|Year : 2019 | Volume
| Issue : 4 | Page : 303-306
Total intestinal atresia: Revisiting the pathogenesis of congenital atresias
Neel Aggerwal, Nidhi Sugandhi, Harshita Kour, Goutam Chakraborty, Samir Kant Acharya, Amit Jadhav, Deepak Bagga
Department of Pediatric Surgery, VMMC and Safdarjung Hospital, New Delhi, India
|Date of Web Publication||29-Aug-2019|
Dr. Nidhi Sugandhi
Department of Pediatric Surgery, VMMC and Safdarjung Hospital, New Delhi - 110 070
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Despite various theories to explain the pathogenesis of atresias, the exact mechanism is still controversial. Currently, atresias are believed to result from vascular accidents and less likely due to the failure of recanalization. We report a case which challenges this belief. A 1-day-old neonate was explored for suspected jejunal atresia. Apart from Type III jejunal atresia, 15 cm from DJ junction, there was surprisingly no distal lumen in the intestine from jejunum till rectum. Multiple enterotomies revealed the whole of the remaining jejunum, ileum, and large colon to be a solid cord-like structure. No distal luminal contents or histopathological evidence of ischemic damage was seen, thus suggesting the probable etiology to be a failure of recanalization of the gut cord rather than a late vascular accident. Such rare cases provide insights into possible embryogenetic mechanisms which can then aid in formulating preventive measures.
Keywords: Congenital gut anomalies, embryological defects, failure of recanalization, total intestinal atresia, vascular accidents
|How to cite this article:|
Aggerwal N, Sugandhi N, Kour H, Chakraborty G, Acharya SK, Jadhav A, Bagga D. Total intestinal atresia: Revisiting the pathogenesis of congenital atresias. J Indian Assoc Pediatr Surg 2019;24:303-6
|How to cite this URL:|
Aggerwal N, Sugandhi N, Kour H, Chakraborty G, Acharya SK, Jadhav A, Bagga D. Total intestinal atresia: Revisiting the pathogenesis of congenital atresias. J Indian Assoc Pediatr Surg [serial online] 2019 [cited 2019 Sep 15];24:303-6. Available from: http://www.jiaps.com/text.asp?2019/24/4/303/265702
| Introduction|| |
Intestinal atresia constitutes one of the most common causes of neonatal intestinal obstruction. It is a serious congenital anomaly that affects approximately 1 in 5000 live births. Duodenum is the most common site accounting for almost 50% of cases, but the jejunum and ileum account for 39% of intestinal atresias. Although various theories have been proposed to explain the pathogenesis of atresias, the exact mechanism is still controversial. Currently, atresias are believed to result from vascular accidents during later phases of gestation and less likely due to the failure of recanalization in the early period of gestation. Here, we report a case which challenges this belief.
| Case Report|| |
A 1-day-old, full-term normally delivered, male child born to Primi gravida mother presented to the emergency department of our hospital with complaints of nonpassage of stools since birth with minimal abdominal distension associated with bilious vomiting. There was no history suggestive of adverse perinatal events or any contributory family history. On examination, the general condition of the child was stable with no signs of sepsis or syndromic changes. The abdomen was distended but soft with no visible loops, and nasogastric output was bilious. The child had a normal external anal opening admitting infant feeding tube till 3 cm with no meconium staining. Plain abdominal X-ray showed dilated proximal bowel loops with the absence of any gas distally, suggestive of proximal intestinal atresia [Figure 1].
|Figure 1: Preoperative X-ray showing dilated proximal bowel loops and absence of distal gas suggestive of proximal atresia|
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On exploratory laparotomy, stomach and duodenum were normal with no evidence of atresia [Figure 1]. Type IIIa jejunal atresia (multiple segmental atresias) was seen at 10 cm and 15 cm distal to DJ flexure. Apart from the defect seen in jejunal mesentery at the site of IIIa atresia, the rest of the mesentery were well formed and adequate with no other defect in any part of the small and large intestinal mesentery [Figure 2].
|Figure 2: Nonatretic stomach and duodenum with proximal jejunal atresia, normal mesentery, and jejunal section showing solid fibrous cord with absence of lumen (arrows)|
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After resecting the atretic type IIIa part of jejunum, rest of the distal jejunum and ileum was checked for continuity as a usual procedure. However, surprisingly, no lumen was found in intestine from jejunum till rectum, as confirmed by multiple enterotomies from the site of atresia till ileocecal junction. The whole of the remaining jejunum, ileum, and large colon was a solid cord-like structure [Figure 2].
On dividing the intestinal serosal and muscularis layer, lumen was seen to be obliterated with white cord-like tissue which was continuous over the entire length of small intestine. Biopsies from ileum and colon along with resected jejunal atretic segment were sent for histopathological evaluation.
With no further treatment option, an end duodenostomy was fashioned, and rest of the contents were repositioned back. Parents were explained the condition and prognosis. The child was managed in postoperative period with intravenous fluids and total parenteral nutrition, but parents chose to take him home after 2 days.
Histopathological examination at the site of IIIa jejunal atresia revealed features of intestinal atresia with atrophic mucosa and focal areas of mucosal ulceration lined with inflammatory granulation tissue [Figure 3]. The segmental intestinal biopsies of rest of the small and large colon along with obliterating intraluminal tissues specimen reported marked intestinal luminal narrowing [Figure 4]. No inflammatory or ulcerative changes were noted in mucosal layer of rest of the bowel, further supporting the lack of any vascular insult [Figure 5].
|Figure 3: High power view (×40) showing mucosal ulceration (black arrow)|
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|Figure 4: Low power (×4) view of jejunum showing microscopic luminal narrowing (red arrow)|
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|Figure 5: High power (×20) view of jejunum showing all four layers (mucosa, submucosa, muscularis, and serosa)|
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| Discussion|| |
More than one-third of congenital bowel obstructions result from intestinal atresias. Small intestinal atresia accounts for majority of the cases while colonic atresias are quite rare.
Congenital atresia has been regarded as a fetal (late gestational) malformation, and the term has customarily been applied to those intestinal occlusions which in themselves are not related to other obstructive lesions such as prenatal volvulus, intussusception, and patent vitellointestinal duct; embryologically, the endoderm gives rise to the gut tube, beginning in the 4th week of gestation. In the 6th week, gut epithelium proliferates rapidly and obliterates the intestinal lumen, which gradually recanalizes over the next several weeks of development. The two most popular theories to explain the occurrence of intestinal atresias are the theory of vascular insult by Louw and Bernard and the theory of nonrecanalization of the gut by Tandler., None of these can explain the entire spectrum of atresias. Currently, the vascular insult theory is thought to be more plausible to explain the occurrence of atresias.
On the basis of their classic experimental work in 1955, Louw and Barnard demonstrated that ligating mesenteric vessels and causing strangulated obstruction in fetal dogs resulted in atretic lesions of the small intestine that were similar to those observed clinically in human neonates. Hence, they postulated that intestinal atresias were the result of ischemic insult and scarring, which was usually a late gestational phenomenon.
Laufman also demonstrated in 1949 that when isolated sterile devascularized loops of intestine were left in the peritoneal cavity, they converted to fibrous bands or disappeared entirely, which is thought to explain the absent intestinal segments and mesenteric defects in Type III and IV atresias. Atresias with mesenteric defects are also known to occur with other conditions that may cause strangulated obstruction of the intestinal tract (e.g., volvulus, intussusception, internal hernias, and gastroschisis). The vascular insult theory has certain shortcomings. It cannot explain the occurrence of duodenal or colonic atresias, and neither does it explain the etiology of Type I atresias which is the presence of only an obstructing intraluminal membrane. The vascular anatomy of the large bowel and duodenum differs significantly from that of the small intestine. These structures seem to be far better protected from local interference with the blood supply, and their fixation to the posterior abdominal wall renders them less susceptible to mechanical factors such as volvulus, kinking, or torsion. Similarly, it is known that development of duodenal atresia is an early event, which occurs before the interruption of fully developed vascular supply can lead to ischemic consequences, as evidenced by the absence of luminal contents distal to the site of atresia. Thus, the failure of recanalization can also be one of the pathogenetic factors for the development of at least some atresias.
Tandler, while investigating the embryology of the duodenum, hypothesized intestinal atresia to result from failure of recanalization of the intestinal lumen following obliteration during the stage of epithelial proliferation. The theory of recanalization has been refuted by some as it cannot explain the findings in jejunoileal atresia, that is the presence of bile, squamous cells, and lanugo distal to the site of obstruction. The presence of these elements distal to the level of atresia indicates that the insult resulting in atretic segment, occurred after the period of intestinal luminal development when some of the contents had already passed distal to the site of obstruction. In our case, there were no intestinal luminal contents, and whole of the bowel was obliterated from jejunum to rectum with no lumen. Various histopathological changes seen in the spectrum of bowel ischemia such as gangrene, perforation, and intramural bowel calcification were not seen in our patient.
In our index case, the mesenteric defect was noted only in small portion of jejunal mesentery, but the stenosis/atresia was seen in rest of the jejunum, ileum, and large colon too. The vasculature supplying the rest of the gut was healthy, and no evidence of hypoplasia of mesentery or ischemia of gut or its sequelae in the form of fibrous cords or absent intestinal segments were seen. Considering no evidence of vascular insult was found to the majority of the atretic gut in our case, it is difficult for the vascular accident theory to account for the etiology. Due to these findings and normal mesentery, we speculate nonrecanalization as a cause for jejunoileal atresia in our case.
The findings seen in our case were similar to Type I atresia or segmental gut stenosis described in literature, the difference being it involved whole of the gut till rectum sparing stomach and duodenum only. To the best of our knowledge, it is the only case of this nature reported till date in literature. Atresia/stenosis of the whole gut with no lumen with a normal mesentery and no associated comorbidities has not been described.
| Conclusion|| |
According to established belief, intestinal atresia occurs due to a vascular insult to the fetal intestine. The theory of failure of recanalization has been refuted over years as the cause of jejunoileal atresia. We speculate that etiopathogenesis of atresias is a complex and probably multifactorial phenomenon. The failure of recanalization may be one of the factors in pathogenesis of at least some jejunoileal atresias, as demonstrated in this case.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]