Although microcephaly is the most dramatic presentation of Congenital Zika Syndrome, the full spectrum of congenital defects caused by maternal infection with the Zika virus isn't yet known.
Some, including ocular defects, have already been documented (see Brazil: Expanded Spectrum of Congenital Ocular Findings in Microcephaly).
But there may well be or other physical impairments, or learning disabilities, that won't show up for years in affected children.
Yesterday the BMJ published a study that possibly links congenital Zika infection with arthrogryposis - or more properly arthrogryposis multiplex congenita (AMC) - a condition that produces joint deformities at birth.
The study looked at seven children from Brazil with arthrogryposis. All were presumed to have had congenital Zika infection - based on brain imaging (and other tests) - after infection with five other viruses known to cause microcephaly (toxoplasmosis, rubella, cytomegalovirus, HIV, and syphilis) were ruled out.
The cerebrospinal fluid of two of the infants also tested positive for Zika antibodies (IgM).
The contractures of the joints appeared to be due to motor neuron abnormalities rather than abnormalities in the joints themselves.
While researchers were unable to say with certainty that maternal Zika infection was the cause of arthrogryposis in these seven cases, they concluded that `Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis.'
The full, open-access report is available on the BMJ at the link below:
BMJ 2016; 354 doi: http://dx.doi.org/10.1136/bmj.i3899 (Published 09 August 2016) Cite this as: BMJ 2016;354:i3899
Vanessa van der Linden, paediatric neurologist1 2, Epitacio Leite Rolim Filho, paediatric orthpaedic surgeon1 3, Otavio Gomes Lins, clinical neurophysiologist3, Ana van der Linden, paediatric neurologist4, Maria de Fátima Viana Vasco Aragão, radiologist5 6, Alessandra Mertens Brainer-Lima, radiologist6 7, Danielle Di Cavalcanti Sousa Cruz, paediatrician4, Maria Angela Wanderley Rocha, paediatric infectologist8, Paula Fabiana Sobral da Silva, paediatric neurologist8, Maria Durce Costa Gomes Carvalho, paediatric neurologist8, Fernando José do Amaral, radiologist2, Joelma Arruda Gomes, paediatrician2, Igor Colaço Ribeiro de Medeiros, paediatrician9, Camila V Ventura, ophthalmologist10 11, Regina Coeli Ramos, paediatric infectologist8
The brain images of all seven children were characteristic of congenital infection and arthrogryposis. Two children tested positive for IgM to Zika virus in the cerebrospinal fluid.
Arthrogryposis was present in the arms and legs of six children (86%) and the legs of one child (14%). Hip radiographs showed bilateral dislocation in seven children, subluxation of the knee associated with genu valgus in three children (43%), which was bilateral in two (29%). All the children underwent high definition ultrasonography of the joints, and there was no evidence of abnormalities.
Moderate signs of remodeling of the motor units and a reduced recruitment pattern were found on needle electromyography (monopolar). Five of the children underwent brain computed tomography (CT) and magnetic resonance imaging (MRI) and the remaining two CT only. All presented malformations of cortical development, calcifications predominantly in the cortex and subcortical white matter (especially in the junction between the cortex and white matter), reduction in brain volume, ventriculomegaly, and hypoplasia of the brainstem and cerebellum. MRI of the spine in four children showed apparent thinning of the cord and reduced ventral roots.
Congenital Zika syndrome should be added to the differential diagnosis of congenital infections and arthrogryposis. The 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. Based on the neurophysiological observations, we suggest two possible mechanisms: tropism of neurones, with involvement of peripheral and central motor neurones, or a relation with vascular disorders.
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