Midgut volvulus in a pediatric patient with chronic constipation, congenital intestinal malrotation and internal transmesocolic hernia

Abstract

Congenital intestinal malrotation occurs in 1 of 500 newborns and can predispose patients to intestinal volvulus and internal herniation, putting patients at risk for intestinal ischaemia. A male patient in early childhood with a history of severe constipation presented with acute abdominal pain, progressing rapidly to compensated shock. CT scan was suspicious for small bowel ischaemia and superior mesenteric artery compression. He underwent emergency exploratory laparotomy. Intraoperative findings were significant for partial intestinal malrotation with mobile ascending colon and high-riding caecum, and internal herniation with midgut volvulus of the ascending colon through a mesenteric defect in the proximal transverse colon. Derotation of the volvulus, reduction of the internal hernia, resection of necrotic segments of the bowel and a modified Ladd’s procedure were performed. Postoperatively, the patient is total parenteral nutrition (TPN) dependent due to short bowel syndrome. A high index of suspicion with prompt imaging is paramount for paediatric patients with symptoms indicating intestinal obstruction.

Background

Congenital intestinal malrotation is the result of an incomplete rotation and fixation of the intestines during embryological development. Intestinal malrotation can be complete or partial, in which there are varying degrees of malrotation during embryonic development as the intestines undergo three 90° counterclockwise turns (figure 1).¹ With complete malrotation, the small intestines are on the right side of the mesenteric axis, and the colon is on the left side. With partial malrotation, the caecum can be ascended and often attached to the upper right side of the abdominal wall.¹ Intestinal malrotation significantly increases the risk for intestinal volvulus with obstruction of the superior mesenteric artery and vein, leading to intestinal ischaemia, venous congestion, arterial and venous thrombosis, and lymphatic obstruction.² Most cases of midgut volvulus due to malrotation present within the first 2 years of life.² Children with a volvulus typically present with signs of intestinal obstruction such as acute onset abdominal pain and vomiting. If left untreated, patients are at risk for loss of bowel and septic shock as a result of intestinal necrosis.²

Figure 1.

Normal intestinal rotation in fetal development. (A) At 5 weeks, a hairpin loop forms around the superior mesenteric artery (SMA), then (B) at 6 weeks, the midgut herniates into the umbilicus and completes a 90° counterclockwise rotation around the SMA. (C) At 10 weeks, the intestines reduce back into the abdomen where they then (D) undergo continued counterclockwise rotation around 11 weeks with the caecum in the upper right quadrant. (E) The intestines complete a total of 270° counterclockwise rotation when the caecum becomes fixed in the right lower quadrant. Image created by Emily Brezler, MD with references from ‘Review of Medical Embryology’.¹⁷

Intestinal malrotation can also predispose patients to internal herniation due to the lack of fixation of the bowel loops.³ Internal herniation is defined as viscera protruding through an anatomical or pathological opening within the peritoneum or mesentery leading to possible strangulation and ischaemia of the viscera. Defects can be either congenital, iatrogenic or acquired.^{4 5} Paraduodenal hernias are the most common type of internal hernia, with pericaecal, intersigmoid, omental and transmesocolic hernias occurring in decreasing frequency.^{4 6} Transmesocolic hernias typically do not have a hernia sac or soft tissue covering, posing a challenge to detect through imaging with the risk for delayed diagnosis and treatment.⁴

Case presentation

A male patient in early childhood with no medical or surgical history complained about the acute onset of excruciating abdominal pain, starting at 05:00. Within 3 hours, the patient presented to an outside hospital emergency department (ED) for initial evaluation. His abdomen appeared diffusely tender, his WBC was 25.6 × 10³/µL, potassium at 3.0 mmol/L and lactate at 6.3 mmol/L. He was started on intravenous antibiotics (cefepime and metronidazole) and intravenous fluids for presumed sepsis. A CT scan was obtained which showed widespread colonic stool burden. The patient was subsequently transferred for further workup of abdominal pain of unclear origin.

On arrival, approximately 10 hours after onset of symptoms, the patient was in compensated shock with a blood pressure of 80/44 mm Hg and a heart rate of 175 beats per minute. His blood work revealed a WBC of 26.3 × 10³/µL and lactate level of 5.8 mmol/L. On physical examination, his abdomen was diffusely tender to palpation with moderate distention. His CT scan was reviewed and showed massive amounts of stool within the entire large bowel and suspicion for ischaemic small bowel injury, as well as abrupt discontinuation of the superior mesenteric artery that is consistent with thrombus or volvulus (figure 2). The patient was taken to the operating room within an hour of arrival for an emergent exploratory laparotomy, approximately 11 hours after onset of symptoms.

Figure 2.

Sequential axial arterial phase CT image showing an abruptly occluding proximal superior mesenteric artery (red arrow), non-enhancing bowel wall in the transverse colon (blue arrow) and mesenteric oedema (arrowhead). Figure prepared by Rita Sico, MD.

Treatment

Shortly after admission, the patient was intubated, and treatment with epinephrine, norepinephrine, cefepime, vancomycin and metronidazole was initiated. He was taken emergently to the operating room for an exploratory laparotomy. Intraoperative findings were significant for partial intestinal malrotation with a completely mobile ascending and transverse colon and a high-riding caecum (figure 3). We noticed an internal herniation of the ascending colon including the entire small bowel and the distal transverse colon through a mesenteric defect of the proximal transverse colon and a midgut volvulus (900° clockwise) of the internally herniated bowel (figure 4). The entire herniated large bowel was filled with a significant amount of hard stool. The caecum was found to be fixed to the gallbladder fossa with fibrotic Ladd’s bands, and the mesenteric root was narrow with complete mobility of the small bowel. The ligament of Treitz was positioned medially over the vertebral body. The herniated bowel appeared cyanotic with complete necrosis of the herniated ascending and transverse colon. The distal vascular mesentery showed areas of diffuse capillary occlusion from extensive thromboembolism (figure 5).

Figure 3.

Partial malrotation with high-riding caecum, narrow mesenteric root, Ladd’s bands and incomplete duodenal C-loop. Image created by Federico Seifarth, MD and Emily Brezler, MD.

Figure 4.

Midgut volvulus, mesenteric defect of proximal transverse colon and internal herniation. Image created by Federico Seifarth, MD and Emily Brezler, MD.

Figure 5.

Cyanotic small bowel, necrotic herniated large bowel within mesenteric defect of proximal transverse colon.

The surgical procedure included reduction of the internal herniated small and large bowel, derotation of the midgut volvulus, extended right hemicolectomy of the ascending and proximal transverse colon including the mesenteric defect with creation of an end ileostomy, distal small bowel resection and a modified Ladd’s procedure (division of the Ladd’s bands). The patient was started on intravenous heparin for the SMA thromboembolism. The majority of the small bowel showed significant recovery with subtotal resolution of cyanosis after derotation. The bowel recovery appeared appropriate at that time, and the decision was made to close the abdomen.

Within the first 18 postoperative hours, the patient had increasing abdominal girth. The increasing bladder pressure raised concern for the patient developing abdominal compartment syndrome. Re-exploration (a second look) was performed with the need for excision of an additional 200 cm of necrotic distal small bowel. There was remaining concern regarding the viability of the proximal small bowel. The patient’s abdomen was therefore left open with a silo bridge closure for planned takebacks.

Over the 4-month long hospital course, the patient underwent 12 abdominal explorations with excision of the ascending and transverse colon, and a total of 410 cm of necrotic small bowel as a result of extensive ischaemia and reperfusion injury. His abdomen was closed on day 29, and peritoneal drains were left in place to control a proximal anastomotic leak. He was left with 94 cm of viable small bowel in continuity and an end-ileostomy. Heparin was discontinued on hospital day 12. Antibiotic treatment with cefepime, vancomycin and metronidazole continued from hospital day 1 to day 29, antifungal treatment with fluconazole from hospital day 21 to day 29 and clindamycin treatment from day 45 to day 55. The patient was extubated on hospital day 27 and was transferred to floor status on day 65 of hospitalisation (figure 6).

Figure 6.

Timeline of early hospital course and surgical intervention.

Outcome and follow-up

The patient developed a jejunocolonic fistula (figure 7) and tolerates increasing amounts of food. He remained TPN dependent due to short bowel syndrome. He was discharged home on hospitalisation day 147, and his care has been transferred to a short gut and bowel transplant centre.

Figure 7.

Jejunocolonic fistula (red arrow) on CT enterography with intravenous contrast. The duodenum (blue arrow) and colon (green arrow) are indicated.

Discussion

Intestinal malrotation occurs in 1 of 500 newborns and predisposes patients to midgut volvulus. The incidence of midgut volvulus secondary to malrotation significantly decreases after the age of 2, and most patients with the anatomical variant remain asymptomatic.^{2 7} Intestinal malrotation can range from incomplete to complete due to the variability that can occur during the three 90° rotations that the intestines undergo during embryonic development.¹ Our patient presented with partial malrotation with a completely mobile ascending colon, fixed caecum within the upper mid-abdomen and a narrow mesenteric root facilitating the intestinal herniation.

Internal herniation of viscera has an estimated incidence of <1%, with transmesenteric being the most common type in the paediatric population at an estimated 35% of cases of internal herniation.⁸ Internal hernias, as well as malrotation, can present with intermittent abdominal pain with or without bilious emesis.² Constipation is very common in children, affecting 12%–18% of healthy toddlers. Most patients suffering from constipation are diagnosed with functional constipation without further testing.⁹ Considering the high prevalence of functional constipation in the paediatric population and the lack of general radiographic workup, intestinal variants or anatomical abnormalities predisposing them to constipation are frequently missed or diagnosed in a delayed fashion.⁸ We speculate that the stool burden within the herniated large bowel facilitated herniation of distal bowel segments, contributed to the entrapment of the bowel and prevented spontaneous reduction, similar to a button being pushed through a buttonhole. Herniation of bowel loops alone can lead to vascular obstruction with the risk for intestinal ischaemia and venous congestion. The combination of intestinal herniation and volvulus is detrimental.

The presented case dramatically illustrates the catastrophic turn a patient’s health can take when unfavourable anatomical pathologies (partial malrotation and a mesenteric defect) coincide with pre-existing conditions (constipation) and poor medical decisions. The ‘Swiss cheese model’ was originally described by James T Reason and is applied to explain system failures such as medical mishaps. The metaphor uses the holes in Swiss cheese as a representation of deficiencies of individual parts in a system. A system fails when a hole in each slice momentarily aligns, permitting ‘a trajectory of accident opportunity’, in our patient’s case leading to bowel necrosis.¹⁰

Completely interrupted intestinal blood supply for greater than 6 hours results in ischaemic injury.¹¹ Mucosal, submucosal, muscular and transmural (irreversible) necrosis occurs in this sequence depending on the severity and duration of compromised blood flow.¹² Intestinal ischaemia causes excruciating pain, and acute onset is typical for strangulating volvulus or bowel herniation. Untreated ischaemia leads to bowel necrosis with high morbidity and mortality, reported at 60%–80%.¹³ Paradoxically, restoration of blood flow can also worsen intestinal injury due to free radicals damaging tissues, with the bowel being one of the most susceptible organs to reperfusion injury.¹⁴ Reperfusion injury can cause more damage than the inciting ischaemic event, leading to continued bowel necrosis, such as in our patient.¹⁴ The diagnosis of intestinal ischaemic compromise in our patient was delayed; reperfusion of the SMA was achieved 11 hours after initial onset of symptoms, resulting in irreversible small and large bowel necrosis.

Due to the significant risk of intestinal volvulus and subsequent ischaemia with both intestinal malrotation and internal herniation, prompt evaluation with appropriate imaging is mandatory for any paediatric patient presenting with an acute onset of severe abdominal pain or signs of intestinal obstruction.¹⁵ Malrotation can be diagnosed by abdominal CT scan or an upper intestinal contrast study, in which the latter is often superior in diagnosis. Ultrasound (US) can also be used as both an efficient and cost-effective method to diagnosing intestinal malrotation in a non-acute setting. On US, the duodenum is found intraperitoneally in cases of malrotation versus its regular position in the retroperitoneum in normally rotated patients.¹⁶ Malrotation can also be determined from the position of the superior mesenteric artery (on the left) and superior mesenteric vein (on the right). The relationship of the vessels is reversed in cases of intestinal malrotation.¹⁶ In an acute setting, intestinal volvulus can be detected by the whirlpool sign on US. The ‘whirlpool’ describes the swirling of the SMV and small intestine around the SMA.¹⁶ Although US can be a fast method of diagnosing intestinal malrotation and volvulus, its sensitivity and specificity are heavily dependent on the experience of the technician and radiologist.¹⁶ Plain radiographs are poor at indicating malrotation alone. Patients with malrotation are frequently initially diagnosed with malrotation after suffering intestinal volvulus with obstruction and ischaemia.⁶ Our patient’s radiograph revealed not only colonic stool burden but increasing pneumatosis intestinalis, indicating bowel necrosis due to ischaemic injury from the midgut volvulus and SMA thrombosis. Intestinal hernias are also challenging to diagnose without surgical exploration. Plain radiographs, US, CT and MRI have been proposed in the diagnosis of transmesocolic hernias. A CT scan can possibly reveal mesenteric vessel stretching, crowding or displacement of the mesenteric trunk towards the transmesocolic hernia.^{4 6}

In our patient, correct initial interpretation of the CT imaging could have revealed the abrupt lack of perfusion in the SMA from the volvulus and herniation earlier, leading to immediate surgical intervention. In light of the potential catastrophic consequences, a high index of suspicion is necessary to allow for early diagnosis and treatment or timely referral of patients with suspected ischaemic intestinal injury to a centre with radiographical and surgical capabilities.

Learning points.

• Severe conditions in paediatric populations, including congenital malrotation, intestinal volvulus and internal herniation, can present with acute or intermittent abdominal pain.

• Intestinal ischaemic injury can occur as early as 6 hours when perfusion is completely interrupted, and if not promptly treated, it can put patients at increased risk for subsequent reperfusion injury that can further progress intestinal necrosis.

• A high index of suspicion is necessary for prompt imaging, diagnosis and surgical intervention of intestinal ischaemic injury to preserve function.

Ethics statements

Patient consent for publication

Consent obtained from parent(s)/guardian(s).