Letters to the Editor

Abstract

The article by Bakshi et al. (I) provides excellent clinical and MRI evidence that occipital lobe seizures can be the major manifestation of the reversible posterior leukoencephalopathy syndrome (RPLS). The authors mention, however, that ictal EEG recordings were unavailable in their patients for definitive proof. Indeed, although chronic occipital epileptic EEG abnormalities have been reported in two patients as a complication of eclampsia (2), and lateralized complex partial status epilepticus was demonstrated in one patient treated with cyclosporine (3), the many reports of RPLS have not yet captured the expected reversible occipital epileptic abnormalities.A case of RPLS with occipital lobe seizures was seen at this hospital in a 50-year-old man on cyclosporine postcardiac transplantation. Three weeks after transplantation, the patient became acutely confused and then had a generalized seizure. No further convulsions occurred after institution of phenytoin therapy, though confusion and intermittent agitation continued. A CT scan done on the day of the generalized seizure showed bilateral occipital white matter hypodensities with extension to involve the occipital grey matter on the right side (Fig. 1A). Focal white matter hypodensities were also noted in the right external capsule and right corona radiata, as well as in the white matter of both cerebellar hemispheres. An EEG 1 day later (Fig. 1B) showed nearly continuous periodic lateralized epileptiform discharges (PLEDs) with a regional predominance over the right occipital lobe and, in addition, the occurrence of two electrographic seizures with ictal onset over the right occipital region, both spreading to involve the entire right posterior quadrant, with reflection over the left occipital region, prior to ictal offset. Each seizure lasted 2-3 min, during which time the patient became increasingly confused and agitated.The presumed etiology of the clinical presentation was cyclosporine-induced neurotoxicity plus or minus acute hypertension. Nitroprusside was required for 3 days after the onset of neurological symptoms to control acutely elevated blood pressure in the range of 180/100. The cyclosporine level was 495 kg/L 2 days before the generalized seizure and the daily dose had been reduced at that time. Cyclosporine was discontinued with the onset of neurological symptomatology and replaced by mycophenalate mofetil as an immunosuppressant. The patient made a gradual, complete recovery from his confusional state over the following 10 days and an MRI scan done 11 days after the generalized seizure was normal. An EEG performed 3 weeks after the first (shortly after reinstitution of low-dose cyclosporine) showed occasional interictal epileptiform potentials over the right occipital pole.Two months later, the patient was doing well and tolerating cyclosporine with no recurrence of seizures. An EEG showed only a minimal residual nonepileptiform disturbance over the right occipital region.Thus, as presumed by Bakshi et al., RPLS in the acute phase may be a...

Posterior Reversible Encephalopathy Syndrome with Bilateral Independent Epileptic Foci Precipitated By Guillain-Barrè Syndrome

“…The EEG finding of periodic sharp waves denotes a subclinical epileptic abnormality associated with the concluding phase of SE and confirms the occipital localizations of the epileptic foci ( Figure 1(c) ). Despite the bilateral synchronous presentation in our patient, this finding could be referred to as paroxysmal lateralized epileptiform discharges (PLEDs), an EEG pattern usually associated with focal brain damage that could mark the interictal period of seizures related to PRES, as also previously reported [ 5 – 7 , 15 ].…”

“…In the pediatric cases described by Muro et al, amaurosis was the main clinical manifestation of bilateral, independent occipital SE [ 9 ]. A major number of reports have documented the occurrence of occipital lobe seizures [ 4 , 5 , 10 – 12 ] and SE related to occipital localizations in PRES [ 13 , 14 ] without demonstrating independent seizure activity on both sides of the brain. Considering the frequent symmetric distribution of the occipital damage in PRES, which is uncommon to see in other brain disorders, we believe that the development of acute independent epileptic foci in both occipital lobes represents a characteristic epileptic phenomenon of this syndrome.…”

“…Seizures classically arise in a clinical context of headache, vomiting, visual loss, and mental abnormalities but may also represent the only symptom of the encephalopathy [ 4 ]. A few reports suggest that occipital lobe seizures may typically occur in PRES because of the predominant posterior distribution of the parenchymal damage [ 4 , 5 ]. Nonetheless, there is still no evidence of epileptic disorders with specific characteristics in this syndrome.…”