A Report on Prenatal Diagnosis of a Rare Case of Fetal Acrania and Omphalocele by Doppler Examination
Author(s): Sabar Butt, Syeda Khadija, Syed Amir Gilani
A congenital anomaly, fetal acrania (exencephaly) is, in which the fetal brain is not surrounded completely or partially by the skull bones. It is suggested that there is lacking of mesenchymal migration in the fourth week of embryological age. The first-trimester diagnosis must be made with restraint because the fetal cranium is not fully calcified before 10-11 weeks; therefore, if only midsagittal views of the fetus are obtained, misdiagnosis may occur. Another anomaly, omphalocele, a ventral defect of the umbilical ring resulting in herniation of the abdominal viscera, is one of the most common congenital abdominal wall defects seen in the newborn. Omphalocele is associated with trisomy . The defect occurs in 1 in 6000 to 1 in 10,000 live births. The anencephaly sequence begins with acrania, which affecting the central nervous system with an incidence of ~1:1000 pregnancies. In our case a female 28 years old visited our ultrasound clinic for anomaly scan. The gestational age was 18 weeks 4 days. On ultrasound examination the presentation of fetus was cephalic and longitudinal lie. The sonographic scan revealed fully developed fetal brain having no calvarium. The brain was covered by a thin membranous structure. Compression of fetal brain by transducer was observed due to absence of cranium. The scan revealed the brain floating in the amniotic fluid over the base of skull. Facial structures were normal. Normal and well-coordinated movements were noted in in the fetal body parts. There was symmetry in Fetal nose and naso-labial folds and were well appreciated. It was also noted that spinal canal showed normal morphology with normal Cervical, thoracic and lumbar spines. The fetal abdomen showed a central mass protruding out from anterior abdominal wall. The mass is covered by a membrane and contains small intestines and liver. There was direct insertion of the umbilical cord into the midline of omphalocele. After taking consent form from the patient and her family, an elective prostaglandin abortion was performed. After delivery placenta was completely removed. Brain was covered by a membrane. There was a mass protruding through anterior abdominal wall and multiple abdominal viscera’s were protruding out through the midline gap in the anterior abdominal wall. This breach was centrally located equivalent to umbilicus connection. About 1-2mm thick was covering the protruding organs.