Diagnosis of Hydrocephalus and its’ Associated Embryological Anomalies on Prenatal Ultrasound

Abstract

Introduction: Hydrocephalus is the enlargement or dilatation of ventricular system due to an increase in cerebrospinal fluid (CSF) volume due to an obstruction which may also lead to an increase in CSF pressure. It has a prevalence rate of 4.65 per 10,000 and an incidence of 1 in 10,000 live births in Pakistan. It is found to be much more common in male fetuses as compared to female fetuses. Etiology of hydrocephalus ranges from idiopathic to chromosomal abnormalities. Maternal hypertension, diabetes, congenital infections and drugs like antidepressants are some of the risk factors. Neural tube defects like spina bifida, meningomyelocele have been found to be commonly associated with hydrocephalus. Therefore, hydrocephalus can be safely and cost-effectively diagnosed by prenatal ultrasound scans done in 1st and 2nd trimesters of pregnancy. Objective: The objective of this study was to identify 1. Hydrocephalus by prenatal trans-abdominal ultrasound in women of ages between 21-30 years and 31-40 years 2. Incidence of different central nervous system and extra-cranial congenital abnormalities associated with hydrocephalus Methods: This was a comparative cross-sectional study, done on 37 patients over a period of 8 months (December 2018 – July 2019) at private ultrasound clinic in Karachi. One participant was excluded from the study because of maternal diabetes mellitus. The study group was divided into 2 groups based on maternal ages (21-30 years and 31-40 years) and transabdominal ultrasound was done in pregnant Pakistani females 2 Results: The results of the study proved that fetal hydrocephalus was more commonly found in fetuses of mothers of younger age group (21-30 years) with a p-value of (≤ 0.01), with maximum cases being of severe type (63%). It most commonly affected the male gender. Fetal hydrocephalus was found to be more commonly associated with cranial anomalies like spina bifida, meningomyelocele, Dandy Walker syndrome and stenosis of cerebra aqueduct, however, 13 of the diagnosed cases were isolated. Normal volumes of amniotic fluid were found to be associated with fetal hydrocephalus (91.7%). 55.6% patients had a positive family history. p-value of ≤ 0.05 was observed between the measurements of atrium of lateral ventricle and ventricular:hemisphere ratio. Highly significant results (p-value ≤ 0.000) were observed when biparietal diameter (BPD) was compared with measurement of atrium of lateral ventricle. No correlation was found between BPD and atrium of lateral ventricle measurements, negative correlation was found between head circumference and head: abdominal ratio with atrium of lateral ventricle measurements and a positive correlation was observed between measurements of atrium of lateral ventricle and ventricular: hemisphere ratio. Conclusion: Transabdominal prenatal ultrasound can hence prove to be a valuable tool in diagnosis of fetal hydrocephalus especially if done in 1st and 2nd trimesters. Hydrocephalus has strong association with male gender, parity, family history and consanguinity. Fetal hydrocephalus is commonly found to be associated with multitude cranial and extracranial anomalies. Therefore, based on these observations and results it is recommended that all pregnant females should undergo transabdominal ultrasound scans as it is a safe, cheap, sensitive and specific tool to diagnose fetal anomalies.