its physiological functioning is affected as expressed by neurovascular decoupling that subsequently leads to hypoperfusion, disrupted parenchymal homeostasis and potentially to seizures". Thus, epilepsy might be a condition characterized by disturbed cerebral microvasculature in which VEGF plays a pivotal role. Additional physiological data from patients is however required to validate findings from models and histological studies on patient biopsies.

Post-Traumatic Status Epilepticus Masquerading as Acute Ischemic Stroke: A Case Report and Literature Review

Patient: Male, 7-year-old

Final Diagnosis: Status epilepticus

Symptoms: Local sezure

Medication: —

Clinical Procedure: Computed tomography • magnetic resonance imaging

Specialty: Neurosurgery

Status epilepticus mimicking stroke recurrence

AIM OF THE STUDY

The aim of the study was to evaluate the clinical characteristics of patients with previous stroke (either ischemic or hemorrhagic), who developed status epilepticus (SE) mimicking a stroke relapse.

MATERIALS AND METHODS

We performed a retrospective cohort study of patients brought to hospital by the emergency service between December 2016 and January 2018 with a stroke code as possible candidates for intravenous thrombolysis and who had already have a previous stroke. Among them, patients admitted for negative symptoms and finally discharged with a diagnosis of SE mimicking stroke were selected and their clinical characteristics collected. All patients underwent routine blood sample analysis, head computed tomography (CT) scan and, when indicated, CT angiography and CT-perfusion imaging of the head. After admission in our stroke unit, an Electroencephalogram (EEG) was performed within 3 h in patients suspected with SE, then classified according to International League Against Epilepsy (ILAE) classification (2015). Outcome measures were SE duration, antiepileptic drugs (AEDs) administered, mortality at 12 months, Engel scale, and modified Rankin scale (m-RS) at 6 months. A second cohort included those consecutive patients discharged with a true stroke relapse in the same considered time span. Clinical characteristics of these two cohorts were compared using Mann-Whitney test or Student t-test (Confidence Interval (C.I.) 95%, p < 0.05) for continuous variable and Fisher exact test or Pearson-Chi test for dichotomic variables (p < 0.05). Survival rates were calculated, and a Log-Rank test was performed to evaluate differences in survival distribution. Only in the group with SE, m-RS at 6 months and recurrence of SE were also evaluated.

RESULTS

Eleven patients were discharged with a diagnosis of SE mimicking stroke and 65 patients with stroke relapse. Temporal lobe localization was significantly more represented in group with SE (p = 0.036) while there was no difference regarding age, sex, and National Institutes of Health Stroke Scale (NIHSS). The m-RS was significantly higher in patients with hemorrhage relapse, mainly due to the high incidence of amyloid angiopathy in this subgroup. Status epilepticus recurred in 36.4% of patients, presenting with the same clinical features, and most patients (62.5%) achieved a good seizure control at 6 months (Engel scale = 1). A difference in mortality at 12 months (all cause considered) appeared only when distinguishing strokes between ischemic and hemorrhagic (Chi-Square: 10.711, p < 0.005).

DISCUSSION AND CONCLUSION

Status epilepticus is not infrequent in patients with previous stroke and may present with negative neurological symptoms, thus mimicking a stroke recurrence. EEG should be considered as a potential diagnostic tool in the acute stroke setting, at least in patients with previous stroke. This article is part of the Special Issue "Seizures & Stroke".