Teaching Case

A 19-year-old female patient, primigravida, was referred for routine antenatal examination. No H/o blood transfusion incompatibility, diabetes mellitus, spontaneous abortions or any blood transfusion reactions.

She was mildly anaemic with haemoglobin 9.8gm%, B.P 140/90mm Hg, fasting blood sugar 82mg%, blood urea 34mg% , S.Bilirubin 0.6, SGOT and SGPT within normal range.

Sonographic features of fetus on antenatal examination were as follow:
Fetal gestational age was 15 weeks 6 days. Amniotic fluid and AFI were within normal range. Placenta was fundal, anterior in location grade 1 maturity with placental thickness of about 4.2cm. There was evidence of thickening of subcutaneous tissue of the fetal scalp and nuchal fold [Fig. 1].
A well defined bilobed cystic mass with a thick central septa was seen in the fetal nape region suggestive of cystic hygroma Colli [Fig. 2].Significant amount of bilateral fetal pleural effusion was seen with partial relaxation atelectasis of both lungs. Marked abdominal subcutaeous oedema measuring about 9-10mm thick[Fig. 3]. Mild degree of pericardial effusion and significant amount of fetal ascites noted [Fig. 4]. Fetal heart rate show some variability in rhythm over the course of examination.No gross cardiac defect was detected.Fetal abortion was finally done due to marked fetal respiratory distress.

Hydrops is defined as an abnormal accumulation of serous fluid in at least two body cavities or tissues. Hydrops may be immune or nonimmune in origin. Non immune is defined as absence of a detectable circulating antibodies against red blood cells in the mother.

This condition was first documented by Ballantyne in 1892 and incorrectly described as hereditary in origin. Levine and coworkers in 1939 reported a link between maternal sensitization of fetal blood antigen Rh factor and hydrops fetalis-erythroblastosis fetalis later known as Immune Hydrops fetalis (IHF). In 1943, Potter reported cases where HF was not due to the antigen immunologic response as previously described by Landsteiner and Weiner, the term Nonimmune Hydrops Fetalis (NHF) was given. The various causes other than maternal blood incompatible were aneuploidy (20%), abnormal fetal cardiac structure/function (35%), haematological disease (15%), infections (10%), lymphatic or venous obstruction due to cystic hygroma and idiopathic causes (5%) [1, 2].

In preliminary studies, less than 20% of all hydrops fetalis cases fell into the NHF category. After the introduction and initiation of immunoglobulin prophylaxis for IHF, the NHF category has increased to approximately 90% of all hydrops cases. The incidence of NHF is about 1 to 1500 to 1 to 4000 deliveries [2]. Although there is no specific test to diagnose NHF, careful sonographic screening for fetal abnormalities is key to early detection and appropriate treatment.

Sonography is the investigation of choice for the detection of hydrops fetalis as it is
mutliplanar, easy operability, low cost and non-invasive. The various sonographic features in HF are: polyhydramnios, placenta oedema (>5cm), dilated umbilical vein, pleural/pericardial effusions, fetal ascites and generalised anasarca with subcutaneous thickness > 5mm [3, 4]. Lymphatic or venous maldevelopment may be the causative factor in NHF either from compression or high cardiac output failure [5].

Earlier hydrops fetalis cases were treated in utero by injecting albumin into the fetal abdominal cavity and by removal of accumulated fluid from the serous cavities [6]. Cordocentesis provides access for direct fetal therapy and diagnostic purposes - blood group and Rhesus typing, serology and PCR for congenital infections and chromosomal studies [7].

Cystic hygroma colli is frequently associated with Turner's syndrome. Karyotypes other than monosomy X are common, and perinatal survival is unlikely in the presence of hydrops fetalis [8].

Hydrops fetalis is a challenging entity for clinicians. Early diagnosis and treatment greatly improves perinatal outcome, though prognosis depends on the underlying etiology.