Diffusion-weighted magnetic resonance imaging in nonconvulsive status epilepticus

Background: In human and experimental models, diffusion-weighted magnetic r esonance imaging (DWI) findings in status epilepticus (SE) have been report ed to show that apparent diffusion coefficients are reduced during the init ial phase and normalized or increased in the later phase of prolonged SE. T his effect is caused by cytotoxic edema induced by excitotoxicity. In human s, only focal DWI abnormalities have been reported in partial SE. Objectives: To report and discuss the DWI findings suggesting diffuse neuro nal injury in a patient with nonconvulsive SE. Design and Methods: A 56-year-old man was admitted because of changing leve ls of consciousness over 3 days. On admission he was comatose. He had nysta gmoid eye movement, forced eye blinking, and oroalimentary automatism. The results of a search for possible infectious and metabolic etiologies were n egative, and electroencephalographic findings showed continuous, semirhythm ic, bifrontal sharp waves of 2 Hz. Phenytoin and midazolam hydrochloride we re infused to alleviate the seizure activities. HE underwent DWI initially (3 days alter 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 h yperintensity throughout the brain. The apparent diffusion coefficient decr eased in the corresponding areas, especially in the occipital lobes. Findin gs from T2-weighted magnetic resonance imaging showed the intense cortical hyperintensity with gyral swelling and no involvement of brainstem, basal g anglia, thalamus, and white matter. The follow-up DWI findings showed marke d atrophy and hypointensity in the corresponding regions. The apparent diff usion coefficient increased in the corresponding regions. Conclusions: Diffusion-weighted imaging in our patient indicated that the m agnetic resonance imaging abnormalities of the affected cortex were due to cytotoxic edema caused by neuronal excitotoxicity during prolonged SE. Diff usion-weighted imaging can be used in the localization of seizure focus for predicting the prognosis of the affected tissue and for researching the ba sic pathophysiology of SE.