Outcome and recurrence 1 year after pediatric arterial ischemic stroke in a population-based cohort

OBJECTIVE

Arterial ischemic stroke (AIS) is an important cause of acquired brain injury in children. Few prospective population-based studies of childhood AIS have been completed. We aimed to investigate the outcome of childhood AIS 12 months after the event in a population-based cohort.

METHODS

Children aged 29 days to < 16 years with radiologically confirmed AIS occurring over a 1-year period residing in southern England (population = 5.99 million children) were eligible for inclusion. Outcome was assessed during a home visit using the Pediatric Stroke Outcome Measure (PSOM). Parental impressions of recovery were assessed using the Pediatric Stroke Recurrence and Recovery Questionnaire. PSOM score was estimated via telephone interview or clinician interview whenever home visit was not possible.

RESULTS

Ninety-six children with AIS were identified. Two children were lost to follow-up. Nine of 94 (10%) children died before the 12-month follow-up. One child had an AIS recurrence. PSOM scores were available for 78 of 85 living children at follow-up. Thirty-nine of 78 (50%) had a good outcome (total PSOM score < 1), and 39 of 78 (50%) had a poor outcome. Seizures at onset of AIS were associated with a poor outcome (odds ratio = 3.5, 95% confidence interval = 1.16-10.6). Twenty-eight of 73 (38%) children were judged by their carers to have fully recovered. Ten of 84 (12%) children had recurrent seizures, and 17 of 84 (20%) reported recurrent headaches.

INTERPRETATION

AIS carries a significant risk of mortality and long-term neurological deficit. However, the rates of mortality, recurrence, and neurological impairment were markedly lower in this study than previously published figures in the United Kingdom. Ann Neurol 2016;79:784-793.

Guillain-Barré syndrome associated with CASPR2 antibodies: two paediatric cases

The pathogenesis of Guillain-Barré syndrome (GBS) is considered to be, at least in part, mediated by autoantibodies directed against neuronal antigens. Antibodies to contactin-associated protein-like 2 (CASPR2), part of the voltage-gated potassium channel complex (VGKC-complex), are associated with neurological disease predominantly affecting the peripheral nervous system but are not known to be associated with GBS. We report two cases of ganglioside antibody-negative paediatric GBS associated with CASPR2 antibodies. Both patients made a complete clinical recovery. The tissue distribution and function of CASPR2 make it a biologically plausible autoimmune target in GBS and its clinical relevance in GBS should be determined in further studies.

Surgery for scoliosis in Duchenne muscular dystrophy

BACKGROUND

Scoliosis in patients with Duchenne muscular dystrophy (DMD) is usually progressive and is treated with surgery. However, it is unclear whether the existing evidence is sufficiently scientifically rigorous to support a recommendation for spinal surgery for most patients with DMD and scoliosis. This is an updated review, and an updated search was undertaken in which no new studies were found for inclusion.

OBJECTIVES

To determine the effectiveness and safety of spinal surgery in patients with DMD with scoliosis. We intended to test whether spinal surgery is effective in increasing survival and improving respiratory function, quality of life, and overall functioning, and whether spinal surgery is associated with severe adverse effects.

SEARCH METHODS

On 16 June 2015 we searched the Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and CINAHL Plus. We also searched ProQuest Dissertation and Thesis database (January 1980 to June 2015), the National Institutes of Health Clinical Trials Database (6 January 2015), and the WHO International Clinical Trials Registry Platform (17 June 2015), and checked references. We imposed no language restrictions.

SELECTION CRITERIA

We planned to include controlled clinical trials using random or quasi-random allocation of treatment evaluating all forms of spinal surgery for scoliosis in patients with DMD in the review. The control interventions would have been no treatment, non-operative treatment, or a different form of spinal surgery.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. Two review authors independently examined the search results and evaluated the study characteristics against inclusion criteria in order to decide which studies to include in the review.

MAIN RESULTS

Of the 49 relevant studies we found, none met the inclusion criteria for the review because they were not clinical trials, but prospective or retrospective reviews of case series.

AUTHORS' CONCLUSIONS

Since no randomized controlled clinical trials were available to evaluate the effectiveness of scoliosis surgery in patients with DMD, we can make no good evidence-based conclusion to guide clinical practice. Patients with scoliosis should be informed as to the uncertainty of benefits and potential risks of surgery for scoliosis. Randomized controlled trials are needed to investigate the effectiveness of scoliosis surgery, in terms of quality of life, functional status, respiratory function, and life expectancy.

Diagnostic delays in paediatric stroke

BACKGROUND

Stroke is a major cause of mortality in children. Conditions that mimic stroke also cause severe morbidity and require prompt diagnosis and treatment. We have investigated the time to diagnosis in a cohort of children with stroke.

METHODS

A population-based cohort of children with stroke was prospectively identified in the south of England. Case notes, electronic hospital admission databases and radiology records were reviewed. Timing of symptom onset, presentation to hospital, first neuroimaging, first diagnostic neuroimaging and presenting clinical features were recorded.

RESULTS

Ninety-six children with an arterial ischaemic stroke (AIS) and 43 with a haemorrhagic stroke (HS) were identified. The median time from symptom onset to diagnostic neuroimaging was 24.3 h in AIS and 2.9 h in HS. The initial imaging modality was CT in 68% of cases of AIS. CT was diagnostic of AIS in 66% of cases. MRI was diagnostic in 100%. If initial neuroimaging was non-diagnostic in AIS, then median time to diagnosis was 44 h. CT was diagnostic in 95% of HS cases. Presentation outside normal working hours resulted in delayed neuroimaging in AIS (13 vs 3 h, p=0.032). Diffuse neurological signs or a Glasgow Coma Scale <9 resulted in more expeditious neuroimaging in both HS and AIS.

CONCLUSIONS

The diagnosis of AIS in children is delayed at every stage of the pathway but most profoundly when the first neuroimaging is CT scanning, which is non-diagnostic. MRI should be the initial imaging modality of choice in any suspected case of childhood AIS.

Novel mutations widen the phenotypic spectrum of slow skeletal/β-cardiac myosin (MYH7) distal myopathy

Laing early onset distal myopathy and myosin storage myopathy are caused by mutations of slow skeletal/β-cardiac myosin heavy chain encoded by the gene MYH7, as is a common form of familial hypertrophic/dilated cardiomyopathy. The mechanisms by which different phenotypes are produced by mutations in MYH7, even in the same region of the gene, are not known. To explore the clinical spectrum and pathobiology, we screened the MYH7 gene in 88 patients from 21 previously unpublished families presenting with distal or generalized skeletal muscle weakness, with or without cardiac involvement. Twelve novel mutations have been identified in thirteen families. In one of these families, the father of the proband was found to be a mosaic for the MYH7 mutation. In eight cases, de novo mutation appeared to have occurred, which was proven in four. The presenting complaint was footdrop, sometimes leading to delayed walking or tripping, in members of 17 families (81%), with other presentations including cardiomyopathy in infancy, generalized floppiness, and scoliosis. Cardiac involvement as well as skeletal muscle weakness was identified in nine of 21 families. Spinal involvement such as scoliosis or rigidity was identified in 12 (57%). This report widens the clinical and pathological phenotypes, and the genetics of MYH7 mutations leading to skeletal muscle diseases.

Episodic ataxia type 1 without episodic ataxia: the diagnostic utility of nerve excitability studies in individuals with KCNA1 mutations

Episodic ataxia type 1 (EA1) is caused by mutations in the KCNA1 gene encoding the fast potassium channel Kv1.1 and is characterized clinically by brief episodes of ataxia and continuous and spontaneous motor unit activity. Atypical presentations, in which the predominant manifestation is related to the peripheral nervous system, may lead to the diagnosis being missed or delayed, with the potential risk of individuals receiving inappropriate or unnecessary investigations and treatment. We present a case of a 15-year-old female with EA1 who had never had episodes of ataxia, and whose hand movements were initially thought to represent a tremor. Genetic screening for KCNA1 mutations was precipitated by the results of the nerve excitability studies (TROND protocol), which showed changes typical of reduced fast potassium channel conductance. This case highlights the utility of nerve excitability studies in identifying individuals with KCNA1 mutations.

Outcome of children with acetylcholine receptor (AChR) antibody positive juvenile myasthenia gravis following thymectomy

Most evidence supporting the benefit of thymectomy in juvenile myasthenia gravis (JMG) is extrapolated from adult studies, with only little data concerning paediatric populations. Here we evaluate the outcome of children with generalized JMG who underwent thymectomy between 1996 and 2010 at 2 tertiary paediatric neurology referral centres in the United Kingdom. Twenty patients (15 female, 5 male), aged 13months to 15.5years (median 10.4years) at disease onset, were identified. Prior to thymectomy, disease severity was graded as IIb in 3, III in 11, and IV in 6 patients according to the Osserman classification. All demonstrated positive anti-acetylcholine receptor (AChR) antibody titres. All patients received pyridostigmine and 14 received additional steroid therapy. Transternal thymectomy was performed at the age of 2.7-16.6years (median 11.1years). At the last follow-up (10months to 10.9years, median 2.7years, after thymectomy), the majority of children demonstrated substantial improvement, although some had required additional immune-modulatory therapies. About one third achieved complete remission. The postoperative morbidity was low. No benefit was observed in one patient with thymoma. We conclude that thymectomy should be considered as a treatment option early in the course of generalised AChR antibody-positive JMG.

Mutations in GDP-mannose pyrophosphorylase B cause congenital and limb-girdle muscular dystrophies associated with hypoglycosylation of α-dystroglycan

Congenital muscular dystrophies with hypoglycosylation of α-dystroglycan (α-DG) are a heterogeneous group of disorders often associated with brain and eye defects in addition to muscular dystrophy. Causative variants in 14 genes thought to be involved in the glycosylation of α-DG have been identified thus far. Allelic mutations in these genes might also cause milder limb-girdle muscular dystrophy phenotypes. Using a combination of exome and Sanger sequencing in eight unrelated individuals, we present evidence that mutations in guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) can result in muscular dystrophy variants with hypoglycosylated α-DG. GMPPB catalyzes the formation of GDP-mannose from GTP and mannose-1-phosphate. GDP-mannose is required for O-mannosylation of proteins, including α-DG, and it is the substrate of cytosolic mannosyltransferases. We found reduced α-DG glycosylation in the muscle biopsies of affected individuals and in available fibroblasts. Overexpression of wild-type GMPPB in fibroblasts from an affected individual partially restored glycosylation of α-DG. Whereas wild-type GMPPB localized to the cytoplasm, five of the identified missense mutations caused formation of aggregates in the cytoplasm or near membrane protrusions. Additionally, knockdown of the GMPPB ortholog in zebrafish caused structural muscle defects with decreased motility, eye abnormalities, and reduced glycosylation of α-DG. Together, these data indicate that GMPPB mutations are responsible for congenital and limb-girdle muscular dystrophies with hypoglycosylation of α-DG.

Long-term benefits and adverse effects of intermittent versus daily glucocorticoids in boys with Duchenne muscular dystrophy

OBJECTIVE

To assess the current use of glucocorticoids (GCs) in Duchenne muscular dystrophy in the UK, and compare the benefits and the adverse events of daily versus intermittent prednisolone regimens.

DESIGN

A prospective longitudinal observational study across 17 neuromuscular centres in the UK of 360 boys aged 3-15 years with confirmed Duchenne muscular dystrophy who were treated with daily or intermittent (10 days on/10 days off) prednisolone for a mean duration of treatment of 4 years.

RESULTS

The median loss of ambulation was 12 years in intermittent and 14.5 years in daily treatment; the HR for intermittent treatment was 1.57 (95% CI 0.87 to 2.82). A fitted multilevel model comparing the intermittent and daily regiments for the NorthStar Ambulatory Assessment demonstrated a divergence after 7 years of age, with boys on an intermittent regimen declining faster (p<0.001). Moderate to severe side effects were more commonly reported and observed in the daily regimen, including Cushingoid features, adverse behavioural events and hypertension. Body mass index mean z score was higher in the daily regimen (1.99, 95% CI 1.79 to 2.19) than in the intermittent regimen (1.51, 95% CI 1.27 to 1.75). Height restriction was more severe in the daily regimen (mean z score -1.77, 95% CI -1.79 to -2.19) than in the intermittent regimen (mean z score -0.70, 95% CI -0.90 to -0.49).

CONCLUSIONS

Our study provides a framework for providing information to patients with Duchenne muscular dystrophy and their families when introducing GC therapy. The study also highlights the importance of collecting longitudinal natural history data on patients treated according to standardised protocols, and clearly identifies the benefits and the side-effect profile of two treatment regimens, which will help with informed choices and implementation of targeted surveillance.

Mutations in RYR1 are a common cause of exertional myalgia and rhabdomyolysis

Mutations in the skeletal muscle ryanodine receptor (RYR1) gene are a common cause of neuromuscular disease, ranging from various congenital myopathies to the malignant hyperthermia (MH) susceptibility trait without associated weakness. We sequenced RYR1 in 39 unrelated families with rhabdomyolysis and/or exertional myalgia, frequent presentations in the neuromuscular clinic that often remain unexplained despite extensive investigations. We identified 9 heterozygous RYR1 mutations/variants in 14 families, 5 of them (p.Lys1393Arg; p.Gly2434Arg; p.Thr4288_Ala4290dup; p.Ala4295Val; and p.Arg4737Gln) previously associated with MH. Index cases presented from 3 to 45 years with rhabdomyolysis, with or without exertional myalgia (n=12), or isolated exertional myalgia (n=2). Rhabdomyolysis was commonly triggered by exercise and heat and, less frequently, viral infections, alcohol and drugs. Most cases were normally strong and had no personal MH history. Inconsistent additional features included heat intolerance, and cold-induced muscle stiffness. Muscle biopsies showed mainly subtle changes. Familial RYR1 mutations were confirmed in relatives with similar or no symptoms. These findings suggest that RYR1 mutations may account for a substantial proportion of patients presenting with unexplained rhabdomyolysis and/or exertional myalgia. Associated clinico-pathological features may be subtle and require a high degree of suspicion. Additional family studies are paramount in order to identify potentially MH susceptible relatives.

Surgery for scoliosis in Duchenne muscular dystrophy

BACKGROUND

Scoliosis in people with Duchenne muscular dystrophy is usually progressive and treated with surgery. However, it is unclear whether the existing evidence is sufficiently scientifically rigorous to support a recommendation for spinal surgery for most people with Duchenne muscular dystrophy and scoliosis. This is an updated review and an updated search was undertaken in which no new studies were found.

OBJECTIVES

To determine the effectiveness and safety of spinal surgery in people with Duchenne muscular dystrophy with scoliosis. We intended to test whether spinal surgery is effective in increasing survival, improving respiratory function, improving quality of life and overall functioning; and whether spinal surgery is associated with severe adverse effects.

SEARCH METHODS

We searched the specialized registers of the Cochrane Neuromuscular Disease Group (31 July 2012), MEDLINE (January 1966 to July 2012), EMBASE (January 1947 to July 2012), CENTRAL (2012, Issue 7 in the Cochrane Library), CINAHL Plus(January 1937 to July 2012), Proquest Dissertation and Thesis Database (January 1980 to July 2012), and the National Institute of Health Clinical Trials Database (July 2012). No language restrictions were imposed.

SELECTION CRITERIA

We planned to include controlled clinical trials using random or quasi-random allocation of treatment evaluating all forms of spinal surgery for scoliosis in people with Duchenne muscular dystrophy in the review. The control interventions would have been no treatment, non-operative treatment, or a different form of spinal surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently examined the search results and evaluated the study characteristics against inclusion criteria to decide which ones would be included in the review.

MAIN RESULTS

On searching, 47 studies were relevant but none met the inclusion criteria for the review, because they were not clinical trials but prospective or retrospective reviews of case series.

AUTHORS' CONCLUSIONS

Since there were no randomized controlled clinical trials available to evaluate the effectiveness of scoliosis surgery in people with Duchenne muscular dystrophy, no evidence-based recommendation can be made for clinical practice. People with scoliosis should be informed about the uncertainty of benefits and potential risks of surgery for scoliosis. Randomized controlled trials are needed to investigate the effectiveness of scoliosis surgery, in terms of quality of life, functional status, respiratory function and life expectancy.

Abstract 74: The Epidemiology of Childhood Stroke in Southern England: A Prospective Study using Multiple Sources of Case Ascertainment

Background: Epidemiological data are vital to quantify the scale of disease and can provide insights into aetiological factors.

Objective: To describe the epidemiology of childhood stroke in southern England.

Methods: Children (>28 days to <16 years) residing in southern England (5.99 million children) who had arterial ischemic stroke (AIS), cerebral sinovenous thrombosis with venous infarction (CSVT) and hemorrhagic stroke (HS) between July 2008 and June 2009 were identified. Multiple sources including pediatric neurologists, pediatricians, neurosurgeons, radiologists, physiotherapists, a national intensive care audit system, and parents notified cases.

Results: 153 cases of stroke were identified (96 cases of AIS, 14 cases of CSVT and 43 cases of HS). The incidence for overall stroke was 2.56 per 100,000 person years (95% CI 2.15 - 2.96). The age distribution is shown in Figure 1. There was no difference between males and females in the risk of ischemic (AIS and CSVT) stroke (RR=1.06, p=0.75), HS (RR=1.46, p=0.22) or overall stroke (RR=1.16, p=0.36). Compared to Whites the relative risk of ischaemic stroke was higher for Asians (RR=2.35, p=0.001) and Blacks (RR=2.52, p=0.003). There was no increased risk of HS for Asians (RR=0.84, p=0.77) or Blacks (RR=1.39, p=0.58).

Conclusions: The incidence of childhood stroke found by this study is higher than previously found in the UK. This is the first study to show disparities in the risk of childhood stroke between ethnic groups in Europe. Although an increased risk for males is commonly reported a number of recent population based studies have found no gender disparity.

Clinical and genetic findings in a large cohort of patients with ryanodine receptor 1 gene-associated myopathies

Ryanodine receptor 1 (RYR1) mutations are a common cause of congenital myopathies associated with both dominant and recessive inheritance. Histopathological findings frequently feature central cores or multi-minicores, more rarely, type 1 predominance/uniformity, fiber-type disproportion, increased internal nucleation, and fatty and connective tissue. We describe 71 families, 35 associated with dominant RYR1 mutations and 36 with recessive inheritance. Five of the dominant mutations and 35 of the 55 recessive mutations have not been previously reported. Dominant mutations, typically missense, were frequently located in recognized mutational hotspot regions, while recessive mutations were distributed throughout the entire coding sequence. Recessive mutations included nonsense and splice mutations expected to result in reduced RyR1 protein. There was wide clinical variability. As a group, dominant mutations were associated with milder phenotypes; patients with recessive inheritance had earlier onset, more weakness, and functional limitations. Extraocular and bulbar muscle involvement was almost exclusively observed in the recessive group. In conclusion, our study reports a large number of novel RYR1 mutations and indicates that recessive variants are at least as frequent as the dominant ones. Assigning pathogenicity to novel mutations is often difficult, and interpretation of genetic results in the context of clinical, histological, and muscle magnetic resonance imaging findings is essential.

Generalized arterial calcification of infancy and pseudoxanthoma elasticum can be caused by mutations in either ENPP1 or ABCC6

Spontaneous pathologic arterial calcifications in childhood can occur in generalized arterial calcification of infancy (GACI) or in pseudoxanthoma elasticum (PXE). GACI is associated with biallelic mutations in ENPP1 in the majority of cases, whereas mutations in ABCC6 are known to cause PXE. However, the genetic basis in subsets of both disease phenotypes remains elusive. We hypothesized that GACI and PXE are in a closely related spectrum of disease. We used a standardized questionnaire to retrospectively evaluate the phenotype of 92 probands with a clinical history of GACI. We obtained the ENPP1 genotype by conventional sequencing. In those patients with less than two disease-causing ENPP1 mutations, we sequenced ABCC6. We observed that three GACI patients who carried biallelic ENPP1 mutations developed typical signs of PXE between 5 and 8 years of age; these signs included angioid streaks and pseudoxanthomatous skin lesions. In 28 patients, no disease-causing ENPP1 mutation was found. In 14 of these patients, we detected pathogenic ABCC6 mutations (biallelic mutations in eight patients, monoallelic mutations in six patients). Thus, ABCC6 mutations account for a significant subset of GACI patients, and ENPP1 mutations can also be associated with PXE lesions in school-aged children. Based on the considerable overlap of genotype and phenotype of GACI and PXE, both entities appear to reflect two ends of a clinical spectrum of ectopic calcification and other organ pathologies, rather than two distinct disorders. ABCC6 and ENPP1 mutations might lead to alterations of the same physiological pathways in tissues beyond the artery.

Congenital lower brachial plexus palsy due to cervical ribs

Congenital brachial plexus palsy (CBPP) usually occurs secondarily to intrapartum trauma, but this is not always the case. Cervical ribs have previously been reported to increase the risk of CBPP in association with birth trauma. We report the cases of two children (one female, one male) with congenital lower brachial plexus palsy in whom the presence of non-ossified cervical ribs was the only identified risk factor. In the female child magnetic resonance imaging (MRI) of the brain, spinal cord, and brachial plexus revealed no abnormality except for the presence of bilateral cervical ribs at the level of the seventh cervical (C7) vertebra. Chest radiography was normal, which suggested that the cervical ribs identified on the MRI were fibrous bands or cartilaginous ribs rather than ossified ribs. In the male child, MRI of the spine and brachial plexus was normal but he was noted to have bilateral cervical ribs at C7. These were not identifiable on chest radiography and, therefore, are likely to reflect fibrous bands or cartilaginous ribs.

Infantile onset myofibrillar myopathy due to recessive CRYAB mutations

Mutations in the αB-crystallin (CRYAB) gene, encoding a small heat shock protein with chaperone function, are a rare cause of myofibrillar myopathy with autosomal-dominant inheritance, late-onset and moderate severity. We report a female infant presenting from 4 months with profound muscle stiffness, persistent creatine kinase elevation and electromyography characterized by spontaneous electrical activity and pseudomyotonic discharges. Muscle biopsy suggested a myofibrillar myopathy and genetic testing revealed homozygosity for the CRYAB mutation c.343delT (p.Ser115ProfsX14). These findings suggest a severe, recessively inherited form of CRYAB-related myofibrillar myopathy. Profound muscle stiffness as the main presenting feature indicates αB-crystallin as a potent modifier of muscle contractility.

Congenital insensitivity to pain: novel SCN9A missense and in-frame deletion mutations

SCN9Aencodes the voltage-gated sodium channel Na(v)1.7, a protein highly expressed in pain-sensing neurons. Mutations in SCN9A cause three human pain disorders: bi-allelic loss of function mutations result in Channelopathy-associated Insensitivity to Pain (CIP), whereas activating mutations cause severe episodic pain in Paroxysmal Extreme Pain Disorder (PEPD) and Primary Erythermalgia (PE). To date, all mutations in SCN9A that cause a complete inability to experience pain are protein truncating and presumably lead to no protein being produced. Here, we describe the identification and functional characterization of two novel non-truncating mutations in families with CIP: a homozygously-inherited missense mutation found in a consanguineous Israeli Bedouin family (Na(v)1.7-R896Q) and a five amino acid in-frame deletion found in a sporadic compound heterozygote (Na(v)1.7-DeltaR1370-L1374). Both of these mutations map to the pore region of the Na(v)1.7 sodium channel. Using transient transfection of PC12 cells we found a significant reduction in membrane localization of the mutant protein compared to the wild type. Furthermore, voltage clamp experiments of mutant-transfected HEK293 cells show a complete loss of function of the sodium channel, consistent with the absence of pain phenotype. In summary, this study has identified critical amino acids needed for the normal subcellular localization and function of Na(v)1.7.