Title: Comprehensive study of Foetal cases of Sirenomelia Sequence with their Embryological Correlations
Authors: Usha Rani Vanagondi *, Saritha. S, Jwalaram Kumar Chaluvadi, Gayathri. P, Nagajyothi. D
DOI: http://dx.doi.org/10.18535/jmscr/v4i4.19
Comprehensive study of congenital anomaly “Sirenomelia” of the fetuses is a rare malformation which is incompatible with life. This is very rare anomaly and it is heart wrenching to hear such cases. The sequence was originally described by Rocheus in 1542 and Palfyn in 1953 and named after the mythical Greek sirens. Sirenomelia sequence is also known as Mermaid Syndrome, a Greek Mythology fact that it has two fused lower limbs look like mermaid’s tail. Sirenomelia was formerly thought to be an extreme case of Caudal Regression Syndrome (CRS); but CRS is now considered to be caused by an anomaly of lower spinal trunk ending (Frog-like). It is encompasses by a wide range of anomalies including partial or complete agenesis of thoraco-lumbosacral spine & pelvic deformities. Sirenomelia may be caused by abnormalities in blastogenesis that affect multiple midline primordial structures during the final stages of Gastrulation at the caudal eminence. This leads to insufficient migration and differentiation of mesoderm which is responsible for the array of defects in caudal region and it also affects the distribution of blood to the caudal region of the fetus. Approximately 300 cases have been reported in the literature with male: female ratio being 3:1. These infants usually do not survive for more than 24 hours. Very few survive even after surgery. Aim: Ultra sound scan may be useful in early antenatal detection of this anomaly. In view of bad prognosis earlier intrauterine diagnosis allows less traumatic therapeutic abortion minimizing termination of pregnancy at advanced gestation. Observation & Results: We observed two cases of Sirenomelia sequence. First case was 25 years old primigravida at 24 weeks of gestation was admitted to the hospital. Prenatal ultrasound demonstrated severe Oligohydramnios and fusion of the lower limbs suggesting the diagnosis of Sirenomelia, pregnancy was terminated. Second case was also 25 years old primigravida gave birth to still born full term baby, sex could not be identified. The specimen was collected from private nursing home and the diagnosed as Sirenomelia. Both the cases had no relevant history of consanguineous marriage or tobacco smoking or drugs taking etc. Both the fetuses were submitted for detailed autopsy in anatomy dissection hall. The findings, with brief review of the literature, discussion of etio-pathogenesis and embryological correlation were presented in this article Key words: Sirenomelia, Caudal Regression Syndrome (CRS), Vascular steal theory and Teratogenesis.
Abstract
