Lateralized Periodic Discharges in a Patient With Dural Arteriovenous Fistula: SPECT and DWI Studies Suggest They are Ictal

Abstract

Lateralized periodic discharges (LPDs) are unilateral electroencephalography (EEG) waveforms, recurring at regular intervals. There has been a long-lasting debate about whether they represent ictal or interictal phenomena. Very few patients in the literature have been investigated with multimodal functional imaging techniques. Here, we present a 58-year-old male patient with symptomatic epilepsy who had cerebral venous sinus thrombosis in the right temporo-parietal area and dural arteriovenous fistula (dAVF) over the left fronto-parietal region. He developed acute speech disturbances and altered mental status after a generalized tonic–clonic seizure. Video-EEG monitoring (VEEGM) demonstrated LPDs over the left fronto-central area, overlapping in part with the dAVF. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) sequences revealed restricted diffusion compatible with cytotoxic edema, whereas single-photon emission computed tomography (SPECT) indicated hyperperfusion in the same region, leading to the conclusion that he was having possible nonconvulsive status epilepticus (NCSE). An increase in antiseizure medications led to gradual improvement in clinical status and the disappearance of LPDs.

Dural arteriovenous fistula presenting with recurrent focal status epilepticus and lateralised periodic epileptiform discharges

“…We searched online databases including MEDLINE and Google Scholar using the search terms “dural arteriovenous fistula” (or AVF) AND “status epilepticus”, “dural arteriovenous fistula” (or AVF) AND “lateralized periodic discharges” (or LPD) and “dural arteriovenous fistula” (or AVF) AND “periodic lateralized epileptiform discharges” (or PLED). Previously reported cases of dAVF with SE or LPDs or both are presented in Table 1 : there have been only a handful of cases reported of focal SE associated with dAVF [ 5 – 11 ], and of these, even fewer demonstrated LPDs on EEG [ 5 , 6 ].…”

“…Previously reported cases of dAVF with SE or LPDs or both are presented in Table 1 : there have been only a handful of cases reported of focal SE associated with dAVF [ 5 – 11 ], and of these, even fewer demonstrated LPDs on EEG [ 5 , 6 ].…”

“…Early dAVF treatment, particularly in aggressive cases, was important in achieving seizure freedom [ 14 ]. The patients in the table reported by Yanagihara [ 10 ], Tamura [ 11 ] and Dericioglu [ 6 ] demonstrated significant reversibility of grey and white matter imaging changes post-dAVF treatment and SE control, indicating that these imaging findings may be related to cytotoxic and vasogenic oedema secondary to venous hypertension, SE or both [ 6 , 9 , 10 ]. In our patient, angioembolisation of the dAVF did reduce her episodes of focal SE, but she still required anti-epileptic therapy with multiple agents to control her SE.…”

Overview of multimodal MRI of intracranial Dural arteriovenous fistulas

“…This leads to vasogenic edema, which manifests as a high T2/FLAIR signal. If venous stasis and venous reflux cannot be rectified in a timely manner, vasogenic edema in the affected area will gradually progress to cytotoxic edema, 26 , 27 resulting in a high DWI signal ( Fig. 1 ).…”

“…1 ). 26 , 27 Whether cytotoxic brain edema with hyperintensity on DWI is clinically reversible is currently unknown. Future studies should explore whether brain tissue with limited diffusion and DWI hyperintensity can be restored to normal levels.…”