In fetal intestinal perforation, inflammation leads to production of ascites. Small bowel is usually involved by perforation with the distal ileum the most frequent site. We report the first case of prenatal perforation of the intraperitoneal part of the rectum, which presented as severe ascites at a 37 weeks’ gestation antenatal ultrasonography. As none of the reported causes of intestinal perforation were identified in our case, its etiology remained idiopathic.
Prenatal rectal perforation is extremely rare. To date, only one report describes three cases of prenatal extraperitoneal rectal perforation, associated with a para-rectal defect of the pelvic floor and diagnosed antenatally as a perineal mass.1 We report a case of idiopathic prenatal perforation of the intraperitoneal part of the rectum, presenting as slightly hyperechoic ascites associated with hyperechogenic intestinal loops on antenatal ultrasonography.
At 37 weeks’ gestation a 31-year-old woman, gravida 1, para 0, underwent ultrasonography to evaluate her twin pregnancy. The study revealed a slightly hyperechoic ascites associated with hyperechogenic intestinal loops and without peritoneal calcifications in one fetus (Figure 1). No other abnormalities were detected. Previous ultrasonography, at 35 weeks’ gestation by the same sonologist, reported normal findings. There was no history of diabetes mellitus or hypertension. Amniocentesis was performed at 20 weeks’ gestation to rule out chromosomal abnormalities. Toxoplasma, other agents, rubella, cytomegalovirus, herpes simplex and parvovirus B19 test results were negative. At 38 weeks’ gestation, two female babies were delivered vaginally. The birth weights were 2300 and 2490 g, respectively. Apgar scores were normal.
Physical examination of the affected infant revealed abdominal distension with hyperemic skin and dilated veins on the surface, and no dysmorphic features. The anus was correctly placed. Abdominal ultrasound scan confirmed copious ascites with floating echogenic material inside. No cardiac or renal anomalies were observed. Plain abdominal X-rays were performed every 3 h and at 6 h after birth a pneumoperitoneum was diagnosed (Figure 2). At 10 h of age laparotomy was performed and a considerable amount of intra-abdominal fluid with meconium was observed. After a meticulous examination of the whole gastrointestinal tract, a rectal localized perforation was found on the anterior-lateral wall approximately 2 cm above the peritoneal reflection. It appeared as a lesion with irregular margins and of about 1 cm in size. No signs of rectal wall ischemia or necrosis were identified. Frozen sections of extramucosal bowel biopsies revealed normal ganglion cells so rectorraphy and diverting sigmoidostomy were performed. The immediate postoperative course was complicated by hemoperitoneum secondary to a superficial splenic injury requiring emergency re-exploration. The internal bleeding was managed successfully without splenectomy. Four weeks later a contrast enema indicated a normal rectum without stricture so intestinal continuity was restored.
Sweat chloride test and the genetic analysis for cystic fibrosis were normal. Follow-up at 7 years showed normal growth and a regular stooling function.
Isolated fetal ascites is rare and usually caused by intra-abdominal pathology such as intestinal perforation, urinary tract obstructive malformations, lymphatic obstruction, ovarian cysts and bowel occlusion. In prenatal intestinal perforation, the extrusion of meconium can appear as a solitary mass inside fetal ascites or as disseminated echogenic masses.2, 3, 4 The portion of the involved intestinal tract is generally the small bowel with the distal ileum being the most frequently involved segment. Prenatal perforation of the rectum is an exceptionally rare event. Only one report describing three cases of prenatal extraperitoneal rectal perforation has been reported and each case was associated with a para-rectal defect of the pelvic floor.1
Establishing the etiology of intestinal perforation can be difficult. The differential diagnosis list includes cystic fibrosis, Hirschsprung disease, vascular insufficiency, infection and bowel occlusion owing to small and large bowel atresia, midgut volvulus, intussusception, congenital bands and meconium ileus.5, 6, 7, 8, 9, 10 Each of these possible causes was excluded in the present patient. As a prenatal sigmoid perforation following amniocentesis has been reported,11 we investigated the circumstances of the early amniocentesis in this patient and found no evidence for complications during and after its execution. Additionally, in the literature several cases of rectal injury owing to rectal thermometers have been described in healthy neonates.12 No rectal probes or catheters were used at birth in our patient. Given that none of the reported causes of prenatal intestinal perforation were identified, the etiology of our case remained idiopathic.
Regarding treatment, during the initial surgery, primary anastomosis was not performed in order to avoid pelvic nerve injury during rectal mobilization. Rectorraphy and diverting sigmoidostomy preserved the rectum allowing a successful two-stage treatment.
In conclusion rectal perforation may appear in late pregnancy as fetal ascites with floating echogenic material. Even though the small bowel is the most common site of intestinal perforation associated with ascites, the possibility of a rectal perforation should be considered for a prompt and accurate treatment.
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Casaccia, G., Giorlandino, C., Catalano, O. et al. Prenatal rectal perforation: an unsuspected cause of isolated ascites. J Perinatol 26, 717–719 (2006). https://doi.org/10.1038/sj.jp.7211602
- fetal ascites
- neonatal surgery
- prenatal bowel perforation
- rectal perforation