Longitudinal evolution of electroencephalogram (EEG): Findings over five years of follow-up in children with Zika-related microcephaly from the Microcephaly Epidemic Research Group Pediatric Cohort (2015-2020)

OBJECTIVE

To assess the longitudinal evolution of EEG findings in children with Zika related-microcephaly (ZRM) and to evaluate the associations of these patterns with the children's clinical and neuroimaging characteristics.

METHODS

As part of the follow-up of the Microcephaly Epidemic Research Group Pediatric Cohort (MERG-PC) in Recife, Brazil, we performed serial EEG recordings in a subgroup of children with ZRM to evaluate changes in background rhythms and epileptiform activity (EA). Latent class analysis was used to identify patterns in the evolution of EA over time; clinical and neuroimaging findings were compared across the identified groups.

RESULTS

Out of the 72 children with ZRM who were evaluated during 190 EEGs/videoEEGs, all participants presented with abnormal background activity, 37.5% presented with an alpha-theta rhythmic activity, and 25% presented with sleep spindles, which were less commonly observed in children with epilepsy. EA changed over time in 79.2% of children, and three distinct trajectories were identified: (i) multifocal EA over time, (ii) no discharges/focal EA evolving to focal/multifocal EA, and (iii) focal/multifocal EA evolving to epileptic encephalopathy patterns (e.g., hypsarrhythmia or continuous EA in sleep). The multifocal EA over time trajectory was associated with periventricular and thalamus/basal ganglia calcifications, brainstem and corpus callosum atrophy and had less focal epilepsy, whereas the children in the trajectory which evolved to epileptic encephalopathy patterns had more frequently focal epilepsy.

SIGNIFICANCE

These findings suggest that, in most children with ZRM, trajectories of changes in EA can be identified and associated with neuroimaging and clinical features.

Zika virus congenital microcephaly severity classification and the association of severity with neuropsychomotor development

BACKGROUND

Zika virus infection during pregnancy is linked to birth defects, most notably microcephaly, which is associated with neurodevelopmental delays.

OBJECTIVE

The goals of the study were to propose a method for severity classification of congenital microcephaly based on neuroradiologic findings of MRI scans, and to investigate the association of severity with neuropsychomotor developmental scores. We also propose a semi-automated method for MRI-based severity classification of microcephaly.

MATERIALS AND METHODS

We conducted a cross-sectional investigation of 42 infants born with congenital Zika infection. Bayley Scales of Infant and Toddler Development III (Bayley-III) developmental evaluations and MRI scans were carried out at ages 13-39 months (mean: 24.8 months; standard deviation [SD]: 5.8 months). The severity score was generated based on neuroradiologist evaluations of brain malformations. Next, we established a distribution of Zika virus-microcephaly severity score including mild, moderate and severe and investigated the association of severity with neuropsychomotor developmental scores. Finally, we propose a simplified semi-automated procedure for estimating the severity score based only on volumetric measures.

RESULTS

The results showed a correlation of r=0.89 (P<0.001) between the Zika virus-microcephaly severity score and the semi-automated method. The trimester of infection did not correlate with the semi-automated method. Neuropsychomotor development correlated with the severity classification based on the radiologic readings and semi-automated method; the more severe the imaging scores, the lower the neuropsychomotor developmental scores.

CONCLUSION

These severity classification methods can be used to evaluate severity of microcephaly and possible association with developmental consequences. The semi-automated methods thus provide an alternative for predicting severity of microcephaly based on only one MRI sequence.

Middle Cerebral Artery Dopplers and Abnormal Neonatal Outcomes among Pregnant Women with Zika Virus Infection

OBJECTIVE

The aim of this study was to investigate the role of middle cerebral artery (MCA) Doppler measurements for the prediction of abnormal neonatal outcomes in pregnancies affected by Zika virus (ZIKV).

METHODS

Secondary analysis of a prospective cohort of pregnant women diagnosed with ZIKV infection from September 2015 to December 2016 at a single regional referral center. Ultrasonography with measurements of MCA peak systolic velocity (PSV), PSV multiples of the median (MoM) for gestational age, and pulsatility index (PI) were collected. The primary outcome was a composite abnormal neonatal outcome. MCA Doppler values of normal and abnormal neonatal outcomes were compared with Wilcoxon rank sum test. The predictive value of MCA Dopplers for development of abnormal neonatal outcome was calculated by logistic regression.

RESULTS

One-hundred twenty-seven ZIKV-positive pregnancies with MCA Doppler measurements and known neonatal outcomes were included. Of the 132 neonates, 66 (50%) had an abnormal neonatal outcome. Lower MCA PSV (p = 0.027) and PSV MoM (p = 0.008) were associated with abnormal neonatal outcomes. There was no significant difference in MCA PI. Abnormal neonatal outcomes had lower MCA PSV by 5.36 cm/s (95% confidence interval [CI]: 0.95-9.77, p = 0.018) and lower MCA PSV MoM by 0.13 (95% CI: 0.05-0.22, p = 0.002). MCA PSV of 30 cm/s had a 65% predicted probability of an abnormal neonatal outcome (95% CI: 51-79%).

CONCLUSION

In ZIKV-infected pregnancies, lower MCA PSV and PSV MoM measurements were seen with abnormal neonatal outcomes. This may represent a physiologic response to fetal ZIKV infection. Evaluation of MCA Dopplers may be of clinical utility in the surveillance of ZIKV-affected pregnancies.

KEY POINTS

· Significantly lower MCA PSV is associated with abnormal neonatal outcomes in ZIKV pregnancies.. · Lower MCA PSV may reflect the underlying neuropathology of ZIKV exposure on the fetus.. · There is potential utility for MCA Doppler evaluation in antepartum surveillance of ZIKV pregnancies..

Characterization of Visual Pathway Abnormalities in Infants With Congenital Zika Syndrome Using Computed Tomography and Magnetic Resonance Imaging

BACKGROUND

Severe visual impairment is present in nearly all infants with congenital Zika syndrome (CZS); however, ocular abnormalities are present only in a subset of these infants. The purpose of this study was to characterize the visual pathway abnormalities seen on computed tomography (CT) and MRI scans in infants with CZS.

METHODS

Preliminary neuroimaging information was obtained from a referred sample of 105 infants with clinical and epidemiologic data consistent with CZS in the Pernambuco state of Brazil. Subjects were excluded if Zika virus infection was not confirmed by serologic or cerebrospinal fluid studies or if images were nondiagnostic. Of the 105 subjects initially screened, head CT images adequate for interpretation were available for 54, and brain MRI images adequate for interpretation were available for 20. Four patients had both CT and MRI images. Magnetic resonance imaging and CT scans from infants with CZS were systematically reviewed for globe malformations, optic nerve and chiasmal atrophy, occipital cortical volume loss, white matter abnormalities, ventriculomegaly, and calcifications. Neuroimaging findings were correlated with measures of visual function and with ocular examinations in these infants.

RESULTS

Thirty-three males and 37 females were included in the analysis. The mean age of the infants at the time of neuroimaging was 16.0 weeks (range 0 days-15.5 months), and the mean gestational age at the time of birth was 38 weeks. All patients were from the Pernambuco state of Brazil. Overall, 70 of 74 (95%) scans showed occipital volume loss, whereas 9 (12%) showed optic nerve atrophy, 3 (4%) showed chiasmal atrophy, and 1 (1%) showed an ocular calcification. Sixty-two of the infants underwent ophthalmologic examinations. A total of 34 (55%) infants had at least one documented structural ocular abnormality, and 26 (42%) had at least one structural ocular abnormality documented in both eyes. Of those with available visual acuity data, all had visual impairment. Among those with visual impairment and normal eye examinations, 100% had visual pathway abnormalities on neuroimaging, including 100% with occipital cortical volume loss, 8% with optic nerve atrophy, and 8% with chiasmal atrophy.

CONCLUSION

Our results suggest that cortical visual impairment related to structural abnormalities of the occipital cortex is likely an important cause of visual impairment in children with CZS with normal eye examinations.

An Examination of the Long-Term Neurodevelopmental Impact of Prenatal Zika Virus Infection in a Rat Model Using a High Resolution, Longitudinal MRI Approach

Since Zika virus (ZIKV) first emerged as a public health concern in 2015, our ability to identify and track the long-term neurological sequelae of prenatal Zika virus (ZIKV) infection in humans has been limited. Our lab has developed a rat model of maternal ZIKV infection with associated vertical transmission to the fetus that results in significant brain malformations in the neonatal offspring. Here, we use this model in conjunction with longitudinal magnetic resonance imaging (MRI) to expand our understanding of the long-term neurological consequences of prenatal ZIKV infection in order to identify characteristic neurodevelopmental changes and track them across time. We exploited both manual and automated atlas-based segmentation of MR images in order to identify long-term structural changes within the developing rat brain following inoculation. The paradigm involved scanning three cohorts of male and female rats that were prenatally inoculated with 10⁷ PFU ZIKV, 10⁷ UV-inactivated ZIKV (iZIKV), or diluent medium (mock), at 4 different postnatal day (P) age points: P2, P16, P24, and P60. Analysis of tracked brain structures revealed significantly altered development in both the ZIKV and iZIKV rats. Moreover, we demonstrate that prenatal ZIKV infection alters the growth of brain regions throughout the neonatal and juvenile ages. Our findings also suggest that maternal immune activation caused by inactive viral proteins may play a role in altered brain growth throughout development. For the very first time, we introduce manual and automated atlas-based segmentation of neonatal and juvenile rat brains longitudinally. Experimental results demonstrate the effectiveness of our novel approach for detecting significant changes in neurodevelopment in models of early-life infections.

Clinical and Biochemical Features of Hypopituitarism Among Brazilian Children With Zika Virus-Induced Microcephaly

IMPORTANCE

The Zika virus infects progenitor neuron cells, disrupts cerebral development, and, in mice, drives hypothalamic defects. Patients with microcephaly caused by congenital Zika infection present with midline cerebral defects, which may result in hypopituitarism.

OBJECTIVE

To analyze postnatal growth and the presence of clinical and biochemical features associated with hypopituitarism in children with congenital Zika infections.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective cohort study at 2 public referral hospitals in Bahia, Brazil, specializing in the treatment of congenital Zika infection, clinical data and growth parameters of 65 patients with the infection were evaluated. Data were analyzed from April 2017 through July 2018.

EXPOSURE

Congenital Zika infection.

MAIN OUTCOMES AND MEASURES

Length, weight, and head circumference were measured at birth and during follow up (ie, at 27 months of life) for each patient. Basal levels of free thyroxine, thyrotropin, cortisol, corticotropin, prolactin, insulin-like growth factor 1, insulin-like growth factor binding protein 3, urine and plasma osmolality, electrolytes, glucose, and insulin were evaluated at the age of 26 months to 28 months. All patients underwent central nervous system computed tomography scans and ophthalmic and otoacoustic evaluations at the time of this investigation or had done so previously.

RESULTS

Among 65 patients (38 [58.4%] male; median [interquartile range] age at enrollment, 27 [26-28] months), 61 patients presented with severe brain defects (93.8%), including corpus callosum agenesis or hypoplasia (ie, midline brain defects; 25 patients [38.5%]) and optic nerve atrophy (38 patients [58.5%]). Most patients presented with severe neurodevelopmental delay (62 of 64 patients [96.9%]). Past or present clinical signs of hypopituitarism were rare, occurring in 3 patients (4.6%). Severe microcephaly, compared with mild or moderate microcephaly, was associated with a shorter length by median (interquartile range) z score at birth (-1.9 [-2.5 to -1.0] vs -0.3 [-1.0 to 0]; P < .001), but this difference did not persist at 27 months (-1.6 [-2.3 to -0.3] vs -2.9 [-4.0 to -1.2]; P = .06). Growth hormone deficiency or hypothyroidism were not observed in any patients, and glucose and insulin levels were within reference ranges for all patients. Low cortisol levels (ie, below 3.9 µg/dL) were observed in 4 patients (6.2%). These 4 patients presented with low (ie, below 7.2 pg/mL) or inappropriately low (ie, below 30 pg/mL) corticotropin levels. Low corticotropin levels (ie, below 7.2 pg/mL) were observed in 6 patients (9.2%). Diabetes insipidus was evaluated in 21 patients; it was confirmed in 1 patient (4.8%) and suggested in 3 patients (14.3%).

CONCLUSIONS AND RELEVANCE

This study found that congenital Zika infection with microcephaly was associated with midline brain defects and optic nerve atrophy. Children with congenital Zika infections presented with prenatal growth impairments with a lack of postnatal catch-up, as shown by persistent short length from birth until 27 months; these impairments were not associated with growth hormone deficiency. Patients also presented with severe developmental delay that was not associated with hypothyroidism, while central adrenal insufficiency and diabetes insipidus occurred in some patients.

Long-term alterations in brain and behavior after postnatal Zika virus infection in infant macaques

Zika virus (ZIKV) infection has a profound impact on the fetal nervous system. The postnatal period is also a time of rapid brain growth, and it is important to understand the potential neurobehavioral consequences of ZIKV infection during infancy. Here we show that postnatal ZIKV infection in a rhesus macaque model resulted in long-term behavioral, motor, and cognitive changes, including increased emotional reactivity, decreased social contact, loss of balance, and deficits in visual recognition memory at one year of age. Structural and functional MRI showed that ZIKV-infected infant rhesus macaques had persistent enlargement of lateral ventricles, smaller volumes and altered functional connectivity between brain areas important for socioemotional behavior, cognitive, and motor function (e.g. amygdala, hippocampus, cerebellum). Neuropathological changes corresponded with neuroimaging results and were consistent with the behavioral and memory deficits. Overall, this study demonstrates that postnatal ZIKV infection in this model may have long-lasting neurodevelopmental consequences.

Review of neuroimaging findings in congenital Zika virus syndrome and its relation to the time of infection

BACKGROUND

Many original articles and case series have been published emphasizing the neuroimaging findings of congenital Zika virus (ZIKV) infection. The majority of these studies do not follow a neuroradiological methodology to describe malformations and brain abnormalities resulting from ZIKV infection. The cause-and-effect correlation between the gestational period of maternal infection and the severity of encephalic changes at birth has rarely been reported. A systematic literature review was conducted on the neuroimaging findings in children affected with microcephaly due to ZIKV.

METHODS

PubMed, Cochrane Library and Web of Science were searched for full-text articles published up to July 2019. Duplicate entries were removed. Two independent reviewers performed a quality assessment of all the studies included.

RESULTS

A total of 2214 publications were identified. Of these 2170 were excluded by analysis of titles and abstracts, resulting in the inclusion of only eight articles. Chi-square and Fisher's exact tests were performed with a 95% confidence interval to verify the statistically significant differences in the neuroradiological findings between the cases of ZIKV infection in the first or second trimester of gestation. The studies published so far have described image abnormalities at random, without utilizing any pre-established neuroradiological criteria, and imaging modalities with different sensitivity and accuracy have been used, which jeopardizes a reliable and adequate statistical analysis.

CONCLUSIONS

Neuroimaging abnormalities are much more prevalent and severe when the infection by ZIKV is contracted in the first or second trimester of pregnancy.

Obstetric Ultrasonography to Detect Fetal Abnormalities in a Mouse Model for Zika Virus Infection

In 2015 Zika virus (ZIKV) emerged for the first time in South America. The following ZIKV epidemic resulted in the appearance of a clinical phenotype with microcephaly and other severe malformations in newborns. So far, mechanisms of ZIKV induced damage to the fetus are not completely understood. Previous data suggest that ZIKV may bypass the placenta to reach the fetus. Thus, animal models for ZIKV infection are important to facilitate studies about ZIKV infection during pregnancy. Here, we used ultrasound based imaging (USI) to characterize ZIKV induced pathogenesis in the pregnant Type I interferon receptor-deficient (IFNAR-/-) mouse model. Based on USI we suggest the placenta to be a primary target organ of ZIKV infection enabling ZIKV spreading to the fetus. Moreover, in addition to direct infection of the fetus, the placental ZIKV infection may cause an indirect damage to the fetus through reduced uteroplacental perfusion leading to intrauterine growth retardation (IUGR) and fetal complications as early as embryonic day (ED) 12.5. Our data confirmed the capability of USI to characterize ZIKV induced modifications in mouse fetuses. Data from further studies using USI to monitor ZIKV infections will contribute to a better understanding of ZIKV infection in pregnant IFNAR-/- mice.

Association Between Neonatal Neuroimaging and Clinical Outcomes in Zika-Exposed Infants From Rio de Janeiro, Brazil

IMPORTANCE

Congenital Zika virus (ZIKV) infection may present with a spectrum of clinical and neuroradiographic findings.

OBJECTIVE

To determine whether neuroimaging findings for infants with a history of ZIKV exposure are associated with infant clinical outcomes and gestational age at antenatal ZIKV infection.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study retrospectively reviewed neuroimaging results (computed tomography and/or magnetic resonance imaging scans) of 110 ZIKV-exposed infants from a maternity and children's hospital in Rio de Janeiro, Brazil, following the 2015 to 2016 ZIKV epidemic. Neuroimaging from March 1, 2016, to June 30, 2017, was evaluated to determine whether findings were associated with clinical outcomes and the timing of maternal ZIKV infection. Data were analyzed from July 1, 2017, to August 30, 2018.

EXPOSURES

Neuroimaging (computed tomography and/or magnetic resonance imaging) was performed on ZIKV-exposed infants after birth. Blood and/or urine specimens from mothers and infants were tested for ZIKV by polymerase chain reaction assay.

MAIN OUTCOMES AND MEASURES

Neuroimaging studies were evaluated for structural abnormalities and other forms of brain injury.

RESULTS

A total of 110 infants with a mean (SD) gestational age of 38.4 (2.1) weeks had neuroimaging and clinical outcome data reviewed. Of these, 71 (65%) had abnormal neuroimaging findings, with the majority (96%) classified as having severe ZIKV infection at birth. The most common neuroimaging abnormalities were structural abnormalities including brain calcifications, especially at the cortico-subcortical white matter junction, cortex malformations, ventriculomegaly, and reduced brain volumes, followed by brainstem hypoplasia, cerebellar hypoplasia, and corpus callosum abnormalities. Frequency of abnormal imaging was higher in infants with specific clinical findings as opposed to those without them; these findings included fetal brain disruption sequence (100% vs 35%), microcephaly (100% vs 30%), congenital contractures (100% vs 58%), ophthalmologic abnormalities (95% vs 44%), hearing abnormalities (100% vs 58%), and neurologic symptoms (94% vs 10%). Four of 39 infants (10%) without initial evidence of severe ZIKV infection and normal findings on neurologic evaluation at birth had abnormal neuroimaging findings. Neuroimaging abnormalities differed by trimester of maternal ZIKV infection, with 63% of infants born to mothers infected in the first trimester, 13% of infants born to mothers infected in the second trimester, and 1% of infants born to mothers infected in the third trimester exhibiting neuroimaging abnormalities. The odds of abnormal neuroimaging were 7.9 times greater for infants with first trimester ZIKV exposure compared with other trimesters combined (odds ratio, 7.9; 95% CI, 3.0-20.4; P < .001).

CONCLUSIONS AND RELEVANCE

Neuroimaging abnormalities of computed tomography and/or magnetic resonance imaging scans were common in ZIKV-exposed infants. While neuroimaging abnormalities were seen in 10% of infants without clinically severe ZIKV, most occurred almost exclusively among those with clinically severe ZIKV, especially among those with a history of ZIKV exposure in the first trimester.

Congenital Zika Virus Infection with Normal Neurodevelopmental Outcome, Brazil

We describe a case of a 20-month-old girl with probable congenital Zika virus infection and normal neurodevelopment, despite microcephaly and abnormal neuroimaging. This case raises questions about early prognostic markers and draws attention to the need for investigation in suspected Zika cases, even if the child’s early neurodevelopment is normal.

Association of Prenatal Ultrasonographic Findings With Adverse Neonatal Outcomes Among Pregnant Women With Zika Virus Infection in Brazil

IMPORTANCE

Congenital Zika virus infection causes a spectrum of adverse birth outcomes, including severe birth defects of the central nervous system. The association of prenatal ultrasonographic findings with adverse neonatal outcomes, beyond structural anomalies such as microcephaly, has not been described to date.

OBJECTIVE

To determine whether prenatal ultrasonographic examination results are associated with abnormal neonatal outcomes in Zika virus-affected pregnancies.

DESIGN, SETTING, AND PARTICIPANTS

A prospective cohort study conducted at a single regional referral center in Rio de Janeiro, Brazil, from September 1, 2015, to May 31, 2016, among 92 pregnant women diagnosed during pregnancy with Zika virus infection by reverse-transcription polymerase chain reaction, who underwent subsequent prenatal ultrasonographic and neonatal evaluation.

EXPOSURES

Prenatal ultrasonography.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was composite adverse neonatal outcome (perinatal death, abnormal finding on neonatal examination, or abnormal finding on postnatal neuroimaging). Secondary outcomes include association of specific findings with neonatal outcomes.

RESULTS

Of 92 mother-neonate dyads (mean [SD] maternal age, 29.4 [6.3] years), 55 (60%) had normal results and 37 (40%) had abnormal results on prenatal ultrasonographic examinations. The median gestational age at delivery was 38.6 weeks (interquartile range, 37.9-39.3). Of the 45 neonates with composite adverse outcome, 23 (51%) had normal results on prenatal ultrasonography. Eleven pregnant women (12%) had a Zika virus-associated finding that was associated with an abnormal result on neonatal examination (adjusted odds ratio [aOR], 11.6; 95% CI, 1.8-72.8), abnormal result on postnatal neuroimaging (aOR, 6.7; 95% CI, 1.1-38.9), and composite adverse neonatal outcome (aOR, 27.2; 95% CI, 2.5-296.6). Abnormal results on middle cerebral artery Doppler ultrasonography were associated with neonatal examination abnormalities (aOR, 12.8; 95% CI, 2.6-63.2), postnatal neuroimaging abnormalities (aOR, 8.8; 95% CI, 1.7-45.9), and composite adverse neonatal outcome (aOR, 20.5; 95% CI, 3.2-132.6). There were 2 perinatal deaths. Abnormal findings on prenatal ultrasonography had a sensitivity of 48.9% (95% CI, 33.7%-64.2%) and a specificity of 68.1% (95% CI, 52.9%-80.1%) for association with composite adverse neonatal outcomes. For a Zika virus-associated abnormal result on prenatal ultrasonography, the sensitivity was lower (22.2%; 95% CI, 11.2%-37.1%) but the specificity was higher (97.9%; 95% CI, 88.7%-99.9%).

CONCLUSIONS AND RELEVANCE

Abnormal results on prenatal ultrasonography were associated with adverse outcomes in congenital Zika infection. The absence of abnormal findings on prenatal ultrasonography was not associated with a normal neonatal outcome. Comprehensive evaluation is recommended for all neonates with prenatal Zika virus exposure.

[18F]DPA-714 PET Imaging Reveals Global Neuroinflammation in Zika Virus-Infected Mice

PURPOSE

The association of Zika virus (ZIKV) infection and development of neurological sequelae require a better understanding of the pathogenic mechanisms causing severe disease. The purpose of this study was to evaluate the ability and sensitivity of positron emission tomography (PET) imaging using [18F]DPA-714, a translocator protein (TSPO) 18 kDa radioligand, to detect and quantify neuroinflammation in ZIKV-infected mice.

PROCEDURES

We assessed ZIKV-induced pathogenesis in wild-type C57BL/6 mice administered an antibody to inhibit type I interferon (IFN) signaling. [18F]DPA-714 PET imaging was performed on days 3, 6, and 10 post-infection (PI), and tissues were subsequently processed for histological evaluation, quantification of microgliosis, and detection of viral RNA by in situ hybridization (ISH).

RESULTS

In susceptible ZIKV-infected mice, viral titers in the brain increased from days 3 to 10 PI. Over this span, these mice showed a two- to sixfold increase in global brain neuroinflammation using [18F]DPA-714 PET imaging despite limited, regional detection of viral RNA. No measurable increase in ionized calcium binding adaptor molecule 1 (Iba-1) expression was noted at day 3 PI; however, there was a modest increase at day 6 PI and an approximately significant fourfold increase in Iba-1 expression at day 10 PI in the susceptible ZIKV-infected group relative to controls.

CONCLUSIONS

The results of the current study demonstrate that global neuroinflammation plays a significant role in the progression of ZIKV infection and that [18F]DPA-714 PET imaging is a sensitive tool relative to histology for the detection of neuroinflammation. [18F]DPA-714 PET imaging may be useful in dynamically characterizing the pathology associated with neurotropic viruses and the evaluation of therapeutics being developed for treatment of infectious diseases.

Imaging findings in congenital Zika virus infection syndrome: an update

BACKGROUND

Zika virus (ZIKV) is a neurotropic and neurotoxic RNA Flavivirus prompt to cause severe fetal brain dysmorphisms during pregnancy, a period of rapid and critical central nervous system development. A wide range of clinico-radiological findings of congenital ZIKV infections were reported in the literature, such as microcephaly, overlapping sutures, cortical migrational and corpus callosum abnormalities, intracranial calcifications, ventriculomegaly, brain stem and cerebellar malformations, spinal cord involvement, and joint contractures. ZIKV is also related to other severe neurological manifestations in grown-up individuals such as Guillain-Barré syndrome and encephalomyelitis.

PURPOSE

Our purpose is to review the radiological central nervous system abnormalities of congenital ZIKV infection syndrome on different imaging modalities.

Progressive lesions of central nervous system in microcephalic fetuses with suspected congenital Zika virus syndrome

OBJECTIVE

To describe the pattern and progression of central nervous system (CNS) lesions in microcephalic fetuses with suspected Zika virus (ZIKV) infection.

METHODS

In this prospective study in Salvador, Brazil, we analyzed fetuses diagnosed with microcephaly and suspected ZIKV infection after a routine primary care ultrasound scan between July 2015 and February 2016 raised suspicion of fetal microcephaly. The pregnancies were followed with serial ultrasound scans until delivery at one of the three main referral centers for fetal abnormalities in Salvador, Brazil. Microcephaly was diagnosed when the head circumference was two or more SDs below the mean for gestational age and its relationship with ZIKV infection was defined according to the World Health Organization's criteria. All women were interviewed, to assess potential factors associated with fetal microcephaly. Serology test results for toxoplasmosis, cytomegalovirus, rubella, syphilis and human immunodeficiency virus (HIV) were recorded, as were previous routine ultrasound results. Signs/symptoms of infection during the pregnancy were noted.

RESULTS

Of 60 cases of suspected ZIKV-related fetal microcephaly seen during the study period, eight were excluded due to serological evidence of other congenital infections or major ultrasound chromosomal markers. In the remaining 52 fetuses, microcephaly was diagnosed between 19 and 40 (median, 27.7; interquartile range, 23.4-32.0) weeks of gestation. The main ultrasound findings were: ventriculomegaly (65.4% of cases), cerebral calcifications (44.2%) and posterior fossa abnormalities (32.7%). 9.6% presented with arthrogryposis as an associated finding. Microcephaly was an isolated finding in four cases (7.7%). While ventriculomegaly was progressive in 41.2% of cases with this finding, the velocity of head circumference increase decreased progressively in almost all cases. Exanthematic disease was present in the majority (86.5%) of the women, 67.3% presenting in the first trimester of pregnancy. Additional lesions were detected after birth in 71.4% of the 35 cases with neonatal follow-up.

CONCLUSIONS

The majority of cases of congenital ZIKV syndrome have other ultrasonographic findings in addition to microcephaly. ZIKV-related CNS anomalies present mainly as progressive CNS lesions and slowing rate of growth of the fetal head, and this seems to be evident only in the late second trimester, even when maternal infection occurs in the first trimester. Other ultrasound findings, such as ventriculomegaly, brain calcifications and posterior fossa destruction lesions, are also common in this congenital syndrome. Posterior fossa destruction lesions and arthrogryposis are an uncommon finding in other congenital infections, perhaps suggesting a novel severe congenital syndrome associated with fetal ZIKV. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Ultrasonographic observations of the fetal brain in the first 100 pregnant women with Zika virus infection in Trinidad and Tobago

OBJECTIVE

To evaluate the fetal brain in pregnant women infected with Zika virus in a limited-resource setting.

METHODS

In an observational study in Trinidad and Tobago, 100 pregnant women infected with Zika virus who were referred for fetal medicine services provided by a single clinician were enrolled from March 31 to September 2, 2016. Two-dimensional ultrasonography was undertaken.

RESULTS

The women were aged 17-41 years (mean 27.5 ± 5.7). Six cases of fetal brain abnormalities consistent with Zika infection were detected before 26 gestational weeks. The gestational period at infection and time of presentation ranged, respectively, from 7⁺³ to 16⁺⁰  weeks and from 23⁺² to 25⁺⁵  weeks. In all cases, centiles of the biparietal diameter and head circumference decreased progressively over time to below the third centile. The skull contour appeared irregular, owing to collapse or overlap of the fetal skull bones. In four cases, brain anomalies were not obvious on the transabdominal scan but were diagnosed on the transvaginal scan. In a further two cases, brain abnormalities presented after 26 weeks of gestation.

CONCLUSION

Overall, 8.0% of women infected with Zika virus had fetuses with brain abnormalities suggestive of Zika congenital syndrome. Six cases were detected before 26 weeks and two cases after 26 weeks.

Nonmicrocephalic Infants with Congenital Zika Syndrome Suspected Only after Neuroimaging Evaluation Compared with Those with Microcephaly at Birth and Postnatally: How Large Is the Zika Virus "Iceberg"?

BACKGROUND AND PURPOSE

Although microcephaly is the most prominent feature of congenital Zika syndrome, a spectrum with less severe cases is starting to be recognized. Our aim was to review neuroimaging of infants to detect cases without microcephaly and compare them with those with microcephaly.

MATERIALS AND METHODS

We retrospectively evaluated all neuroimaging (MR imaging/CT) of infants 1 year of age or younger. Patients with congenital Zika syndrome were divided into those with microcephaly at birth, postnatal microcephaly, and without microcephaly. Neuroimaging was compared among groups.

RESULTS

Among 77 infants, 24.6% had congenital Zika syndrome (11.7% microcephaly at birth, 9.1% postnatal microcephaly, 3.9% without microcephaly). The postnatal microcephaly and without microcephaly groups showed statistically similar imaging findings. The microcephaly at birth compared with the group without microcephaly showed statistically significant differences for the following: reduced brain volume, calcifications outside the cortico-subcortical junctions, corpus callosum abnormalities, moderate-to-severe ventriculomegaly, an enlarged extra-axial space, an enlarged cisterna magna (all absent in those without microcephaly), and polymicrogyria (the only malformation present without microcephaly). There was a trend toward pachygyria (absent in groups without microcephaly). The group with microcephaly at birth compared with the group with postnatal microcephaly showed significant differences for simplified gyral pattern, calcifications outside the cortico-subcortical junctions, corpus callosum abnormalities, moderate-to-severe ventriculomegaly, and an enlarged extra-axial space.

CONCLUSIONS

In microcephaly at birth, except for polymicrogyria, all patients showed abnormalities described in the literature. In postnatal microcephaly, the only abnormalities not seen were a simplified gyral pattern and calcifications outside the cortico-subcortical junction. Infants with normocephaly presented with asymmetric frontal polymicrogyria, calcifications in the cortico-subcortical junction, mild ventriculomegaly, and delayed myelination.

Diagnostic Accuracy of Ultrasound Scanning for Prenatal Microcephaly in the context of Zika Virus Infection: A Systematic Review and Meta-analysis

To assess the accuracy of ultrasound measurements of fetal biometric parameters for prenatal diagnosis of microcephaly in the context of Zika virus (ZIKV) infection, we searched bibliographic databases for studies published until March 3rd, 2016. We extracted the numbers of true positives, false positives, true negatives, and false negatives and performed a meta-analysis to estimate group sensitivity and specificity. Predictive values for ZIKV-infected pregnancies were extrapolated from those obtained for pregnancies unrelated to ZIKV. Of 111 eligible full texts, nine studies met our inclusion criteria. Pooled estimates from two studies showed that at 3, 4 and 5 standard deviations (SDs) Collapse

Key Words Collapse

MESH Headings

• Fetal Diseases/diagnostic imaging
• Fetal Diseases/virology
• Humans
• Microcephaly/diagnostic imaging
• Microcephaly/embryology
• Microcephaly/virology
• Reproducibility of Results
• Sensitivity and Specificity
• Ultrasonography, Prenatal/methods
• Zika Virus/isolation & purification
• Zika Virus/physiology
• Zika Virus Infection/diagnostic imaging
• Zika Virus Infection/embryology
• Zika Virus Infection/virology

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Grants

• 001 World Health Organization

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Affiliation(s)

Ezinne C Chibueze Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan.
Alex J Q Parsons Department of Global Health Policy, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
Katharina da Silva Lopes Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan
Takemoto Yo Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan
Toshiyuki Swa Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan Graduate School of Human Sciences, Osaka University, Osaka, Japan
Chie Nagata Department of Education for Clinical Research, National Center for Child Health and Development, Tokyo, Japan
Nobuyuki Horita Pulmonology, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
Naho Morisaki Department of Social Medicine, National Center for Child Health and Development, Tokyo, Japan
Olukunmi O Balogun Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan
Amarjargal Dagvadorj Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan Department of Health Informatics, Kyoto University, Yoshida Konoe-cho, Syako-ku, Kyoto, Japan
Erika Ota Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan St. Luke's International University, Graduate school of Nursing, Global Health Nursing, Tokyo, Japan
Rintaro Mori Department of Health Policy, National Center for Child Health and Development, Tokyo, Japan
Olufemi T Oladapo UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), Department of Reproductive Health and Research World Health Organization, Geneva, Switzerland

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Spectrum of Spinal Cord, Spinal Root, and Brain MRI Abnormalities in Congenital Zika Syndrome with and without Arthrogryposis

BACKGROUND AND PURPOSE

Arthrogryposis is among the malformations of congenital Zika syndrome. Similar to the brain, there might exist a spectrum of spinal cord abnormalities. The purpose of this study was to explore and describe in detail the MR imaging features found in the spinal cords, nerve roots, and brains of children with congenital Zika syndrome with and without arthrogryposis.

MATERIALS AND METHODS

Twelve infants with congenital Zika syndrome (4 with arthrogryposis and 8 without) who had undergone brain and spinal cord MR imaging were retrospectively selected. Qualitative and quantitative analyses were performed and compared between groups.

RESULTS

At visual inspection, both groups showed reduced thoracic spinal cord thickness: 75% (6/8) of the group without arthrogryposis and 100% (4/4) of the arthrogryposis group. However, the latter had the entire spinal cord reduced and more severely reduced conus medullaris anterior roots (respectively, P = .002 and .007). Quantitative differences were found for conus medullaris base and cervical and lumbar intumescences diameters (respectively, P = .008, .048, .008), with more prominent reduction in arthrogryposis. Periventricular calcifications were more frequent in infants with arthrogryposis (P = .018).

CONCLUSIONS

Most infants had some degree of spinal cord thickness reduction, predominant in the thoracic segment (without arthrogryposis) or in the entire spinal cord (with arthrogryposis). The conus medullaris anterior roots were reduced in both groups (thinner in arthrogryposis). A prominent anterior median fissure of the spinal cord was absent in infants without arthrogryposis. Brain stem hypoplasia was present in all infants with arthrogryposis, periventricular calcifications, in the majority, and polymicrogyria was absent.

Echocardiographic findings in infants with presumed congenital Zika syndrome: Retrospective case series study

Objective

To report the echocardiographic evaluation of 103 infants with presumed congenital Zika syndrome.

Methods

An observational retrospective study was performed at Instituto de Medicina Integral Prof. Fernando Figueira (IMIP), Recife, Brazil. 103 infants with presumed congenital Zika syndrome. All infants had microcephaly and head computed tomography findings compatible with congenital Zika syndrome. Zika IgM antibody was detected in cerebrospinal fluid samples of 23 infants. In 80 infants, the test was not performed because it was not available at that time. All infants had negative serology for HIV, syphilis, rubella, cytomegalovirus and toxoplasmosis. A complete transthoracic two-dimensional, M-mode, continuous wave and pulsed wave Doppler and color Doppler echocardiographic (PHILIPS HD11XE or HD15) examination was performed on all infants.

Results

14/103 (13.5%) echocardiograms were compatible with congenital heart disease: 5 with an ostium secundum atrial septal defect, 8 had a hemodynamically insignificant small apical muscular ventricular septal defect and one infant with dyspnea had a large membranous ventricular septal defect. The echocardiograms considered normal included 45 infants with a persistent foramen ovale and 16 with a minimum patent ductus arteriosus.

Conclusions

Preliminarily this study suggests that congenital Zika syndrome may be associated with an increase prevalence of congenital heart disease. However the types of defects noted were septal defects, a proportion of which would not be hemodynamically significant.

The phenotypic spectrum of congenital Zika syndrome

In October 2015, Zika virus (ZIKV) outbreak the Brazilian Ministry of Health (MoH). In response, the Brazilian Society of Medical Genetics established a task force (SBGM-ZETF) to study the phenotype of infants born with microcephaly due to ZIKV congenital infection and delineate the phenotypic spectrum of this newly recognized teratogen. This study was based on the clinical evaluation and neuroimaging of 83 infants born during the period from July, 2015 to March, 2016 and registered by the SBGM-ZETF. All 83 infants had significant findings on neuroimaging consistent with ZIKV congenital infection and 12 had confirmed ZIKV IgM in CSF. A recognizable phenotype of microcephaly, anomalies of the shape of skull and redundancy of the scalp consistent with the Fetal Brain Disruption Sequence (FBDS) was present in 70% of infants, but was most often subtle. In addition, features consistent with fetal immobility, ranging from dimples (30.1%), distal hand/finger contractures (20.5%), and feet malpositions (15.7%), to generalized arthrogryposis (9.6%), were present in these infants. Some cases had milder microcephaly or even a normal head circumference (HC), and other less distinctive findings. The detailed observation of the dysmorphic and neurologic features in these infants provides insight into the mechanisms and timings of the brain disruption and the sequence of developmental anomalies that may occur after prenatal infection by the ZIKV.

Congenital Zika syndrome with arthrogryposis: retrospective case series study

OBJECTIVE

To describe the clinical, radiological, and electromyographic features in a series of children with joint contractures (arthrogryposis) associated with congenital infection presumably caused by Zika virus.

DESIGN

Retrospective case series study.

SETTING

Association for Assistance of Disabled Children, Pernambuco state, Brazil.

PARTICIPANTS

Seven children with arthrogryposis and a diagnosis of congenital infection presumably caused by Zika virus during the Brazilian microcephaly epidemic.

MAIN OUTCOME MEASURES

Main clinical, radiological, and electromyographic findings, and likely correlation between clinical and primary neurological abnormalities.

RESULTS

The brain images of all seven children were characteristic of congenital infection and arthrogryposis. Two children tested positive for IgM to Zika virus in the cerebrospinal fluid. Arthrogryposis was present in the arms and legs of six children (86%) and the legs of one child (14%). Hip radiographs showed bilateral dislocation in seven children, subluxation of the knee associated with genu valgus in three children (43%), which was bilateral in two (29%). All the children underwent high definition ultrasonography of the joints, and there was no evidence of abnormalities. Moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography (monopolar). Five of the children underwent brain computed tomography (CT) and magnetic resonance imaging (MRI) and the remaining two CT only. All presented malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. MRI of the spine in four children showed apparent thinning of the cord and reduced ventral roots.

CONCLUSIONS

Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis. The arthrogryposis was unrelated to the abnormalities of the joints themselves, but was possibly of neurogenic origin, with chronic involvement of central and peripheral motor neurones leading to deformities as a result of fixed postures in utero. Based on the neurophysiological observations, we suggest two possible mechanisms: tropism of neurones, with involvement of peripheral and central motor neurones, or a relation with vascular disorders.

Microcephaly and Zika virus: neonatal neuroradiological aspects

PURPOSE

The aim of this study is to describe some radiological features in the newborns with microcephaly caused by Zika virus infection during pregnancy.

METHODS

We radiologically analyzed 13 cases of newborns with microcephaly born to mothers who were infected by the Zika virus in the early stage of pregnancy.

RESULTS

The most frequently observed radiological findings were microcephaly and decreased brain parenchymal volume associated with lissencephaly, ventriculomegaly secondary to the lack of brain tissue (not hypertensive), and coarse and anarchic calcifications mainly involving the subcortical cortical transition, and the basal ganglia.

CONCLUSIONS

Although it cannot be concluded that there is a definitive pathognomonic radiographic pattern of microcephaly caused by Zika virus, gross calcifications and anarchic distribution involving the subcortical cortical transition and the basal ganglia, in association with lissencephaly and in the absence of hypertensive ventriculomegaly, are characteristic of this type of infection.