Pandemrix vaccination is a precipitating factor for narcolepsy, especially in combination with HLA-DQB1*0602. The incidence of narcolepsy was 25 times higher after the vaccination compared with the time period before. The children in the postvaccination group had a lower age at onset and a more sudden onset than that generally seen.

ObjectivesOur aime was to study the short- and long-term effects of ketogenic diet on the disease course and disease-related outcomes in patients with pyruvate dehydrogenase complex deficiency, the metabolic factors implicated in treatment outcomes, and potential safety and compliance issues.MethodsPediatric patients diagnosed with pyruvate dehydrogenase complex deficiency in Sweden and treated with ketogenic diet were evaluated. Study assessments at specific time points included developmental and neurocognitive testing, patient log books, and investigator and parental questionnaires. A systematic literature review was also performed.ResultsNineteen patients were assessed, the majority having prenatal disease onset. Patients were treated with ketogenic diet for a median of 2.9 years. All patients alive at the time of data registration at a median age of 6 years. The treatment had a positive effect mainly in the areas of epilepsy, ataxia, sleep disturbance, speech/language development, social functioning, and frequency of hospitalizations. It was also safe—except in one patient who discontinued because of acute pancreatitis. The median plasma concentration of ketone bodies (3-hydroxybutyric acid) was 3.3 mmol/l. Poor dietary compliance was associated with relapsing ataxia and stagnation of motor and neurocognitive development. Results of neurocognitive testing are reported for 12 of 19 patients.ConclusionKetogenic diet was an effective and safe treatment for the majority of patients. Treatment effect was mainly determined by disease phenotype and attainment and maintenance of ketosis.Electronic supplementary materialThe online version of this article (doi:10.1007/s10545-016-0011-5) contains supplementary material, which is available to authorized users.

Summary:Purpose: The study purpose was to evaluate sleep structure during ketogenic diet (KD) treatment in children with therapy-resistant epilepsy and to correlate possible alterations with changes in clinical effects on seizure reduction, seizure severity, quality of life (QOL), and behavior.Methods: Eighteen children were examined with ambulatory polysomnographic recordings initially and after 3 months of KD treatment. Eleven children continued with the KD and were also evaluated after 12 months. Sleep parameters were estimated. Seizure frequency was recorded in a diary and seizure severity in the National Health Seizure Severity Scale (NHS3). QOL was assessed with a visual analogue scale. Child behavior checklist and Ponsford and Kinsella's rating scale of attentional behavior were used.Results: KD induced a significant decrease in total sleep (p = 0.05) and total night sleep (p = 0.006). Slow wave sleep was preserved, rapid eye movement (REM) sleep increased (p = 0.01), sleep stage 2 decreased (p = 0.004), and sleep stage 1 was unchanged. Eleven children continued with the KD and were also evaluated after 12 months. They showed a significant decrease in daytime sleep (p = 0.01) and a further increase in REM sleep (p = 0.06). Seizure frequency (p = 0.001, p = 0.003), seizure severity (p < 0.001, p = 0.005) and QOL (p < 0.001, p = 0.005) were significantly improved at 3 and 12 months. Attentional behavior was also improved, significantly so at 3 months (p = 0.003). There was a significant correlation between increased REM sleep and improvement in QOL (Spearman r = 0.6, p = 0.01) at 3 months.Conclusion: KD decreases sleep and improves sleep quality in children with therapy-resistant epilepsy. The improvement in sleep quality, with increased REM sleep, seems to contribute to the improvement in QOL.

Aim To assess the prevalence and incidence of Dravet syndrome in children diagnosed in Sweden between 2007 and 2011, and to describe neurological comorbidity, disease course, phenotypes, and treatment effects. Method All neuropaediatricians at university and county hospitals were asked to supply information for patients that matched the electro‐clinical profile of Dravet syndrome. Genetic laboratories and referral clinicians were also contacted and requested to supply information. Results The estimated incidence was one in 33 000 live births (95% CI 1:20 400–1:56 200) and prevalence on December 31, 2011 was one in 45 700 children aged less than 18 years of age (95% CI 1:33 800–1:63 400). The median age of the 42 children (18 males, 24 females) was 7 years (range 1–17y), the median age at seizure onset was 6 months (range 0–12mo), and the median age at diagnosis was 3 years (range 1–14y). A mutation in the SCN1A gene was found in 37 patients (88%), four were familial. Intellectual disability was diagnosed in 28 (67%) children, and 18 out of 30 patients investigated had autism spectrum disorder. Thirty participants had neurological deficits. Stiripentol, as an add‐on medication, was used in 18 patients. Among these patients, seven were seizure free, six had >50% seizure reduction, and five <50% seizure reduction. Interpretation This is the first population‐based study of Dravet syndrome in Sweden. Our data confirm international findings of incidence and highlights the severe and progressive course of this genetic epilepsy syndrome.