Studies show extensive, haunting brain damage
Much of the public alarm about Zika has focused on the dramatic, heartbreaking pictures of children with a condition known as microcephaly characterized by an abnormally small head. But a paper published Tuesday from the epicenter of the epidemic in northeastern Brazil shows that the damage to a baby’s brain may be far more extensive and diverse than has been previously known.
While there have been sporadic case studies about fetal abnormalities beyond microcephaly, this is the first to provide a comprehensive breakdown of the type of defects that radiologists are seeing in the womb and after babies are born.
In a series of striking images in the journal Radiology, researchers detail a halfdozen brain defects that they found in nearly all the babies in their study. This is significant because, technically speaking, microcephaly is a superficial diagnosis that is based on the how a child’s head circumference compares to others. Some children with the condition go on to develop normally or have only minimal delays. This study confirms fears that the babies with Zika may be more severely impacted.
“What this tells you is that Zika is a devastating infection. There is evidence the brain just didn’t form normally,” Deborah Levine, a professor of radiology at Harvard Medical School and a study co-au-
thor, said in an interview.
The research involved 45 children, including one set of twins, who were referred to the Instituto de Pesquisa in Campina Grande from June 2015 to May 2016. Most of them had a head circumference below the 5th percentile and were confirmed or presumed to have been infected with Zika while in utero. Researchers used magnetic resonance or other imaging technology to track their development over time.
In total, researchers documented eight main types of brain abnormalities and presented a theory for the unusual appearance of the heads of Zika babies — many of whom not only have small head sizes but skulls with a collapsed shape.
It may be “due to a combination of the small brain as it develops and a result of what, at some point, was likely a larger head size (as a result of fluid buildup) that then decompresses,” they wrote.
One of the most common abnormalities, which showed up in 43 of the babies, is a condition known as ventriculomegaly. It’s characterized by the fluidfilled structures in the brain being too large. In some cases it can be left untreated, but in others surgery or other intervention is necessary to try to prevent serious, longterm neurological damage.
Forty-three babies also had intracranial calcifications (deposits of calcium in the tissue) which can impair brain function. This is common in a lot of different kind of infections, but what’s unusual in the babies with Zika is that these regions are very dense and they are located near the gray matterwhite matter juncture in the brain rather than on the outsides of the brain, as is typically seen.
Thirty-eight of the children had abnormalities of the corpus callosum, the tract of nerve fibers that joins the two hemispheres of the brain.