Diagnosis of perinatal stroke II: mechanisms and clinical phenotypes.

INTRODUCTION: Here (and in an accompanying article dealing with definitions, differential diagnosis and registration), a structured sequential diagnostic flow is proposed to discern clinical phenotypes for perinatal stroke, including arterial ischaemic stroke (AIS), cerebral sinovenous thrombosis (CSVT) and haemorrhagic stroke.

MATERIAL AND RESULTS: For neonatal AIS, the diagnostic sequence is infection, trauma, embolism, arteriopathy, other, primary thrombosis and unclassifiable; for neonatal CSVT, the sequence is infection, trauma, venopathy, other, primary thrombosis and unclassifiable. The proposed hierarchical diagnostic flows are an initial step towards a standard for registration of the causes of neonatal stroke. Such standardization should guide attempts at prevention and intervention. An extensive literature search and study of a retrospective cohort of 134 newborn infants with stroke suggest that embolism is the most common identifiable cause for stroke in general (25%), preceding trauma (10%) and infection (8%). Other causes, such as asphyxia, acute blood loss, extracorporeal membrane oxygenation, genetic disorders or prothrombotic conditions, are seen in <5% of cases. For neonatal AIS, the presence of an embolic phenotype is 33% in this cohort. The designation unclassifiable scored 34% for the entire stroke group and 25% for neonatal AIS. Complex arterial stroke with multiple arteries involved is often seen when the underlying cause is infection, cranial trauma or embolism. One important conclusion is that a means of prevention is avoidance of embolism from thrombosis outside the brain.

CONCLUSION: To prevent the occurrence and recurrence of neonatal ischaemic stroke, clinicians must develop a standardized diagnostic approach that results in characterization of the clinical phenotype.