An autopsy case of drug-induced diffuse cerebral axonopathic leukoencephalopathy: the pathogenesis in relation to reversible posterior leukoencephalopathy syndrome

White matter alterations in the dorsal attention network contribute to a high risk of unsafe driving in healthy older people

Aim

Healthy older drivers may be at high risk of fatal traffic accidents. Our recent study showed that volumetric alterations in gray matter in the brain regions within the dorsal attention network (DAN) were strongly related to the risk of unsafe driving in healthy older people. However, the relationship between white matter (WM) structural connectivity and driving ability in healthy older people is still unclear.

Methods

We used diffusion tensor imaging to examine the association between microstructural alterations in the DAN and the risk of unsafe driving among healthy older people. We enrolled 32 healthy older individuals aged over 65 years and screened unsafe drivers using an on-road driving test. We then determined the pattern of WM aberrations in unsafe drivers using tract-based spatial statistics.

Results

The analysis demonstrated that unsafe drivers had significantly higher axial diffusivity values in nine WM clusters compared with safe drivers. These results were primarily observed bilaterally in the dorsal superior longitudinal fasciculus, which is involved in the DAN. Furthermore, correlation analyses showed that higher axial diffusivity values in the superior longitudinal fasciculus were associated with lower Trail Making Test A scores within unsafe drivers. This result suggests that functionally, WM microstructural alterations in the DAN are associated with attention problems, which may contribute to the risk of unsafe driving among healthy older people.

Conclusion

Our findings may elucidate the neurobiological mechanisms underlying the increased risk of unsafe driving in healthy older people, potentially facilitating the development of new interventions to prevent fatal accidents.

Colony stimulating factors in the nervous system

Although traditionally seen as regulators of hematopoiesis, colony-stimulating factors (CSFs) have emerged as important players in the nervous system, both in health and disease. This review summarizes the cellular sources, patterns of expression and physiological roles of the macrophage (CSF-1, IL-34), granulocyte-macrophage (GM-CSF) and granulocyte (G-CSF) colony stimulating factors within the nervous system, with a particular focus on their actions on microglia. CSF-1 and IL-34, via the CSF-1R, are required for the development, proliferation and maintenance of essentially all CNS microglia in a temporal and regional specific manner. In contrast, in steady state, GM-CSF and G-CSF are mainly involved in regulation of microglial function. The alterations in expression of these growth factors and their receptors, that have been reported in several neurological diseases, are described and the outcomes of their therapeutic targeting in mouse models and humans are discussed.

Neuropathological findings from an autopsied case showing posterior reversible encephalopathy syndrome-like neuroradiological findings associated with premedication including tacrolimus for autologous peripheral blood stem cell transplantation

Posterior reversible encephalopathy syndrome (PRES) is diagnosed based on neuroradiological findings. Typically, PRES is reversible and presents with a good outcome; however, fatal outcomes have been reported. We report an autopsied case showing PRES-like neuroradiological findings associated with premedication including tacrolimus for autologous peripheral blood stem cell transplantation in a 28-year-old woman with a 2-year history of acute myeloid sarcoma/acute myeloid leukemia. Neurological examination revealed disturbed consciousness, muscle weakness in all extremities, and bilaterally diminished tendon reflexes. Brain fluid attenuated inversion recovery MRI showed multiple bilateral hyper-intensity areas in the posterior white matter and left corona radiate. She died of respiratory arrest within 24h after PRES diagnosis. Neuropathological examination revealed diffuse cerebral edema, multiple cerebral hematomas that extended into the lateral ventricles and subarachnoid cavities, and multiple microbleeds predominantly in the inferior surface of the occipital white matter. Microscopic findings revealed paler myelin sheaths, enlargement of the vascular endothelium, leakage of plasma components and red blood cells, and clasmatodendrosis within the occipital white matter. Cerebral herniation and diffuse cerebral edema due to vascular endothelial dysfunction were concluded to be the cause of death. These pathological findings may aid in the pathophysiological recognition of acute-stage PRES.

Posterior reversible encephalopathy syndrome induced by enzalutamide in a patient with castration-resistant prostate cancer

Posterior reversible encephalopathy syndrome (PRES) is a clinical/radiological syndrome characterized by symptoms that can include seizure, headache, impaired vision and hypertension, and can be confirmed by magnetic resonance imaging. Numerous reports have emerged that describe PRES in cancer patients. The list of medications linked to PRES can include traditional cytotoxic chemotherapeutics (e.g., cisplatin, cyclophosphamide, and high-dose corticosteroids), newer agents that target the vascular endothelial growth factor pathway (e.g., bevacizumab, sunitinib, and pazopanib), and supportive care mediations (e.g., granulocyte colony stimulating factors and erythropoietin). We report, for the first time, a case of PRES that is secondary to treatment with enzalutamide, a potent androgen receptor antagonist used in the treatment of metastatic castration-resistant prostate cancer. Enzalutamide is approved for the treatment of both docetaxel-pretreated and chemotherapy-naïve metastatic castration-resistant prostate cancer. Enzalutamide has been previously linked to the increased risk of seizures. Clinicians should be aware that, in rare cases, patients treated with enzalutamide could potentially be at risk for PRES. If symptoms suggestive of PRES arise in patients receiving enzalutamide, the drug should be discontinued immediately and the diagnostic process should be initiated.

Amyloid-related imaging abnormalities in amyloid-modifying therapeutic trials: recommendations from the Alzheimer's Association Research Roundtable Workgroup

Amyloid imaging related abnormalities (ARIA) have now been reported in clinical trials with multiple therapeutic avenues to lower amyloid-β burden in Alzheimer's disease (AD). In response to concerns raised by the Food and Drug Administration, the Alzheimer's Association Research Roundtable convened a working group to review the publicly available trial data, attempts at developing animal models, and the literature on the natural history and pathology of related conditions. The spectrum of ARIA includes signal hyperintensities on fluid attenuation inversion recoverysequences thought to represent "vasogenic edema" and/or sulcal effusion (ARIA-E), as well as signal hypointensities on GRE/T2* thought to represent hemosiderin deposits (ARIA-H), including microhemorrhage and superficial siderosis. The etiology of ARIA remains unclear but the prevailing data support vascular amyloid as a common pathophysiological mechanism leading to increased vascular permeability. The workgroup proposes recommendations for the detection and monitoring of ARIA in ongoing AD clinical trials, as well as directions for future research.

Lysergic acid amide-induced posterior reversible encephalopathy syndrome with status epilepticus

INTRODUCTION

Posterior reversible encephalopathy syndrome (PRES) is known to occur in association with several substances. However, lysergic acid amide (LSA) is not among the previously reported causes of PRES.

METHODS

We report on a patient with PRES presenting as convulsive status epilepticus associated with hypertensive encephalopathy after LSA ingestion. Magnetic resonance imaging was performed and catecholamine metabolites assayed.

RESULTS

The patient achieved a full recovery after aggressive antihypertensive therapy and intravenous anticonvulsivant therapy. The clinical history, blood and urinary catecholamine levels, and response to treatment strongly suggest that PRES was induced by LSA.

CONCLUSION

LSA, a hallucinogenic agent chiefly used for recreational purposes, should be added to the list of causes of PRES.

Reversible posterior leucoencephalopathy syndrome associated with anticancer drugs

BACKGROUND

Reversible posterior leucoencephalopathy syndrome (RPLS) is an underappreciated clinical-radiologic syndrome characterized by reversible cortical dysfunction preferentially involving the occipital lobes in conjunction with imaging findings of reversible subcortical oedema. As RPLS is being increasingly identified within the oncology population in association with cytotoxic chemotherapy and targeted agents, a review of the published work in English was carried out.

METHODS

A MEDLINE search of the published work in English was conducted to identify cases of RPLS in patients more than 16 years of age who were treated with anticancer drugs for documented malignancy. Only cases with adequate documentation regarding demographic and treatment data, cerebral magnetic resonance imaging and outcome were selected.

RESULTS

We identified 24 patients with RPLS associated with a variety of anticancer drugs, most commonly complicating polychemotherapy and/or bevacizumab-containing regimens. There was a female predominance: 18 females and 6 males (P= 0.023). Women were of premenopausal age and were younger than males: 49.3 +/- 16.4 years versus 60.7 +/- 6.4 years (P= 0.09). Most patients presented with acute headache (67%), seizures (63%), confusion (54%) or cortical blindness (46%) with mean systolic and diastolic blood pressure of 168 +/- 15 and 98 +/- 15 mm Hg, respectively. Findings on magnetic resonance imaging showed hyperintense lesions on T(2)-weighted images in all patients, which involved the occipital lobes in 75% of patients; all patients experienced clinical and radiologic resolution within days to weeks. No deaths were directly attributed to RPLS.

CONCLUSIONS

Combination and single-agent chemotherapy as well as novel anticancer drugs are associated with RPLS. We found RPLS to be overrepresented in premenopausal woman; the prevalence in this subgroup may be related to an anticancer drug-oestrogen interaction inducing altered cerebral vasoreactivity and endothelial dysfunction.

An autopsy case of Fabry disease with neuropathological investigation of the pathogenesis of associated dementia

The pathogenesis of dementia associated with Fabry disease was examined neuropathologically in an autopsy case. The patient was a 47-year-old computer programmer who developed renal failure at the age of 36, necessitating peritoneal dialysis, and thereafter suffered in succession episodic pulmonary congestion, bradyacusia, heart failure, and dementia, before dying of acute myocardial infarction. MRI of the brain demonstrated leuko-araiosis. The CNS parenchyma showed widespread segmental hydropic swelling of axons in the bilateral cerebral and cerebellar deep white matter in addition to neuronal ballooning due to glycolipid storage in a few restricted nuclei and multiple tiny lacunae. Hydropic axonal swelling was also sparsely distributed in the pyramidal tract, pedunculus cerebellaris superior and brachium colliculi inferioris, but wallerian degeneration of these tracts was absent. Additional features included angiopathy of the subarachnoidal arteries due to Fabry disease, such as medial thickening resulting from glycolipid deposition in smooth muscle cells (SMCs) and adventitial fibrosis with lymphocytic infiltration, together with widespread subtotal or total replacement of medial SMCs by fibrosis, associated with prominent intimal fibrous thickening and undulation of the internal elastic membrane of medium-sized (1000-100 microm diameter) arteries. The findings in this case suggest that axonopathic leukoencephalopathy due to multisegmental hydropic swelling of axons in the bilateral cerebral deep white matter is responsible for the dementia associated with Fabry disease, and may be caused by ischemia resulting from widespread narrowing and stiffening of medium-sized subarachnoidal arteries and progressive heart failure.