Case 317: Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia.

HISTORY: A 44-year-old previously healthy man with a 9-month history of progressive cognitive decline, depression, urinary incontinence, and inability to perform tasks of daily living presented to the emergency department with worsening cognitive and neuropsychiatric symptoms. He had become more distressed, and his family noticed him departing the house without closing doors, leaving water faucets running, and sending his children to school on Sundays. History taken from the patient's wife revealed that his brother had passed away in his late 30s after a slowly progressing functional and cognitive decline over the course of 5 years. No further detailed family history could be obtained. The review of systems was negative; he had no prior medical, psychiatric, or surgical history; and he denied any history of recent travel, camping, hiking, or vaccination. The patient was not taking any dietary supplements, nor was he taking any over-the-counter or prescription medication. Examination revealed vital signs were within normal limits. Neurocognitive assessment revealed a conscious, coherent, and alert patient with impaired memory and concentration. He showed poor attention, depressed mood, and restricted affect. He was unable to spell the word world forward, nor was he able to understand a request to spell it backward. The rest of the physical and neurologic examination revealed no abnormalities. Extensive laboratory work-up was conducted and included the following: toxicology screening; screening for HIV-1, HIV-2, and syphilis treponemal antibodies; COVID-19 polymerase chain reaction; and measurement of B1 and B12 levels. The results of screening were negative. Cerebrospinal fluid (CSF) assays, including CSF oligoclonal bands and CSF flow cytometry, revealed values within normal limits. CT of the brain without intravenous contrast material was performed in the emergency department to rule out acute intracranial abnormality. Multiplanar multisequence MRI of the brain without and with intravenous contrast material was ordered for further assessment. CT images of chest, abdomen, and pelvis were unremarkable (images not shown).

Capecitabine-induced leukoencephalopathy in a patient with triple-negative breast cancer: A case report and review of the literature.

INTRODUCTION: Capecitabine is an orally administered prodrug that converts preferentially to 5-fluorouracil within tumors, resulting in enhanced concentrations of 5-fluorouracil in tumor tissue. The use of capecitabine has shown efficacy in the metastatic setting for breast cancer, and more recently, efficacy as adjuvant therapy for triple-negative breast cancer (TNBC). Capecitabine has been shown to be well tolerated with minimal side effects, but the incidence of leukoencephalopathy is rare with a risk of less than one percent. CASE REPORT: We report on a 34-year-old female patient with left TNBC, moderately differentiated, stage IIB that experienced symptoms of neurotoxicity following initiation of adjuvant chemotherapy with capecitabine. MANAGEMENT AND OUTCOME: Naranjo Algorithm Assessment score of nine indicated patient had drug-induced leukoencephalopathy leading to discontinuation of capecitabine and resolution of the neurotoxicity symptoms. DISCUSSION: Early detection of capecitabine-induced neurotoxicity by magnetic resonance imaging is crucial as symptoms may be reversible to the condition that capecitabine is immediately discontinued.

Remitting and exacerbating white matter lesions in leukoencephalopathy with thalamus and brainstem involvement and high lactate.

BACKGROUND: Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is a hereditary disorder caused by biallelic variants in the EARS2 gene. Patients exhibit developmental delay, hypotonia, and hyperreflexia. Brain magnetic resonance imaging (MRI) reveals T2-hyperintensities in the deep white matter, thalamus, and brainstem, which generally stabilize over time. Herein, we report a case of LTBL, showing remitting and exacerbating white matter lesions. CASE DESCRIPTION: A non-consanguineous Japanese boy exhibited unsteady head control with prominent hypotonia, with no family history of neurological diseases. Brain MRI at one year of age revealed extensive T2-hyperintensities on the cerebral white matter, cerebellum, thalamus, basal ganglia, pons, and medulla oblongata. Magnetic resonance spectroscopy of the lesions showed lactate and myoinositol peaks. Whole-exome sequencing yielded novel compound heterozygous EARS2 variants of c.164G>T, p.Arg55Leu and c.484C>T, p.Arg162Trp. Interestingly, the lesions were reduced at three years of age, and new lesions emerged at eight years of age. At 10 years of age, the lesions were changed in the corpus callosum, deep cerebral white matter, and cerebellum, without physical exacerbation. The lesions improved one year later. CONCLUSION: We present the first case with remitting and exacerbating brain lesions in LTBL. EARS2 could relate to selective and specific brain regions and age dependency. Although the exact role of EARS2 remains unknown, the remitting and exacerbating imaging changes may be a clue in elucidating a novel EARS2 function in LTBL.

Identification of a Novel Variant in EARS2 Associated with a Severe Clinical Phenotype Expands the Clinical Spectrum of LTBL.

The EARS2 nuclear gene encodes mitochondrial glutamyl-tRNA synthetase, a member of the class I family of aminoacyl-tRNA synthetases (aaRSs) that plays a crucial role in mitochondrial protein biosynthesis by catalyzing the charging of glutamate to mitochondrial tRNA(Glu). Pathogenic EARS2 variants have been associated with a rare mitochondrial disorder known as leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL). The targeted sequencing of 150 nuclear genes encoding respiratory chain complex subunits and proteins implicated in the oxidative phosphorylation (OXPHOS) function was performed. The oxygen consumption rate (OCR), and the extracellular acidification rate (ECAR), were measured. The enzymatic activities of Complexes I-V were analyzed spectrophotometrically. We describe a patient carrying two heterozygous EARS2 variants, c.376C>T (p.Gln126*) and c.670G>A (p.Gly224Ser), with infantile-onset disease and a severe clinical presentation. We demonstrate a clear defect in mitochondrial function in the patient's fibroblasts, suggesting the molecular mechanism underlying the pathogenicity of these EARS2 variants. Experimental validation using patient-derived fibroblasts allowed an accurate characterization of the disease-causing variants, and by comparing our patient's clinical presentation with that of previously reported cases, new clinical and radiological features of LTBL were identified, expanding the clinical spectrum of this disease.

Altered Mental Status: A Case Report of Toxic Leukoencephalopathy Following Heroin Exposure.

: Toxic leukoencephalopathy is a rare illness that causes diffuse white matter destruction, and as a result may mimic psychiatric disorders. Multiple causes have been identified including nerve related injury from exposure to a toxin. When symptoms present, they typically improve after the offending agent is eliminated. However, the clinical presentation in this report is unique in that the syndrome got worse several weeks after the toxin was removed. Research indicates that supportive supplements and vitamins can be used to facilitate neurological recovery. This report outlines a case of toxic leukoencephalopathy following heroin overdose that was treated with vitamin supplementation.

Pathogenic variants in NUBPL result in failure to assemble the matrix arm of complex I and cause a complex leukoencephalopathy with thalamic involvement.

Disorders of the white matter are genetically very heterogeneous including several genes involved in mitochondrial bioenergetics. Diagnosis of the underlying cause is aided by pattern recognition on neuroimaging and by next-generation sequencing. Recently, genetic changes in the complex I assembly factor NUBPL have been characterized by a consistent recognizable pattern of leukoencephalopathy affecting deep white matter including the corpus callosum and cerebellum. Here, we report twin boys with biallelic variants in NUBPL, an unreported c.351 G > A; p.(Met117Ile) and a previously reported pathological variant c. 693 + 1 G > A. Brain magnetic resonance imaging showed abnormal T2 hyperintense signal involving the periventricular white matter, external capsule, corpus callosum, and, prominently, the bilateral thalami. The neuroimaging pattern evolved over 18 months with marked diffuse white matter signal abnormality, volume loss, and new areas of signal abnormality in the cerebellar folia and vermis. Magnetic resonance spectroscopy showed elevated lactate. Functional studies in cultured fibroblasts confirmed pathogenicity of the genetic variants. Complex I activity of the respiratory chain was deficient spectrophotometrically and on blue native gel with in-gel activity staining. There was absent assembly and loss of proteins of the matrix arm of complex I when traced with an antibody to NDUFS2, and incomplete assembly of the membrane arm when traced with an NDUFB6 antibody. There was decreased NUBPL protein on Western blot in patient fibroblasts compared to controls. Compromised NUBPL activity impairs assembly of the matrix arm of complex I and produces a severe, rapidly-progressive leukoencephalopathy with thalamic involvement on MRI, further expanding the neuroimaging phenotype.

Functional brain connectome and its relation to mild cognitive impairment in cerebral small vessel disease patients with thalamus lacunes: A cross-sectional study.

To investigate the functional connectome alterations in cerebral small-vessel disease (CSVD) patients with thalamus lacunes and its relation to cognitive impairment.This case-control study was approved by the local research ethics committee, and all participants provided informed consent. There were 14 CSVD patients with thalamus lacunes (CSVDw.), 27 without (CSVDwo.), and 34 healthy controls (HC) recruited matched for age, sex, and education to undergo a 3T resting-state functional MR examination. The whole-brain functional connectome was constructed by thresholding the Pearson correlation matrices of 90 brain regions, and the topologic properties were analyzed by using graph theory approaches. Networks were compared between CSVD patients and HC, and associations between network measures and cognitive function were tested.Compared with HC, the functional connectome in CSVDw. patients showed abnormalities at the global level and at the nodal level (P < .05, false discovery rate corrected). The network-based statistics method identified a significantly altered network consisting 6 nodes and 13 connections. Among all the 13 connections, only two connections had significant correlation with episodic memory (EM) and processing speed (PS) respectively (P < .05). The CSVDwo. patients showed no significant network alterations relative to controls (P > .05).The configurations of brain functional connectome in CSVDw. patients were perturbed but not obvious for those without, and correlated with the mild cognitive impairment, especially for EM and PS. This study suggested that lacunes on thalamus played a vital role in mediating the neural functional changes of CSVD patients.

Cytotoxic Lesions of the Corpus Callosum Caused by Thermogenic Dietary Supplements.

Consumption of over-the-counter dietary supplements to reduce body weight is common among the population. Thermogenics are herbal combinations that claim to produce a fat-burning process through an increase in the cellular metabolic rate and greater cellular energy consumption, having a high risk for patients developing toxic leukoencephalopathy. We present a series of 6 patients with acute neurologic symptoms and MR imaging showing restricted diffusion and decreased apparent diffusion coefficient values (mean value, 400 mm2/s × 10-6) in the entire corpus callosum compatible with a cytotoxic lesion of the corpus callosum. Although patients responded favorably to the product discontinuation with rapid recovery of neurologic symptoms, there was a more prolonged resolution on imaging alterations. Because of the widespread availability and unregulated nature of thermogenic dietary supplements, physicians must be aware of the clinical and radiologic characteristics of these potential complications of their use.

Leukoencephalomyelopathy in cats linked to abnormal fatty acid composition of the white matter of the spinal cord and of irradiated dry cat food.

Four outbreaks of leukoencephalomyelopathy in colonies of SPF cats on a long-term diet of irradiated dry cat food were observed in the Netherlands between 1989 and 2001. As a primary defect in myelin formation was suspected to be the cause of the disease and myelin consists mainly of lipids and their fatty acids, we investigated the fatty acid composition of the white matter of the spinal cord of affected and control cats and of irradiated and non-irradiated food. The irradiated food had low levels of alpha-linolenic acid compared to linoleic acid as well as a high total omega-6:omega-3 ratio of 7:1 in the irradiated and of 2:1 in the non-irradiated food. The white matter of the spinal cord showed low levels of linoleic acid and absence of alpha-linolenic acid in affected cats as well as absence of lignoceric and nervonic acid in both affected and control cats. These abnormalities in fatty acid composition of the white matter of the spinal cord may reflect an increased need for alpha-linolenic acid as a substrate for longer chain omega-3 fatty acids to compose myelin and thus indicate a particular species sensitivity to dietary deficiency in omega-3 polyunsaturated fatty acids, particularly alpha-linolenic acid in cats. Our findings indicate that abnormalities in fatty acid metabolism in myelin play an essential role in the pathogenesis of this acquired form of leukoencephalomyelopathy in cats.

Explaining the heterogeneity of functional connectivity findings in multiple sclerosis: An empirically informed modeling study.

To understand the heterogeneity of functional connectivity results reported in the literature, we analyzed the separate effects of grey and white matter damage on functional connectivity and networks in multiple sclerosis. For this, we employed a biophysical thalamo-cortical model consisting of interconnected cortical and thalamic neuronal populations, informed and amended by empirical diffusion MRI tractography data, to simulate functional data that mimic neurophysiological signals. Grey matter degeneration was simulated by decreasing within population connections and white matter degeneration by lowering between population connections, based on lesion predilection sites in multiple sclerosis. For all simulations, functional connectivity and functional network organization are quantified by phase synchronization and network integration, respectively. Modeling results showed that both cortical and thalamic grey matter damage induced a global increase in functional connectivity, whereas white matter damage induced an initially increased connectivity followed by a global decrease. Both white and especially grey matter damage, however, induced a decrease in network integration. These empirically informed simulations show that specific topology and timing of structural damage are nontrivial aspects in explaining functional abnormalities in MS. Insufficient attention to these aspects likely explains contradictory findings in multiple sclerosis functional imaging studies so far.

A Callosal Catastrophe: Toxic Leukoencephalopathy Associated with Thermogenic Weight Loss Supplement Use.

BACKGROUND: The use of weight loss drugs and dietary supplements is common, but safety profiles for these drugs are largely unknown. Reports of toxicity have been published, and the use of these agents should be considered in clinical differential diagnoses. METHODS: We report the case of a patient with toxic leukoencephalopathy and hyponatremia associated with oral consumption of a thermogenic dietary supplement and essential oils. RESULTS: A 30-year-old woman presented after 2 days of headache, blurred vision, photophobia, vomiting, and hand spasms. She was taking a thermogenic dietary supplement daily for 6 months as well as a number of essential oils. Examination revealed mild right sided ataxia and diffuse hyperreflexia. Neuroimaging demonstrated bilaterally symmetric T2 hyperintensities of the corpus callosum and periventricular white matter. Approximately 18 h after admission she became unresponsive with brief extensor posturing and urinary incontinence. She partially recovered, but 1 h later became unresponsive with dilated nonreactive pupils and extensor posturing (central herniation syndrome). She was intubated, hyperventilated, and given hyperosmotic therapy. Emergent imaging showed diffuse cerebral edema. Intracranial pressure was elevated but normalized with treatment; she regained consciousness the following day. She was extubated one day later and discharged on hospital day 5. She was seen 2 months later with no further symptoms and a normal neurologic examination. CONCLUSIONS: The pathophysiology of this patient's hyponatremia and toxic leukoencephalopathy is unknown. However, physicians must be aware of the association between thermogenic dietary supplements and toxic leukoencephalopathy. Vigilance for life-threatening complications including hyponatremia and cerebral edema is critical.

Long-term outcome of delayed neuropsychiatric sequelae after carbon monoxide poisoning

OBJECTIVE: Delayed neuropsychiatric sequelae (DNS) following carbon monoxide (CO) poisoning, which may result from a demyelinating leukoencephalopathy, is a disease with a poor prognosis. This study examined the factors affecting the long-term prognosis of DNS and the efficacy of hyperbaric oxygen therapy (HBOT) in patients with DNS. METHODS: This retrospective study included 84 patients with DNS following CO poisoning from January 2013 to June 2016. HBOT was given to 24 patients. The patients were divided into an improvement group and non-improvement group based on their clinical condition on a telephone interview at intervals between 3 months and 3 years after the onset of DNS. The improvement group was defined as having Cerebral Performance Category (CPC) scores in their daily life that improve to 1 or 2 grade. RESULTS: Of the 594 patients, DNS were found in 18.2%, and 70.2% (59 of 84) of the patients with DNS improved. The prognostic factors for the improvement of DNS were an age of 45 years or less (odds ratio [OR], 12.068; 95% confidence interval [CI], 2.393–60.858; P 0.1). CONCLUSION: Patients aged less than 45 years, low grade CPC score of 1 and 2, and lucid interval longer than 20 days are more likely to have a good prognosis. On the other hand, HBOT failed to produce a benefit for DNS patients.

Acute toxic leukoencephalopathy associated with a non-prescription weight loss supplement: a report of two cases.

Weight loss dietary supplements are used with some frequency by an increasingly overweight population. Some products are not adequately regulated and may pose potential health risks. We report two new cases of acute toxic leukoencephalopathy (ATL) due to the use of a supplement marketed as a thermogenic weight loss aid. ATL is a heterogeneous clinic-radiological entity that has been associated with various compounds, such as chemotherapeutic drugs and immunomodulators. It is characterized by an often reversible periventricular and infratentorial demyelination. The commercialization of non-regulated weight loss products continues to be a health risk in our population.

The Phe932Ile mutation in KCNT1 channels associated with severe epilepsy, delayed myelination and leukoencephalopathy produces a loss-of-function channel phenotype.

Sodium-activated potassium (KNa) channels contribute to firing frequency adaptation and slow after hyperpolarization. The KCNT1 gene (also known as SLACK) encodes a KNa subunit that is expressed throughout the central and peripheral nervous systems. Missense mutations of the SLACK C-terminus have been reported in several patients with rare forms of early onset epilepsy and in some cases severely delayed myelination. To date, such mutations identified in patients with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), epilepsy of infancy with migrating focal seizures (EIMFS) and Ohtahara syndrome (OS) have been reported to be gain-of-function mutations (Villa and Combi, 2016). An exome sequencing study identified a p.Phe932Ile KCNT1 mutation as the disease-causing change in a child with severe early infantile epileptic encephalopathy and abnormal myelination (Vanderver et al., 2014). We characterized an analogous mutation in the rat Slack channel and unexpectedly found this mutation to produce a loss-of-function phenotype. In an effort to restore current, we tested the known Slack channel opener loxapine. Loxapine exhibited no effect, indicating that this mutation either caused the channel to be insensitive to this established opener or proper translation and trafficking to the membrane was disrupted. Protein analysis confirmed that while total mutant protein did not differ from wild type, membrane expression of the mutant channel was substantially reduced. Although gain-of-function mutations to the Slack channel are linked to epileptic phenotypes, this is the first reported loss-of-function mutation linked to severe epilepsy and delayed myelination.

Severe Metabolic Acidosis and Hepatopathy due to Leukoencephalopathy with Thalamus and Brainstem Involvement and High Lactate.

Leukoencephalopathy with thalamus and brainstem involvement and high lactate (LTBL) is a recently described autosomal recessive mitochondrial disease characterized by early onset of neurological symptoms, a biphasic clinical course, and distinctive neuroimaging. Pathogenic variants in the EARS2 gene that encode for mitochondrial glutamyl-tRNA synthetase are responsible for LTBL. Here, we describe the clinical course of an infant diagnosed with an acute crisis of LTBL and severe liver disease. This article illustrates the utility of blood lactate quantification in addition to basic metabolic testing and brain imaging in a child with low tone and poor growth. In addition, this case demonstrates the utility of current genetic diagnostic testing, in lieu of more invasive procedures, in obtaining rapid answers in this very complicated group of disorders.