Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis (joint contractures), results from a case series study in Brazil suggest.

“Brain impairment in the presence of microcephaly is the main characteristic of a congenital Zika virus syndrome,” researchers led by Vanessa van der Linden, MD, wrote in a study published online Aug. 9 in the BMJ. “However, little is still known about this condition and its clinical spectrum, which also concerns newborns with a normal head circumference. Two studies have described the association between arthrogryposis and microcephaly in newborns presumed to have congenital Zika virus infection [See Morb Mortal Wkly. Rep. 2016;65:59-62 and Ultrasound Obstet Gynecol. 2016;47:6-7 ].” The authors went on to note that while arthrogryposis might be considered more of a sign than a specific disease, “it might be associated with several disorders. However, there are no reports in the literature about other congenital infections in humans associated with arthrogryposis.”

Dr. van der Linden, a pediatric neurologist with the Association for Assistance of Disabled Children, Recife, Brazil, and her associates retrospectively evaluated the medical records of seven patients with arthrogryposis associated with congenital infection believed to be caused by Zika virus, during the Brazilian microcephaly epidemic ( BMJ. 2016;354:i3899 ). The main outcomes of interest were clinical, radiologic, and electromyographic findings, and likely collaboration between clinical and primary neurological abnormalities.

The researchers reported that brain images of all seven children revealed characteristics of congenital infection and arthrogryposis. Two children (29%) tested positive for IgM antibody for Zika virus in the cerebrospinal fluid, while arthrogryposis was present in the arms and legs of six children (86%) and in the legs of one child (14%). In addition, hip x-rays showed bilateral dislocation in all seven children and subluxation of the knee associated with genu valgus in three (43%). No evidence of abnormalities was seen on high-definition ultrasonography of the joints, but moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography. Results from brain computed tomography conducted in all seven patients and magnetic resonance imaging conducted in five revealed malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter, reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. Spinal MRI conducted in four children showed apparent thinning of the cord and reduced ventral roots.

“Further research is needed with a larger number of cases to study the neurological abnormalities behind arthrogryposis, including histopathology of autopsy samples or tissues from stillborn babies,” the researchers concluded. “As we do not know the potential implications of congenital Zika virus infection as it evolves, children must receive orthopedic follow-up, even those with a standard first orthopedic evaluation, because they could develop musculoskeletal deformities secondary to neurological impairment, central or peripheral, or both, as these occur in patients with cerebral palsy and other chronic encephalopathies.”

The researchers reported having no financial disclosures.