Echogenic foci in the dilated fetal colon may be associated with the presence of a rectourinary fistula

A Neonatal Case of Lower Urinary Tract Obstruction and Imperforate Anus: Urethral Decompression Due to Rectourinary Fistula

Lower urinary tract obstruction (LUTO) is a rare fetal condition associated with significant perinatal morbidity and mortality. Herein, we report a neonatal case of LUTO with anal atresia complicated by anhydramnios and pulmonary hypoplasia. After treatment for severe postnatal respiratory distress, the neonate underwent vesicostomy and colostomy. Postoperatively, respiratory status and renal function improved. This case highlights a unique feature where a large rectovesical fistula channeled fetal urine into the colon, which minimized obstructive damage to the urinary tract and preserved renal morphology. Fetal colonic dilatation and numerous enteroliths indicate urine influx into the intestinal tract. Our case suggests the importance of recognizing such exceptions in complete LUTO to predict postnatal outcomes diagnosed in utero.

First trimester lower abdominal cysts as early predictor of anorectal malformations

INTRODUCTION

Prenatal ultrasound diagnosis of anorectal malformations (ARMs) is challenging and often missed as direct visualization of the anal sphincter is not routinely performed, plus the technique is operator-dependent and inaccurate, also in expert hands. Other indirect signs, such as rectosigmoid overdistension or intraluminal calcifications, are occasionally present in late pregnancy. The detection of a cyst of the lower abdomen in the first trimester may be an early sign of ARM. Here we reported our experience and a review of the literature of such cases.

MATERIAL AND METHODS

Isolated cases of lower abdomen cysts encountered in the first trimester at the Prenatal Diagnosis Unit during the last 5 years were retrieved and compared with those found in literature. Post-natal clinical data were analyzed to check the presence and type of malformations.

RESULTS

A total of three cases of lower abdomen cysts were found in our center and 13 in literature. In our case series all the cysts spontaneously regressed and were no longer visible since the second trimester of pregnancy, while in literature this was reported in only 4 out of 13 cases. ARM was confirmed in all patients at birth or post-mortem.

CONCLUSIONS

The finding of a lower abdomen cyst during the first trimester of pregnancy could be an early predictive sign of ARM, even if it disappears during pregnancy. In these cases, we suggest mentioning to the parents the possibility of an ARM during the counseling and to refer the couple to a Colorectal Center.

A Spectrum of Ultrasound and MR Imaging of Fetal Gastrointestinal Abnormalities: Part 2 Anorectal Malformation, Liver, and Abdominal Wall Anomalies

Ultrasound (US) and magnetic resonance imaging (MRI) are two modalities for diagnosing fetal gastrointestinal (GI) anomalies. Ultrasound (US) is the modality of choice. MRI can be used as a complementary method. Despite its expanding utilization in central nervous system (CNS) fetal malformation, MRI has not yet been established for evaluation of fetal GI abnormalities. Therefore, more attention should be paid to the clinical implications of MRI investigations following screening by US.

Significance of the 'line sign' in the diagnosis of congenital imperforate anus on prenatal ultrasound

Background

The prenatal diagnosis of foetal imperforate anus is difficult. Most previous studies have been case reports. To provide useful information for diagnosing foetal imperforate anus, a retrospective review of diagnostic approaches was conducted. Ultrasonography was performed in 19 cases of foetal imperforate anus from 2016 to 2019 at our prenatal diagnostic centre. The prenatal sonographic features and outcomes of each case were collected and evaluated.

Result

The anal sphincter of a normal foetus shows the ‘target sign’ on cross-sectional observation. Of the 19 cases of imperforate anus, 16 cases were diagnosed by the ultrasound image feature called the ‘line sign’. 1 case with tail degeneration was low type imperforate anus with the irregular ‘target sign’ not a real ‘target sign’. There was two false-negative case, in which the ‘target sign’ was found, but irregular.

Conclusion

In this study, we find that the anus of a foetus with imperforate anus presents a ‘line sign’ on sonographic observation. The absence of the ‘target sign’ and then the presence of the ‘line sign’ can assist in the diagnosis of imperforate anus. The ‘line sign’ can be used as a secondary assessment to determine the type of the malformation following non visualization of the ‘target sign’. The higher the position of the imperforate anus is, the more obvious the ‘line sign’. It is worth noting that the finding of the short ‘line sign’ and irregularr ‘target sign’ can not ignore the low type imperforate anus.

A Fetus with Imperforate Anus Developing Pulmonary Hypoplasia Triggered by Transient Urethral Obstruction

Pulmonary hypoplasia is a rare entity in a fetus with imperforate anus. The fetus was diagnosed with high-type imperforate anus with rectourethral fistula based on the dilated fetal bowel and the presence of bowel calcification at 19 weeks of gestation. As gestation advanced, fetal ultrasonography demonstrated development of pulmonary hypoplasia, progressive bowel dilation, and persistent oligohydramnios from 28 weeks of gestation despite a fluid-filled bladder without hydroureter or hydronephrosis. To prevent further worsening of pulmonary hypoplasia caused by thoracic compression due to bowel dilation and oligohydramnios, a male neonate was delivered by cesarean section at 32 weeks of gestation. The neonate showed respiratory failure requiring full respiratory support. Although a catheter did not pass through the urethra into the bladder at birth, cystourethrography revealed the patency of fistula and stenosed lower urinary tract. Prenatal and postnatal findings strongly suggested that the meconium in the colon might have passed into the urethra in the penis, resulting in the physical blockage of urine outflow to the amniotic space which leads urine flow from the bladder to the colon through the fistula, which resulted in subsequent oligohydramnios and bowel dilation. To the best of our knowledge, this is the first case report of a fetus with imperforate anus developing pulmonary hypoplasia possibly due to urethral obstruction.

Can Anorectal Atresia Be Diagnosed in the First Trimester of Pregnancy? A Systematic Literature Review

Anorectal atresia (ARA) is a common congenital anomaly, but prenatal diagnosis is difficult, late, and unspecific. Utilizing a case of a 46 year old primipara with an egg donation In Vitro Fertilization (IVF) pregnancy, diagnosed at the first trimester scan with an anechoic isolated structure, which indicates anal atresia, we performed a systematic literature review in order to evaluate early prenatal ARA diagnosis. A total of 16 cases were reported as first trimester ARA suspicion, and only three had no associated anomalies. The most frequent ultrasound (US) sign was the presence of a cystic, anechoic pelvic structure of mainly tubular shape, or a plain abdominal cyst. In the majority of cases, structures were thin-walled and delimitated from the bladder. The presence of hyperechoic spots signifying enterolithiasis and peristaltic movements were helpful in order to establish the bowel origin of the lesion. Considering the high eventuality that the lesion is transitory, meaning later in pregnancy the fetus looks normal, early detection of such a sign should prompt further structural detailed evaluation, karyotyping, and appropriate pregnancy and postnatal counselling.

Prenatal Evaluation for Detection of Anorectal Atresia: Value of Ultrasound

OBJECTIVES

To investigate the applicability and value of ultrasound (US) in the diagnosis of anorectal atresia.

METHODS

Between January 2008 and January 2016, we prospectively evaluated 63,101 fetuses (gestational age, 20-38 weeks), including low- and high-risk populations using 2-dimensional US scans. An abnormal imaging finding was defined as an anal canal diameter of less than the 95% confidence interval (small anal canal) of the normal range or the absence of an anal canal and rectum. Imaging findings were considered normal on detection of an anal canal with a normal width and the absence of abnormalities. Prenatal imaging findings were confirmed by a postnatal or postmortem examination.

RESULTS

Among the investigated fetuses, 28 showed evidence of anorectal atresia on US scans, and 22 of those with anorectal atresia had additional anomalies. Six cases of isolated anorectal atresia were successfully detected during the preclusive prenatal US scans. Four cases of a low imperforate anus (including 2 covered anuses) yielded false-negative results, indicating a diagnostic rate of 87.5% (28 of 32). The normal appearance of the fetal rectum and anal canal ruled out anorectal atresia in 30 fetuses with a dilated colon. Additionally, there were 3 false-positive cases, in which a narrow anal canal was observed.

CONCLUSIONS

Identifying the abnormal appearance or absence of the fetal anal canal and rectum on preclusive US anomaly scans is useful for prenatal diagnosis or exclusion of anorectal atresia, which may help improve the detection of isolated anorectal atresia. Furthermore, a combined evaluation of the longitudinal and axial appearances of the fetal anal canal and rectum can improve diagnostic accuracy.

Prenatal Diagnosis of Enterolithiasis in 20 Cases

BACKGROUND

Enterolithiasis is a sonographic sign defined by hyperechogenic foci within the - often distended - fetal bowel.

OBJECTIVES

We report on a series of 20 cases with enterolithiasis diagnosed prenatally and illustrate the spectrum of associated malformations.

METHOD

This was a retrospective study involving 20 fetuses with enterolithiasis at two large tertiary referral centers in Germany over a 17-year period (2000-2017).

RESULTS

Median diagnosis was made with ultrasound at 18+2 weeks of gestation (IQR25,75: 14+5, 26+5). Additional malformations included urogenital malformations (cloacal malformation in 7/20 fetuses [35%] and kidney defects in 7/20 fetuses [35%]), cardiac malformations (3/20 fetuses [15%]), and vertebral malformations (5/20 fetuses [25%]). Of 20 fetuses, 14 could be attributed to the anorectal malformation spectrum, 3/20 fetuses presented with caudal regression syndrome, and 1 fetus with bilateral kidney agenesis, congenital diaphragmatic aplasia, and enterovesical fistula, respectively.

CONCLUSION

Enterolithiasis is a rare prenatal sonographic feature. Because of the frequent occurrence of uro-recto-genital malformations, thorough prenatal counseling should be performed.

First trimester expression of anorectal malformation: Case report and review of the literature

A 26-years-old woman, underwent an ultrasound examination at 13.4 weeks. A cystic structure was identified in the right lower abdomen. Gradually, the cystic mass was replaced by echogenic content and eventually attained the appearance of hyperechoic bowel. At 21.2 weeks, the anal sphincter could not be demonstrated which was consistent with the diagnosis of isolated anal agenesis. Amniocentesis revealed 46XY karyotype with normal comparative genomic hybridization. After termination of pregnancy at 23 weeks, an autopsy revealed an isolated high type anorectal malformation (ARM) without fistula. We reviewed all 14 cases reported in the literature of first trimester sonographic expression of ARM.

Abdominal ultrasonography of the pediatric gastrointestinal tract

Ultrasound is an invaluable imaging modality in the evaluation of pediatric gastrointestinal pathology; it can provide real-time evaluation of the bowel without the need for sedation or intravenous contrast. Recent improvements in ultrasound technique can be utilized to improve detection of bowel pathology in children: Higher resolution probes, color Doppler, harmonic and panoramic imaging are excellent tools in this setting. Graded compression and cine clips provide dynamic information and oral and intravenous contrast agents aid in detection of bowel wall pathology. Ultrasound of the bowel in children is typically a targeted exam; common indications include evaluation for appendicitis, pyloric stenosis and intussusception. Bowel abnormalities that are detected prenatally can be evaluated after birth with ultrasound. Likewise, acquired conditions such as bowel hematoma, bowel infections and hernias can be detected with ultrasound. Rare bowel neoplasms, vascular disorders and foreign bodies may first be detected with sonography, as well. At some centers, comprehensive exams of the gastrointestinal tract are performed on children with inflammatory bowel disease and celiac disease to evaluate for disease activity or to confirm the diagnosis. The goal of this article is to review up-to-date imaging techniques, normal sonographic anatomy, and characteristic sonographic features of common and uncommon disorders affecting the gastrointestinal tract in children.

Prenatal diagnosis of enterolithiasis at 18 weeks: multiple foci of intraluminal calcified meconium within echogenic bowel

Enterolithiasis is an uncommon finding of a dilated hyperechogenic bowel with multiple ball-like echogenic structures at a routine prenatal check-up using ultrasonography. We here report a case of prenatally diagnosed enterolithiasis at 18 weeks of gestation, showing multiple hyperechogenic foci rolling within the bowel fluid after peristalsis. The size of the dilated bowel gradually increased during pregnancy. Magnetic resonance image demonstrated the dilated lower bowel with blind-ending rectum. A postnatal contrast medium study with retrograde urethrography revealed a middle imperforate anus and a rectourethral fistula. A careful examination, even before 20 weeks of gestation, is extremely useful in demonstrating intraluminal coarse calcifications within an echogenic bowel.

Sonographic depiction of the fetal anus and its utility in the diagnosis of anorectal malformations

OBJECTIVES

The purpose of this study was to describe the sonographic appearance of the fetal anus and its usefulness in diagnosis of anal atresia.

METHODS

An anomaly scan was performed in 13,150 patients over 8 years. Gestational ages ranged from 16 to 38 weeks. A tangential scan of the fetal perineum was performed. The anus was seen as a hypoechoic ring representing the wall of the anal canal with a central echogenic dot representing the lumen. This appearance was seen posterior to the external genitalia. If there was failure to see this appearance, a coronal scan of the fetal pelvis was done to look for the anal canal in contiguity with the rectum and to confirm its extension up to perineum. Failure to see these two features was considered diagnostic of anal atresia.

RESULTS

On the basis of these criteria, anal atresia was diagnosed in 17 fetuses. Sixteen of these fetuses also had other associated anomalies. The appearance of the anus was useful for ruling out anal atresia in 2 fetuses with a dilated colon containing echogenic meconium balls.

CONCLUSIONS

The anus is visible on a tangential scan of the fetal perineum. It can be seen routinely during an anomaly scan to diagnose or rule out anal atresia.

In-utero development of the fetal anal sphincter

OBJECTIVE

To investigate the in-utero development of the fetal anal sphincter using transabdominal ultrasound.

METHODS

This was a cross-sectional study in which the diameter of the fetal anal sphincter was measured sonographically once in 631 well-dated, non-anomalous fetuses scanned between 19 and 38 weeks of gestation. Visualization rates were determined. Regression analysis was used to assess the relationship between the diameter of the fetal anal sphincter and gestational age (GA), and reference values including the mean and 95% reference interval were calculated for each GA.

RESULTS

The sonographic visualization rate of the fetal anal sphincter increased with gestational age, plateauing at 90-100% between 23-34 weeks of gestation. There was a significant positive relationship between fetal anal sphincter diameter and GA, which was best described by the equation: anal sphincter diameter (mm) = - 0.014 x GA(2) + 1.107 x GA - 11.664 (R(2) = 0.62).

CONCLUSION

We have provided reference values for the in-utero development of the fetal anal sphincter throughout gestation.

Calcified meconium balls in a newborn: an unusual case with imperforate anus, rectourinary fistula, colpocephaly, and agenesis of corpus callosum

Calcified intraluminal meconium is a rare finding in newborn infants. It is often associated with communication between the urinary and gastrointestinal tracts. Intra-abdominal calcifications are unusual radiographic findings in the newborn and can easily be misinterpreted as meconium peritonitis. We report on a newborn infant with anorectal malformation, meconium balls, intraluminal calcifications, colpocephaly, and agenesis of the corpus callosum, a rare association.

Enterolithiasis: a case report and review

BACKGROUND

Enterolithiasis is an uncommon finding of intraluminal calcified meconium. Whereas extraluminal calcifications are commonly reported and usually indicate intrauterine intestinal perforation with intraperitoneal extravasation of meconium (meconium peritonitis), true intraluminal calcifications of meconium in newborns are rare.

CASE REPORT

We report a case of a newborn boy with pneumothorax and pneumoperitoneum because of a transmediastinal air leakage who unfortunately died on the fifth postnatal day after a pneumopericard. The baby had lung hypoplasia and a hypoplastic thorax. Oligohydramnion was present because of urethral agenesis and anal atresia with rectourinary fistula. Enterolithiasis was found, distributed from the transverse to the rectosigmoid colon. Enterolithiasis was not diagnosed prenatally in this boy, and any of those preexisting pathologies were therefore not assumed before birth except the suspicion for urethral valves because of oligohydramnion.

DISCUSSION

Approximately 48 cases of human neonatal enterolithiasis have been described in the medical literature. The etiology of enterolithiasis appears to be intraluminal mixture of meconium und alkaline urine--as it appears in anal atresia with enterourinary fistula. Most cases of enterolithiasis are associated with major urogenital and intestinal malformations--especially VACTERL association. With support of modern high-resolution imaging devices, enterolithiasis can be detected antenatally. We suppose that prenatal diagnosis of enterolithiasis is a warning sign of underlying pathologies.