A 'Healthy' Baby With Developmental Delay: Could It Be Zika?

Cynthia A. Moore, MD


January 06, 2020


When determining if a patient had possible exposure to Zika virus during pregnancy, it's important to ask whether the mother or mother's partner traveled to an area with risk for Zika virus transmission and whether the mother ever had symptoms of Zika virus disease during her pregnancy (eg, fever, rash, conjunctivitis, arthralgia). Tools containing screening questions for clinicians to use can be found on CDC's website.

Upon probing for more information, the physician learns that the woman and her husband had traveled to an area experiencing a Zika outbreak during the second trimester of her pregnancy. Neither of them developed any symptoms of Zika virus infection. Upon her return to the United States, the woman was not tested for Zika virus during the remainder of her pregnancy; no microcephaly was noted on the midpregnancy ultrasound.

Zika virus testing is not routinely recommended for asymptomatic pregnant women who have had possible recent but not ongoing Zika virus exposure; however, guidance might vary among jurisdictions. The updated guidance for maternal testing is intended to reduce the possibility of false-positive results in the setting of the lower pretest probability.

Evaluation of this infant would include a standard evaluation and assessment of the brain, eyes, and hearing, as well as Zika testing. Because of his age and the presence of focal neurologic findings, this infant should receive neuroimaging beyond ultrasound and referral to a pediatric neurologist. As with the infant in Case 2, Zika-specific IgM testing in serum should be done, as well as in the CSF if obtained for other purposes.

Postnatal-onset of microcephaly is most often attributable to genetic conditions, prenatal or postnatal toxic exposures, or trauma. Although microcephaly can be familial, focal neurologic findings are not a feature of this condition and the microcephaly is usually present from birth. Kernicterus, caused by toxic levels of bilirubin in the brain, can be symptomatic in the first few days of life, but typical characteristics of the condition usually develop by 3-4 years of age. Infant botulism due to honey intake is rare; muscle weakness including ptosis and hypotonia are typical neurologic symptoms in this condition. The brain findings, neurologic findings, and postnatal-onset microcephaly in this infant are indicative of a prenatal insult and consistent with prenatal exposure to Zika infection requiring further evaluation of a possible congenital infection.

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