Transient abnormalities on magnetic resonance imaging after partial status epilepticus

We report two patients who developed focal abnormalities on MRI after partial status epilepticus.Maximum radiological modification occurred in the area of maximal epileptic discharge. Subsequent MRI failed to demonstrate persistent abnormalities.These transient abnormalities on MRI could be an expression of cerebral edema caused by focal epileptic status.

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Sommario Riportiamo due casi che hanno sviluppato anomalie transitorie alla RMN dopo stato di male parziale non convulsivo. La massima modificazione radiologica si è verificata in corrispondenza della zona di maggior attività critica. Le RMN eseguite successivamente sono risultate negative. La transitorietà delle alterazioni è probabilmente da interpretare sulla base di un edema critico. Alterazioni di neuroimaging possono essere quindi una conseguenza piuttosto che una lesione causale dello stato di male.

     

Transient and permanent magnetic resonance imaging abnormalities after complex partial status epilepticus

Epileptic seizures, especially status epilepticus can produce MRI changes. In contrast to convulsive status epilepticus (CSE), permanent parenchymal loss is not well documented with nonconvulsive status epilepticus (NCSE) and the observed MRI changes are transient. We describe a patient with non-lesional right-sided temporal lobe epilepsy with complex partial seizures and repeated episodes of untreated complex partial status epilepticus (CPSE). Diffusion-weighted MRI exhibited marked and extended signal changes within the right temporal, frontal, insular and cingulate regions. The affected areas are considered propagation pathways of temporal lobe epilepsies. After admission, the patient was treated with i.v. antiepileptic drugs. Behavioral, EEG and MRI signal changes resolved. An atrophy of the right temporal lobe not seen in the pre-status MRI examinations was observed 6 weeks after the resolution of MRI hyperintensities. Prior episodes of CPSE had been correctly treated and remained without permanent brain damage. This case report is in favour of immediate and aggressive treatment of partial NCSE in order to avoid irreversible parenchymal loss.     

Diffusion-weighted magnetic resonance imaging in patients with partial status epilepticus

Purpose:   Diffusion-weighted magnetic resonance imaging (DWI) is used to detect changes in the distribution of water molecules in regions affected by various pathologies. Like other conditions, ictal epileptic activity, such as status epilepticus (SE), can cause regional vasogenic/cytotoxic edema that reflects hemodynamic and metabolic changes. This study describes the electroclinical and neuroimaging findings in 10 patients with partial SE whose DWI evaluation disclosed periictal changes related to sustained epileptic activity.
Patients and Methods:   In this retrospective study we selected 10 patients with partial SE of different etiologies (six acute symptomatic SE; four with previous epilepsy and concomitant precipitating factors) who underwent video-EEG (electroencephalography) monitoring and a DWI study during the periictal phase. We analyzed ictal electroclinical features and DWI changes in the acute phase and during the follow-up period.
Results:   DWI images revealed significant signal alterations in different brain regions depending on the location of ictal activity. DWI changes were highly concordant with the electroclinical findings in all 10 patients. As the SE resolved and the clinical conditions improved, DWI follow-up showed that the signal alterations gradually disappeared, thereby documenting their close relationship with ictal activity.
Conclusions:   This study confirms the usefulness of DWI imaging in clinical practice for a more accurate definition of the hemodynamic/metabolic changes occurring during sustained epileptic activity.     

Diffusion-weighted magnetic resonance imaging in nonconvulsive status epilepticus

BACKGROUND: In human and experimental models, diffusion-weighted magnetic resonance imaging (DWI) findings in status epilepticus (SE) have been reported to show that apparent diffusion coefficients are reduced during the initial phase and normalized or increased in the later phase of prolonged SE. This effect is caused by cytotoxic edema induced by excitotoxicity. In humans, only focal DWI abnormalities have been reported in partial SE. OBJECTIVES: To report and discuss the DWI findings suggesting diffuse neuronal injury in a patient with nonconvulsive SE. DESIGN AND METHODS: A 56-year-old man was admitted because of changing levels of consciousness over 3 days. On admission he was comatose. He had nystagmoid eye movement, forced eye blinking, and oroalimentary automatism. The results of a search for possible infectious and metabolic etiologies were negative, and electroencephalographic findings showed continuous, semirhythmic, bifrontal sharp waves of 2 Hz. Phenytoin and midazolam hydrochloride were infused to alleviate the seizure activities. He underwent DWI initially (3 days after the onset of seizure) and at the 5-month follow-up. SETTING: The neurology department of a tertiary referral center. RESULTS: During SE, DWI findings showed marked, diffuse gyriform cortical hyperintensity throughout the brain. The apparent diffusion coefficient decreased in the corresponding areas, especially in the occipital lobes. Findings from T2-weighted magnetic resonance imaging showed the intense cortical hyperintensity with gyral swelling and no involvement of brainstem, basal ganglia, thalamus, and white matter. The follow-up DWI findings showed marked atrophy and hypointensity in the corresponding regions. The apparent diffusion coefficient increased in the corresponding regions. CONCLUSIONS: Diffusion-weighted imaging in our patient indicated that the magnetic resonance imaging abnormalities of the affected cortex were due to cytotoxic edema caused by neuronal excitotoxicity during prolonged SE. Diffusion-weighted imaging can be used in the localization of seizure focus for predicting the prognosis of the affected tissue and for researching the basic pathophysiology of SE.     

Transient abnormalities associated with status epilepticus on diffusion-weighted MR imaging]

We report on two patients with transient abnormalities on MRI during status epilepticus(SE). Diffusion-weighted MR imaging(DWI) and T2-weighted and fluid-attenuated inversion recovery (FLAIR) MR images showed cortical and thalamic hyperintensity with swelling of the cortex. The lesions did not respect vascular territories. We also observed an increased signal in the ipsilateral middle cerebral artery on magnetic resonance angiography(MRA), and leptomeningeal enhancement on postcontrast MRI. Follow-up imaging revealed that the abnormal findings resolved within a few weeks, although a residual area of increased T2 signal intensity persisted. These findings suggest the presence of reversible cytotoxic and vasogenic edema induced by seizure. We conclude that this disorder should be taken into consideration in the differential diagnosis of other conditions, including ischemic stroke.     

MRI abnormalities associated with partial status epilepticus

OBJECTIVE: To report neuroimaging findings in patients with complex partial status epilepticus. BACKGROUND: During status epilepticus, neuroimaging may be used to exclude other neurologic conditions. Therefore, it is important to identify the neuroimaging features that are associated with status epilepticus. In addition, MRI characteristics may provide insight into the pathophysiologic changes during status epilepticus. METHODS: The history and neuroimaging examination results of three patients with complex partial status epilepticus were reviewed. Studies obtained during status epilepticus included diffusion-weighted MRI (DWI), MR angiography (MRA), postcontrast T1-weighted MRI, T2-weighted MRI, and CT. Follow-up MRI was obtained in two patients, and autopsy results were available for the third. RESULTS: Some of the MRI and CT findings during partial status epilepticus mimicked those of acute ischemic stroke: DWI and T2-weighted MRI showed cortical hyperintensity with a corresponding low apparent diffusion coefficient, and CT showed an area of decreased attenuation with effacement of sulci and loss of gray-white differentiation. However, the lesions did not respect vascular territories, there was increased signal of the ipsilateral middle cerebral artery on MRA, and leptomeningeal enhancement appeared on postcontrast MRI. On follow-up imaging, the abnormalities had resolved, but some cerebral atrophy was present. CONCLUSIONS: The radiologic characteristics of status epilepticus resemble those of ischemic stroke but can be differentiated based on lesion location and findings on MRA and postcontrast MRI. The MRI abnormalities indicated the presence of cytotoxic and vasogenic edema, hyperperfusion of the epileptic region, and alteration of the leptomeningeal blood-brain barrier. These changes reversed, but they resulted in some regional brain atrophy.     

Structural consequences of status epilepticus demonstrated with serial magnetic resonance imaging

Objectives - To investigate MRI changes during tonicclonic and focal motor status epilepticus. Material and methods - Serial MRI-investigations with saggital, coronal and axial spin-echo (SE) T₁ weighted 500/15 (repetition time [TR] msec/echo time [TE] msec) with and without application of gadolinium-DTPA, proton-density-SE 2100/30 and SE T₂-weighted 2100/90 images. Correlation with seizure frequency and general clinical state and by using constant EEG recordings as well as video-EEG monitoring. Results - Initially, images were normal but several days after onset of status epilepticus focal hyperintensive signal changes on T₂-weighted images consistent with focal oedema were seen. The oedema produced a local mass effect as demonstrated with angiography. These changes occurred at a time when there were massive epileptic discharges registered by EEG monitoring in both cases. On subsequent images the oedema resolved but atrophy in combination with a high signal on T₂-weighted images suggestive of gliosis were noted in identical regions. In the 1st case it could not completely be ruled out that the signal changes were caused by an encephalitis. However, the signal changes occurred in close time correlation with the epileptic seizure activity rendering the assumption less likely that the signal changes were caused by the encephalitis. In the 2nd case the signal changes could not be attributed to cortical dysplasia or any other condition than the epileptic activity itself. Conclusion - Prolonged epileptic seizure activity may cause neuronal damage associated with a typical pattern of MRI signal changes.     

Transient Kluver-Bucy syndrome following complex partial status epilepticus

The characteristic features of Kluver-Bucy syndrome include hypersexuality, hyperorality, placidity, hypermetamorphosis, visual agnosia, changes in dietary habits, and memory impairment. Human cases have been reported with herpes simplex encephalitis, head injury, Pick's disease, transtentorial herniation, adrenoleukodystrophy, and Reye's syndrome, all involving bilateral temporal lobe pathology. We present the case of a patient with no evidence of a structural lesion in the temporal lobes and behavioral changes consistent with Kluver-Bucy syndrome following complex partial status epilepticus.     

Periictal diffusion abnormalities of the thalamus in partial status epilepticus

Purpose:   To identify and describe thalamic dysfunction in patients with temporal as well as extratemporal status epilepticus (SE) and to also analyze the specific clinical, radiological, and electroencephalography (EEG) characteristics of patients with acute thalamic involvement.
Methods:   We retrospectively identified patients who presented with clinical and electrographic evidence of partial SE and had thalamic abnormalities on diffusion-weighted imaging (DWI) within 5  days of documentation of lateralized epileptiform discharges (group 1). The spatial and temporal characteristics of the periodic lateralized epileptiform discharges (PLEDs) and the recorded electrographic seizures were analyzed and correlated with magnetic resonance imaging (MRI)-DWI hyperintense lesions. The findings of group 1 patients were compared with those of patients with partial SE without thalamic abnormalities on DWI (group 2).
Results:   The two groups were similar with regard to clinical presentation and morphology of epileptiform discharges. Group 1 patients had thalamic hyperintense lesions on DWI that appeared in the region of the pulvinar nucleus, ipsilateral to the epileptiform activity. Statistically significant relationship was noted between the presence of thalamic lesions and ipsilateral cortical laminar involvement (p = 0.039) as well as seizure origin in the posterior quadrants (p = 0.038). A trend towards PLEDs originating in the posterior quadrants was also noted (p = 0.077).
Discussion:   Thalamic DWI hyperintense lesions may be observed after prolonged partial SE and are likely the result of excessive activity in thalamic nuclei having reciprocal connections with the involved cortex. The thalamus likely participates in the evolution and propagation of partial seizures in SE.     

Retrospective inventory of EEG abnormalities in partial status epilepticus.

In this retrospective study, EEG activity in partial status epilepticus (PSE) was classified into different patterns from analysis of both ictal and interictal discharges. In 64 patients with recorded PSE, continuous seizures and closely spaced seizures interrupted by only brief flat periods were uncommon. PLEDs, defined as classic periodic lateralized epileptiform discharges, and PLEDs Plus, defined as PLEDs associated with stereotyped low amplitude, were the most common abnormalities. PLEDs and PLEDs Plus can each occur alone or sequentially (sequential PLEDs) between consecutive seizures. The quantity of ictal activity was significantly lower with PLEDs, sporadic spikes and with the absence of epileptiform abnormalities than with PLEDs Plus and sequential PLEDs. EEG monitoring is important to gauge the effectiveness of treatment, particularly in patients with patterns associated with a high incidence of seizure activity, namely continuous seizures with or without flat periods, sequential PLEDs and PLEDs Plus. From serial recordings, a sequence was reconstructed which may be relied upon to further assess the need for additional energetic therapeutic measures. The reconstructed sequence differed in patients with chronic lesions since sequential PLEDs and PLEDs Plus were identified exclusively in patients with acute or subacute lesions.     

Palatal myoclonus occurring during complex partial status epilepticus

Summary Palatal myoclonus is thought to occur after damage to certain brain-stem structures, and with a delay following the causative lesion. A case of palatal myoclonus, probably of epileptic nature, is described.     

Nonconvulsive status epilepticus in patients with cancer: imaging abnormalities

BACKGROUND: Convulsive status epilepticus may cause reversible neuroimaging abnormalities. These cortical changes have been reported rarely in association with nonconvulsive status epilepticus. OBJECTIVE: To describe patients with cancer who had reversible magnetic resonance (MR) imaging abnormalities from nonconvulsive status epilepticus and whose altered mental status and MR imaging findings were initially considered to result from a structural lesion related to their underlying tumor. DESIGN: Retrospective study. SETTING: Department of Neurology at Memorial Sloan-Kettering Cancer Center, New York, NY. PATIENTS: Eight patients with a diagnosis of nonconvulsive status epilepticus who underwent MR imaging. RESULTS: Enhancing cortical abnormalities were observed on MR images in 4 (50%) of 8 patients with cancer who had impaired mental status and an electroencephalogram demonstrating seizure activity. Follow-up MR images showed neuroimaging improvement or resolution in all patients. CONCLUSIONS: Cortical enhancement on MR images in patients with cancer who have altered mental status may be due to nonconvulsive status epilepticus and not recurrent or metastatic tumor. If electroencephalography is not immediately available at initial evaluation, a trial of anticonvulsant therapy deserves consideration.     

The role of magnetic resonance imaging in the follow-up of children with convulsive status epilepticus

Aim The aim of this study was to determine the yield of magnetic resonance imaging (MRI) after an episode of childhood convulsive status epilepticus (CSE) and to identify the clinical predictors of an abnormal brain scan. Method Children were recruited following an episode of CSE from an established clinical network in north London. Eighty children (age range 1mo–16y; 39 males; 41 females) were enrolled and seen for clinical assessment and brain MRI within 13 weeks of suffering from an episode of CSE. Scans were reviewed by two neuroradiologists and classified as normal (normal/normal‐variant) or abnormal (minor/major abnormality). Factors predictive of an abnormal scan were investigated using logistic regression. Results Eighty children were recruited at a mean of 31.8 days (5–90d) after suffering from CSE. Structural abnormalities were found in 31%. Abnormal neurological examination at assessment (odds ratio [OR] 190.46), CSE that was not a prolonged febrile seizure (OR 77.12), and a continuous rather than an intermittent seizure (OR 29.98) were all predictive of an abnormal scan. No children with previous neuroimaging had new findings that altered their clinical management. Interpretation Brain MRI should be considered for all children with a history of CSE who have not previously undergone MRI, especially those with non‐prolonged febrile seizure CSE, those with persisting neurological abnormalities 2 to 13 weeks after CSE, and those with continuous CSE.