Juvenile Xanthogranuloma of the Head and Neck: Imaging Findings in 11 Cases.

BACKGROUND: Juvenile Xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis, occurring mainly in infancy. With an extracutaneous lesion, its diagnosis is difficult, because of a wide clinical spectrum. Here we demonstrate and characterize imaging features of 11 patients with JXG of the head and neck in various locations. MATERIAL AND METHODS: We recorded clinical data and reviewed all imaging studies of 11 patients with JXG of the head and neck. Ultrasonography (US) alone was performed in 1 patient; MRI alone in 6 patients; US and MRI in 1 patient; and US, CT, and MRI in 3 patients. We evaluated the following characteristics in all studies: location and number of lesions, echogenicity and vascularization on US, density on CT, signal intensity on T1- and T2-weighted images, ADC and enhancement on MRI, and tumor boundaries and bone involvement. RESULTS: Lesions were well-defined in 9 cases, and bone erosion was present in 2. On US, lesions were hypoechoic or hyperechoic and with or without vascularization. On CT, lesions were hyper-dense, with no calcification. On MRI, lesions were mildly hyper-intense or iso-intense on T1-weighted images in 8 of 9 patients, hypo-intense on T2-weighted images in 7 of 10, low ADC in 7 of 9, and enhancement in 7 of 7. CONCLUSIONS: The diagnosis of extra cutaneous JXG may be proposed, with the following suggestive criteria: age < 1 year, well-defined lesion, mild hyper-intensity on T1-weighted images, hypo-intensity on T2-weighted images, low ADC, enhancement, and possible adjacent bone involvement.

Severe Meningococcal Meningitis Revealing a Novel Form of Properdin Deficiency in a Previously Healthy 13-year-old Child.

A 13-year-old boy was admitted with severe meningococcal meningitis. Immunologic workup revealed a properdin deficiency, and genetic sequencing of CFP identified a novel, private and predicted pathogenic variant in exon 8. The patient received broad immunizations and penicillin prophylaxis. Children with invasive meningococcal disease should be tested for complement deficiency.

French guidelines on TIPS: Indications and modalities.

Transjugular intrahepatic portosystemic shunt (TIPS) has become essential in the treatment or prevention of portal hypertension-related complications. In the early 1990s, the primary indication was refractory bleeding. It is now proposed for the treatment of ascites for the prevention of bleeding and in patients with vascular diseases of the liver. Thus, there are a growing number of patients being treated with TIPS all over the world. The broadening of indications, the involvement of multiple stakeholders, the need for an accurate selection, the positioning in relation to transplantation and the lack of standardization in pre-therapeutic assessment, in the procedure itself and in the follow-up have led the board of the French Association for the Study of the Liver to establish recommendations.

Clinical, Neuroimaging, and Metabolic Footprint of the Neurodevelopmental Disorder Caused by Monoallelic HK1 Variants.

Background and Objectives: Hexokinase 1 (encoded by HK1) catalyzes the first step of glycolysis, the adenosine triphosphate-dependent phosphorylation of glucose to glucose-6-phosphate. Monoallelic HK1 variants causing a neurodevelopmental disorder (NDD) have been reported in 12 individuals. Methods: We investigated clinical phenotypes, brain MRIs, and the CSF of 15 previously unpublished individuals with monoallelic HK1 variants and an NDD phenotype. Results: All individuals had recurrent variants likely causing gain-of-function, representing mutational hot spots. Eight individuals (c.1370C>T) had a developmental and epileptic encephalopathy with infantile onset and virtually no development. Of the other 7 individuals (n = 6: c.1334C>T; n = 1: c.1240G>A), 3 adults showed a biphasic course of disease with a mild static encephalopathy since early childhood and an unanticipated progressive deterioration with, e.g., movement disorder, psychiatric disease, and stroke-like episodes, epilepsy, starting in adulthood. Individuals who clinically presented in the first months of life had (near)-normal initial neuroimaging and severe cerebral atrophy during follow-up. In older children and adults, we noted progressive involvement of basal ganglia including Leigh-like MRI patterns and cerebellar atrophy, with remarkable intraindividual variability. The CSF glucose and the CSF/blood glucose ratio were below the 5th percentile of normal in almost all CSF samples, while blood glucose was unremarkable. This biomarker profile resembles glucose transporter type 1 deficiency syndrome; however, in HK1-related NDD, CSF lactate was significantly increased in all patients resulting in a substantially different biomarker profile. Discussion: Genotype-phenotype correlations appear to exist for HK1 variants and can aid in counseling. A CSF biomarker profile with low glucose, low CSF/blood glucose, and high CSF lactate may point toward monoallelic HK1 variants causing an NDD. This can help in variant interpretation and may aid in understanding the pathomechanism. We hypothesize that progressive intoxication and/or ongoing energy deficiency lead to the clinical phenotypes and progressive neuroimaging findings.

Vitamin deficiencies in children: Lessons from clinical and neuroimaging findings.

BACKGROUND AND AIMS: Water-soluble vitamins play an essential coenzyme role in the nervous system. Acquired vitamin deficiencies are easily treatable, however, without treatment, they can lead to irreversible complications. This study aimed to provide clinical, laboratory parameters and neuroimaging data on vitamin deficiencies in an attempt to facilitate early diagnosis and prompt supplementation. METHODS: From July 1998 to July 2023, patients at Necker-Enfants-Malades Hospital presenting with acute neurological symptoms attributed to acquired vitamin deficiency were included. Clinical data were extracted from Dr Warehouse database. Neuroimaging, biochemical and electrophysiological data were reviewed. RESULTS: Patients with vitamin B1 deficiency exhibited abnormal eye movements (n = 4/4), fluctuations in consciousness (n = 3/4), and ataxia (n = 3/4). Brain MRI showed alterations of fourth ventricle region (n = 4/4), periaqueductal region (n = 4/4), tectum (n = 3/4), and median thalami (n = 3/4). Patients with vitamin B2 deficiency presented with early onset hypotonia (n = 3/4), hyperlactatemia (n = 4/4), and hyperammonemia (n = 4/4). Plasma acylcarnitines revealed a multiple acyl-coA dehydrogenase deficiency-like profile (n = 4/4). In vitamin B12 deficiency, young children presented with developmental delay (n = 7/7) and older children with proprioceptive ataxia (n = 3/3). Brain MRI revealed atrophy (n = 7/7) and spinal MRI hyperintensity in posterior cervical columns (n = 3/3). Metabolic findings showed elevated methylmalonic acid (n = 6/7) and hyperhomocysteinemia (n = 6/7). Patients with vitamin C deficiency exhibited gait disturbances and muscle weakness (n = 2/2). CONCLUSIONS: Acquired vitamin deficiencies may display reversible clinical symptoms mimicking inherited metabolic disorders. Some situations raise suspicion for diagnosis: concordant clinical presentation, suggestive neuroimaging findings, and/or biochemical evidence. Any acute neurological condition should be treated without waiting for definitive biochemical confirmation.

Portal hypertension is associated with poorer outcome and clinical liver decompensation in patients with HCC treated with Atezolizumab-Bevacizumab.

BACKGROUND: Portal hypertension (PHT) often complicates hepatocellular carcinoma (HCC) treatment and prognosis. We aimed to assess PHT's impact on AtezoBev outcomes and identify predictors of acute variceal bleeding (AVB) and clinical ascites occurrence. METHODS: A prospective cohort of 200 HCC patients treated with AtezoBev was studied alongside a retrospective cohort of 123 patients treated with Sorafenib. We assessed factors influencing progression-free survival (PFS), overall survival (OS), AVB and clinical ascites development, focusing on PHT parameters, and comparing outcomes within and between the two cohorts (time-dependent Cox model and adjusted survival curves). RESULTS: Among the AtezoBev cohort, 10% experienced AVB, 24% had high-risk esophageal varices (EV) and 46% vascular invasion. Median PFS and OS in the AtezoBev cohort was 5.13 and 12.2 months. AVB (HR=1.81;[95%CI:1.03-3.17]) and clinical ascites occurrence (HR=2.29;[95%CI:1.52-3.45]) were independently associated with mortality. AVB incidence was 12% at 12 months in AtezoBev patients and EV, history of AVB<6months and vascular invasion were independently associated with AVB. The Sorafenib cohort had shorter median PFS and OS, with similar AVB incidence and only EV were associated with AVB. CONCLUSIONS: PHT-related events significantly affect not only liver decompensation but also OS in AtezoBev-treated patients. We suggest a more widespread use of NSBB to prevent liver decompensation, with intensified prophylaxis for high-risk patients.

Feasibility of Liver Transplantation after 90Y Radioembolization: Lessons from a Radiation Protection Incident.

ABSTRACT: Radioembolization using 90Y is a growing procedure in nuclear medicine for treating hepatocellular carcinoma. Current guidelines suggest postponing liver transplantation or surgical resection for a period of 14 to 30 d after radioembolization to minimize surgeons' exposure to ionizing radiation. In light of a radiation protection incident, we reevaluated the minimum delay required between radioembolization and subsequent liver transplantation. A patient with a hepatocellular carcinoma underwent a liver transplantation 44 h after undergoing radioembolization using 90Y (860 MBq SIR-Spheres). No specific radioprotection measures were followed during surgery and pathological analysis. We subsequently (1) evaluated the healthcare professionals' exposure to ionizing radiation by conducting dose rate measurements from removed liver tissue and (2) extrapolated the recommended interval to be observed between radioembolization and surgery/transplantation to ensure compliance with the radiation dose limits for worker safety. The surgeons involved in the transplantation procedure experienced the highest radiation exposure, with whole-body doses of 2.4 mSv and extremity doses of 24 mSv. The recommended delay between radioembolization and liver transplantation was 8 d when using SIR-Spheres and 15 d when injecting TheraSphere. This delay can be reduced further when considering the specific 90Y activity administered during radioembolization. This dosimetric study suggests the feasibility of shortening the delay for liver transplantation/surgery after radioembolization from the 8th or 15th day after using SIR-Spheres or TheraSphere, respectively. This delay can be decreased further when adjusted to the administrated activity while upholding radiation protection standards for healthcare professionals.

Development of Collateral Vessels after Anterior Circulation Large Vessel Occlusion in Pediatric Arterial Ischemic Stroke Relates to Stroke Etiology: A Longitudinal Study.

BACKGROUND AND PURPOSE: The characteristics of large vessel occlusion (LVO) in the acute phase of pediatric arterial ischemic stroke and their natural history according to stroke etiology are poorly explored. This studied aimed at describing the prevalence and the radiological evolution of LVO in pediatric AIS. MATERIALS AND METHODS: This single-center retrospective study included consecutive non-neonate children with acute arterial ischemic stroke, intracranial proximal LVO in the anterior circulation (MCA, anterior cerebral artery, and/or ICA), and clinical and imaging follow-up for at least 18 months, during a 9-year period. RESULTS: Intracranial LVO was observed in 24.8% of patients with anterior circulation arterial ischemic stroke and adequate follow-up (n = 26/105), with a median age of 4.2 years (IQR 0.8-9), sex ratio 1.16. The main stroke etiology associated with LVO was unilateral focal cerebral arteriopathy (n = 12, 46%). During follow-up, a specific pattern of unilateral poststroke anastomotic bridge was observed in 8/26 patients, with the poststroke development of nonperforating collaterals forming a bridge in bypass of the LVO site with visible distal flow, within a median delay of 11 months. The development of unilateral poststroke anastomotic bridge was only observed in patients with unilateral focal cerebral arteriopathy. No patient with this pattern experienced stroke recurrence or further progressive vascular modifications. CONCLUSIONS: After stroke, the development of unilateral poststroke anastomotic bridge is specifically observed in children with focal cerebral arteriopathy, appearing in the first year after stroke. This clinical-radiologic pattern was not associated with stroke recurrence or arterial worsening, differentiating it from progressive intracranial arteriopathy, such as Moyamoya angiopathy.

Enhanced therapeutic outcomes with atezolizumab-bevacizumab and SIRT combination compared to SIRT alone in unresectable HCC: A promising approach for improved survival.

BACKGROUND: Integrating immunotherapy with locoregional therapies marks a significant milestone in the realm of hepatocellular carcinoma (HCC) treatment . This study aimed to assess the impact of addition of Atezolizumab-Bevacizumab (AtezoBev) on the outcome patients treated with SIRT. METHODS: We conducted a study that included all Child-Pugh A HCC treated with SIRT since 2017. We examined the effects of the addition of 3 infusions of AtezoBev before the SIRT procedure and after SIRT on patients outcome (AtezoBev-SIRT group). Time-to-event data were analyzed using Kaplan-Meier with the log-rank test. RESULTS: Thirty five HCC patients treated with SIRT were included, of whom 23 % also received AtezoBev infusions. The two groups were similar in terms of liver function and HCC parameters. The median OS was not reached for patients who received AtezoBev in combination with SIRT and 14 months for patients only treated by SIRT. The median PFS was higher in the group treated by SIRT and AtezoBev vs SIRT alone (11.3 months vs 5.8 months). In the global cohort, 8 patients presented a downstaging (23 %), 4 underwent liver surgery (1 in the AtezoBev-SIRT group) and 4 liver transplantation (1 in the AtezoBev-SIRT group) CONCLUSIONS: The administration of AtezoBev, both before and after SIRT, is associated with enhanced OS and PFS outcomes compared to SIRT alone for unresectable HCC.

Pediatric intracranial empyema complicating otogenic and sinogenic infection.

OBJECTIVE: To describe and compare clinical and microbiological features, surgical and medical management, and outcomes of children with otogenic and sinogenic intracranial empyema (IE) in an institution with an established multidisciplinary protocol. To use the study findings to inform and update the institutional algorithm. METHODS: Retrospective analysis was carried out on the electronic healthcare records of all children with oto-sinogenic IE admitted in a 5-year period. RESULTS: A total of 76 patients were identified and treated according to an institutional protocol. Two distinct groups were identified: intracranial empyema related to otogenic infection (OI-IE, n = 36) or sinogenic infection (SI-IE, n = 40). SI-IE was seen in older children and had a significantly higher morbidity. Sub-dural IE was seen in a minority (n = 16) and only in SI-IE and required urgent collaborative ENT-neurosurgery. Extra-dural IE occurred more frequently and was seen in both SI-IE and OI-IE. No death and overall low morbidity were observed. Particularities found in SI-IE and OI-IE groups (as thrombosis, microbiology, antibiotic treatment, duration and outcome) permitted the delineation of these groups in our updated algorithm. CONCLUSION: The presence of a collaborative multidisciplinary protocol permits the step-wise co-ordination of care for these complex patients in our institution. All patients received prompt imaging, urgent surgical intervention, and antibiotic treatment. Microbiological identification was possible for each patient and antibiotic rationalization was permitted through use of Polymerase chain reaction (PCR) testing in cases of sterile cultures. Of note, intracranial empyema related to sinogenic infection is shown to have significantly more severe clinical presentation, a higher morbidity, and a longer duration of antibiotic therapy than that related to otogenic infection. Study findings allowed for the update and clarification of the institutional protocol, which now clearly demarcates the clinical presentation, biological evidence, radiology, surgical and medical treatments in children with oto-sinogenic IE.

Imaging features to distinguish posterior fossa ependymoma subgroups.

OBJECTIVES: Posterior fossa ependymoma group A (EPN_PFA) and group B (EPN_PFB) can be distinguished by their DNA methylation and give rise to different prognoses. We compared the MRI characteristics of EPN_PFA and EPN_PFB at presentation. METHODS: Preoperative imaging of 68 patients with posterior fossa ependymoma from two centers was reviewed by three independent readers, blinded for histomolecular grouping. Location, tumor extension, tumor volume, hydrocephalus, calcifications, tissue component, enhancement or diffusion signal, and histopathological data (cellular density, calcifications, necrosis, mitoses, vascularization, and microvascular proliferation) were compared between the groups. Categorical data were compared between groups using Fisher's exact tests, and quantitative data using Mann-Whitney tests. We performed a Benjamini-Hochberg correction of the p values to account for multiple tests. RESULTS: Fifty-six patients were categorized as EPN_PFA and 12 as EPN_PFB, with median ages of 2 and 20 years, respectively (p = 0.0008). The median EPN_PFA tumoral volume was larger (57 vs 29 cm3, p = 0.003), with more pronounced hydrocephalus (p = 0.002). EPN_PFA showed an exclusive central position within the 4th ventricle in 61% of patients vs 92% for EPN_PFB (p = 0.01). Intratumor calcifications were found in 93% of EPN_PFA vs 40% of EPN_PFB (p = 0.001). Invasion of the posterior fossa foramina was mostly found for EPN_PFA, particularly the foramina of Luschka (p = 0.0008). EPN_PFA showed whole and homogeneous tumor enhancement in 5% vs 75% of EPN_PFB (p = 0.0008). All mainly cystic tumors were EPN_PFB (p = 0.002). The minimal and maximal relative ADC was slightly lower in EPN_PFA (p = 0.02 and p = 0.01, respectively). CONCLUSION: Morphological characteristics from imaging differ between posterior fossa ependymoma subtypes and may help to distinguish them preoperatively. CLINICAL RELEVANCE STATEMENT: This study provides a tool to differentiate between group A and group B ependymomas, which will ultimately allow the therapeutic strategy to be adapted in the early stages of patient management. KEY POINTS: • Posterior fossa ependymoma subtypes often have different imaging characteristics. • Posterior fossa ependymomas group A are commonly median or lateral tissular calcified masses, with incomplete enhancement, affecting young children and responsible for pronounced hydrocephalus and invasion of the posterior fossa foramina. • Posterior fossa ependymomas group B are commonly median non-calcified masses of adolescents and adults, predominantly cystic, and minimally invasive, with total and homogeneous enhancement.

Association between acute complications in PMM2-CDG patients and haemostasis anomalies: Data from a multicentric study and suggestions for acute management.

OBJECTIVES: Patients with PMM2-CDG develop acute events (stroke-like episodes (SLEs), thromboses, haemorrhages, seizures, migraines) associated with both clotting factors (factor XI) and coagulation inhibitors (antithrombin, protein C and protein S) deficiencies. The aim of the study was to correlate acute events to haemostasis and propose practical guidelines. METHODS: In this multicentric retrospective study, we evaluated clinical, radiological, haemostasis and electroencephalography data for PMM2-CDG patients hospitalized for acute events. Cerebral events were classified as thrombosis, haemorrhage, SLE, or "stroke mimic" (SM: normal brain imaging or evoking a migraine). RESULTS: Thirteen patients had a total of 31 acute episodes: 27 cerebral events with 7 SLEs, 4 venous thromboses, 4 haemorrhages (3 associated with thrombosis), 15 SMs at a mean age of 7.7 years; 4 non-cerebral thromboses, one of which included bleeding. A trigger was frequently involved (infection, head trauma). Although sometimes normal at baseline state, factor XI, antithrombin and protein C levels decreased during these episodes. No correlation between haemostasis anomalies and type of acute event was found. DISCUSSION: Acute events in PMM2-CDG are not negligible and are associated with haemostasis anomalies. An emergency protocol is proposed for their prevention and treatment (https://www.filiere-g2m.fr/urgences). For cerebral events, brain Magnetic Resonance Imaging with perfusion weight imaging and diffusion sequences, electroencephalogram and haemostasis protein levels guide the treatment: anticoagulation, antithrombin or fresh frozen plasma supplementation, antiepileptic therapy. Preventing bleeding and thrombosis is required in cases of surgery, prolonged immobilization, hormone replacement therapy. CONCLUSION: Acute events in PMM2-CDG are associated with abnormal haemostasis, requiring practical guidance.

Baveno VI and VII criteria are not suitable for screening for large varices or clinically significant portal hypertension in patients with hepatocellular carcinoma.

BACKGROUND: Baveno VI and VII criteria are used in patients with cirrhosis to rule out large size oesophageal varices (EV) and rule in/out clinically significant portal hypertension (CSPH). AIM: To evaluate their diagnostic performance in these patients. METHODS: We retrospectively included all patients with Child-Pugh A cirrhosis and HCC who had endoscopy, liver stiffness measurement (LSM) and platelet count within 6 months. They were classified according to the BCLC stage. Favourable Baveno VI criteria were defined by LSM < 20 kPa and platelets > 150 G/L (to rule out large EV), favourable Baveno VII criteria if LSM ≤ 15 kPa and platelets ≥ 150 G/L (to rule out CSPH, which was defined by a HVPG ≥ 10 mm Hg. RESULTS: We included 185 patients; 46% were BCLC-0/A, 28% BCLC-B and 26% BCLC-C. EV were present in 44% (23% large), and HVPG ≥ 10 mm Hg in 42% (mean 8 mm Hg). In patients with favourable Baveno VI criteria, 8% of the whole cohort (Se 93%, NPV 92%), 11% of BCLC-0-A (Se 89%, NPV 89%) and 10.0% of BCLC-C patients (Se 91%, NPV 90%) had large EV. Among patients with HVPG < 10 mm Hg, 6% had large EV and 17% small. CSPH was present in 23% of patients with favourable Baveno VII criteria among the whole cohort, and in 25% of those with BCLC-0/A. The specificity of LSM ≥ 25 kPa to rule in CSPH was 48%. CONCLUSIONS: Favourable Baveno VI criteria are not appropriate to rule out the presence of high-risk EV, or Baveno VII criteria to rule CSPH in/out in patients with HCC.

Case Report: Zolpidem's paradoxical restorative action: A case report of functional brain imaging.

Zolpidem is a sedative drug that has been shown to induce a paradoxical effect, restoring brain function in wide range of neurological disorders. The underlying functional mechanism of the effect of zolpidem in the brain in clinical improvement is still poorly understood. Thus, we aimed to investigate rest brain function to study zolpidem-induced symptom improvement in a patient who developed postoperative pediatric cerebellar mutism syndrome, a postoperative complication characterized by delayed onset transient mutism/reduced speech that can occur after medulloblastoma resection. The patient experienced clinical recovery after a single dose of zolpidem. Brain function was investigated using arterial spin labeling MRI and resting-state functional MRI. Imaging was performed at three time-points: preoperative, postoperative during symptoms, and after zolpidem intake when the symptoms regressed. Whole brain rest cerebral blood flow (CBF) and resting state functional connectivity using Pearson coefficient correlations between pairs of regions of interest were investigated two-by-two at the different time points. A comparison between postoperative and preoperative images showed a significant decrease in rest CBF in the left supplementary motor area, Broca's area, and the left striatum and a decrease in functional connectivity within the dentato-thalamo-cortical and cortico-striato-pallido-thalamo-cortical loops. Post-zolpidem images showed increased CBF in the left striatum and increased functional connectivity within the disrupted loops relative to postoperative images. Thus, we observed functional changes within the broader speech network and thalamo-subcortical interactions associated with the paradoxical effect of zolpidem in promoting clinical recovery. This should encourage further functional investigations in the brain to better understand the mechanism of zolpidem in neurological recovery.

Spectrum of neuroradiological manifestations in primary hemophagocytic lymphohistiocytosis: a comparative study of EBV-induced versus non-EBV-induced forms in 75 genetically confirmed pediatric cases.

OBJECTIVES: Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening condition affecting young children. It is potentially triggered by Epstein-Barr virus (EBV). This study describes the neuroradiological features observed in 75 children with genetically confirmed primary HLH, comparing EBV-induced with non-EBV-induced HLH forms. METHODS: Brain MRIs between 2007 and 2021 from 75 children with HLH according to the 2004 Histiocyte Society criteria and with a confirmed HLH-related mutation, were retrospectively reviewed by two pediatric neuroradiologists blinded to EBV status and to mutation status. At diagnosis, 17 children with EBV viremia above a threshold of 1000 copies/mL were included in the EBV-induced HLH group. The remaining 58 patients were included in the non-EBV-induced HLH group. RESULTS: Of the 75 children initially included, 21 had abnormal MRI (21/75 (28%); 9/17 in the EBV-induced HLH group and 12/58 in the non-EBV-induced HLH group). All patients with abnormal MRI had neurological symptoms. Abnormal MRIs showed white matter lesions; the posterior fossa was affected in all but one case. There was no significant difference between groups regarding the localization or morphology of white matter lesions. The striatum was more frequently affected in the EBV-induced HLH group (8/9 (89%) versus 1/12 (8%), p = 0.00037). All lesions, whether in the white matter or in the basal ganglia, presented increased ADC values on diffusion weighted imaging (DWI). CONCLUSION: In this study of 75 children with genetically confirmed HLH, only children with neurological signs had abnormal brain MRI. Bilateral striatum involvement suggested an EBV-induced form of HLH. KEY POINTS: • In children with genetically proven HLH, only those with neurological signs did have brain abnormalities at MRI. • All patients with abnormal brain MRI had multiple white matter lesions with increased ADC values, including in the posterior fossa in almost all cases. • Basal ganglia and in particular the striatum were bilaterally and symmetrically affected in almost all EBV-induced HLH patients, in contrast to the non-EBV-induced HLH patients.

Clinical and radiological description of 120 pediatric stroke-like episodes.

BACKGROUND AND PURPOSE: Stroke-like episodes (SLEs) are defined as acute onset of neurological symptoms mimicking a stroke and radiological lesions non-congruent to vascular territory. We aimed to analyze the acute clinical and radiological features of SLEs to determine their pathophysiology. METHODS: We performed a monocenter retrospective analysis of 120 SLEs in 60 children over a 20-year period. Inclusion criteria were compatible clinical symptoms and stroke-like lesions on brain magnetic resonance imaging (MRI; performed for all 120 events) with focal hyperintensity on diffusion-weighted imaging in a non-vascular territory. RESULTS: Three groups were identified: children with mitochondrial diseases (n = 22) involving mitochondrial DNA mutations (55%) or nuclear DNA mutations (45%); those with other metabolic diseases or epilepsy disorders (n = 22); and those in whom no etiology was found despite extensive investigations (n = 16). Age at first SLE was younger in the group with metabolic or epilepsy disorders (18 months vs. 128 months; p < 0.0001) and an infectious trigger was more frequent (69% vs. 20%; p = 0.0001). Seizures occurred in 75% of episodes, revealing 50% episodes of SLEs and mainly leading to status epilepticus (90%). Of the 120 MRI scans confirming the diagnosis, 28 were performed within a short and strict 48-h period and were further analyzed to better understand the underlying mechanisms. The scans showed primary cortical hyperintensity (n = 28/28) with decreased apparent diffusion coefficient in 52% of cases. Systematic hyperperfusion was found on spin labeling sequences when available (n = 18/18). CONCLUSION: Clinical and radiological results support the existence of a vicious circle based on two main mechanisms: energy deficit and neuronal hyperexcitability at the origin of SLE.