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.

[Glutaric aciduria type 1: phenotypic variability. Report of 6 patients]

We report six patients with glutaric aciduria type 1 in four families. The patients had marked clinical variability, even within families. Three of the patients studied were normal until the onset of neurologic abnormalities, that presented as an encephalitis-like illness in the first year of age. One patient had an early and important developmental delay, but never suffered an encephalopathic crisis. Two patients have intellectual preservation; one of them has a mild tremor and choreoathetosis since the first year of age, and the other had only two afebrile seizures in infancy and no other neurologic signs. Three patients are severely handicapped, with a severe dystonic-dyskinetic disorder and unable to even sit. All the six patients have macrocephaly and in all the computed tomography showed enlarged CSF spaces and sulcal separation over the frontal and temporal lobes. Urine organic acids study of all patients showed large quantities of glutaric acid.