IMPORTANCE Sudden cardiac death (SCD) is the most common mode of death in childhood hypertrophic cardiomyopathy (HCM), but there is no validated algorithm to identify those at highest risk. OBJECTIVE To develop and validate an SCD risk prediction model that provides individualized risk estimates. DESIGN, SETTING, AND PARTICIPANTS A prognostic model was developed from a retrospective, multicenter, longitudinal cohort study of 1024 consecutively evaluated patients aged 16 years or younger with HCM. The study was conducted from January 1, 1970, to December 31, 2017. EXPOSURES The model was developed using preselected predictor variables (unexplained syncope, maximal left-ventricular wall thickness, left atrial diameter, left-ventricular outflow tract gradient, and nonsustained ventricular tachycardia) identified from the literature and internally validated using bootstrapping. MAIN OUTCOMES AND MEASURES A composite outcome of SCD or an equivalent event (aborted cardiac arrest, appropriate implantable cardioverter defibrillator therapy, or sustained ventricular tachycardia associated with hemodynamic compromise). RESULTS Of the 1024 patients included in the study, 699 were boys (68.3%); mean (interquartile range [IQR]) age was 11 (7-14) years. Over a median follow-up of 5.3 years (IQR, 2.6-8.3; total patient years, 5984), 89 patients (8.7%) died suddenly or had an equivalent event (annual event rate, 1.49; 95% CI, 1.15-1.92). The pediatric model was developed using preselected variables to predict the risk of SCD. The model's ability to predict risk at 5 years was validated; the C statistic was 0.69 (95% CI, 0.66-0.72), and the calibration slope was 0.98 (95% CI, 0.59-1.38). For every 10 implantable cardioverter defibrillators implanted in patients with 6% or more of a 5-year SCD risk, 1 patient may potentially be saved from SCD at 5 years. CONCLUSIONS AND RELEVANCE This new, validated risk stratification model for SCD in childhood HCM may provide individualized estimates of risk at 5 years using readily obtained clinical risk factors. External validation studies are required to demonstrate the accuracy of this model's predictions in diverse patient populations.

Myelin oligodendrocyte glycoprotein antibodies (MOG-Ab) are highly specific for acquired demyelinating syndromes (ADS). Myelin oligodendrocyte glycoprotein antibodies are not identified in children with peripheral demyelination or genetic leukodystrophies/hypomyelination. Up to 48% of MOG-Ab ADS paediatric patients relapse, higher than previously thought. Seroconversion to MOG-Ab negative status is infrequent; patients may test MOG-Ab positive at follow-up sampling even when asymptomatic. Myelin oligodendrocyte glycoprotein antibodies status should only be used in conjunction with the clinical information to guide maintenance therapy.

Objective: To identify predictors of epilepsy and clinical relapses in children presenting with acute disseminated encephalomyelitis (ADEM). Methods: Children presenting with ADEM between 2005 and 2017 and tested clinically for MOG-Ab were identified from three tertiary paediatric neurology centres in the United Kingdom. Patients were followed up for a median of 6 years (range, 1–16 years). Results: A total of 74 children were studied (38 females; median age at first presentation: 4.5 years (range, 1.4–16 years)). MOG-Ab was positive in 50/74 (67.6%) of cases, and 27 (54%) of MOG-Ab positive children presented with a neurological relapse over time. MOG-Ab was more frequently positive in the relapsing group than in the monophasic group (27/31 vs 23/43; odds ratio 5.9 (95% CI: 1.8–19.7); p = 0.002). 16/74 (22%) children had seizures during the acute presentation with ADEM and 12/74 (16.2%) patients were diagnosed with post-ADEM epilepsy. The diagnosis of post-ADEM epilepsy was more frequently observed in children with relapsing disease than monophasic disease (10/31 vs 2/43; odds ratio 9.8 (95% confidence interval (CI): 2.0–48.7); p = 0.003), in children who had positive intrathecal oligoclonal bands than those with negative bands (4/7 vs 4/30; odds ratio 8.7 (95% CI: 1.4–54.0); p = 0.027) and in children who had positive MOG-Ab than negative MOG-Ab cases (11/12 vs 39/62; odds ratio 6.5 (95% CI:0.8–53.6); p = 0.051). Conclusion: A higher relapse rate and a greater risk of post-ADEM epilepsy in children with MOG-Ab-associated disease may indicate a chronic disease with immune-mediated seizures in these children.

In selected patients with unresectable CCA, long-term survival can be achieved using neoadjuvant chemoradiotherapy and OLT although short-term mortality is high. Prospective international registries may aid patient selection and refinement of neoadjuvant regimens.

Multiple sclerosis is a chronic immune‐mediated demyelinating disease of the central nervous system. The diagnosis of multiple sclerosis in children, as in adults, requires evidence of dissemination of inflammatory activity in more than one location in the central nervous system (dissemination in space) and recurrent disease over time (dissemination in time). The identification of myelin oligodendrocyte glycoprotein antibodies (MOG‐Ab) and aquaporin‐A antibodies (AQP4‐Ab), and the subsequent discovery of their pathogenic mechanisms, have led to a shift in the classification of relapsing demyelinating syndromes. This is reflected in the 2017 revised criteria for the diagnosis of multiple sclerosis, which emphasizes the exclusion of multiple sclerosis mimics and aims to enable earlier diagnosis and thus treatment initiation. The long‐term efficacy of individual therapies initiated in children with multiple sclerosis is hard to evaluate, owing to the small numbers of patients who have the disease, the relatively high number of patients who switch therapy, and the need for long follow‐up studies. Nevertheless, an improvement in prognosis with a globally reduced annual relapse rate in children with multiple sclerosis is now observed compared with the pretreatment era, indicating a possible long‐term effect of therapies. Given the higher relapse rate in children compared with adults, and the impact multiple sclerosis has on cognition in the developing brain, there is a question whether rapid escalation or potent agents should be used in children, while the short‐ and long‐term safety profiles of these drugs are being established. With the results of the first randomized controlled trial of fingolimod versus interferon‐β1a in paediatric multiple sclerosis published in 2018 and several clinical trials underway, there is hope for further progress in the field of paediatric multiple sclerosis. What this paper adds Early and accurate diagnosis of multiple sclerosis is crucial. The discovery of antibody‐mediated demyelination has changed the diagnosis and management of relapsing demyelination syndromes. Traditional escalation therapy is being challenged by induction therapy.