Delayed leukoencephalopathy from suspected polymer embolism after neuroendovascular procedures

Abstract

As the neurointervention field grows, a new side effect emerges. Delayed leukoencephalopathy (DL) is believed to be an inflammatory or allergic reaction to polymer material that is shed from catheters during endovascular procedures. We present four cases of DL after aneurysm treatment in two patients, endovascular stroke treatment and diagnostic arteriography. We present our diagnostic process, including biopsy results in two patients, our anti-inflammatory treatment and outcomes together with a review of the literature. In our series, prognosis was variable with ongoing seizures in two patients. Our literature review reveals that asymptomatic shedding of polymer material is common, occurring in a third of endovascular stroke procedures, whereas symptomatic DL occurs in <0.5% of therapeutic neuroendovascular procedures. Clinicians should be aware of this rare complication, and oral glucocorticoids seem to be a reasonable first-line treatment strategy.

Incidence, clinical spectrum, and immunotherapy of non-ischemic cerebral enhancing lesions after endovascular therapy

“…This is in line with other reports describing various symptoms including seizures, headache, motor deficits and visual disturbances. 8 , 12 In the diagnostic workup, CSF analysis revealed a pleocytosis only in two out of five patients, consistent with the literature, 4 , 5 , 9 , 13 , 17 , 19 where normal and pathological CSF findings have been reported.…”

“…Regarding CYC, we found only one report 9 on a patient treated in addition to GCS for recurrent delayed leukoencephalopathy after thrombectomy (without stenting) resulting in a stable disease course. CYC given in cases 2 and 3 (given after the first and second EVT) resulted in a reduction of NICE lesions, the patients remained symptom-free.…”

“…The disorder has also been described as delayed cerebral hypersensitivity, 4 leukoencephalopathy 9 or descriptively as reversible intracranial parenchymal changes. 7 For ease, in this study MRI lesions described in the literature for this disorder are uniformly named as NICE lesions, though knowing that not all MRI lesions occuring in this disorder are contrast enhancing.…”

“…2 –8 Punctate, nodular or annular foci of leptomeningeal, cortical, and subcortical enhancements and perilesional edema 8 in the territory of the endovascular access of EVT represent characteristics of NICE lesions. The disorder has also been termed as delayed cerebral hypersensitivity, 4 leukoencephalopathy 9 or descriptively as reversible intracranial parenchymal changes. 7 Incidence rates after EVT are reported to be as high as 0.05% 10 to 0.9%, 11 except for one study reporting a higher incidence rate of 2.3%.…”