Is Zika linked to another birth defect?
In addition to microcephaly, the Zika virus’s impact on the fetal brain may be linked to arthrogryposis, congenital contracture of joints, according to results of a small new study published in the BMJ.
For the retrospective case series, researchers reviewed records from children seen at the Association for Assistance of Disabled Children in the Pernambuco state in Brazil. Seven children with arthrogryposis and a diagnosis of a congenital infection, which was presumed to be Zika virus contracted during the Brazilian microcephaly epidemic, were identified. Clinical, radiologic, and electromyographic findings were assessed for likely correlations between clinical and primary neurologic abnormalities.
In all 7 children, brain images were consistent with congenital infection and arthrogryposis. In 2 children, testing of cerebrospinal fluid was positive for immunoglobulin M to Zika virus. Arthrogryposis was present in the arms and legs of 6 children and in 1 child’s legs. All 7 children had bilateral dislocation on radiography and 3 children had subluxation of the knee, which was bilateral in 2 of them. No evidence of joint abnormalities was found on high-definition ultrasonography.
Computed tomography (CT) and magnetic resonance imaging (MRI) were performed on 5 of the children’s brains and the other 2 received CT brain scans. Each child had calcifications, predominantly in the cortex and subcortical white matter, reduction in brain volume, ventriculomegaly, hypoplasia of the brainstem and cerebellum, and malformations of cortical development. Spine MRIs of 4 children showed apparent thinning of the cord and reduced ventral roots.
The researchers concluded that congenital Zika infection should be added to the differential diagnosis for arthrogryposis. The findings showed that the arthrogryposis was not related to abnormalities in the joints themselves, but rather, to tropism of neurons or to vascular disorders.