W. K. Chong

Posterior circulation stroke in childhood: Risk factors and recurrence

Objective: To ascertain whether posterior circulation stroke in children has distinctive clinical or radiologic features. Methods: Patients were identified retrospectively from two pediatric neurology centers. Clinical details were ascertained by chart review, and radiologic data were reviewed by three neuroradiologists. Results: Twenty-two cases were identified (17 boys). Twenty children had evidence of vertebrobasilar arterial abnormalities, which were multifocal in 12. The etiology of these was vertebral artery dissection in 10 cases and unclear in the remaining 10. Cardiac abnormalities were rare (n = 4). Other risk factors for stroke in childhood were hypertension (n = 9), the thermolabile methylene tetrahydrofolate reductase gene mutation (n = 4), and the factor V Leiden mutation (n = 2). Two children had subluxation of the upper cervical spine at the extreme of normal limits. In follow-up for 6 months to 11 years (median 4 years), five patients had further strokes and seven had TIA. Overall, 12 patients had no residual neurologic deficits. Conclusions: The male preponderance, frequency of arterial dissection, rarity of cardiac embolism, and >20% recurrence were notable. Cerebral angiography is usually indicated if a definitive diagnosis is not made on MRI. Additional investigations should include echocardiography and cervical spine radiography in flexion and extension.

Lesion volume, lesion location, and outcome after middle cerebral artery territory stroke

AIM To investigate the relation between lesion volume, lesion location, and clinical outcome in children with infarction in the territory of the middle cerebral artery (MCA). PATIENTS AND METHODS Children with MCA territory infarcts were selected retrospectively from a database of children with ischaemic stroke. Lesion volumes were expressed as a percentage of the supratentorial intracranial volume and were categorised as “small”, “moderate”, or “large”. Lesion location was categorised as cortical or purely subcortical. Outcome was ascertained by parental questionnaire and was categorised as “good” or “poor”. RESULTS 38 patients were identified (median age 6 years); 21 patients had lesions that involved cortical tissue. Outcome was good in 12 cases and poor in 26 cases (including 2 children who died). Although there was no significant effect of lesion size or lesion location on outcome for the group as a whole, all children who had infarcted more than 10% of intracranial volume had a poor outcome. Of note, some children with small subcortical lesions had pronounced residual deficits. CONCLUSIONS Although the outcome after a small infarct in the MCA territory is variable and unpredictable, infarction of more than 10% of intracranial volume is universally associated with a poor outcome. Characterisation of lesion volume and topography might be helpful in identification of such children for participation in future trials of treatments for acute stroke.

Sickle cell disease: ischemia and seizures

Although the prevalence of seizures in children with sickle cell disease (SCD) is 10 times that of the general population, there are few prospectively collected data on mechanism. With transcranial Doppler and magnetic resonance imaging (MRI) and angiography, we evaluated 76 patients with sickle cell disease, 29 asymptomatic and 47 with neurological complications (seizures, stroke, transient ischemic attack, learning difficulty, headaches, or abnormal transcranial Doppler), who also underwent bolus‐tracking perfusion MRI. The six patients with recent seizures also had electroencephalography. Group comparisons (seizure, nonseizure, and asymptomatic) indicated that abnormal transcranial Doppler was more common in the seizure (4/6; 67%) and nonseizure (26/41; 63%) groups than in the asymptomatic (10/29; 34%) group (χ2; p = 0.045), but abnormal structural MRI (χ2; p = 0.7) or magnetic resonance angiography (χ2; p = 0.2) were not. Relative decreased cerebral perfusion was found in all seizure patients and in 16 of 32 of the remaining patients with successful perfusion MRI (p = 0.03). In the seizure patients, the perfusion abnormalities in five were ipsilateral to electroencephalographic abnormalities; one had normal electroencephalogram results. These findings suggest that vasculopathy and focal hypoperfusion may be factors in the development of sickle cell disease–associated seizures. Ann Neurol 2005;58:290–302

Pyridoxine-dependent seizures: a family phenotype that leads to severe cognitive deficits, regardless of treatment regime.

The neuropsychological and clinical histories of three male siblings affected by pyridoxine‐dependent seizures with known homozygous antiquitin mutations are presented. Neuropsychological evaluation is reported from when the siblings were 11, 9, and 7 years of age. Two of the siblings had received early pyridoxine treatment (antenatal, 2–4wks into pregnancy) and one had received late treatment (2mo postnatal). However, there was no differential effect on cognitive outcome, with all three siblings having moderate to severe learning disability. Unlike previously reported cases that received early postnatal treatment, none of the siblings had relatively preserved non‐verbal cognitive skills. Equally, their intellectual performance over time did not increase above the 1st centile despite high maintenance doses of vitamin B6 (range 16–26mg/kg/d), and mild sensory neuropathy was reported on nerve conduction studies. The findings in these siblings challenge assumptions that early and high dose pyridoxine treatment can benefit cognition in this population and suggest routine electromyography monitoring may be beneficial.

Taylor‐type Focal Cortical Dysplasia in Infants: Some MRI Lesions Almost Disappear with Maturation of Myelination

Summary:u2002 Identification of focal cortical dysplasia (FCD) on magnetic resonance (MR) images of young children with refractory focal epilepsy is important, as surgical resection may offer improvement of seizure control and subsequent developmental progress. However, the MR appearances of malformations of cortical development may change during brain maturation. We report 4 children with refractory focal epilepsy, whose MR images in infancy showed localized cortical and subcortical signal abnormalities (hypointense on T2‐weighted and hyperintense on T1‐weighted images), suggestive of abnormal cortical development. The visibility of these lesions was significantly reduced on later MR images. Subtle blurring of the gray–white matter junction in these areas was the only indicator of cortical abnormality in 3 patients, which was recognized only after comparison with earlier images. Taylor‐type FCD was subsequently confirmed in all patients, following surgical cortical resection of the lesions. MR images performed early within the first year of life in children with epilepsy are important to identify areas of FCD. The appearances of FCD on later scans can be very subtle escaping recognition, and conclusions may be misleading with respect to diagnosis and appropriateness of surgical treatment.

Familial congenital saccade initiation failure and isolated cerebellar vermis hypoplasia.

The underlying lesion in congenital saccade initiation failure (c‐SIF) (‘congenital ocular motor apraxia’, ‘Cogans apraxia’) is uncertain. Often no abnormality can be found, yet in others a midline cerebellar abnormality has often been reported. We examined this cerebellar association in a brother and sister. In addition to standard ophthalmological and neurological examinations, both siblings underwent ocular motor testing and neuroradiological investigations including CT and MRI. Both siblings exhibited the typical signs of c‐SIF, including headthrusting, synkinetic blinking, niissed‐nystagmus quick phases, mild developmental delay, and speech difficulties. CT and MRI revealed cerebellar vermis hypoplasia in the brother, but appeared normal in the sister. No other neuroradiological abnormalities were detected. These cases highlight the wide variability in the association of vermis abnormalities with c‐SIF, despite the inheritance and similar clinical manifestations. They show that either: (1) the vermis is causal in saccade triggering, but that c‐SIF may result from very subtle damage that is beyond MRI resolution in some cases; or (2) that a vermis abnormality per se is not causative but only a marker of another subtle abnormality, either structural or possibly biochemical.

Diffusion weighted magnetic resonance imaging of compromised tissue in stroke

Diffusion weighted imaging (DWI) and T2 weighted magnetic resonance imaging were performed on at least two occasions in 28 children presenting with stroke. In previous reports of DWI in human stroke, eventual infarction was observed (with only one exception) in all regions in which early DWI hyperintensity occurred. In the present report, two children had regions of DWI hyperintensity which did not progress to infarction. One patient who presented with right hemiplegia showed extensive high signal on DWI, with T2 evidence of tissue swelling but without hyperintensity. DWI changes persisted over weeks, with no imaging indication of infarction. This child recovered completely. A second child who had a major vessel infarct with concomitant regions of hyperintensity on T2 weighted imaging and DWI, also had DWI hyperintensity in an adjacent territory which did not develop any subsequent evidence of infarction. Thus in clinical practice DWI can demonstrate tissue which is compromised but not irreversibly so.

Painful and painless ophthalmoplegia with cavernous sinus pseudotumour.

Acquired isolated ophthalmoplegia in childhood has many potential causes. Although other ophthalmological or clinical features may aid lesion localisation, the absence of these does not preclude structural pathology. Two cases of cavernous sinus pseudotumour presented as ophthalmoplegia with and without pain. Magnetic resonance imaging of the cavernous sinus revealed the presence of enhancing tissue consistent in appearance with pseudotumour in both cases, and they responded well to steroid treatment. These cases emphasise the importance of detailed imaging of the cavernous sinus in the investigation of these symptoms in order to exclude this treatable condition.

Congenital perisylvian dysfunction – is it a spectrum?

Aimu2002 This study examines the overlap between children with bulbar cerebral palsy (Worster–Drought syndrome [WDS]) and perisylvian polymicrogyria.