Arthrogryposis is characterized by joint contractures at birth and has been described in patients with congenital Zika virus exposure. The authors of the current study suggest that "[t]he pathophysiology of this condition might be related to the tropism of the virus by the upper and lower motor neurons, or to embryonic vascular change affecting these two segments."
Researchers led by Vanessa van der Linden, MD, from the Association for Assistance of Disabled Children, Reclife, Brazil, evaluated data from seven children with presumed congenital Zika virus infection who had microcephaly and arthrogryposis. They included infants in whom other infectious causes of microcephaly were excluded; two of the children had positive serology results for Zika infection in cerebrospinal fluid samples. All children underwent neurologic and orthopedic evaluations, advanced neuroimaging, joint ultrasound, nerve conduction studies, and electromyography.
Six children (86%) had arthrogryposis in both the arms and legs, and all seven children had bilateral hip dislocation. Other leg joint abnormalities included club foot in six children (86%), knee flexion contracture in five children (71%), and hyperextension with subluxation of the knee in three children (43%). Joint deformities in the arms included camptodactyly in six children (86%), deformities in hyperextension of the elbow in four children (57%), and flexion abnormalities in the second to fifth chirodactylus in all seven children. Five children (71%) had adduction of the thumb, and two (29%) had abduction of the thumb.
Sensory nerve testing was normal, although motor action potentials were of low amplitude in most children. Needle electromyography showed moderate signs of remodeling. All children also demonstrated cortical calcification, reduced brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum on advanced imaging. The researchers note that the presence of cortical malformations suggests infection likely occurred within the first 5 months of pregnancy.
The authors note that in these patients, "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."
The researchers acknowledge that further research with a larger number of cases is needed to further elucidate the pathophysiology of this association and to determine appropriate follow-up for infants with neurological impairment.
A recent study by the same research group discussed the clinical features and neuroimaging findings in infants with microcephaly and Zika virus exposure. The present study, however, elucidates the association with arthrogryposis and underscores that there is still much that is unknown about the complex clinical spectrum of Zika infection.
"This disease goes beyond microcephaly, with other symptoms such as visual and hearing impairment, and unusual signs and symptoms different from other congenital infections, such as arthrogryposis and no microcephaly, suggesting that the term congenital Zika syndrome is more appropriate," the researchers write.
Zika virus should be considered a differential diagnosis in infants with congenital infections and arthrogryposis, the authors conclude.
The authors have disclosed no relevant financial relationships.
BMJ. 2016;354:i3899. Full text
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Cite this: Arthrogryposis Associated With Zika Infection In Utero - Medscape - Aug 15, 2016.