Intestinal or Midgut Volvulus

ICD-10 XI K63.8, ICD-11 13 DB30.1

 (http://apps.who.int/classifications/apps/icd/icd10online/)

Intestinal or midgut volvulus refers to a condition in which small bowel loops or the proximal part of the colon twist around the superior mesenteric artery (1, 2).

Prenatal volvulus is a rare condition. The incidence is not described in the literature.

There are three types of volvulus which are seen in the prenatal or newborn period: classic type, segmental type, and volvulus without malrotation (3). The classic type is defined as malposition of bowel due to clockwise rotation of the small bowel and ascending colon around the superior mesenteric artery without evidence of any anomaly predisposing to the rotation (3). Segmental volvulus has been described as twisting of bowel loops due to an anomaly including meconium ileus commonly seen with cystic fibrosis, bowel atresia, mesenteric defects, intestinal duplication, mesenteric cysts, congenital diaphragmatic hernia, abdominal wall defects or idiopathic (3). Volvulus without malrotation is a diagnosis of exclusion and is more common in extremely premature or low birthweight infants (3).

The most frequent cause of midgut volvulus is bowel malrotation, which represents an incomplete rotation of the intestine during fetal development (2, 4, 5). Other causes include cystic fibrosis, gastrointestinal duplication, intestinal atresia and the presence of either a cyst or tumor mass (1, 5, 6).

Midgut volvulus is commonly associated with intestinal malrotation or intestinal atresia (2, 7). In the absence of these abnormalities, a mesenteric defect or the presence of cystic fibrosis should be considered as etiologic factors (2).

When midgut volvulus occurs in utero, it may be complicated by ischemic necrosis because of vascular compromise (7).

The recurrence risk of prenatal volvulus is not described in the literature, but is dependent on the underlying cause such as for instance cystic fibrosis or intestinal atresia.

The prenatal presentation of this condition is quite rare, with the vast majority of cases reported after the 27^th week of gestation (2, 5, 8). Diagnosis is challenging, because of a lack of specific fetal symptoms or ultra-sonographic signs. A recent study described the ‘whirlpool’ sign in 10 out of 13 cases with prenatal volvulus (77%) (5). The ‘whirlpool’ sign is characterized by direct visualization of the twisted bowel loop using 2D-ultrasound imaging (4, 5, 7). In addition, identification of the mesenteric vessels twisting around the main superior mesenteric artery on color Doppler constitutes the traditional sign of midgut volvulus, a concept derived from postnatal sonography (2). However, the definitive prenatal diagnosis of midgut volvulus is possible by visualizing twisted bowel loops even if the whirlpool sign is absent with color Doppler examination. The absence of identifiable flow between the loops may suggest poor bowel perfusion (2, 7). Ultrasound findings that may increase suspicion of prenatal midgut volvulus include hyper-echogenic and dilated bowel loops, intraluminal sludge in dilated bowel loops, intra-abdominal calcifications, abdominal mass, polyhydramnios, gastric dilatation (3, 9), absence of intestinal peristalsis and ascites (3, 8). Doppler studies can demonstrate an elevated peak systolic velocity (greater than or equal to 1.5 MoM) in the middle cerebral artery due to severe fetal anemia, secondary to hemorrhagic ascites (3).

It is unclear if the whirlpool sign is always associated with volvulus (7). A prospective study conducted in neonates showed that the sensitivity and specifity of the whirlpool sign were 89% and 92% respectively, but not pathognomonic (4, 7).

Polyhydramnios can occur in cases with midgut volvulus and usually develops during the third trimester of pregnancy, when the amniotic fluid swallowed exceeds the resorptive capacity of the remaining available proximal intestinal surface.

Signs of fetal distress, like decrease in fetal movements and fetal tachycardia, can occur (5). However, the decrease in fetal movements is a non-specific finding and difficult to quantify (5).

If the typical ‘whirlpool’ sign is absent, the differential diagnosis includes intestinal duplication cysts, Meckel’s diverticulum, omphalomesenteric cysts, segmental small bowel dilatation, cystic mass lesions (teratoma, lymphangioma and mesenteric cysts), intestinal atresia and cystic meconium peritonitis without volvulus (8).

When midgut volvulus is suspected, a thorough search for associated anomalies is recommended. Fetal well-being should be assessed with BPP or CTG. 

Midgut volvulus is a surgical emergency associated with high morbidity and mortality when it presents during intrauterine life (7). Complications of fetal midgut volvulus that are reported in the literature include bowel perforation, hypovolemia, heart failure, pleural and pericardial effusions, and fetal demise (3).

The outcome of fetuses with intestinal volvulus depends on the length of and level of obstruction of viable bowel, the presence of meconium peritonitis, associated anomalies, birth weight and gestational age at diagnosis or delivery (7). In the absence of complete volvulus of the entire bowel (in cases of intestinal malrotation) or association with cystic fibrosis, the prognosis appears good (5). Spontaneous resolution has been described in some cases (5).

Long term outcome for the neonate depends on the amount of bowel which remains functional after surgical resection. Neonates may suffer from ‘short bowel syndrome’ (SBS). SBS defines a condition in which the normal absorptive capacity of the small intestine is compromised (10), due to removal of a large portion of the small and/or large intestines, significant damage to the small intestine or poor motility of the bowel. This results in suboptimal resorption of water, minerals, vitamins, protein, fat calories and other nutrients from the food.

An advanced (targeted) anomaly scan should be performed to evaluate the fetus for additional abnormalities. MRI can be complementarily used to detect gastrointestinal anomalies, such as bowel atresia and cystic lesions (1, 3). Non-invasive diagnostic tests should include carrier screening for cystic fibrosis in both parents (6). Genetic consultation can be considered, especially in the presence of associated anomalies. Invasive diagnostic testing should be offered to exclude chromosomal anomalies and cystic fibrosis as is available locally. Counselling by a pediatric surgeon can be helpful.

Ultrasound scans should be performed weekly to monitor the increase in the volume of the bowel loops and fetal assessment with BPP and CTG (5). Routine Doppler screening of the MCA at first presentation can be considered. MCA PSV to screen for anemia should be performed in case of ascites.

Delivery at a center with neonatal intensive care and pediatric surgery facilities is required. Preterm delivery and surgical intervention should be considered for this condition when the diagnosis is made prenatally in the presence of definitive sonographic findings and fetal distress. Clinical judgement is necessary to determine the delivery recommendations and a team decision should be made in consultation with the pediatric surgeon. Postnatal screening for associated anomalies is recommended (7, 9). 

1.       Chen D, Tam KH, Zhang Y, Xiao S, Yang C, Tang X. Prenatal diagnosis of midgut volvulus with jejunal atresia by ultrasonography. J Obstet Gynaecol Res. 2020;46(7):1203-6.

2.       Musilova I, Elias P, Kacerovsky M. Second-trimester presentation of midgut volvulus without intestinal malrotation. Ultrasound Obstet Gynecol. 2019;54(3):422-3.

3.       Best EJ, O'Brien CM, Carseldine W, Deshpande A, Glover R, Park F. Fetal Midgut Volvulus with Meconium Peritonitis Detected on Prenatal Ultrasound. Case Rep Obstet Gynecol. 2018;2018:5312179.

4.       Chao HC, Kong MS, Chen JY, Lin SJ, Lin JN. Sonographic features related to volvulus in neonatal intestinal malrotation. Journal of Ultrasound in Medicine. 2000;19(6):371-6.

5.       Bartholmot C, Faure JM, Grosjean F, Couture A, Forgues D, Fuchs F, et al. Prenatal diagnosis of antenatal midgut volvulus: Specific ultrasound features. Prenat Diagn. 2019;39(1):16-25.

6.       Chouikh T, Mottet N, Cabrol C, Chaussy Y. Prenatal intestinal volvulus: look for cystic fibrosis. BMJ Case Rep. 2016;2016.

7.       Has R, Gunay S. ‘Whirlpool’ sign in the prenatal diagnosis of intestinal volvulus. Ultrasound in Obstetrics & Gynecology. 2002;20(3):307-8.

8.       Sciarrone A, Teruzzi E, Pertusio A, Bastonero S, Errante G, Todros T, et al. Fetal midgut volvulus: report of eight cases. J Matern Fetal Neonatal Med. 2016;29(8):1322-7.

9.       Fukushima S, Fujioka K, Ashina M, Ohyama S, Ikuta T, Nishida K, et al. Fetal Primary Small Bowel Volvulus Associated with Acute Gastric Dilatation Detected by Ultrasonography. Kobe J Med Sci. 2019;64(4):E157-E9.

10.     Sala D, Chomto S, Hill S. Long-Term Outcomes of Short Bowel Syndrome Requiring Long-Term/Home Intravenous Nutrition Compared in Children With Gastroschisis and Those With Volvulus. Transplantation Proceedings. 2010;42(1):5-8.

Please note that the maximum upload size is 5MB, and larger images and video clips can be sent to [email protected].