Which conditions that cause hyperechoic bowel should be considered in the differential diagnoses of cystic fibrosis (CF)?

Updated: Sep 28, 2020
  • Author: Girish D Sharma, MD, FCCP, FAAP; Chief Editor: Kenan Haver, MD  more...
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In addition to meconium ileus, hyperechoic bowel may occur with Down syndrome, intrauterine growth retardation, prematurity, in utero cytomegalovirus (CMV) infection, intestinal atresias, abruptio placenta, and fetal demise. The importance of hyperechoic fetal bowel relates to gestational age at detection, ascites, calcification, volume of amniotic fluid, and presence of other fetal anomalies.

Furthermore, a prenatal diagnosis of meconium ileus using the sonographic feature of hyperechoic bowel must consider the parents' a priori risk. The positive predictive value of hyperechoic masses in a high-risk fetus is estimated at 52%, while the predictive value for a low-risk fetus is just 6.4%.

While reviews of pregnancies with 1-in-4 risk of CF show a 25%-60% association between hyperechoic bowel and CF, this association is less prevalent in the general population. In 1992, Dicke and Crane reviewed 12,776 fetal sonograms performed after 14 weeks' gestation and noted hyperechoic bowel in 30 (0.2%) of these patients. Of these, 13.3% had CF. This team also reported a 16.7% associated risk of perinatal death, a 23.3% risk of growth retardation, and a 3.3% risk of genetic abnormality. [39]

Note that hyperechoic bowel is a normal variant in both the second and third trimesters. Hyperechoic bowel, when it occurs as an isolated event early during the second trimester, may represent a normal variant and indicates the need for follow-up prenatal examinations. Although an increased risk of meconium ileus and CF is associated with hyperechoic bowel, the prevalence, degree of risk, and decisions involving prenatal management remain uncertain.

Prenatal ultrasonographic findings of dilated bowel in association with CF have been reported less frequently than findings of hyperechoic bowel.

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