Presence Of Leukoencephalopathy Research Articles

Chapter 4 - Primary mitochondrial diseases

Primary mitochondrial diseases (PMDs) are a heterogeneous group of hereditary disorders characterized by an impairment of the mitochondrial respiratory chain. They are the most common group of genetic metabolic disorders, with a prevalence of 1 in 4,300 people. The presence of leukoencephalopathy is recognized as an important feature in many PMDs and can be a manifestation of mutations in both mitochondrial DNA (classic syndromes such as mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; myoclonic epilepsy with ragged-red fibers [RRFs]; Leigh syndrome; and Kearns-Sayre syndrome) and nuclear DNA (mutations in maintenance genes such as POLG, MPV17, and TYMP; Leigh syndrome; and mitochondrial aminoacyl-tRNA synthetase disorders). In this chapter, PMDs associated with white matter involvement are outlined, including details of clinical presentations, brain MRI features, and elements of differential diagnoses. The current approach to the diagnosis of PMDs and management strategies are also discussed. A PMD diagnosis in a subject with leukoencephalopathy should be considered in the presence of specific brain MRI features (for example, cyst-like lesions, bilateral basal ganglia lesions, and involvement of both cerebral hemispheres and cerebellum), in addition to a complex neurologic or multisystem disorder. Establishing a genetic diagnosis is crucial to ensure appropriate genetic counseling, multidisciplinary team input, and eligibility for clinical trials.

Heterozygous NOTCH1 Variants Cause CNS Immune Activation and Microangiopathy.

NOTCH1 belongs to the NOTCH family of proteins that regulate cell fate and inflammatory responses. Somatic and germline NOTCH1 variants have been implicated in cancer, Adams-Oliver syndrome, and cardiovascular defects. We describe 7 unrelated patients grouped by the presence of leukoencephalopathy with calcifications and heterozygous de novo gain-of-function variants in NOTCH1. Immunologic profiling showed upregulated CSF IP-10, a cytokine secreted downstream of NOTCH1 signaling. Autopsy revealed extensive leukoencephalopathy and microangiopathy with vascular calcifications. This evidence implicates that heterozygous gain-of-function variants in NOTCH1 lead to a chronic central nervous system (CNS) inflammatory response resulting in a calcifying microangiopathy with leukoencephalopathy. ANN NEUROL 2022;92:895-901.

Long-term neuroimaging follow-up of COVID-19-related leukoencephalopathy.

More than a year after the start of the COVID-19 pandemic, long-term neurological manifestations of COVID-19 are increasingly being reported. The long-term sequelae of COVID-19-related leukoencephalopathy, however, remain unclear. Here, we present long-term neuroimaging follow-up in two cases of COVID-19-related leukoencephalopathy. The two cases demonstrate the utility of brain MRI for evaluating neurologic symptoms in critically ill patients with COVID-19, for diagnosis of underlying neural injury and prognostication of future recovery. The presence of leukoencephalopathy may result in chronic neurologic manifestations and may represent a poor prognosticator of neurologic recovery. The presence of leukoencephalomalacia on follow-up neuroimaging is potentially an indicator of irreversible white matter damage, which may be associated with more severe chronic deficits.

Cerebral Microbleeds and Leukoencephalopathy in Critically Ill Patients With COVID-19.

We conducted this study to investigate the prevalence and distribution of cerebral microbleeds and leukoencephalopathy in hospitalized patients with coronavirus disease 2019 (COVID-19) and correlate with clinical, laboratory, and functional outcomes. We performed a retrospective chart review of 4131 COVID-19 positive adult patients who were admitted to 3 tertiary care hospitals of an academic medical center at the epicenter of the COVID-19 pandemic in New York City from March 1, 2020, to May 10, 2020, to identify patients who had magnetic resonance imaging (MRI) of the brain. We evaluated the MRIs in detail, and identified a subset of patients with leukoencephalopathy and/or cerebral microbleeds. We compared clinical, laboratory, and functional outcomes for these patients to patients who had a brain MRI that did not show these findings. Of 115 patients who had an MRI of the brain performed, 35 (30.4%) patients had leukoencephalopathy and/or cerebral microbleeds. Patients with leukoencephalopathy and/or cerebral microbleeds had neuroimaging performed later during the hospitalization course (27 versus 10.6 days; P<0.001), were clinically sicker at the time of brain MRI (median GCS 6 versus 14; P<0.001), and had higher peak D-dimer levels (8018±6677 versus 3183±3482; P<0.001), lower nadir platelet count (116.9±62.2 versus 158.3±76.2; P=0.03), higher peak international normalized ratio (2.2 versus 1.57; P<0.001) values when compared with patients who had a brain MRI that did not show these findings. They required longer ventilator support (34.6 versus 9.1 days; P<0.001) and were more likely to have moderate and severe acute respiratory distress syndrome score (88.6% versus 23.8%, P<0.001). These patients had longer hospitalizations (42.1 versus 20.9 days; P<0.001), overall worse functional status on discharge (mRS 5 versus 4; P=0.001), and higher mortality (20% versus 9%; P=0.144). The presence of leukoencephalopathy and/or cerebral microbleeds is associated with a critical illness, increased mortality, and worse functional outcome in patients with COVID-19.

Clinical and electrophysiological characteristics of methotrexate encephalopathy in paediatric practice

Methotrexate-induced subacute encephalopathy is one of the side effects of the aforementioned drug. The effect is characterized by certain neurological symptoms, presence of leukoencephalopathy on a magnetic resonance imaging (MRI) and slow-wave activity shown on an electroencephalogram (EEG). The aim of this work is to determine the clinical and electrophysiological characteristics of methotrexate-induced encephalopathy in paediatric patients with various types of cancer, as well as to compare the obtained data with researches and precedents presented in medical literature. The study was approved by the Independent Ethics Committee of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology. A retrospective analysis of treatment results was performed on 31 patients aged 1.5-17 who had subacute methotrexate-induced encephalopathy. Most patients (n = 26) have been diagnosed with acute lymphoblastic leukemia (ALL). According to the theurapeutic protocols, the patients received intravenous, intrathecal and intraventricular methotrexate treatment. The severity of methotrexate-induced encephalopathy was determined according to the NCI-CTCAE scale (version 4.0). All the patients underwent the EEG study. MRI was performed on 26 patients. Methotrexate-induced encephalopathy developed after 2-12 (on average 5.3 ± 3.1) days after methotrexate administration. Encephalopathy of grade I occurred in 35.45% of cases, of grade II - in 19.6%, of grade III and IV - in 25.8 and 19.4% of cases. 5 patients had symptoms recurred after therapy continuation. The most frequent neurological symptoms were: pathological level of sleepiness (50.1%), impaired consciousness (32.3%), cognitive impairment (25.8%), epileptic seizures (19.6%) and ataxia (19.6%). Regression of neurological symptoms occurred in 26 patients after 1-10 (on average 3.3 ± 2.2) days, 5 patients had persistent neurological deficit. The EEG pattern was represented by diffuse theta-wave activity (39%), theta-delta activity (42%), delta activity (6.5%), beta activity (3.0%), a decrease of alpha rhythm amplitude (6.5%), where no changes occurred for only 1 patient. Pathologic changes were seen on MRI in 84.6% of cases. The interdependence between the EEG changes, the time of debut and resolution of encephalopathy has been established. However, there has been no connection found between the severity of encephalopathy, the EEG pattern, the way of methotrexate administration, the age of the patients, the clearance of methotrexate and previous neurological disoders. The data obtained on the clinical picture and the time frame of methotrexate-induced encephalopathy initiation were similar to foreign ones. In different cases of patients with methotrexate-induced encephalopathy, EEG is not always represented as diffuse slow-wave theta-activity. The patients are recommended to undergo initial EEG in order for the electrophysiological studies on methotrexate encephalopathy to be assessed correctly. Further studies of the risk factors of methotrexate-induced encephalopathy are required.

Brain MRI/MRA Findings after Hydroxyurea Treatment in Children with Sickle Cell Anemia

Background: Up to 40% of children with sickle cell anemia (SCA) will have abnormalities on brain imaging due to their hematologic disorder, much of which is subclinical. Common abnormalities on brain magnetic resonance imaging/magnetic resonance angiography (MRI/MRA) include leukoencephalopathy from microvascular ischemic insult and vascular stenosis from endothelial damage. Silent cerebral ischemic insults are progressive; further neurologic abnormalities, including overt stroke, are more common among children with ischemic findings on MRI compared to children without them. Furthermore, poor performance on neuropsychological testing, lower IQ, and higher rates of grade retention are common in children with SCA and cerebral ischemic disease. The effect of hydroxyurea treatment on the development and progression of vascular stenosis and leukoencephalopathy is unclear. This study aimed to longitudinally evaluate the development of intracerebral abnormalities through serial MRI/MRA in children with SCA (HbSS and HbSβ0-thalassemia) who receive long-term therapy with hydroxyurea.Methods: Children with SCA and no prior history of overt stroke enrolled in the Hydroxyurea Study of Long-Term Effects (HUSTLE NCT00305175) underwent brain MRI/MRA, transcranial doppler (TCD) examinations, and laboratory evaluations immediately before hydroxyurea initiation and after 3 and 6 years of treatment to maximum tolerated dose. MRI/MRAs were reviewed for the presence or absence of vascular stenosis and leukoencephalopathy. Leukoencephalopathy was defined as white matter T2 hyperintensity. Proportions of abnormal MRI/MRA findings were compared between baseline and 3 years and baseline and 6 years using McNemar’s test and the Wilcoxon-Mann-Whitney exact test was used to explore associations with laboratory parameters.Results: Forty-six children with SCA, mean age 9.4 years (range 1-17.3), had an MRI/MRA at baseline and 3 years post-initiation of hydroxyurea. Ten children had an additional MRI/MRA after 6-years of hydroxyurea therapy. Frequencies of leukoencephalopathy and vascular stenosis are shown in the table. Prevalence of leukoencephalopathy before hydroxyurea therapy was higher than that reported in the literature for untreated children with SCA of similar age. There were no significant differences between baseline imaging findings and those at 3 and 6 years.Table:Prevalence of leukoencephalopathy and vascular stenosis at baseline, 3 and 6 yearsBaseline (n=47) Median age 9.6 years (range 1.0 to 17.3)3 years (n=46) Median age 13.1 years (range 4.4 to 21.1)6 years (n=10) Median age 14.5 years (range 8.3 to 18.3)Leukoencephalopathy27 (57.4%)28 (60.9%)*5 (50%)*Stenosis3 (6.4%)1 (2.2%)*0*all p>0.05Children with leukoencephalopathy at baseline and 3 years were older than those without (mean 10.7 vs. 7.7 years, p=0.01; 10.5 vs. 7.5 years, p=0.02 respectively). Lower HbF at baseline was associated with the presence of leukoencephalopathy at year 3 (median HbF 4.6% vs. 12.4%, p=0.008), but there was no association between HbF at 3-years and the presence of leukoencephalopathy at 3-years (median HbF 16.4% vs. 13.2%, p=0.55). When stratified by age, these findings were similar. TCD velocities and other hematologic parameters were not associated with MRI/MRA abnormalities. The small number of vascular stenosis cases precluded further analyses of this outcome.Conclusions: In this longitudinal study, children treated with hydroxyurea for 3-6 years did not demonstrate an increased frequency of vascular stenosis or leukoencephalopathy on brain MRI/MRA during treatment. Older age at hydroxyurea initiation and lower pre-hydroxyurea HbF percentage were associated with the presence of leukoencephalopathy at baseline and 3-years. These findings suggest that hydroxyurea may mitigate the expected progression of vascular stenosis and leukoencephalopathy in children with SCA, and that this therapy should be initiated early on, before the development of cerebrovascular disease, particularly among those with a low HbF percentage. DisclosuresOff Label Use: hydroxyurea for children with sickle cell disease.

Leukoencephalopathy-Related Cerebral Amyloid Angiopathy With Cystatin C Deposition

We have described sporadic cases of cerebral amyloid angiopathy with cerebral hemorrhage showing a low cystatin C level in the cerebrospinal fluid detected by enzyme-linked immunosorbent assay. Recently, several cases of leukoencephalopathy in patients with cerebral amyloid angiopathy have been reported. We describe a sporadic case of leukoencephalopathy with cystatin C-type cerebral amyloid angiopathy diagnosed during life by enzyme-linked immunosorbent assay. A 74-year-old man who had suffered from progressive dementia for 3 years was admitted with right hemiparesis, dysarthria, and ataxia. MRI revealed pontine infarction and multiple lacunar state with leukoaraiosis. We suspected cystatin C-type cerebral amyloid angiopathy because of the low level of cystatin C in the cerebrospinal fluid. The patient died of sepsis 3 months later, and the presence of leukoencephalopathy with cerebral amyloid angiopathy was confirmed by autopsy. Immunohistological examination disclosed cystatin C and beta-protein deposition in amyloid structures of the cortical cerebral arteries. Measurement of cystatin C in the cerebrospinal fluid by enzyme-linked immunosorbent assay is a useful method of diagnosing leukoencephalopathy related to sporadic cystatin C-type cerebral amyloid angiopathy.