Idiopathic fetal stroke diagnosed antenatally and the need for uniform diagnostic definitions.

Introduction

• Fetal stroke often presents as fetal intracranial haemorrhage(ICH).
• Idiopathic fetal ICH is a rare but well reported phenomenon with the true in incidence of ICH in utero remaining undetermined.
• Various predisposing risk factors for fetal ICH are recognised:
  • Maternal risk factors:
    • Genetic and autoimmune causes
    • Coagulopathies
    • Severe maternal trauma recreational drug use.
  • Fetal risk factors:
    • Congenital coagulopathy
    • Monochorionic twin pregnancies
    • Feto-maternal haemorrhages.
• In the majority of cases the cause of fetal ICH remains unknown.
• Fetuses diagnosed prenatally with ICH are exposed to higher risks of adverse neurodevelopmental outcomes, perinatal mortality, neonatal death and long-term neurological deficit
• Antenatally, such events are diagnosed sonographically. 
• Here we present a case of an idiopathic fetal stroke diagnosed antenatally.

Case Report

• A 35 year old woman, gravida 1 para 0 was referred for serial growth scans at 31 and 36 weeks of gestation as per hospital policy due to low BMI (17.5 g/m²).
• Her medical history was unremarkable. Her antenatal fetal ultrasound scans at 20 and 31 weeks both showed normal appearances of the brain.
• The scan at 36+5 weeks, however, showed a fetus with severe 43mm unilateral, left sided ventriculomegaly with biparietal diameter and head circumference above the 95^th centile (Fig 1a and 1b).
• Subsequent fetal MRI showed macrocephaly with bilateral ventriculomegaly and stigmata of previous germinal matrix haemorrhage and significant white matter injury.
• After a multidisciplinary team discussion, feticide and termination of pregnancy were offered due to potential fetal sequelae.
• The mother consented and had an uncomplicated feticide and vaginal breech delivery. 
• Subsequent maternal bacteriological and virological screens were negative.
• Parental genetic screening and the fetal cytogenetic studies were unremarkable
• Neonatal alloimmune thrombocytopenia test was negative.
• Postmortem examination showed no congenital malformations or evidence of hydrops.

Discussion

• It is recognised that the preterm brain possesses vulnerabilities that predispose the fetus to stroke.
• This case demonstrates the importance of accurate diagnosis of perinatal stroke syndromes due to the implication for onward management.
• A key challenge in the literature has been to identify the true incidence of fetal ICH due to different terms being used to define the same entity.
• A universal diagnostic criteria looking at various sonographic markers to determine severity would allow uniform diagnosis allowing this phenomenon be better studied.
• There is also a deficiency in the data for long term post-natal outcomes which would allow better counselling and management of patients.

Conclusion

• Early diagnosis of fetal stroke is essential for appropriate counselling and management of patients.
• Clear, universal diagnostic terminology would allow better diagnosis.
• Further data on long term postnatal outcomes would aid in appropriate parental counselling regarding management options.