Basilar artery occlusion and the dense artery sign in the newborn

Facial Weakness and Ophthalmoplegia in a 4-Day-Old Infant

We present a neonate with neurologic deficits recognized at 4 days of age. A male infant was born at term via emergency cesarian section due to failure to progress and fetal decelerations. He underwent therapeutic hypothermia for hypoxic ischemic encephalopathy. Upon completion of rewarming, he was noted to have left facial palsy, abduction deficit on the left eye past the midline, and nystagmus involving the right eye. Brain magnetic resonance imaging showed a pontine stroke, and computed tomography angiogram revealed basilar artery thrombosis. He was treated with enoxaparin for 3 months, followed by low-dose aspirin. The mechanism of the stroke remains unclear, and there is limited evidence to guide management.

Diagnosis of perinatal stroke I: definitions, differential diagnosis and registration

INTRODUCTION

Perinatal stroke can be divided into three subtypes: ischaemic stroke, either arterial or sinovenous and haemorrhagic stroke. For the sake of universal registration and to perform intervention studies, we propose a detailed diagnostic registration system for perinatal stroke taking 10 variables into account. These variables are discussed here and in the accompanying article.

MATERIAL AND RESULTS

Differentiation is needed from focal brain changes as a result of disorders other than stroke, whereby accurate timing is possible only when early neonatal imaging is available. Detailed templates are presented for arterial and venous vascular classification. AIS is further subdivided into single territory and complex infarction and some stratification is proposed in the complicated stroke group. This registration system has been applied to a retrospective cohort of 134 newborns with stroke (single-centre observation from 1999 to 2007) and the results are compared with published data. By applying this registration system, intervention studies for one homogeneous stroke type (e.g. complete middle cerebral artery stroke) may be facilitated.

CONCLUSION

Ten variables may be sufficient to register a perinatal stroke. These include gestational age, birthweight, gender, delivery mode, time of detection, presentation, type of stroke, vessel affected or type of cavity, imaging method at detection and clinical context.

Top of the basilar artery embolic stroke and neonatal myoclonus

Cerebellar stroke has been virtually unreported in the living newborn infant. A term newborn male weighing 3380g at birth suffered myoclonic seizures within 24 hours of birth by spontaneous vaginal delivery. Apgar scores were 3 and 4 at 1 and 5 minutes. Myoclonus persisted for 9 days, responding poorly to step-up anticonvulsant treatment including lidocaine, midazolam, and clonazepam. Imaging documented arterial ischaemic stroke within the left posterior cerebral and both superior cerebellar arteries, compatible with top of the basilar artery stroke. There was no electrographic correlate for the seizures. Disturbed oscillation within the dentato-rubro-olivary circuitry was the likely mechanism. The probable cause was embolism from an in-utero-onset inferior caval vein thrombosis. At 22 months the child was sitting unsupported. Scores on the Bayley Scales of Infant Development II were equivalent to those of a 12-month/year-old. He showed ataxic motor behaviour. Embolism can cause neonatal top of the basilar artery stroke, which may present with myoclonus due to cerebellar injury.

The Hyperdense Cerebral Artery Sign on Head CT Scan

The hyperdense artery sign on noncontrast head CT is thought to be one of the earliest and most useful signs of intra-arterial clot and probable (clinical) stroke. It should be evaluated in the context of the clinical scenario. Rigorous criteria should be applied in order to reduce potential false positives. The hyperdense middle cerebral artery sign is the most studied version and correlates with patient outcome. Our data suggest that the density on noncontrast head CT is not likely to universally represent in situ clot.

Successful endovascular therapy for acute basilar thrombosis in an adolescent

Pediatric stroke is an underrecognized, potentially treatable cause of childhood neurologic disease. Acute basilar artery thrombosis is a devastating disease rarely encountered in children. Acute interventions with both chemical and mechanical thrombolysis techniques can improve outcomes in adults with arterial thrombosis of the posterior cerebral circulation. We report a case of intervention with both intra-arterial alteplase (tissue plasminogen activator) and cerebral balloon angioplasty to treat a prolonged basilar artery occlusion secondary to idiopathic thrombosis in an adolescent. Despite the patient being clinically locked-in and intervention being delayed at least 20 hours from symptom onset, he obtained complete neurologic recovery. Issues of pediatric stroke, late therapeutic intervention, chemical thrombolysis, and cerebral angioplasty are discussed. This case highlights the underrecognition and subsequent delay in diagnosis of pediatric stroke and how acute intervention may cure otherwise catastrophic strokes in children.