Cloacal Dysgenesis Sequence in a Preterm Neonate

Background

Cloaca malformations arise from an imbalance of apoptosis, cell growth, and maturation [1]. A classic cloaca is defined as a single perineal orifice for the drainage of the urinary, gastrointestinal, and reproductive tracts, and is the most severe type of anorectal malformation [2–4]. The numerous types of cloaca malformations stem from variations in the timing at which the development of the urorectal septum and urogenital sinus arrest [5]. Although the cause is unknown and heavily debated, there has been evidence alluding to the homeobox gene, sonic hedgehog, and bone morphogenetic protein signaling pathways [5]. Typically, the formation of the cloaca in the embryo’s ducts occurs in the fifth week of development and divides into 2 distinct pathways during the sixth and seventh weeks; however, the concept of cloacal subdivision remains a controversial topic [6]. The reported incidence for classic cloaca is 1 in every 50 000 births; however, the incidence of cloacal dysgenesis sequence (CDS), a rare cloaca variant, is 1 in every 250 000 neonates [4,7]. There is a large spectrum of cloacal malformations with a lack of a simple classification system, but if there is no perineal orifice, the diagnosis is CDS [5], also known as urorectal septum malformation sequence [8].

Anorectal malformations may potentially be seen prenatally, mainly via prenatal magnetic resonance imaging (MRI) as well as antenatal ultrasounds [9]. Sonographic findings that may reveal a cloacal malformation include urinary tract abnormalities, dilated bowel loops, or a cystic pelvic mass [2]. A study of 95 newborns by Bischoff et al reported that only 6% of their patients diagnosed with cloacal malformation at birth had suspected prenatal diagnosis of the condition, even though 62% had abnormal ultrasonographic findings [9]. However, even if not seen prenatally and only at birth, early diagnosis and prompt medical and surgical treatment with careful post-reconstruction follow-up is imperative for a newborn with cloacal malformation. In the present study, we present the unique case of a female neonate born with CDS, status post-vesicoamniotic shunt, who was transferred to our institution and underwent diverting colostomy, tube vaginostomy, removal of vesicoamniotic shunt, and placement of an 8 French suprapubic tube.

Case Report

Our patient was a female neonate (46XX) born to a 23-year-old woman following full prenatal care. The pregnancy was complicated by prenatal diagnosis of bilateral multicystic dys-plastic kidneys, for which vesicoamniotic shunt placement was performed in utero at a different hospital. Maternal history was negative for diabetes. The patient was born preterm, at 33 weeks, at a community hospital via urgent cesarean section due to placental abruption and nonreassuring fetal status. At birth, her Apgar scores were 7 and 8 at 1 and 5 minutes, respectively. Birth weight was 2520 grams, 94th percentile. Glucose screening was negative for hypoglycemia, and amniotic fluid was clear. The patient arrived at our institution intubated and sedated 4 hours after birth. Physical exam was significant for a large, distended abdomen with diminished abdominal musculature with associated laxity, ascites, vesicoamniotic shunt present, ambiguous genitalia without urethra or vaginal opening, no presence of any perineal opening, and club foot (Figure 1). The patient suffered from respiratory failure and was subsequently intubated and transferred to our Neonatal Intensive Care Unit (NICU) for a higher level of care.

Postnatal workup included transthoracic echocardiogram, which was positive for patent ductus arteriosus with bidirectional shunt, small patent foramen ovale, and mildly diminished ventricular function. Abdominal and pelvic ultrasound demonstrated moderate-to-large volume ascites, multicystic kidney disease of the left kidney, hyperechoic right kidney with bilateral hydronephrosis, partially decompressed bladder with shunt in place, and a 9×7 mm uterine-like structure. The rectum was grossly dilated with internal echogenic material consistent with meconium. Initial radiographs demonstrated well-aerated lungs without evidence of focal consolidation, with mild bilateral increased interstitial lung markings. A dis-tended, gaseous loop of bowel was present in the mid abdomen, consistent with large volume abdominal ascites due to the relative paucity of gas throughout the rest of the abdomen (Figure 2). Spine ultrasound demonstrated a normal position of the conus medullaris without evidence of a tethered cord.

The patient was evaluated by pediatric surgery, pediatric nephrology, and pediatric urology. Given the abdominal distention in the setting of no anal opening or evidence of perineal fistula, the decision was made to proceed with an exploratory laparotomy with diverting colostomy, mucous fistula, tube vaginostomy, removal of the vesicoamniotic shunt, and placement of a suprapubic vesicostomy tube. A laparoscopic approach was not considered to be technically feasible due to the abdominal wall muscle overstretch, which would make insufflation challenging and could potentially further compromise the respiratory status. In the operating room, the absence of urethral meatus, vaginal opening, and anal opening was confirmed. The vesicoamniotic shunt was removed over a 0.35 cm wire and replaced with an 8 French suprapubic catheter. The laparotomy was performed via a left lower quadrant oblique incision. Upon entry into the abdominal cavity, a large amount of clear ascites was encountered. A large fluid-filled structure was identified superior to the bladder, consistent with the uterus and with associated hydrocolpos observed on preoperative ultrasound. An 8.5 French catheter was then inserted through the right abdomen into the hydrocolpos using the Seldinger technique with drainage of clear fluid. The sigmoid colon was then delivered into the wound. After confirming the appropriate orientation of the bowel, a point was chosen in the proximal sigmoid colon, and the mesocolon was divided with electrocautery. Saline irrigation was delivered through a red rubber Robinson catheter to decompress the distal bowel of meconium until the output was clear. The divided ends of the bowel were then pulled to either end of the initial incision, with the mucous fistula in the medial end of the wound and the diverting colostomy in the lateral end of the wound. The incision was then closed in layers in the standard fashion. This patient required mechanical ventilation for 6 days postoperatively. She was extubated without complications to bubble continuous positive airway pressure, then switched to vapotherm on day of life 13 and weaned to room air on day of life 32. She required intermittent supplemental oxygen for frequent desaturations until day of life 73. The clinical course was suggestive of broncho-pulmonary dysplasia, and the patient recovered gradually over time. The colostomy functioned well postoperatively, and the patient was able to advance to full enteral feeds. Abdominal radiography demonstrated resolution of the gas-distended loop of bowel in the right abdomen with improved gas extending through multiple loops (Figure 3). The hydrocolpos drain was clamped and then removed at 3 weeks of life without issues. Urine output was adequate, and the suprapubic catheter was exchanged at 4 weeks of life. The patient returned to the operating room at 9 weeks of life and underwent planned vesicostomy placement via a midline suprapubic incision. The thickened bladder was opened and matured to the skin as a stoma. A 12 French catheter was placed through the stoma into the bladder. The patient was extubated without complications to room air 4 days after this operation. On the day of discharge, the patient was saturating well on room air and supplementing breast-feeding with gavage feeds with good vesicostomy and colostomy function. She was discharged with scheduled follow-up with the pediatric urology and pediatric surgery clinics. At the time of writing, the patient was 6 months old, her left kidney was nonfunctional, and she had been hospitalized recently for an episode of Klebsiella pneumoniae pyelonephritis. Her stomas were continuing to function well.

Discussion

Prompt recognition of patients with cloacal anomalies at birth is essential to facilitate all necessary urgent urologic, medical, and surgical consultations and evaluations. Standard care for patients with anorectal malformations includes waiting until the neonate reaches 18 to 24 hours of age to perform a colostomy [10]. In this case, surgery was delayed until the patient reached 2 days old, an appropriate age for undergoing a colostomy. The timing of the surgical intervention was related to the necessary time to stabilize the patient and also perform the necessary workup. Moreover, post-birth abdominal and pelvic ultrasound is imperative in diagnosis and follow-up care. In our patient, ultrasound was necessary to diagnose the multitude of renal abnormalities present. To rule out hidden spinal pathologies like tethered cord or cord lipoma, it is advised for all neonates to undergo spinal ultrasonography or MRI [11,12].

Patients with a cloacal malformation experience considerable morbidity and mortality, attributed to both renal impairment and the substantial involvement of the gastrointestinal tract in cloacal exstrophy [13,14]. Fetal ascites, an abnormal free fluid collection in the fetal peritoneal cavity, is often associated with other fetal or intrauterine abnormalities, including intrauterine infections, gastrointestinal processes, genitourinary tract abnormalities, and polyhydramnios [15,16]. Our patient had a large amount of fetal ascites seen during physical examination, on abdominal and pelvic ultrasound, and during surgical entry into the abdominal cavity, most likely from a possible leak of the vesicoamniotic shunt.

Our case is distinctive and not a classic cloaca presentation since there was no perineal opening. Treatment of cloacal malformations is challenging due to the absence of a straightforward classification system, as these conditions encompass a broad range of variations. However, in this case, our patient had CDS given the absence of a perineal orifice, also known as urorectal septum malformation sequence, a rare variant of classic cloaca presentation.

Surgical management of CDS involves colostomy and vaginal reconstruction, with the initial procedure after the neonate reaches 24 hours of age [10]. Postoperative cloaca patients typically spend time in the NICU for a duration of 2 to 3 weeks; during this time, they need a comprehensive plan for managing oral or enteral feeds, regular stooling, colostomy care teaching, and achieving proficiency in intermittent catheterizations for proper voiding. Reconstructive surgery should be performed within a timeframe of 3 to 12 months, contingent on the infant’s growth and overall health condition [17]. Some patients additionally require bladder drainage. If there is a presence of hydrocolpos, as in our case, the surgeon is required to not only create a colostomy but also to prevent complications like ureteral obstruction or pyocolpos [18,19]. Our patient had a successful removal of the hydrocolpos drain at 3 weeks of life without any issues; however, we recognize the possibility of this reaccumulating. During the hospital course, the patient did not experience any respiratory stress related to the abdominal wall muscle overstretch, and there was no need for respiratory support at discharge.

Reconstructive options for CDS vary widely but include total urogenital mobilization, vaginal switch, or vaginal replacement with rectum, colon, or small bowel [18]. For patients who are suitable surgical candidates for complete urogenital mobilization, there is a higher probability of attaining optimal outcome. In cases where patients exhibit exceptionally short vaginas in the upper pelvic region, it becomes imperative to consider a form of vaginal replacement. In instances where both vaginas are significantly dilated (bilateral hydrocolpos), and the patient presents with an extensive common channel, a specialized technique known as a “vaginal switch” is the most suitable approach for surgical repair [18]. Physical examination and visualization of our patient’s anatomy at the time of the pre-operative phase will be crucial in determining the most appropriate reconstructive approach. Management of patients with CDS can be challenging due to the complexity and variability of the anatomy, as well as the associated urologic problems these patients face. Early diagnosis of the disease and timely determination of medical and surgical treatment is essential in patients with CDS.

Conclusions

CDS is a rare malformation in pediatric patients. Sonographic findings may detect urinary tract abnormalities; however, prenatal imaging may not always detect CDS. Our report demonstrates the unique aspects of this case, highlighting the importance of early diagnosis, prompt medical and surgical treatment, and attentive post-intervention follow-up.