Transient Focal Abnormalities of Neuroimaging Studies During Focal Status Epilepticus

Abstract

We report transient changes in computed tomography (CT) and magnetic resonance imaging (MRI) scans in a patient with focal status epilepticus, referred to us with a tentative diagnosis of neoplasm based on CT and angiographic findings. EEG seizures originated independently from each temporal-occipital area, predominantly from the right. Previous EEGs had shown almost exclusively right temporo-occipital epileptogenic activity. MRI showed increased signal intensity, and CT showed decreased right hemisphere attenuation without enhancement. One month later, there was resolution of the radiological and clinical abnormalities. The transient CT and MRI changes probably represented focal cerebral edema, developing during focal status epilepticus. Lack of change in the left hemisphere probably reflected the quantitative difference in epileptic activity. Clues to the diagnosis of focal edema due to status include: (1) changes on electrical and imaging studies that correlate anatomically with the clinical status, and (2) resolution of abnormalities with appropriate seizure control. In patients with suspected seizure disorders, electrical and clinical data should be correlated before interpretation is made of focal lesions seen by neuroimaging techniques.

Delayed, Transient Neurological Deterioration After Mild Head Injury. Case Report.

“…Increased oxygen consumption in the cortical epileptogenic zone and the resulting hypoxia are assumed to lead to an accumulation of CO 2 and lactic acid, which in turn causes vasodilation, loss of autoregulation, and increased cerebral blood flow. 13,17) Such neuroradiological findings mentioned above were similar to those of the present case, but no EEG findings to support the diagnosis of epilepsy were obtained. EEG findings of status epilepticus may be normal when the epileptic focus is small 11) or deep in the brain structure.…”

“…11,16,32) Neuroimaging signs of transient abnormalities in patients with status epilepticus characteristically involve a focal area either in the white matter or in the combined white and gray matter, appearing as low density areas by CT, and as decreased signal intensity on T 1 -weighted images and/or increased signal intensity on T 2 -weighted ones by MR imaging, without a mass effect. 9,13,31) Such changes are thought to be due to vasogenic edema induced by hyperemia. Increased oxygen consumption in the cortical epileptogenic zone and the resulting hypoxia are assumed to lead to an accumulation of CO 2 and lactic acid, which in turn causes vasodilation, loss of autoregulation, and increased cerebral blood flow.…”

“…7,8,25,27,29) Post-traumatic hyperemia can be divided into malignant and benign types depending on the association with intracranial hypertension. 4,[12][13][14][15]19,23,26,27) Analysis of intracranial pressure and cerebral blood flow in 59 patients with moderate or severe head injuries showed that the median duration of hyperemia associated with intracranial hypertension was longer (median 6 days, range 1-14 days) than that of hyperemia without intracranial hypertension (median 2.5 days, range 0-5 days). 12) Our findings indicate that certain cases of mild head injury may represent a more delayed or prolonged hyperemia phase linked to a favorable outcome.…”

Magnetic Resonance Imaging in the Study of the Lithium–Pilocarpine Model of Temporal Lobe Epilepsy in Adult Rats

“…Many observations in epilepsy patients (19)(20)(21)(22)(23)(24), confirmed by animal studies (25)(26)(27)(28), demonstrated that SE provokes transient BBB breakdown and vasogenic edema in the area of the seizure focus. It is commonly proposed that local (relative hypoxia secondary to increased ictal metabolism with an increase in local PCO 2 and lactate) and systemic (increase in blood pressure and decrease in blood pH) physiologic changes induce a vasodilatation, resulting in increased regional blood flow and BBB breakdown (25,26,29).…”

Hippocampal sclerosis and status epilepticus: cause or consequence? A MRI study

“…The above-mentioned metabolic phenomena are proportional to the frequency and duration of the seizures 1,11,12 . They determine a transitory alteration of the BBB, an increased of vascular permeability and the subsequent appearance of cerebral edema.…”