Case Study: Aminotic Band Syndrome in 20 Weeks Foetus Associated With Limb Defects

ABSTRACT

Amniotic Band Syndrome is a series of congenital malformations ranging from minor constriction rings to complex multiple congeni- tal anomalies, that are attributed to amniotic bands that entangle and disrupt foetal parts. While mild variants have a good progno- sis with normal life expectancy, severe cases may be incompatible with life. We report a case of a 20 week old foetus with an amniotic band around the right upper limb, entanglement around the neck and a Congenital Talipus Equin- ovarus deformity of the right foot, delivered from a 31 year old female patient, who came for a routine check up to the Department of Obstetrics and Gynecology at DM Wayanad Institute of Medical Sciences, Meppadi post, Kerala. Early prenatal diagnosis of this defect by Ultrasonography is a boon to Obstetricians, Pediatricians and Surgeons.

INTRODUCTION

Amniotic Band Syndrome (ABS) has been studied since the time of Hippocrates and Aristotle.BS is a group of sporadic congenital anomalies of varying severity involving limbs, the craniofacial region or trunk.2 Reported incidence ranges widely, from 1 in 1200 to 1 in 15000, depending on the criteria used.2 Amongst women pregnant with ABS foetuses, spontaneous abortion is a common outcome and incidence can be as high as 178/10000.1

The case discussed here is a presentation with simultane- ous amniotic band constriction around the right upper limb, en- tanglement around the neck, and congenital Talipus Equinovarus deformity of the right foot, as seen in a fetus delivered from a 31 year old woman at 20 weeks gestation. This case offers important insights for gynaecologists, radiologists and pediatricians for early prenatal diagnosis and treatment.

CASE REPORT

A 31 year old woman in a non- consanguineous marriage who had conceived naturally presented at 20 week gestation to the Department of Obstetrics and Gynecology OPD at DM Wayanad Institute of Medical Sciences, Mepaddi, Kerala for a routine check-up. The patient’s past two pregnancies had been uneventful. She was taking regular antenatal care with folic acid supplementation for the present pregnancy and the first trimes- ter scan had been normal. There was no past history of trauma, drug intake or amniocentesis.

P/A examination of the uterus at 18-20 weeks showed this to be relaxed, with no foetal heart sound (FHS). On ultrasonographic examination, the foetus showed no cardiac activity and indicated oligohydramnios. Hence the pregnancy was terminated with consent of the patient by extra- aminotic Foley’s induction.

A foetal examination after the termination of pregnancy showed a constriction band around the right upper limb and an entanglement around the neck.

There was a right lower limb deformity with similar presentation to Congenital Talipus Equino- Varus deformity.

DISCUSSION

Amniotic band syndrome (ABS) comprises of a spectrum of anomalies which vary in severity. 2 The triad of ABS includes amnion- denudation of the placenta; foetal attachment or entanglement by amniotic remnants; and foetal de- formation, malformation and disruption. 2 In the present case, we report an amniotic band around the right shoulder, entanglement around the neck and Congenital Talipus Equinovarus Deformity.

Embryological basis of TA

In 1930, Streeter’s intrinsic hypothesis proposed disruption in embryogenesis at the time of for- mation of the germ disk as a cause for ABS.3 In 1965 Torpin’s extrinsic hypothesis suggested that the birth defects are instead caused by the primary rupture of the amnion early in gestation.3In 1992, Moer- man .et.al proposed that ABS is a collection of three distinct lesions- constrictive tissue bands, amniotic adhesions and the more complex limb-body wall complex.4

Kalousek .et.al divided the amnion defects into the Limb Body Wall Complex (LBWC), caused by an early defect of the amniotic sac, and the amnion rupture sequence, caused by amniotic bands. 5 They also reported that the incidence of amnion rupture sequence is much higher in previable spontaneous abortions than in term foetuses, indicating that most cases are spontaneously aborted. 5

Etiological factors for Amniotic

Band Syndrome:

Various studies point to different etiological factors, including maternal drug abuse, cigarette smoking, unplanned pregnancy, anorexia, hyperthermia, young maternal/paternal age, dietary glycaemic index, abdominal trauma, infections, amniocentesis etc. which have been implicated in the causation of ABS.2 A human homologue of the mouse Disorganisation gene (Ds) has been proposed as a cause of some cases of amnion disruption by a two-hit mechanism (the gene is yet to be identified). Some cases of ABS-like anomalies associated with cleft lip and palate may result from mutations in the genes Disorganization p63 or IRF6.6

There have been reported asso- ciations with underlying diseases including Ehler Danlos Syndrome and osteogenesis imperfecta. The malformations of ABS should be distinguished from others occur- ring in a syndromic setting by the fact that the clefts do not follow anatomic lines of closure and the lesions are asymmetrical.7 This is important since most cases of Am- niotic band syndrome are sporadic and there is no risk of recurrence in subsequent pregnancies. 2 In the present case, an exact etiology was not found.

The accepted modality of treatment for amniotic band syndrome in utero is by foetoscopic laser surgery before the bands begin to compress the fetal parts.1

CONCULSION

An awareness of Amniotic Band Syndrome helps the obstetrician in identifying foetal anomalies, prognosticating about them to expectant parents, terminating pregnancy in appropriate situations and counseling the parents on the possibility of recurrence of the anomaly in subsequent pregnancies. Radiologists should be aware of Amniotic Band Syndrome as one of the causes for intrauterine fetal demise during prenatal ultrasound examination. Early detection of this will help to deliver appropriate treatment.

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