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AS PUBLISHED IN THE CANADIAN JOURNAL OF NEUROLOGICAL SCIENCES
funded, two-phase RCT comparing angiographic and clinical
outcomes. The lead-in phase aims to verify superior anatomical
results of clipping and determine its risks. Phase II will compare
clinical outcomes including overall re-treatment rates and bleeding
at five years.
J.01
PEDIATRICS
The metabolic phenotype guiding the discovery of treatable
intellectual disability genes
C van Karnebeek (Vancouver)* R Salvarinova (Vancouver) C Shyr
(Vancouver) G Sinclair (Vancouver) A Lehman (Vancouver) A
Waheed (St Louis) W Sly (St Louis) W Wasserman (Vancouver) S
Sylvia (Vancouver)
Introduction: Intellectual disability (ID) is a lifelong, debilitating
condition affecting 2.5% of children and adults worldwide. Our
TIDEX project aimed to identify novel, potentially treatable ID
genes employing the utility of the metabolic phenotype. Methods:
Criteria were applied to select patients for NGS: patient with
unexplained, Mendelian ID plus metabolic abnormalities. Whole
exome sequencing was performed for trio’s with customized bioinformatics
and subsequent validation. Results: In seven families
meeting the selection criteria, we discovered five new genes,
including a new treatable disorder Mitochondrial carbonic
anhydrase VA (CA-VA) deficiency identified in two nonconsanguineous
siblings with neonatal lethargy, hyperammonemia,
hyperlactatemia, hypoglycemia. CA-VA deficiency impairs
bicarbonate provision to four mitochondrial enzymes with a central
role in the urea cycle and intermediary metabolism. CA-VA
deficiency is amenable to preventive and emergency treatment, and
expands the number of treatable IDs. The other discovered genes
(various phases validation) include a nuclear mitochondrial disease,
biotin responsive, neuronal arborization, early endosomal recycling
genes. Conclusions: Our high success rate (>70%) emphasizes the
importance of the metabolic phenotype for gene discovery using
NGS technologies. Advantages include: facilitation candidate gene
hypothesis, validation causality identified variants, and targets for
treatment. Most important, such discoveries can be directly
translated into improved patient outcomes.
J.02
Evaluating the exposure of radiation from CT scans of children
presenting with primary headache
R Gandhi (Ottawa)* E Lewis (Ottawa) J Evans (Ottawa) E Sell
(Ottawa)
Objective: To determine the frequency of computed tomography
(CT) scanning ordered by a range of medical practioners for
pediatric patients presenting with migraine headaches. Background:
Headaches are a common problem in the pediatric population. In
2004, The American Academy of Neurology (AAN) developed
guidelines on neuroimaging for headache. The medical-legal climate
may be causing physicians to disregard these guidelines. Methods: A
retrospective chart review was conducted at the Children’s Hospital
of Eastern Ontario (CHEO), a tertiary care center in Ontario.
Records from 2004-2010 were collected for pediatric patients
referred to the outpatient neurology clinic at CHEO with ‘headache’
as the primary complaint. Results: Thirty-four percent (34/99) of
patients presenting with normal neurologic exams had undergone a
CT scan. Zero percent (0/34) of CT scans showed significant
findings, of which zero percent (0/34) of these CT scans changed the
headache diagnosis or management. Thirty-eight percent (13/34) of
CT scans were ordered by neurologists, thirty-eight percent (13/34)
by community physicians, and twenty-four percent (8/34) by CHEO
emergency physicians. Conclusion: Physicians are performing
unnecessary CT scans on children presenting with primary
headaches, despite well established AAN guidelines regarding
neuroimaging. The reality of the medical-legal climate in North
America encourages physicians to over-investigate, unnecessarily
increasing the risk of adverse events from radiation exposure to
pediatric patients.
J.03
MRI findings in infants with infantile spasms after neonatal
hypoxic-ischemic encephalopathy
D Gano (Vancouver)* MA Sargent (Vancouver) SP Miller (Toronto)
MB Connolly (Vancouver) P Wong (Vancouver) HC Glass (San
Francisco) KJ Poskitt (Vancouver) V Chau (Vancouver)
Background: Neonatal hypoxic-ischemic encephalopathy (HIE)
is a common cause of infantile spasms (IS). The purpose of this
study was to evaluate the predominant pattern of brain injury and the
anatomic areas of injury in children with IS following neonatal HIE.
Methods: A nested case-control of IS in children with term neonatal
HIE was performed. All patients had T1/T2-weighted MRI with
diffusion-weighted imaging on day 3 of life. Using a validated
scoring system, the predominant pattern of injury was prospectively
classified as: normal, watershed, basal ganglia/thalamus (BG/T),
total, or focal-multifocal. Two study investigators scored additional
anatomic areas of injury (cortical extent, brainstem, hypothalamus)
blinded to the outcome. The pattern of injury and anatomic areas of
injury were compared between cases with IS and randomly selected
controls. Results: Eight patients who developed IS were identified
among a cohort of 176 term newborns with HIE (~4.5%). There
were no significant differences in the perinatal and neonatal course
between newborns who developed IS and controls. The development
of IS was significantly associated with BG/T and total brain injury
(P=.001), extent of cortical injury ≥50% (OR=11.67, 95% CI=1.1-
158.5, P=.01), injury to the midbrain (OR=13, 95% CI=1.3-172,
P=.007) and hypothalamic abnormalities (P=.01). Conclusions: The
development of IS after HIE is associated with extensive brain
injury on neonatal MRI, particularly when the midbrain is involved.
J.04
Malignant infarction of the middle cerebral artery in children
AV Andrade (Toronto)* I Yau (Toronto) G deVeber (Toronto)
Background: Large hemispheric strokes have a high risk of fatal
cerebral edema. This syndrome has been described as “Malignant
infarction of the middle cerebral artery” (MIMCA), this
complication is commonly seen in adults. The description of this
syndrome in the pediatric population is scarce. The goal for the
study is to identify possible clinical, radiological and electrographic
features associated with MIMCA syndrome in children. Patients and
Methods: We reviewed retrospectively, patients with a definite
diagnosis of arterial ischemic stroke of the middle cerebral artery
Canadian Neurological Sciences Federation • 48th Annual Congress • Montreal, Quebec • June 12-14, 2013 • Pre-Congress June 11
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