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BackgroundCentral venous catheters (CVCs) represent one of the main risk factors for venous thrombotic events (VTEs) in children.MethodsWe studied the Italian Registry of Pediatric Thrombosis (RITI) with regard to systemic radiologically confirmed CVC-related VTEs (CVC-VTEs) occurred during 6.5 years in children aged 29 days to 18 years.ResultsA total of 78 CVC-VTEs were included, which occurred in 76 patients (40/76, 53% males). CVC-VTEs comprised 67 non-cardiac VTEs (86%) and 11 intracardiac thrombotic events (ICTEs) (14%); the median age at onset was 19 and 17 months, respectively. The most frequent reason for CVC insertion was supportive therapy. The catheters were placed percutaneously in 85% of cases (56/66) and surgically in the remaining 15% (10/66). Peripherally inserted central catheters (PICCs) were used in 47% (31/66) cases, partially implanted catheters in 42% (28/66), non-implantable catheters in 7% (5/66), and totally implanted catheters (Port) in 2% (1/66). CVC-VTEs were symptomatic in 77% of cases (60/78), while in the remaining 23%, they were incidentally detected on the imaging performed for the underlying condition. The median time between CVC insertion and the onset of symptoms was 10 days in non-cardiac VTEs and 39 days in ICTEs. Doppler ultrasound was the diagnostic technique most frequently used. The venous compartment most frequently affected was the veins of the lower extremities (52%, 43/73). Anti-thrombotic treatment was administered in 96% of CVC-VTEs (75/78). About 2.6% (2/76) of patients experienced a second thrombotic event. At discharge, post-thrombotic syndrome was reported in 13.5% (5/37) events with available data, CVC replacement in 10.8% (4/47), and ischemic necrosis with toe finger amputation in 2.7% (1/37). Three patients died due to an underlying condition; no CVC-VTE-related deaths were reported.ConclusionsWe have carried out a registry-based study on CVC-VTEs in the children in Italy, providing the data that may help improve the detection and management of this CVC-related complication.

IMPORTANCE: Overall, immunotherapy has been shown to improve outcomes and reduce relapses in individuals with N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis (NMDARE); however, the superiority of specific treatments and combinations remains unclear. OBJECTIVE: To map the use and safety of immunotherapies in individuals with NMDARE, identify early predictors of poor functional outcome and relapse, evaluate changes in immunotherapy use and disease outcome over the 14 years since first reports of NMDARE, and assess the Anti-NMDAR Encephalitis One-Year Functional Status (NEOS) score. DATA SOURCES: Systematic search in PubMed from inception to January 1, 2019. STUDY SELECTION: Published articles including patients with NMDARE with positive NMDAR antibodies and available individual immunotherapy data. DATA EXTRACTION AND SYNTHESIS: Individual patient data on immunotherapies, clinical characteristics at presentation, disease course, and final functional outcome (modified Rankin Scale [mRS] score) were entered into multivariable logistic regression models. MAIN OUTCOMES AND MEASURES: The planned study outcomes were functional outcome at 12 months from disease onset (good, mRS score of 0 to 2; poor, mRS score greater than 2) and monophasic course (absence of relapse at 24 months or later from onset). RESULTS: Data from 1550 patients from 652 articles were evaluated. Of these, 1105 of 1508 (73.3%) were female and 707 of 1526 (46.3%) were 18 years or younger at disease onset. Factors at first event that were significantly associated with good functional outcome included adolescent age and first-line treatment with therapeutic apheresis, corticosteroids plus intravenous immunoglobulin (IVIG), or corticosteroids plus IVIG plus therapeutic apheresis. Factors significantly associated with poor functional outcome were age younger than 2 years or age of 65 years or older at onset, intensive care unit admission, extreme delta brush pattern on electroencephalography, lack of immunotherapy within the first 30 days of onset, and maintenance IVIG use for 6 months or more. Factors significantly associated with nonrelapsing disease were rituximab use or maintenance IVIG use for 6 months or more. Adolescent age at onset was significantly associated with relapsing disease. Rituximab use increased from 13.5% (52 of 384; 2007 to 2013) to 28.3% (311 of 1100; 2013 to 2019) (P < .001), concurrent with a falling relapse rate over the same period (22% [12 of 55] in 2008 and earlier; 10.9% [35 of 322] in 2017 and later; P = .006). Modified NEOS score (including 4 of 5 original NEOS items) was associated with probability of poor functional status at 1 year (20.1% [40 of 199] for a score of 0 to 1 points; 43.8% [77 of 176] for a score of 3 to 4 points; P = .05). CONCLUSIONS AND RELEVANCE: Factors influencing functional outcomes and relapse are different and need to be considered independently in development of evidence-based optimal management guidelines of patients with NMDARE.

ObjectiveWe characterised the clinical course, treatment and outcomes in 59 patients with relapsing myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination.MethodsWe evaluated clinical phenotypes, annualised relapse rates (ARR) prior and on immunotherapy and Expanded Disability Status Scale (EDSS), in 218 demyelinating episodes from 33 paediatric and 26 adult patients.ResultsThe most common initial presentation in the cohort was optic neuritis (ON) in 54% (bilateral (BON) 32%, unilateral (UON) 22%), followed by acute disseminated encephalomyelitis (ADEM) (20%), which occurred exclusively in children. ON was the dominant phenotype (UON 35%, BON 19%) of all clinical episodes. 109/226 (48%) MRIs had no brain lesions. Patients were steroid responsive, but 70% of episodes treated with oral prednisone relapsed, particularly at doses ConclusionRelapsing MOG antibody-associated demyelination is strongly associated with ON across all age groups and ADEM in children. Patients are highly responsive to steroids, but vulnerable to relapse on steroid reduction and cessation.

Epidemiological studies, animal models, and case-control studies indicate maternal immune activation may be an important factor involved in disease expression of autism spectrum disorder (ASD), Tourette syndrome, and obsessive-compulsive disorder (OCD). We report eight children (mean age 6y 6mo [range 4-15y]; six males and two females) referred over a 2-year period with at least one of these neurodevelopmental disorders plus a maternal history of thyroid autoimmunity. Seven of eight children presented with an abrupt onset of neuropsychiatric symptoms (OCD [n=6], tics [n=5], and/or psychosis [n=1]), associated with an autistic or global regression. Four children had a pre-existing diagnosis of ASD. Six presentations were preceded by infection, and symptoms followed a relapsing-remitting course in seven children. All children responded to immunomodulatory treatment as indicated by a reduction in psychiatric symptoms, and seven children were also managed with conventional treatment with additional improvement. We propose that maternal autoimmunity can activate fetal microglia or alter transcription of neurodevelopmental vulnerability and/or immune genes in utero, and is an environmental factor that increases the expression and severity of neurodevelopmental problems, and susceptibility to deteriorations after infectious or stress stimuli. WHAT THIS PAPER ADDS: Maternal thyroid autoimmunity may represent a risk factor for neuropsychiatric disorders in offspring. Atypical neuropsychiatric features in these children may be due to maternal immune activation in utero.AUTOINMUNIDAD MATERNA TIROIDEA ASOCIADA CON TRASTORNOS NEUROPSIQUIÁTRICOS DE INICIO AGUDO Y REGRESIÓN GLOBAL EN LA DESCENDENCIA: Los estudios epidemiológicos, los modelos animales y los estudios de casos y controles indican que la activación inmune materna puede ser un factor importante involucrado en la expresión de la enfermedad del trastorno del espectro autista (TEA), el síndrome de Tourette y el trastorno obsesivo compulsivo (TOC). Informamos ocho niños (edad media 6 años de edad y 6 meses [rango 4-15 años]; 6 varones y 2 mujeres) remitidos durante un período de 2 años con al menos uno de estos trastornos del desarrollo neurológico más un historial materno de autoinmunidad tiroidea. Siete de ocho niños presentaron un inicio brusco de síntomas neuropsiquiátricos (TOC [n = 6], tics [n = 5] y / o psicosis [n = 1]), asociados con una regresión autista o global. Cuatro niños tenían un diagnóstico preexistente de TEA. Seis presentaciones fueron precedidas por infección, y los síntomas siguieron un curso de recaídas y remisiones en siete niños. Todos los niños respondieron al tratamiento inmunomodulador según lo indicado por una reducción en los síntomas psiquiátricos, y siete niños también fueron tratados con tratamiento convencional con una mejora adicional. Proponemos que la autoinmunidad materna puede activar la microglía fetal o alterar la transcripción de la vulnerabilidad del desarrollo neurológico y / o los genes inmunes en el útero, y es un factor ambiental que aumenta la expresión y la gravedad de los problemas del desarrollo neurológico, y la susceptibilidad a deterioros después de estímulos infecciosos o estresantes.AUTOIMUNIDADE TIREÓIDE MATERNA ASSOCIADA COM DESORDENS NEUROPSIQUIÁTRICAS DE INÍCIO AGUDO E REGRESSÃO GLOBAL NA PROLE: Estudos epidemiológicos, modelos animais, e estudos de caso-controle indicam que a ativação imune materna pode ser um importante fator envolvido na expressão de doenças do transtorno do espectro autista (TEA), síndrome de Tourette, e transtorno obsessivo compulsivo (TOC). Reportamos oito crianças (média de idade 6a 6m [variação 4-15a]; 6 do sexo masculino e 2 do sexo feminino) encaminhadas em um período de 2 anos com pelo menos uma desordem neurodesenvolvimental e história de auto-imunidade tireóide materna. Sete das oito crianças apresentaram início agudo de sintomas neuropsiquiátricos (TOC [n=6], tiques [n=5], e/ou psicose [n=1]), associados com regressão autística ou global. Quatro crianças tinham diagnóstico pré-existente de TEA. Seis apresentações foram precedidas por infecção, e os sintomas seguiram um curso recorrência-remisão em sete crianças. Todas as crianças responderam ao tratamento imunomodulatório, indicado pela redução nos sintomas psiquiátricos, e sete crianças também foram abordadas com tratamento convencional, com melhora adicional. Nós propomos que a autoimunidade maternal pode ativar a microglia fetal ou alterar a transcrição de genes de vulnerabilidade neurodesenvolvimental e/ou imunes, e um fator ambiental pode aumentar a expressão e severidade de problemas neurodesenvolvimentais e suscetibilidade a deterioração após estímulo infeccioso ou estresse.

We used magnetic resonance imaging (MRI) to compare the neuroimaging of children with their first episode of clinical enterovirus 71-associated transverse myelitis (EV71-TM), myelin oligodendrocyte glycoprotein antibody positive transverse myelitis (MOG-TM), aquaporin-4 antibody positive transverse myelitis (AQP4-TM), transverse myelitis in multiple sclerosis (MS-TM), and unclassified transverse myelitis (UNC-TM).We performed a retrospective blinded radiological assessment and compared the neuroimaging of 52 children (32 females, 20 males; mean age 9y 8mo, SD 5y 5mo, range 5mo-17y) presenting with their first episode of myelitis caused by EV71-TM (n=11), MOG-TM (n=10), AQP4-TM (n=9), MS-TM (n=13), and UNC-TM (n=9).In the EV71-TM group, lesions were distributed throughout the cord and enhancement of nerve roots (ventral and dorsal) was common. The MOG-TM group had lesions distributed throughout the cord and most commonly longitudinally extensive transverse myelitis and lesions involving the grey matter alone on axial scans. The AQP4-TM group had lesions distributed in the cervicothoracic spine, cavitation, and contrast enhancing lesions. All patients with AQP4-TM had an abnormal brain MRI scan. The MS-TM group characteristically had multiple short segment lesions of the cord involving the cervicothoracic spine. The UNC-TM group did not have distinctive spinal MRI findings but had a relative paucity of lesions on their brain MRI scans.There are neuroimaging findings that are helpful in differentiating between myelitis associated with EV71, MOG, AQP4, and multiple sclerosis in children. These features may be useful early in the presentation of transverse myelitis while awaiting infectious/immunological testing, and/or further demyelinating events.Magnetic resonance imaging can help identify aetiologies for children presenting with a first episode of myelitis. Entervirus-71-associated myelitis lesions are distributed throughout the cord and enhancement of nerve roots is common. Lesions distributed throughout the cord are commonly seen in myelin oligodendrocyte-associated myelitis. Aquaporin-4-associated myelitis lesions are distributed in the cervicothoracic spine, cavitation and contrast enhancing lesions are common. Short segment lesions in the cervicothoracic spine are commonly seen in multiple sclerosis-associated myelitis.IMÁGENES DE RESONANCIA MAGNÉTICA EN ENTEROVIRUS-71, ANTICUERPOS DE GLICOPROTEÍNA DE LA MIELINA DEL OLIGODENDROCITO, ANTICUERPOS AQUAPORIN-4, Y ESCLEROSIS MÚLTIPLE-ASOCIADA A MIELITIS EN NIÑOS: OBJETIVO: Utilizamos imágenes de resonancia magnética (IRM) para comparar la neuroimagen de los niños con su primer episodio clínico de enterovirus 71-asociado a mielitis transversa (EV71-TM), mielitis transversa con anticuerpos de glicoproteína de la mielina del oligodendrocito positivos (MOG-TM), mielitis transversa con anticuerpos aquaporin-4 positivos (AQP4-TM), mielitis transversa en esclerosis múltiple (MS-TM) y mielitis transversa no clasificada (UNC-TM). MÉTODO: Se realizó un análisis radiológico, ciego, retrospectivo y se comparó la neuroimagen de 52 niños (32 mujeres, 20 varones; con edad promedio 9 años 8 meses, La DS 5 años 5 meses, el rango de 5 meses -17 años) que presentaron su primer episodio de mielitis causada por EV71-TM (n= 11), MOG-TM (n= 10), AQP4-TM (n= 9), MS-TM (n= 13) y UNC-TM (n= 9). RESULTADOS: En el grupo de EV71-TM, fue común observar lesiones distribuidas a través de la medula con realce de las raíces de nervio (ventrales y dorsales). El grupo de MOG-TM tenía lesiones distribuidas a través de la médula, más comúnmente mielitis transversa longitudinalmente extensa y lesiones que implican solamente la sustancia gris en exploraciones axiales. El grupo AQP4-TM tenía lesiones distribuidas en la medula cervicodorsal, cavitación y lesiones con realce en el contraste. Todos Pacientes con AQP4-TM tenían una IRM cerebral anormal. El grupo de MS-TM característicamente tenía lesiones múltiples de segmentos pequeños de la medula que involucran las regiones cervical y dorsal. El grupo UNC-TM no tenía hallazgos de IRM distintivos en la medula espinal, pero tenía una relativa escasez de lesiones cerebrales IRM. INTERPRETACIÓN: Hay hallazgos de neuroimagen en niños que son útiles en diferenciar entre mielitis asociada a EV71, a MOG, a AQP4, y esclerosis múltiple. Estas características pueden ser útiles al inicio de la presentación de la mielitis transversa mientras se espera la prueba infecciosa/inmunológica y/u otros acontecimientos desmielinizantes.IMAGEM POR RESSONÂNCIA MAGNÉTICA EM ENTEROVÍRUS-71, ANTICORPO DA GLICOPROTEÍNA DE OLIGODENDRÓCITO DA MIELINA, ANTICORPO AQUAPORINA-4, E MIELITE ASSOCIADA A ESCLEROSE MÚLTIPLA EM CRIANÇAS: OBJETIVO: Usamos imagens de ressonância funcional (IRM) para comparar as neuroimagens de crianças com o primeiro episósio de mielite transversa clínica associada a enterovírus-71 (MT-EV71), mielite transversa positiva para anticorpo da glicoproteína de oligodendrócit oda mielina (MT-GOM), mielite transversa positiva para anticorpo aquaporina-4 (MT-AQP4), mielite transversa em esclerose múltipla (MT-EM), e mielite transversa não classificada (MT-NC). MÉTODO: Realizamos uma avaliação radiológica retrospectiva cega, e comparamos a neuroimagem de 52 crianças (32 do sexo feminino, 20 do sexo masculino; média de idade 9a 8m, DP 5a 5m, variação 5m-17a) apresentando seu primeiro episódio de mielite causada por MT-EV71 (n=11), MT-GOM (n=10), MT-AQP4 (n=9), MT-EM (n=13), e MT-NC (n=9). RESULTADOS: No grupo MT-EV71, as lesões se distribuíram por toda a medula, e realces das raízes nervosas (ventrais e dorsais) eram comuns. O grupo MT-GOM teve lesões distribuídas por toda a medula, e mais comumente mielite transversa extensiva longitudinalmente e lesões envolvendo apenas a substância cinzenta nas imagens axiais. O grupo MT-AQP4 teve lesões distribuídas na coluna cérvico-torácica, cavitação, e lesões realçadas pelo contraste. Todos os pacientes com MT-AQP4 -tiveram uma IRM cerebral anormal. O grupo MT-EM caracteristicamente teve múltiplas lesões de segmentos curtos da medula envolvendo a região cérvico-torácica. O grupo MT-NC não teve achados distintivos de IRM espinhal, mas tiveram relativamente menos lesões nas imagens cerebrais. INTERPRETAÇÃO: Há achados de neuroimagem úteis para diferenciar a mielite associada com EV71, GOM, AQP4 e esclerose múltipla em crianças. Estes aspectos podem ser úteis na apresentação precoce da mielite transversa, enquanto se aguarda testes infecciosos/imunológicos, e e/ou outros eventos desmielinizantes.

Menkes disease is a rare multisystem X-linked disorder of copper metabolism. Despite an early, severe, and progressive neurologic involvement, our knowledge of brain involvement remains unsatisfactory. The first part of this retrospective and review MR imaging study aims to define the frequency rate, timing, imaging features, and evolution of intracranial vascular and white matter changes. According to our analysis, striking but also poorly evolutive vascular abnormalities characterize the very early phases of disease. After the first months, myelination delay becomes evident, often in association with protean focal white matter lesions, some of which reveal an age-specific brain vulnerability. In later phases of the disease, concomitant progressive neurodegeneration might hinder the myelination progression. The currently enriched knowledge of neuroradiologic finding evolution provides valuable clues for early diagnosis, identifies possible MR imaging biomarkers of new treatment efficacy, and improves our comprehension of possible mechanisms of brain injury in Menkes disease.

This is the second part of a retrospective and review MR imaging study aiming to define the frequency rate, timing, imaging features, and evolution of gray matter changes in Menkes disease, a rare multisystem X-linked disorder of copper metabolism characterized by early, severe, and progressive neurologic involvement. According to our analysis, neurodegenerative changes and focal basal ganglia lesions already appear in the early phases of the disease. Subdural collections are less common than generally thought; however, their presence remains important because they might challenge the differential diagnosis with child abuse and might precipitate the clinical deterioration. Anecdotal findings in our large sample seem to provide interesting clues about the protean mechanisms of brain injury in this rare disease and further highlight the broad spectrum of MR imaging findings that might be expected while imaging a child with the suspicion of or a known diagnosis of Menkes disease.

SummaryData from large case series of children with cerebral thrombotic events are pivotal to improve prevention, early recognition and treatment of these conditions. The Italian Registry of Pediatric Thrombosis (R. I. T. I.) was established in 2007 by a multidisciplinary team, aiming for a better understanding of neonatal and paediatric thrombotic events in Italy and providing a preliminary source of data for the future development of specific clinical trials and diagnostic-therapeutic protocols. We analysed data relative to the paediatric cerebral thrombotic events of the R. I. T. I. which occurred between January 2007 and June 2012. In the study period, 79 arterial ischaemic stroke (AIS) events (49 in males) and 91 cerebral sinovenous thrombosis (CSVT) events (65 in males) were enrolled in the R. I. T. I. Mean age at onset was 4.5 years in AIS, and 7.1 years in CSVT. Most common modes of presentation were hemiparesis, seizures and speech disturbances in AIS, and headache, seizures and lethargy in CSVT. Most common etiologies were underlying chronic diseases, vasculopathy and cardiopathy in AIS, and underlying chronic diseases and infection in CSVT. Time to diagnosis exceeded 24 hours in 46 % AIS and 59 % CSVT. Overall data from the Italian Registry are in substantial agreement with those from the literature, despite small differences. Among these, a longer time to diagnosis compared to other registries and case series poses the accent to the need of an earlier recognition of paediatric cerebrovascular events in Italy, in order to enable prompt and effective treatment strategies.

Background: Purified cannabidiol (CBD) was administered to highly refractory patients with Dravet (DS) or Lennox–Gastaut (LGS) syndromes in an ongoing expanded access program (EAP). Herein, we report interim results on CBD safety and seizure outcomes in patients treated for a 12-month period.Material and Methods: Thirty centers were enrolled from December 2018 to December 2019 within the open-label prospective EAP up to a maximum of 25 mg/kg per day. Adverse effects and liver function tests were assessed after 2 weeks; 1, 3, and 6 months of treatment; and periodically thereafter. Seizure endpoints were the percentage of patients with ≥50 and 100% reduction in seizures compared to baseline.Results: A total of 93 patients were enrolled and included in the safety analysis. Eighty-two patients [27 (32.9%) DS, 55 (67.1%) LGS] with at least 3 months of treatment have been included in the effectiveness analysis; median previously failed antiseizure medications was eight. Pediatric and adult patients were uniformly represented in the cohort. At 3-month follow-up, compared to the 28-day baseline period, the percentage of patients with at least a 50% reduction in seizure frequency was 40.2% (plus 1.2% seizure-free). Retention rate was similar according to diagnosis, while we found an increased number of patients remaining under treatment in the adult group. CBD was mostly coadministered with valproic acid (62.2%) and clobazam (41.5%). In the safety dataset, 29 (31.2%) dropped out: reasons were lack of efficacy [16 (17.2%)] and adverse events (AEs) [12 (12.9%)], and one met withdrawal criteria (1.1%). Most reported AEs were somnolence (22.6%) and diarrhea (11.9%), followed by transaminase elevation and loss of appetite.Conclusions: CBD is associated with improved seizure control also in a considerable proportion of highly refractory patients with DS and LGS independently from clobazam use. Overall, CBD safety and effectiveness are not dose-related in this cohort.

Autoimmune encephalitis associated with antibodies against neuronal surface targets (NSAE) are rare but still underrecognized conditions that affect adult and pediatric patients. Clinical guidelines have recently been published with the aim of providing diagnostic clues regardless of antibody status. These syndromes are potentially treatable but the choice of treatment and its timing, as well as differential diagnoses, long-term management, and clinical and paraclinical follow-up, remain major challenges. In the absence of evidence-based guidelines, management of these conditions is commonly based on single-center expertise. Taking into account different published expert recommendations in addition to the multicenter experience of the Italian Working Group on Autoimmune Encephalitis, both widely accepted and critical aspects of diagnosis, management and particularly of immunotherapy for NSAE have been reviewed and are discussed. Finally, we provide consensus-based practical advice for managing hospitalization and follow-up of patients with NSAE.

Epidemiologic data on neuronal surface antibody (NSAb)-associated autoimmune encephalitides (NSAE) are scarce and heterogeneous. We review our 13-year-long biobank-data collection and provide the incidence of NSAE in two Italian provinces (approx. Population of 1,400,000) over a 5-year period (July 2013-June 2018). NSAbs were diagnosed in 75 out of 1179 tested patients (6.4%). The most common NSAbs were anti-LGI1 (30 cases), followed by NMDAR (24). Eleven cases of NSAE were diagnosed in Treviso and Trento provinces with an estimated incidence of 1.54 per 1,000,000 population (LGI1-encephalitis 0.84; C.I. 0.38-1.88). LGI1-E is the most frequent NSAE among adults.

Background and purpose : Autoimmune encephalitides (AE) include a spectrum of neurological disorders whose diagnosis revolves around the detection of neuronal antibodies (Abs). Consensus-based diagnostic criteria (AE-DC) allow clinic-serological subgrouping of AE, with unclear prognostic implications. The impact of AE-DC on patients’ management was studied, focusing on the subgroupofAb-negative-AE. Methods: This was a retrospective multicenter study on patients fulfilling AE-DC. All patients underwent Ab testing with commercial cell-based assays (CBAs) and, when available, in-house assays (immunohistochemistry, live/fixed CBAs, neuronal cultures) that contributed to defining final categories. Patients were classified as Ab-positive-AE [N-methyl-d-aspartate-receptor encephalitis (NMDAR-E), Ab-positive limbic encephalitis (LE), definite-AE] or Ab-negative-AE (Ab-negative-LE, probable-AE, possible-AE). Results: Commercial CBAs detected neuronal Abs in 70/118 (59.3%) patients. Testing 37/48 Ab-negative cases, in-house assays identified Abs in 11 patients (29.7%). A hundred and eighteen patients fulfilled the AE-DC, 81 (68.6%) with Ab-positive-AE (Ab-positive-LE, 40; NMDAR-E, 32; definite-AE, nine) and 37 (31.4%) with Ab-negative-AE (Ab-negative-LE, 17; probable/possible-AE, 20). Clinical phenotypes were similar in Ab-positive-LE versus Ab-negative-LE. Twenty-four/118 (20.3%) patients had tumors, and 19/118 (16.1%) relapsed, regardless of being Ab-positive or Ab-negative. Ab-positive-AE patients were treated earlier than Ab-negative-AE patients (P=0.045), responded more frequently to treatments (92.3% vs. 65.6%, P&nbsp

Aim: To identify factors that may predict and affect the risk of relapse in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Method: This was a retrospective study of an Italian cohort of patients with paediatric (≤18y) onset anti-NMDAR encephalitis. Results: Of the 62 children included (39 females; median age at onset 9y 10mo, range 1y 2mo–18y; onset between 2005 and 2018), 21 per cent relapsed (median two total events per relapsing patient, range 2–4). Time to first relapse was median 31.5months (range 7–89mo). Severity at first relapse was lower than onset (median modified Rankin Scale [mRS] 3, range 2–4, vs median mRS 5, range 3–5; admission to intensive care unit: 0/10 vs 3/10). At the survival analysis, the risk of relapsing was significantly lower in patients who received three or more different immune therapies at first disease event (hazard ratio 0.208, 95% confidence interval 0.046–0.941; p=0.042). Neurological outcome at follow-up did not differ significantly between patients with relapsing and monophasic disease (mRS 0–1 in 39/49 vs 12/13; p=0.431), although follow-up duration was significantly longer in relapsing (median 84mo, range 14–137mo) than in monophasic patients (median 32mo, range 4–108mo; p=0.002). Interpretation: Relapses may occur in about one-fifth of children with anti-NMDAR encephalitis, are generally milder than at onset, and may span over a long period, although they do not seem to be associated with severity in the acute phase or with outcome at follow-up. Aggressive immune therapy at onset may reduce risk of relapse. What this paper adds: Relapses of anti-N-methyl-D-aspartate receptor encephalitis may span over a long period. Relapses were not associated with severity in the acute phase or outcome at follow-up. Aggressive immune therapy at onset appears to decrease risk of relapse.