Midgut Malrotation Causing Intermittent Intestinal Obstruction in a Young Adult

Midgut malrotation is a congenital anomaly of intestinal rotation and fixation that is generally seen in neonatal population. Adult cases are rarely reported. Early diagnosis is crucial to avoid life threatening complications. Here, we present an adulthood case of midgut volvulus as a rare cause of acute abdomen.


Introduction
Midgut malrotation (MM) as a congenital anomaly of intestinal rotation and fixation is generally seen in the neonatal population [1]. It usually occurs due to incomplete rotation or a complete fail of rotation in which the primitive intestinal loops ought to do around the superior mesenteric artery axis in the fetal period [2]. Rare adult cases have been reported [2][3][4]. Early diagnosis is crucial to avoid life-threatening complications such as volvulus, internal herniation, and intussusception [3]. While symptomatic malrotation is seen in one of 5000 live births, 90% of the infants with malrotation become symptomatic up to the end of the first year of life [5]. However, adult-age MM is difficult to diagnose and should be kept in mind in differential diagnosis of acute abdomen due to its nonspecific presentation. Here, we present a case of adult age chronic MM with recurrent abdominal pain attacks.

Case
An 18-year-old female admitted to our emergency clinic with complaints of abdominal pain and vomiting for the last three days. Her past medical history revealed chronic abdominal pain and occasional vomiting since her childhood but she did not go under further investigation. Vital signs were within the normal range. Physical examination revealed only nonspecific abdominal tenderness without abdominal guarding, rebound tenderness, and abdominal distention. White blood cell count was 6500/ L (normal range 4500-9900/ L) and C-reactive protein value was 0.3 mg/L (normal range 0-5 mg/L). Computed tomography (CT) showed whirllike appearance of the superior mesenteric vein and the bowel around the superior mesenteric artery axis ( Figure 1). It was also noted that cecum and the ascending colon were predominately located on the left side, just adjacent to the sigmoid colon. The small intestines occupied right side of the abdomen.
The patient was taken to the operating theatre with the diagnosis of MM. At the exploration, rotation of minimally dilated small intestines ( Figure 2) with no apparent intestinal ischemia was seen. Detorsion of the malrotated loops of the small intestine was performed in the anticlockwise direction. Intra-abdominal adhesions and Ladd's bands ( Figure 3) as fibrous stalks of peritoneal tissues attaching cecum to the abdominal wall were dissected. The small intestines and the colon were placed to the right and the left side of the abdomen, respectively (Figures 4 and 5). Appendectomy was added. At the postoperative fourth day, she was discharged without any complaint. At the third month of the follow-up, she had no complaints with taking regular diet.

Discussion
Intestinal rotation and fixation begin at the 6th gestational week with a total of 270 degree anticlockwise rotation. At the 12th week, the intestinal segments were fixed as the ascending and descending colon on the right and left quadrants, respectively [6]. According to stringer classification which is based on the embryological state of development, there are three different types of MM as type I (nonrotation), type II (duodenal malrotation), and type III (combined duodenal and cecal malrotation) [7]. In this case, there was type I MM which includes left positioned cecum and ascending colon with right-sided duodenojejunal junction accompanied by inverted position of the superior mesenteric vessels and hypoplasia of the uncinate process of the pancreas.
Due to presence of the atypical symptoms, the diagnosis of MM is mostly made either incidentally during surgery or in autopsies [8]. There were many reports of MM cases that were operated due to ileus or acute appendicitis with lower left quadrant pain [9][10][11]. It is also possible to see an increased risk of morbidity and mortality due to delayed diagnosis of MM for various diseases such as acute appendicitis [12]. Although plain X-ray, Doppler ultrasound, and contrast studies might be used for diagnosis, it can be possible to diagnose this entity preoperatively by using CT scans due to the presence of specific anatomic features [13,14]. In the present case,  presence of intermittent attacks of intestinal obstruction in a young patient was regarded as a clue for the diagnosis of MM. Therefore, clinical suspicion and use of CT in selected cases can be regarded as the most appropriate way to reach the preoperative diagnosis [14].
In case of MM, the most commonly encountered presentation is the inability of cecum positioned to the rightlower quadrant and the pressure on the duodenum due to peritoneal Ladd's bands that fix the ectopically established cecum to the posterior wall [15]. Following description of the reduction of volvulus for the first time in 1932, Ladd described the liberalization of the bands that apply pressure to duodenum. Hence, the aim of Ladd's procedure is to dissect the bands that apply pressure to duodenum and jejunum and relief of the small intestine as in the present case [16].
As a conclusion, in case of intermittent intestinal obstruction in young adults, the physicians should keep in mind that early and accurate diagnosis of MM with an appropriate Figure 5: Left-sided cecum (black asterisk) and ascending colon and the terminal ileum (white asterisk) running to the right side.
surgical treatment may save patients from unexpected complications. In acute presentations, CT should be chosen as the primary imaging modality.

Consent
The written informed consent of patient was obtained about this case report.