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Prenatal, postnatal neuroimaging IDs most Zika-related brain injuries

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Many challenges remain for diagnosis, treatment of Zika

While the study by Mulkey et al. adds to the body of evidence of prenatal and postnatal brain abnormalities, there are still many unanswered questions about the Zika virus and how to handle its unique diagnostic and clinical challenges, Margaret A. Honein, PhD, MPH, and Denise J. Jamieson, MD, MPH, wrote in a related editorial.

For example, Centers for Disease Control and Prevention recommendations state that infants with possible Zika exposure should receive an ophthalmologic and ultrasonographic examination at 1 month, and if the hearing test used otoacoustic emissions methods only, an automated auditory brainstem response test should be administered. While Mulkey et al. examined brain abnormalities in utero and in infants, it is not clear whether all CDC guidelines were followed in these cases.

In addition, because there is no reliable way to determine whether infants acquired Zika virus through the mother or through vertical transmission, assessing the proportion of congenitally infected infants or vertical-transmission infected infants who have neurodevelopmental disabilities and defects is not possible, they said. More longitudinal studies are needed to study the effects of the Zika virus and to prepare for the next outbreak.

“Zika was affecting pregnant women and their infants years before its teratogenic effect was recognized, and Zika will remain a serious risk to pregnant women and their infants until we have a safe vaccine that can fully prevent Zika virus infection during pregnancy,” they said. “Until then, ongoing public health efforts are essential to protect mothers and babies from this threat and ensure all disabilities associated with Zika virus infection are promptly identified, so that timely interventions can be provided.”

Dr. Honein is from the National Center on Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention, and Dr. Jamieson is from the department of gynecology & obstetrics at Emory University School of Medicine, Atlanta. These comments summarize their editorial in response to Mulkey et al. (JAMA Pediatr. 2018 Nov. 26. doi: 10.1001/jamapediatrics.2018.4164). They reported no relevant conflicts of interest.



Prenatal ultrasound can identify most abnormalities in fetuses exposed to Zika virus during pregnancy, and neuroimaging after birth can detect infant exposure in cases that appeared normal on prenatal ultrasound, according to research published in JAMA Pediatrics.

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“Absence of prolonged maternal viremia did not have predictive associations with normal fetal or neonatal brain imaging,” Sarah B. Mulkey, MD, PhD, from the division of fetal and transitional medicine at Children’s National Health System, in Washington, and her colleagues wrote. “Postnatal imaging can detect changes not seen on fetal imaging, supporting the current CDC [Centers for Disease Control and Prevention] recommendation for postnatal cranial [ultrasound].”

Dr. Mulkey and her colleagues performed a prospective cohort analysis of 82 pregnant women from Colombia and the United States who had clinical evidence of probable exposure to the Zika virus through travel (U.S. cases, 2 patients), physician referral, or community cases during June 2016-June 2017. Pregnant women underwent fetal MRI or ultrasound during the second or third trimesters between 4 weeks and 10 weeks after symptom onset, with infants undergoing brain MRI and cranial ultrasound after birth.

Of those 82 pregnancies, there were 80 live births, 1 case of termination because of severe fetal brain abnormalities, and 1 near-term fetal death of unknown cause. There was one death 3 days after birth and one instance of neurosurgical intervention from encephalocele. The researchers found 3 of 82 cases (4%) displayed fetal abnormalities from MRI, which consisted of 2 cases of heterotopias and malformations in cortical development and 1 case with parietal encephalocele, Chiari II malformation, and microcephaly. One infant had a normal ultrasound despite abnormalities displayed on fetal MRI.

After birth, of the 79 infants with normal ultrasound results, 53 infants underwent a postnatal brain MRI and Dr. Mulkey and her associates found 7 cases with mild abnormalities (13%). There were 57 infants who underwent cranial ultrasound, which yielded 21 cases of lenticulostriate vasculopathy, choroid plexus cysts, germinolytic/subependymal cysts, and/or calcification; these were poorly characterized by MRI.

“Normal fetal imaging had predictive associations with normal postnatal imaging or mild postnatal imaging findings unlikely to be of significant clinical consequence,” they said.

Nonetheless, “there is a need for long-term follow-up to assess the neurodevelopmental significance of these early neuroimaging findings, both normal and abnormal; such studies are in progress,” Dr. Mulkey and her colleagues said.

The researchers noted the timing of maternal infections and symptoms as well as the Zika testing, ultrasound, and MRI performance, technique during fetal MRI, and incomplete prenatal testing in the cohort as limitations in the study.

This study was funded in part by Children’s National Health System and by a philanthropic gift from the Ikaria Healthcare Fund. Dr. Mulkey received research support from the Thrasher Research Fund and is supported by awards from the National Institutes of Health National Center for Advancing Translational Sciences. The other authors reported no relevant conflicts of interest.

SOURCE: Mulkey SB et al. JAMA Pediatr. 2018 Nov. 26. doi: 10.1001/jamapediatrics.2018.4138.

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