The prenatal diagnosis of imperforate anus with rectourinary fistula: dilated fetal colon with enterolithiasis

Fetal and Newborn Management of Cloacal Malformations

Cloaca is a rare, complex malformation encompassing the genitourinary and anorectal tract of the female in which these tracts fail to separate in utero, resulting in a single perineal orifice. Prenatal sonography detects a few cases with findings such as renal and urinary tract malformations, intraluminal calcifications, dilated bowel, ambiguous genitalia, a cystic pelvic mass, or identification of other associated anomalies prompting further imaging. Multi-disciplinary collaboration between neonatology, pediatric surgery, urology, and gynecology is paramount to achieving safe outcomes. Perinatal evaluation and management may include treatment of cardiopulmonary and renal anomalies, administration of prophylactic antibiotics, ensuring egress of urine and evaluation of hydronephrosis, drainage of a hydrocolpos, and creation of a colostomy for stool diversion. Additional imaging of the spinal cord and sacrum are obtained to plan possible neurosurgical intervention as well as prognostication of future bladder and bowel control. Endoscopic evaluation and cloacagram, followed by primary reconstruction, are performed by a multidisciplinary team outside of the neonatal period. Long-term multidisciplinary follow-up is essential given the increased rates of renal disease, neuropathic bladder, tethered cord syndrome, and stooling issues. Patients and families will also require support through the functional and psychosocial changes in puberty, adolescence, and young adulthood.

The diagnosis of an imperforate anus in female fetuses

Imperforate anus is an anomaly caused by a defect in the development of the hindgut during early pregnancy. It is a relatively common congenital malformation and is more common in males. Although there are cases of a solitary imperforate anus, the condition is more commonly found as a part of a wider spectrum of other congenital anomalies. Although urgent reconstructive anorectal surgery is not necessary, immediate evaluation is important and urgent decompressive surgery may be required. Moreover, as there are often other anomalies that can affect management, prenatal diagnosis can help in optimizing perinatal care and prepare parents through prenatal counseling. In the past, imperforate anus was diagnosed by prenatal ultrasonography based on indirect signs such as bowel dilatation or intraluminal calcified meconium. Currently, it is diagnosed by directly checking the perineum with prenatal ultrasonography. Despite advances in ultrasound technology, accurate prenatal diagnosis is impossible in most cases and imperforate anus is detected after birth. Here, we present two cases of imperforate anus in female fetuses that were not diagnosed prenatally.

Prenatal and postnatal imaging techniques in the evaluation of disorders of sex development

Imaging of the reproductive tract is challenging and requires a general knowledge of congenital variations in anatomy. The anatomy of the developing fetus, whether a male phenotype or female phenotype, is also a dynamic process with many changes occurring during gestation. Families may ask details about the genitalia during prenatal imaging and when variations in what is thought to be normal are present, further investigation is sometimes needed to make sense of what is seen. This overview will describe categories of disorders of sex development (DSD), whether chromosomal or structural or both, and the current state of imaging of these anomalies.

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.

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.

Evaluation of the perianal muscular complex in the prenatal diagnosis of anorectal atresia in a high-risk population

OBJECTIVES

To investigate whether sonographic identification of the fetal perianal muscular complex (PAMC) is of value in the prenatal detection of anorectal atresia in a high-risk population.

METHODS

During an 8-year study period, a total of 189 pregnancies at high risk for fetal anorectal atresia were prospectively examined for the presence/absence of the PAMC on axial ultrasound views of the fetal perineum. The prenatal findings were confirmed postnatally or at the time of postmortem examination.

RESULTS

The median gestational age at examination was 27 (range, 15-37) weeks. The PAMC was identified in 175 fetuses, all of which had a normal anorectal canal at the time of delivery or at postmortem examination. The PAMC was not identified prenatally in the 14 remaining cases, and the anus was absent in 11 fetuses with anorectal atresia and in two with urorectal septum malformation sequence. There was one false-positive case, in which the anus was anatomically and functionally normal but ectopically located, opening into the vaginal vestibule. Among these 14 cases of anorectal malformation, prenatal dilatation of the distal bowel was seen in nine (64.3%) and intraluminal calcified meconium or enterolithiasis in five (35.7%). Overall, absent PAMC on prenatal sonography in this high-risk population had a sensitivity of 100%, specificity of 99%, true-positive rate of 93% and false-positive rate of 7% for the diagnosis of anorectal atresia.

CONCLUSIONS

In a high-risk population, the absence of PAMC seems to be a highly sensitive and specific sonographic marker for anorectal atresia. The role of routine sonographic identification of the PAMC at the second-trimester scan to screen for cases of isolated anal atresia remains to be determined.

Fetal MRI clues to diagnose cloacal malformations

BACKGROUND

Prenatal US detection of cloacal malformations is challenging and rarely confirms this diagnosis.

OBJECTIVE

To define the prenatal MRI findings in cloacal malformations.

MATERIALS AND METHODS

We performed a retrospective study of patients with cloacal malformations who had pre- and post-natal assessment at our institution. Fetal MRI was obtained in six singleton pregnancies between 26 and 32 weeks of gestation. Imaging analysis was focused on the distal bowel, the urinary system and the genital tract and compared with postnatal clinical, radiological and surgical diagnoses.

RESULTS

The distal bowel was dilated and did not extend below the bladder in five fetuses. They had a long common cloacal channel (3.5-6 cm) and a rectum located over the bladder base. Only one fetus with a posterior cloacal variant had a normal rectum. Three fetuses had increased T2 signal in the bowel and two increased T1/decreased T2 signal bladder content. All had renal anomalies, four had abnormal bladders and two had hydrocolpos.

CONCLUSION

Assessment of the anorectal signal and pelvic anatomy during the third trimester helps to detect cloacal malformations in the fetus. The specificity for this diagnosis was highly increased when bowel fluid or bladder meconium content was identified.

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.

Bladder outlet obstruction causes fetal enterolithiasis in anorectal malformation with rectourinary fistula

Extraluminal calcified meconium is found frequently by prenatal ultrasound in cases with bowel perforation and meconium peritonitis. Intraluminal intestinal meconium calcifications are rarely seen in prenatal sonography. Meconium calcifications result from a mixture of meconium and urine that indicates a connection between intestinal and urinary tract. We report a case of a male newborn prenatally diagnosed with intraluminal echogenic calcifications at 23 weeks of gestation, suggesting an anorectal malformation (ARM) with rectourinary fistula. At birth, the child presented with a complex ARM including high anal atresia with both perineal and rectourethral fistula. Furthermore, a bladder outlet obstruction due to a urethral stenosis was diagnosed. Vesicostomy was performed as an emergency procedure followed by colostomy during neonatal period. Posterior sagittal anorectoplasty was performed at the age of 4 months. Prenatal echogenic calcifications within bowel should raise the suspicion of ARM with rectourinary fistula and bladder outlet obstruction.

Fetal megalourethra associated with hypoplastic left heart and imperforate anus: a previously unreported association

We report two cases of a fetus with a megalourethra associated with a hypoplastic left heart, dilated and echogenic bowels, vesico-colonic fistula and an imperforate anus. This combination of fetal abnormalities may represent an unclassified syndrome.

Imperforate anus: A relatively common anomaly rarely diagnosed prenatally

OBJECTIVE

Despite the relatively common occurrence of imperforate anus, prenatal diagnosis is rarely reported. In this study, we investigated the presence and diagnosis of imperforate anus along with strategies for improving prenatal diagnosis of the condition.

PATIENTS AND METHODS

Fetuses and infants with imperforate anus who had been examined prenatally by ultrasound at the National Center for Fetal Medicine (NCFM) from 1987 to 2004, were evaluated.

RESULTS

Of 69 cases with imperforate anus, only 11 (15.9%) were diagnosed prenatally, at a median gestation of 18 + 4 (range, 15 + 6 to 35 + 6) weeks. In all 11, dilatations of the rectum or lower part of the bowel were seen. Additional anomalies, most of them diagnosed prenatally, were present in 59/69 (85.5%) of the cases. The most frequent additional anomalies were urogenital (53.6%). The karyotype was abnormal in nine cases (13.0%). A retrospective evaluation of available videotapes of 22 cases of imperforate anus that were not diagnosed prenatally revealed that it was possible to suspect the diagnosis in 11/22 (50%) cases. Sixteen infants were born with imperforate anus without prenatal diagnosis of any abnormality. In total, 31/69 (44.9%) cases were terminated, two (2.9%) died in utero and 12 (17.4%) died postnatally. Twenty-four (34.8%) infants survived, including all 10 with isolated imperforate anus and seven of eight cases with only one additional anomaly.

CONCLUSIONS

The prenatal detection rate of imperforate anus was only 15.9%. Imperforate anus is often associated with other anomalies; in this study, 85.5% had additional anomalies. Prenatal diagnosis makes prenatal counseling possible and facilitates optimized postnatal care. We believe that the prenatal detection rate of imperforate anus could be improved. Examiners should intensify their search for typical findings of imperforate anus especially when other anomalies that frequently accompany this condition are present.

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

Intraintestinal meconium calcification in the fetus and newborn is a rare finding, occurring in patients with intestinal obstruction. The intraluminal location of the enterolithiasis enables differentiation from calcifications that are secondary to bowel perforation and meconium peritonitis. We report on a term male neonate with VACTERL (vertebral defects, imperforate anus, cardiac anomalies, tracheoesophageal fistula, renal anomalies, limb anomalies) association and rectourethral fistula, in whom enterolithiasis was documented by prenatal ultrasound imaging at 21 weeks' gestation. A review of the literature and a summary of all previously described cases of neonates with intraluminal meconium calcifications are provided. Prenatal ultrasonographic detection of enterolithiasis in fetuses with anal atresia may indicate the presence of an enterourinary fistula.

Fetal enterolithiasis: prenatal sonographic and MRI diagnosis in two cases of urorectal septum malformation (URSM) sequence

OBJECTIVES

Enterolithiasis (multiple calcifications of intraluminal meconium) is a rare, prenatal ultrasonographic finding. In this study, our aim was to evaluate the prenatal diagnostic features and discuss the management of the patients.

METHODS

The data of two cases of prenatally diagnosed fetal enterolithiasis were collected from ultrasound scan, magnetic resonance imaging (MRI) and neonatal or postnatal autopsy records. The findings were evaluated in both prenatal and postnatal periods. Chromosomal analysis was performed in one case. An evaluation of primary and secondary malformations was done. Coexisting anomalies were searched for via radiology, neonatal surgery and histopathology.

RESULTS

Malformations in two cases (both males) with partial and complete urorectal septum malformation (URSM) sequence were described. The absence of an anal opening and presence of a fistula between the urinary and gastrointestinal tract were common findings. These features were considered as primary malformations contributing to the formation of enterolithiasis. Secondary anomalies (urinary and gastrointestinal system malformations, pulmonary hypoplasia, genital and other coexisting anomalies) were evaluated.

CONCLUSIONS

The prenatal detection of enterolithiasis carries a poor prognosis. Most of the previously reported cases were invariably associated with major fetal malformations of the urinary and gastrointestinal tract. It is a warning sign for large bowel obstruction with or without enterourinary fistula. Therefore, adequate gastrointestinal and urologic studies must be undertaken after birth for the final diagnosis. There is a high mortality rate in the reported cases, mostly attributed to associated anomalies, and all survivors required neonatal surgery. It is important to differentiate the partial from the full URSM sequence because the prognosis in the partial URSM sequence is generally good, with long-term survival being common.

Prenatal Diagnosis and Therapy of Persistent Cloaca: A Case Report

Persistent cloaca is a rare abnormality that occurs only in females and is characterized by a direct communication between the gastrointestinal, urinary, and genital structures resulting in a single perineal opening. A case with massive ascites, two cystic structures arising from the fetal pelvis, bilateral hydroureters, calcified meconium, and cardiac anomalies, in which this condition was diagnosed prenatally is presented here.

A proposed mechanism for intermediate atresia ani (AA), based on a porcine case of AA and hypospadias

BACKGROUND

Atresia Ani (AA) is one of the most common malformations of the lower gastrointestinal tract. It occurs in 1 in 1500 to 1 in 5000 human births. These patients suffer physically and psychologically from this disorder, and thus there is a research interest in the condition. There are 3 subcategories of AA: high, intermediate, and low. Each of these forms is likely related to separate etiological processes.

METHODS

An anatomical study was performed on a porcine case of AA with a urorectal fistula and malformed urethra.

RESULTS

This animal was found to have the intermediate form of AA.

CONCLUSIONS

A new mechanism is hypothesized, distinct from that described for the high and low forms of AA. This proposed mechanism involves the persistence of the cloacal membrane. Evidence to support this hypothesis includes: location of the urorectal fistula in the region of the embryonic cloacal duct, the lack of anomalies usually seen in conjunction with AA associated with mutations of the Sonic Hedgehog gene, and the presence of a malformed urethra, which is significantly correlated to intermediate AA. This form of AA could be related to a failure of the cloacal membrane to break down at the appropriate time during urorectal separation.

Calcified meconium: an important sign in the prenatal sonographic diagnosis of cloacal malformation

Cloacal malformation is a rare abnormality, characterized by direct communication between the gastrointestinal, urinary, and genital structures, resulting in a single perineal opening. Prenatal diagnosis is difficult because of nonvisualization of the communication. We report a case of prenatal diagnosis of this condition, in which the recognition of calcified meconium in the colon and urinary tract provided an important clue.

Prenatal diagnosis of isolated anorectal atresia with colonic perforation

We report here a case of prenatal diagnosis of isolated anorectal atresia with intrauterine colonic perforation at 34 weeks of gestation, characterized by the presence of a bilobed cystic pelvic mass with a V-shape appearance separated from the bladder with changing features during observation. Mild ascites was also visualized. Other structures were normal on detailed ultrasound. The patient had spontaneously delivered a male infant weighing 2,100 g at 34 weeks of gestation. The infant died one day after birth, before surgical correction secondary to respiratory distress syndrome. Autopsy revealed isolated anorectal atresia, and high (supraelevator) lesions. In conclusion, the findings of bilobed cystic pelvic mass with a V-shape were useful to diagnose anorectal atresia in this case. Prenatal ultrasound can facilitate early diagnosis and treatment.

Fetal defaecation: is it a normal physiological process?

It has been long known that the late gestation human fetus passes meconium in response to hypoxia. However, there is good evidence, from amniotic fluid studies measuring bile pigment and enteric enzyme content, to suggest that passage of meconium is a normal physiological event in the second trimester. Similarly there is some indirect evidence that fetal defaecation is a normal physiological process in the third trimester. However, this evidence is less strong, and it is safer to assume that in most cases meconium staining of liquor at this time is associated with fetal hypoxia. Dilation of the rectosigmoid portion of the distal bowel found in newborn infants with anorectal malformations supports the hypothesis that fetal colonic peristalsis and defaecation is a normal physiological process.

Prenatal diagnosis of cloacal anomaly

The authors present a case of prenatal diagnosis of cloacal anomaly, characterized by the presence of oligohydramnios and cystic pelvic mass with changing features during observation. Postnatal study confirmed the presence of a recto-cloacal fistula, with a high confluence of the urinary, genital and intestinal systems. Both parents had a chromosome 9 inversion (p11q13), but the child was chromosomally normal.

Early sonographic detection of fetal intestinal obstruction and possible diagnostic pitfalls

We present five fetuses at 15-17 weeks' gestation with a sonographic diagnosis of intestinal obstruction. Dilation of the intestine was the presenting sonographic finding in fetuses with a volvulus and/or anal atresia. Two of the fetuses also had other abnormalities. Intestinal peristalsis may be observed in early pregnancy as transient dilation of intestinal segments. Sonographers are cautioned about a false-positive diagnosis of intestinal obstruction in such cases.

Fetal gastrointestinal anomalies

A review of fetal gastrointestinal anomalies is presented. Normal abdominal development and anatomy, including basic embryology and recommended ultrasound techniques, are first outlined. Next is a more detailed discussion of the abnormal examination, including abdominal wall defects and intra-abdominal abnormalities. The goal of this work is to present a practical approach to the abnormal fetal abdominal examination enabling the sonographer and sonologist to suggest precise differential diagnoses.

Prenatal diagnosis of cloacal malformation

Cloacal malformation is a rare abnormality, occurring only in females and characterized by a direct communication between the gastrointestinal, urinary, and genital structures resulting in a single perineal opening. We report 2 cases of prenatal diagnosis of this condition with a varied ultrasonic appearance including fetal ascites, cystic retrovesical mass, ambiguous genitalia, nonvisualization of the bladder, and oligohydramnios.