Meckel’s Diverticulitis in a Teenager With Unknown Intestinal Malrotation: A Case Report and Review of the Literature

The clinical presentation of congenital abnormalities in adult life is a rare condition since they usually make their appearance in early childhood. A combination of two different congenital deformities is even more infrequent, a fact that might complicate the differential diagnosis of acute abdomen. This is a case report of an inflamed Meckel’s diverticulum in a 16-year-old male with intestinal malrotation presented in an acute setting, and a review of the literature. The patient presented at the emergency department with an atypical abdominal pain located in the right abdomen and quite elevated inflammatory markers. Computed tomography revealed Meckel’s diverticulitis in combination with intestinal malrotation, findings that were confirmed intraoperatively. A partial enterectomy with a side-to-side anastomosis was performed, and the patient was discharged uneventfully. Only a few cases of this combination have been reported in the literature till nowadays. This article indicates the importance of the computed tomography scan in the differential diagnosis of abdominal pain since it might reveal rare clinical entities and determine the further therapeutic plan. Furthermore, it is a reminder that congenital abnormalities might make their clinical appearance not only in early childhood but also in adult life, pointing out the ability of the general surgeon to deal with such cases.


Introduction
Congenital abnormalities of the gastrointestinal tract, such as Meckel's diverticulum and intestinal malrotation, are rare clinical entities, and they usually present clinically in early childhood. Meckel's diverticulum appears in a prevalence ranging between 0.3% and 2.9% of the population [1], but only 3% of the cases become symptomatic [2]. Likewise, the incidence of intestinal malrotation is estimated at about 1 in 6000 births [3], though the real percentage is higher since many individuals remain asymptomatic. The coexistence of different congenital abnormalities is also possible. Because of the rarity of this clinical condition, the differential diagnosis of abdominal pain may become complicated and even delayed. The computed tomography scan nowadays is a useful and widely available diagnostic tool that determines further therapeutic management [4]. A 16-year-old Caucasian male presented to the emergency department with a history of seven-day right abdominal pain, progressively deteriorating, and coexisting anorexia. No history of previous abdominal surgery or any health problems from his medical history were noted.

Case Presentation
His vital signs were stable; the blood pressure was 125/72 mm Hg with 80 heartbeats per minute, 100% oxygen saturation, and a temperature of 37.2 degrees Celsius. The clinical examination revealed tenderness in the right lower, as well as upper, abdominal quadrant. Blood tests revealed elevated inflammatory markers, white blood cells were 12000 x 10^3 /μL (3800-10500x10^3), with 74% neutrophils, and C-reactive protein was 17,4 mg/L (>6 mg/L).
Ultrasound of the right lower abdomen was inconclusive. Investigation was decided to proceed with a computed tomography scan, in which a tubular formation, 5,1x2,6x2,3 cm in size, was described beneath the liver, containing air and liquid, enhancing during the arterial phase and connected to the small intestine, suggesting an inflamed Meckel's diverticulum (Figures 1, 2). Moreover, the cecum, the ascending colon (Figure 3), and the appendix ( Figure 4) were located at the midline, whereas the small intestine was lying lateral to the ascending colon ( Figure 5), suggesting intestinal malrotation. The patient underwent an exploratory laparotomy, where through a midline incision, the inflamed Meckel's diverticulum ( Figure 6) was recognized above the duodenum and beneath the right hepatic flexure after the division of peritoneal bands. It was located within 2 feet of the ileocecal valve. A partial enterectomy with a stapled side-to-side anastomosis was performed. The small intestine was repositioned to the right side of the abdomen, whereas the ascending colon and cecum to the midline. The laparoscopic approach was not considered a safe option based on the atypical anatomic location of the inflamed Meckel's diverticulum and the lack of experience of our center with the management of congenital abnormalities.

Discussion
Meckel's diverticulum is the most common anatomic abnormality of the gastrointestinal tract, with a prevalence ranging between 0.3 and 2.9% [1], according to a recent systematic review published by Hansen and Soreide. It occurs as the result of incomplete erasure of the omphalomesenteric duct during embryogenesis. There is a clear male predominance (1.5-4 males for every female) [1], and it is considered a disease of the youth, as more than 50% of the patients who become symptomatic are under the age of 10. Approximately 3% of the individuals will become symptomatic and eventually be surgically treated [2].
Τhe most common clinical manifestations of Meckel's diverticulum are bleeding because of ectopic gastric or pancreatic tissue, inflammation (diverticulitis) which can evolve into perforation and therefore peritonitis, and obstruction by the mechanism of intussusception or volvulus, when Ladd's bands are present. Meckel's diverticulum might also present as an inguinal hernia (Littre's hernia) in rare cases. The existence of benign or malignant tumors is infrequent but also possible.
The midgut formation takes place between the fourth and 10th weeks of the embryonic period. At first, the small bowel rotates 90 degrees counterclockwise around the superior mesentery artery axis. Then the small bowel elongates and rotates again 180 degrees counterclockwise, taking its final position in the peritoneal cavity. The incidence of symptomatic intestinal malrotation is estimated to be 1 in 6000 births [3]. 90% of the cases with intestinal malrotation present within the first year of life, whereas the incidence in adults is estimated at around 0.2%, with most of the cases presenting in the acute setting [5]. Intestinal malrotation is categorized as the non-rotation type, the reverse rotation type, the incomplete rotation, and the anomalous fixation of the mesentery type. The most common type is non-rotation, as described in the case presented.
The combination of Meckel's diverticulum and intestinal malrotation is a rare clinical entity, with only a few case reports published in the literature. A literature search using the terms Meckel's diverticulum and intestinal malrotation or midgut malrotation was conducted using the PubMed database. Based on this search, only 10 case reports were noted, with nine being in the English language and therefore included in this review ( Table 1).   Harvey and Giles first reported two clinical cases of this association in adults in 1974 [6]. The age of clinical presentation ranges from infancy to elderly [7], and it involves complications, such as perforation [7,8], obstruction [9], and even adenocarcinoma [10]. A common symptom among many cases is the presence of chronic pain before the acute onset and the absence of Ladd's bands, explaining the older age of appearance [8]. All of the cases published in the literature are presented in Table 1. Interestingly, in our case, the patient was 16 years old with no history of previous abdominal pain until Meckel diverticulitis presented.
Ford et al [11] announced that in up to 11% of the children with intestinal malrotation, Meckel's diverticulum is identified. However, the accurate percentage remains unknown since many individuals remain asymptomatic.
Several combinations of congenital deformities, including Meckel's diverticulum and midgut malrotation, have been reported. Elrouby et al. [12] presented a case of a neonate with gastroschisis, malrotation, midgut duplication, and Meckel's diverticulum. Bilal Mirza et al. [13] announced a case of an 18-year-old male with a symptomatic pulmonary sequestration cyst and diaphragmatic hernia, where malrotation with Ladd's band and Meckel's diverticulum were also present. It is of interest that malrotation is seen in 42% of the patients with congenital diaphragmatic hernia [14]. Basani et al. presented a case of a three-month-old infant with a diaphragmatic hernia, Meckel's diverticulum, and midgut malrotation [15]. Weitzman and Brennan described two cases with bronchogastric fistula, pulmonary sequestration, malrotation, and Meckel's diverticulum [16]. Although the exact pathogenesis of this association remains unknown, the diagnosis is set in early childhood when multiple congenital abnormalities are present.
There is a variety of diagnostic imaging tools available for the evaluation of the complications of Meckel's diverticulum. A plain radiograph might reveal small bowel obstruction, an enterolith, and in rare cases, a calcified Meckel's diverticulum. Ultrasonography is a widely available tool, frequently used for the initial diagnostic management of acute abdomen in children because of the lack of radiation exposure, but its sensitivity is low, and its findings depend on the operator's experience. Computed tomography scan, with thin-slice images and the capability of multiplanar reconstruction, is the imaging of choice for the complications of Meckel diverticulum since it has higher sensitivity, especially in the diagnosis of small bowel obstruction. Only in cases of gastrointestinal bleeding from ectopic gastric mucosa, in pediatric patients, 99m-Tc scintigraphy might be proven superior [17]. However, the preoperative diagnosis of Meckel's diverticulum is achieved only in 5-15% of the patients, and therefore most of the cases are diagnosed during laparoscopy, especially in the absence of fecolith or foreign body [7]. In the presented case, the evaluation began with ultrasonography, which was inconclusive, and continued with computed tomography scan, which set the accurate diagnosis and was determinant for the further therapeutic management of the patient. If the computed tomography scan was inconclusive or unavailable, exploratory laparoscopy would be an appropriate next step.
Ladd's procedure, laparoscopic or open, is the standard surgical operation for malrotation with or without intestinal volvulus. It involves the division of peritoneal bands, Ladd's bands or other adhesions, widening of the mesentery base, the repositioning of the small intestine and ascending colon to the right and left side of the abdomen, respectively, as well as appendicectomy, with the last one not being mandatory in adults. It is the treatment of choice in case of acute obstruction, chronic abdominal pain, or non-specific symptoms due to malrotation. If intestinal malrotation is incidentally discovered during a laparotomy, Ladd's procedure is also recommended in order to avoid future volvulus [18].
A reasonable question that arises is whether or not to perform incidental appendectomy in case of malrotation in adults. The presence of malrotation suggests a problem for the differential diagnosis in case of a possible future abdominal pain since the appendix is not located at its typical anatomic place. Taking into consideration that the lifetime risk for appendicitis is approximately 7% [19] and the complication rate is extremely low, incidental appendectomy is strongly recommended in case of a laparotomy for any other pathology in cases with malrotation as a cost-saving procedure that would prevent future radiation and even surgery. On the other hand, according to a study published by Brungardt et al. [20], adults with malrotation who underwent simultaneous appendicectomy were more likely to have a clean-contaminated wound classification whether those who did not undergo appendicectomy were more likely to have a clean wound classification. However, no significant differences in the postoperative outcomes were noticed. Since it was not really necessary, we decided not to perform an appendicectomy.
Moreover, the management of an incidentally found Meckel's diverticulum still remains controversial. The lifetime risk of developing complications is up to 3% [2], and it increases with younger age, the presence of ectopic gastric tissue or fibrous bands, or when the length of the diverticulum is more than 2 cm [1]. These factors should be taken into consideration by the surgeon. In the aforementioned case, taking into consideration diverticulum size and the level of its inflammation, a partial enterectomy was performed, followed by a side-to-side stapled anastomosis.
In conclusion, this case report is a reminder that, although rare, it is possible that congenital abnormalities make their presentation not only later in life but also in the acute setting. In these cases, clinical awareness is essential for the diagnosis and the proper therapeutic management. Atypical abdominal pain, especially when combined with chronic symptoms, raises clinical suspicion, and a computed tomography scan is the imaging of choice. Another important take-away lesson from this case is that every general surgeon should be familiar with Ladd's procedure and the indications of a simultaneous appendicectomy, as well as the resection of an inflamed or not Meckel's diverticulum.

Conclusions
The combination of midgut malrotation and Meckel's diverticulum is a rare clinical entity presenting in adult life, which is usually associated with chronic symptoms before the acute onset. Their coexistence with other congenital abnormalities has also been reported in the literature. Increased awareness of these anatomic variants is essential among emergency physicians, radiologists, and surgeons in cases of atypical abdominal pain, and further imaging is recommended before proceeding with surgery. The computed tomography scan is a necessary tool in terms of diagnosis and further therapeutic management of the acute abdomen. Every general surgeon should be capable of performing a Ladd's procedure; otherwise, the assistance of a pediatric surgeon is a reasonable option. Incidental appendectomy is recommended in patients with malrotation in order to avoid future diagnostic dilemmas.

Additional Information Disclosures
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