The Centers for Disease Control and Prevention (CDC) recently released a report on a study that has linked congenital Zika syndrome (CZS) with dysphagia, or trouble swallowing, in 9 Brazilian infants. The report was published in Emerging Infectious Diseases.
For the study, the researchers sought out to evaluate dysphagia in children with CZS and identify the characteristics associated with the condition. In a “descriptive, retrospective, case series study,” using data from 3 tertiary care institutions, they reviewed medical records for 9 Brazilian children who had dysphagia and had also been diagnosed with CZS-associated microcephaly during the “2015 epidemic of microcephaly.”
The researchers used 2 instrumental methods to assess dysphagia in the infants: fiberoptic endoscopic evaluation of swallowing (FEES) and the videoflouroscopic swallowing study (VFSS), two methods that “are considered the reference standards for instrumental evaluation of all phases of dysphagia,” the authors noted.
“All infants had a degree of neurologic damage, with global developmental delays, hypertonia of the limbs, and pyramidal and extrapyramidal signs,” according to the report. Furthermore, the majority of the infants also had “abnormal movement of the tongue,” which contributed to dysphagia. In some of the infants, hypertonia was responsible for abnormal posture and neck hyperextension. Hyperextension of the neck was linked with irritability in 6 out of the 9 infants, a symptom that is common in infants with CZS; this also contributes to dysphagia. The authors also reported that the infants’ brain imaging results—which showed calcifications in the cortical and subcortical region as well as in the “border between white matter and the cortex”—were consistent with other data for infants with CZS-associated microcephaly. Eight of the 9 infants in the study had malformations associated with cortical development as well.
In 8 of the 9 infants, onset of dysphagia began at 3 months of age. According to the report, the infants’ mothers reported that some of the early symptoms of dysphagia presented as the following: choking, coughing, regurgitation, respiratory infections, and a longer feeding time.
The authors noted that “swallowing is a reflex activity,” in the first few months of an infant’s life. Furthermore, the “oral or preparatory phase, usually established at that age, is a voluntary activity that requires intact cortical function, which is absent in many children with CZS.” All 9 of the infants had difficulty swallowing, which “was characterized by premature spillage, and marked loss of voluntary activity during the oral phase of swallowing.” The authors explained that for the infants involved in this study, transferring from a reflexive activity (swallowing) to a “complex voluntary sensorimotor process” resulted in “abnormal oral phase movements” that ended up hindering “normal swallowing after 3 months of age.”
The authors concluded that dysphagia associated with CZS microcephaly is “severe and has an onset of 3 months of age.” They continued, “Affected children have marked oral dysfunction, with dystonic movements of the tongue, and lack pharyngeal sensitivity, leading to risk of aspiration, in particular of liquid foods.” They noted that the infants fared better when it came to pureed foods rather than liquid foods. Therefore, the researchers suggest that CZS microcephaly infants with dysphagia be fed “pureed or thickened food.” They also recommend that “care be taken during feeding to avoid the overextended posture characteristics of many children with CZS,” as this posture can contribute to aspiration. Lastly, they advise that follow-up for CZS children should be done by a “comprehensive and multidisciplinary team of childhood specialists in neurology, gastroenterology, speech pathology, nutrition, and otorhinolaryngology, using clinical and instrumental swallowing assessments (with FEES and VFSS) to identify different aspects of dysphagia.” They added, “For clinical management, the clinical evaluation remains key.”