Does gut atresia cause polyhydramnios?

Prenatal Detection of Congenital Duodenal Obstruction—Impact on Postnatal Care

Background: Duodenal obstruction is a rare cause of congenital bowel obstruction. Prenatal ultrasound could be suggestive of duodenal atresia if polyhydramnios and the double bubble sign are visible. Prenatal diagnosis should prompt respective prenatal care, including surgery. The aim of this study was to investigate the rate and importance of prenatally diagnosed duodenal obstruction, comparing incomplete and complete duodenal obstruction. Methods: A retrospective, single-center study was performed using data from patients operated on for duodenal obstruction between 2004 and 2019. Prenatal ultrasound findings were obtained from maternal logbooks and directly from the investigating obstetricians. Postnatal data were obtained from electronic charts, including imaging, operative notes and follow-up. Results: A total of 33/64 parents of respective patients agreed to provide information on prenatal diagnostics. In total, 11/15 patients with complete duodenal obstruction and 0/18 patients with incomplete duodenal obstruction showed typical prenatal features. Prenatal diagnosis prompted immediate surgical treatment after birth. Conclusion: Prenatal diagnosis of congenital duodenal obstruction is only achievable in cases of complete congenital duodenal obstruction by sonographic detection of the pathognomonic double bubble sign. Patients with incomplete duodenal obstruction showed no sign of duodenal obstruction on prenatal scans and thus were diagnosed and treated later.

Prenatal Diagnosis of a Vanishing Gastroschisis With Subsequent Neonatal Bowel Complications: A Case Study

Background:

Gastroschisis is a well-known birth defect in which bowel protrudes through a perforation in the fetal abdominal wall. High antenatal detection rates typically lead to good outcomes with modern neonatal treatments.

Case:

We describe a rare phenomenon in which gastroschisis appears to resolve antenatally, with associated bowel dilation and polyhydramnios. No evidence of an abdominal wall defect was seen at birth, but imaging was suggestive of bowel atresia. Surgical exploration showed a microcolon and most of the small bowel was absent. An extensive surgical repair was required, which resulted in short bowel syndrome.

Conclusion:

Gastroschisis that undergoes apparent resolution on sonography can be associated with necrosis due to strangulation of the exteriorized bowel and short bowel syndrome. This is associated with high neonatal morbidity and mortality.

A Singleton Infant with Bilateral Renal Agenesis and Normal Pulmonary Function

Bilateral renal agenesis leads to anhydramnios and other sequelae including pulmonary hypoplasia. There have been rare case reports of normal pulmonary function in the presence of bilateral renal agenesis in monoamniotic discordant twins, but this has never been reported in a singleton pregnancy. The few reported cases in twins have all been fatal in the neonatal period with no reported cases of survival beyond 2 months. We describe the first case of a singleton infant with bilateral renal agenesis who had normal pulmonary function and did well on peritoneal dialysis for 4 years while awaiting a renal transplant.

In Utero Development of Fetal Thirst and Appetite: Potential for Programming

Thirst and appetite-mediated ingestive behavior develop and are likely programmed in utero, thus preparing for newborn and adult ingestive behavior. Fetal swallowing activity is markedly different from that of the adult, as spontaneous fetal swallowing occurs at a markedly (six-fold) higher rate compared with spontaneous adult drinking activity. This high rate of fetal swallowing is critical for the regulation of amniotic fluid volume and the development of the fetal gastrointestinal tract. Disordered fetal swallowing has been associated with both a decrease (oligohydramnios) and increase (polyhydramnios) in amniotic fluid volume. Both conditions are associated with a significant increase in perinatal morbidity and mortality, and limited treatment modalities are currently available. The mechanisms underlying the high rate of human fetal swallowing are regulated, in part, by tonic activity of central angiotensin II, glutamate N-methyl-D-aspartate receptors, and neuronal nitric oxide synthase. Fetal hypertonicity-mediated dipsogenesis is likely programmed in utero, as offspring of water-restricted ewes demonstrate a programmed syndrome of plasma hypertonicity, with significant hematologic and cardiovascular alterations. Similar to dipsogenic mechanisms, peripheral and central fetal orexic mechanisms also develop in utero, as demonstrated by increased fetal swallowing after both oral sucrose infusion and central injection of neuropeptide Y. The role of leptin in regulating fetal ingestive behavior is interesting because, contrary to actions in adults, leptin does not suppress fetal ingestive behavior. Teleologically, this may be of value during the newborn period, as unopposed appetite stimulatory mechanisms may facilitate rapid fetal and newborn weight gain. An adverse intrauterine environment, with altered fetal orexic factors during the critical developmental period of fetal life, may alter the normal setpoints of appetitive behavior and potentially lead to programming of adulthood hyperphagia and obesity. Further research is needed to delineate the mechanistic relationship between the intrauterine environment and the development of the setpoints of adult appetite and thirst.

Prenatal counselling of small bowel atresia:watch the fluid!

OBJECTIVE

To evaluate polyhydramnios as a sign of extreme disproportion of atretic segments in small bowel atresia (SBA).

METHODS

Twenty-eight patients with a prenatal diagnosis (PD) of SBA undergoing neonatal surgical treatment were reviewed retrospectively. Parameters recorded were gestational age, birth weight, surgical procedure, rate of complications, parenteral nutrition (PN) days and length of stay (LOS). Patients were divided into two groups: Group A with delayed anastomosis and Group B with direct anastomosis.

RESULTS

Seventeen subjects were in Group A while 11 were in Group B. The two groups did not differ with regard to gestational age at diagnosis, birth weight and obstetrical management. Polyhydramnios was present in both Group A (64.7%) and Group B (9%) (p < 0.05). Patients in Group A needed a longer period on PN, had a longer LOS and exhibited significantly higher rates of complication.

CONCLUSION

In the absence of other malformations, association of dilated bowel loops and polyhydramnios is highly predictive of severe SBA, which can in no instance be amenable to one-stage reconstruction. Because of its consequences on postnatal treatment, such information should be conveyed to the prospective parents at the time of counselling.

Adriamycin-induced fetal hydronephrosis

INTRODUCTION

At the end of pregnancy, the amniotic fluid (AF) depends basically on renal function, corresponding to fetal urine. Changes in AF, especially oligohydramnios, are reported in association with fetal hydronephrosis (FH). The experimental model using adriamycin in pregnant female rats has a teratogenic effect and has been classically employed to study esophageal atresia. Nevertheless, adriamycin promotes FH with high frequency as well. In the present study, using this animal model, we tried to identify the incidence and microscopic changes of FH, as well as its correlation with AF weight.

MATERIALS AND METHODS

Eight Spreague-Dawley pregnant female rats received adriamycin 2.2 mg/kg on the 8th and 9th gestational days (considering term gestation = 22 days). Those fetuses that received adriamycin (Adriamycin Group) were compared with fetuses from 2 female rats (Control Group), which received 0.9% saline solution. On the 21.5 gestational day, the fetuses were collected by cesarean incision, sacrificed, and examined for macro and microscopic changes in kidneys and ureters. Fetuses with bilateral hydronephrosis formed the Hydronephrosis Group. AF weight was determined as well.

RESULTS

Hydronephrosis occurred in 70 (95%) of the 74 fetuses in the adriamycin group against none of the 21 fetuses from the control group. The amniotic fluid weight was increased in the adriamycin group in relation to the control group (p < 0.001). The histomorphometric study revealed dilation of the renal pelvis and reduction of renal parenchyma in the hydronephrosis group in relation to the control group. Severe cortical atrophy, cortical tubular atrophy and medullar atrophy were observed in the hydronephrosis group.

CONCLUSIONS

Slight renal lesions were in agreement with changes in AF weight, since they suggest that there was production of urine with the maintenance of AF.

Central angiotensin II AT1 receptors mediate fetal swallowing and pressor responses in the near-term ovine fetus

Swallowed volumes in the fetus are greater than adult values (per body weight) and serve to regulate amniotic fluid volume. Central ANG II stimulates swallowing, and nonspecific ANG II receptor antagonists inhibit both spontaneous and ANG II-stimulated swallowing. In the adult rat, AT1 receptors mediate both stimulated drinking and pressor activities, while the role of AT2 receptors is controversial. As fetal brain contains increased ANG II receptors compared with the adult brain, we sought to investigate the role of both AT1 and AT2 receptors in mediating fetal swallowing and pressor activities. Five pregnant ewes with singleton fetuses (130 +/- 1 days) were prepared with fetal vascular and lateral ventricle (LV) catheters and electrocorticogram and esophageal electromyogram electrodes and received three studies over 5 days. On day 1 (ANG II), following a 2-h basal period, 1 ml artificial cerebrospinal fluid (aCSF) was injected in the LV. At time 4 h, ANG II (6.4 microg) was injected in the LV, and the fetus was monitored for a final 2 h. On day 3, AT1 receptor blocker (losartan 0.5 mg) was administered at 2 h, and ANG II plus losartan was administered at 4 h. On day 5, AT2 receptor blocker (PD-123319; 0.8 mg was administered at 2 h and ANG II plus PD-123319 at 4 h. In the ANG II study, LV injection of ANG II significantly increased fetal swallowing (0.9 +/- 0.1 to 1.4 +/- 0.1 swallows/min; P < 0.05). In the losartan study, basal fetal swallowing significantly decreased in response to blockade of AT1 receptors (0.9 +/- 0.1 to 0.4 +/- 0.1 swallows/min; P < 0.05), while central injection of ANG II in the presence of AT1 receptor antagonism did not increase fetal swallowing (0.6 +/- 0.1 swallows/min). In the PD-123319 study, basal fetal swallowing did not change in response to blockade of AT2 receptor (0.9 +/- 0.1 swallows/min), while central injection of ANG II in the presence of AT2 blockade significantly increased fetal swallowing (1.5 +/- 0.1 swallows/min; P < 0.05). ANG II caused significant pressor responses in the control and PD-123319 studies but no pressor response in the presence of AT1 blockade. These data demonstrate that in the near-term ovine fetus, AT1 receptor but not AT2 receptors accessible via CSF contribute to dipsogenic and pressor responses.

Esophageal atresia and other visceral anomalies in a modified Adriamycin rat model and their correlations with amniotic fluid volume variations

The Adriamycin rat model (ARM) has been used to produce visceral malformations in fetuses to explain the mechanisms of foregut division. The models vary in the dosage of Adriamycin (ADR) and in the number of applications. Our study of a modified ARM using 2.2 mg/kg of ADR for 2 days only, intraperitoneally in pregnant rats, is presented. A total of 81 fetuses were obtained with this model from the ADR group, 74 (91%) alive. Uretero-hydronephrosis (UHN) was observed in 70 fetuses (95%), esophageal atresia (EA) in 68 (92%), duodenal atresia (DA) in 68 (92%), bladder hypoplasia (BH) in 67 (90%), plus other malformations. In evaluating amniotic fluid (AF) volume of the fetuses with EA with tracheo-esophageal fistula (TEF) (group I) and EA without TEF (group II), both associated with bilateral UHN when compared with the control group (group III), groups I and II showed higher AF volume in groups I and II than the control group (group III) did ( p=0.0001). In conclusion, ARM was adequate to produce EA and other visceral malformations. The use of ADR in a higher dosage for a shorter period of time produced better results than those presented in previous literature. The increase of AF volume obtained in fetuses presenting EA plus bilateral UHN strongly suggests, despite ureteral dilatation (urinary obstruction), that a malformed communication may exist between the urinary system and the amniotic cavity, permitting the existence of polyhydramnios that is due to digestive obstruction such as EA and DA.

Neuronal NO modulates spontaneous and ANG II-stimulated fetal swallowing behavior in the near-term ovine fetus

Spontaneous fetal swallowing occurs at a markedly higher rate compared with spontaneous adult drinking activity. This high rate of fetal swallowing is critical for amniotic fluid volume regulation. Central NO is critical for maintaining the normal rate of fetal swallowing, as nonselective inhibition of NO (with central N(G)-nitro-L-arginine methyl ester) suppresses spontaneous and angiotensin II (ANG II)-stimulated swallowing. We sought to differentiate the contributions of central endothelial vs. neuronal NO in the regulation of spontaneous and stimulated fetal swallowing, using a selective neuronal NO synthase (nNOS) inhibitor. Six time-dated pregnant ewes and fetuses were chronically prepared with fetal vascular and intracerebroventricular (i.c.v.) catheters and electrocorticogram (ECoG) and esophageal electromyogram electrodes and studied at 130 +/- 1 days of gestation. After an initial 2-h baseline period (0-2 h), the selective nNOS inhibitor N-propyl-L-arginine (NPLA) was injected i.c.v. (2-4 h). At 4 h, the dose of NPLA was repeated, together with ANG II, and fetal swallowing was monitored for a final 2 h. Four fetuses also received an identical control study (on an alternate day) in which NPLA was replaced with artificial cerebrospinal fluid (aCSF). Suppression of nNOS by i.c.v. NPLA significantly reduced mean (+/- SE) spontaneous fetal swallowing (1.35 +/- 0.12 to 0.50 +/- 0.07 swallows/min; P < 0.001). Injection of ANG II in the presence of NPLA had no dipsogenic effect on fetal swallowing (0.68 +/- 0.09 swallows/min). In the aCSF study, i.c.v. aCSF did not change fetal swallowing (0.93 +/- 0.10 vs. 0.95 +/- 0.09 swallows/min), whereas i.c.v. ANG II resulted in a significant increase in the rate of fetal swallowing (2.0 +/- 0.04 swallows/min; P = 0.001). We speculate that the suppressive dipsogenic effects of central NPLA indicate that spontaneous and ANG II- stimulated fetal swallowing is dependent on central nNOS activity.