Posterior reversible encephalopathy syndrome (PRES): electroencephalographic findings and seizure patterns

Abstract

To better describe seizure type, frequency, and electroencephalographic (EEG) findings in posterior reversible encephalopathy syndrome (PRES) and correlate these data with clinical and magnetic resonance imaging (MRI) data, we retrospectively assessed medical charts and EEG studies of patients with PRES treated between 2004 and 2011. Data collected included patients' underlying pathology, lesion distribution by MRI, seizure type and frequency, EEG pathologic background activity, focal pathology, and epileptogenic activity. Thirty-eight of 49 adults with PRES suffered from seizures; 17 underwent EEG and were included in the analysis. Perpetuating factors were similar to those reported in the literature. In 15 of 17 patients, MRI showed widespread involvement rather than purely occipital lesions. Nine patients had subcortical and cortical involvement. Seizures were single short grand mal (GM) in 11, serial GM in 2, recurrent GM in 2, and additional focal seizures in 2. No seizures were noted beyond the first day. After discontinuation of antiepileptic medication, no patients experienced seizure recurrence during 6-month follow-up. EEG showed diffuse theta/delta slowing in 13 patients and epileptogenic activity with focal sharp-wave and periodic lateralizing epileptiform discharges in 2 patients. Seizures in PRES are most commonly single GM and are usually of limited duration. EEG shows variable theta/delta slowing. Focal EEG pathology is seen in patients with focal seizures. Seizures occur early after disease onset and terminate spontaneously or under therapy during the first 24 h. Seizure recurrence beyond 24 h and chronic epilepsy were not seen. Seizures in PRES are frequent but appear to be uncomplicated and do not herald worse prognosis. EEG is helpful in evaluating the degree of encephalopathy and monitoring epileptic activity. Long-term antiepileptic medication does not appear to be warranted.

Posterior reversible encephalopathy syndrome (PRES) after bevacizumab therapy for metastatic colorectal cancer

“…Seizures are the most common presenting complaint, and tonic-clonic in nature. Encephalopathy is an integral part of presentation present in about 50–80% of patients [17]. Headache is present in about 50% of patients and mostly gradual in onset and dull in character.…”

“…Antiepileptics should be tapered quickly in patients without a seizure recurrence and after resolution of MRI abnormalities. Seizures associated with PRES have a good prognosis without any long-term sequelae [17]. …”

Review Of Antiepileptic Therapy Of a Case Association With Eclampsia And PRESS

“…Özellikle uzamış parsiyel nöbetleri ve status epileptikusu olan olguların kraniyal MRG incelemelerinde geçici özellikte gölge tarzında sinyal değişiklikleri görülmüştür. [19,20] Elektroensefalografi çalışmalarında ise yaygın yavaşlama (delta ve teta) epileptik aktivite veya periyodik lateralizan epileptiform değişiklikler olduğu gösterilmiştir. [20] Bizim olgumuzun EEG'si normal sınırlar içerisinde idi.…”

“…[2,7,24] Olgularda ikinci seçenek olarak benzodiazepam kullanımı önerilmektedir. Tedavide öncelikle diazem, clonazepam ve/ veya midazolam uygulanmakta, [15] nöbeti durmayan olgularda ise intravenöz fenitoin, oral ve/veya i.v fenobarbital, [25] i.v valproat [20] infüzyonu yapılarak nöbetler kontrol altına alınmaktadır.…”

“…Tedavi sonrası hastaların 10-15 gün içerisinde çekilen kontrol EEG'leri genellikle normal bulunmuştur. [20] Status epileptikus oldukça nadir görülen bir tablodur. [17] Özellikle bu tablo ile seyreden olgularda kombine tedavi önerilmektedir.…”