Adult Acute Appendicitis Complicated by Intestinal Malrotation: A Case Analysis

Introduction

Intestinal malrotation (IM) is a very rare developmental rotation anomaly of the embryonic intestine. It can be divided into foregut, midgut, and hindgut malrotation, with midgut being the more common [1]. Midgut malrotation can be categorized into the following types: non-rotation, incomplete rotation, reverse rotation, and abnormal fixation of the mesentery. The non-rotation type is the most common and is characterized by malposition of the bowel and malfixation of the mesentery [2]. Conversely, acute appendicitis is the most prevalent condition necessitating emergency abdominal surgery in both children and adults [3,4]. Typically, it presents with diffuse abdominal pain, nausea, and vomiting within the first 24 hours, subsequently localizing to the right lower quadrant as the inflamed parietal peritoneum in the adjacent area becomes irritated [5]. In adults, IM often poses a significant diagnostic challenge, particularly when it coexists with conditions such as acute appendicitis that present with atypical anatomical findings or symptom patterns. We report a rare case of a 20-year-old woman with acute appendicitis (AA) and IM.

Case Report

A 20-year-old female, non-smoking patient with no known medical history presented to the Emergency Department (ED) with 3 days of persistent mid-abdominal pain. The pain was described as constant, with an intensity of the Numerical Rating Scale (NRS) rated at 5/10, and with exacerbations of cramping reaching NRS 8/10. She reported no vomiting, but she did experience nausea. Her last bowel movement was the day before presentation, and it was normal in color and consistency. She denied dysuria or the presence of macroscopic hematuria. Her medical history was unremarkable, with no prior abdominal surgeries and no history of colonoscopies. She had no known allergies and no relevant pre-existing conditions aside from acne. Gynecologically, she was in the menstrual phase of her cycle. In previous cycles, she had experienced only mild menstrual discomfort, but she described the current pain as distinctly different. Given the timing within the menstrual cycle, gynecological causes such as dysmenorrhea or ovarian pathology were considered as potential confounders in the differential diagnosis.

The bowel sounds were normal. The abdomen was soft with no signs of peritonism. Palpation and percussion of the mid-abdomen revealed tenderness. Laboratory tests revealed a slightly elevated C-reactive protein (CRP) of 35 mg/l, white blood cell (WBC) count of 4500 cells/μL, hemoglobin (Hb) of 125 g/L, and platelet count (PLT) of 203 000 platelets/μL. Urea, electrolytes, and liver function test results were within normal ranges. Abdominal ultrasound showed a high suspicion of acute appendicitis located in the midline in the lower quadrant, without abscess-suspicious fluid collections or intra-abdominal fluid. However, the terminal ileum and cecum could not be clearly visualized due to gas overlay; nonetheless, a target sign (coiled appearance) was identified, and localized tenderness was reproducible with probe compression in that area. Consequently, she was transferred to the operating room for a diagnostic laparoscopy and appendectomy. The standard approach was an open Hasson’s supraumbilical 12-mm approach with 5-mm trocars inserted into the left lower abdomen and suprasymphysis, with the patient in Trendelenburg and left lateral position. Laparoscopic exploration was initially challenging due to difficulty locating the ileocecal region. Despite systematic small-bowel revision, the ileocecal area remained elusive. The sigmoid colon was then accessed, and the colon was retrogradely inspected, revealing IM (non-rotation type), with the colon in the left hemi-abdomen and the small bowel in the right, displacing the cecum in the midline (Figure 1). Once identified, the appendix appeared inflamed, requiring repositioning of the operating team to the right side of the patient and the placement of an additional 5-mm trocar in the right lower quadrant for better access (Figure 2). After dividing the mesoappendix, the appendix was divided at the base using a stapler device and removed through the supraumbilical trocar incision with a specimen collection bag. In the absence of any documented instances of obstruction or bowel movement issues, no intervention for the malrotation was deemed necessary. Furthermore, the patient had not been informed preoperatively about the possibility of a Ladd procedure, as the intestinal malrotation was an incidental intraoperative finding. The postoperative course was uneventful, and the patient was discharged on the second postoperative day.

Discussion

During the developmental process of the embryo, the small intestine undergoes a 270° counterclockwise rotation around the superior mesenteric artery (SMA). This process consists of 3 distinct stages. In the initial stage (weeks 5–10), the midgut herniates into the umbilical cord, elongates, and rotates 90° counterclockwise. In stage 2 (week 11), the intestine retracts into the fetal abdominal cavity and completes an additional 180° counterclockwise rotation, reaching a total of 270°. Finally, in stage 3, the mesentery is fixed in its final position [1,10]. In non-rotation type IM, the midgut rotates no more than 90° and the cephalad midgut is fixed to the right of the SMA, while the caudad midgut is fixed to the left of the SMA. The cephalad midgut develops into the small intestine, while the caudad midgut gives rise to the cecum and large intestine [14].

The precise etiology of malrotation remains unclear; however, studies have indicated a genetic component. Martin et al identified an association between malrotation and mutations in the forkhead box transcription factor (FOXF1) and L-R asymmetry genes [13].

The incidence of IM is approximately 0.2–0.5% of all live births, with most symptomatic cases presenting in the early weeks of life. Thirty percent of cases occur in the first month of life, 60% by approximately 1 year of age, and over 75% by the age of 5 years [6].

The manifestation of symptoms varies according to age. In infants, symptoms can include bilious emesis, distended abdomen, bloody stools, or slowed development. In contrast, adults often remain asymptomatic or present with nonspecific symptoms, such as abdominal discomfort, pain, or, in rare instances, acute abdomen that can progress to ileus [6–10]. These symptoms can be secondary to Ladd’s bands, causing acute or chronic intestinal obstruction or volvulus. These congenital bands extend from the right lateral abdominal wall, across the duodenum, and attach to the undescended cecum [11]. Ladd’s bands derive their name from William Ladd, who first described the surgical removal of these fibrous bands in 1932 [8,12]. Our patient had no history of chronic abdominal pain, and this was her first presentation at a medical facility.

Diagnosing this condition can be challenging, especially in adults, due to the absence of specific symptoms. The following diagnostic procedures are available: a plain radiograph with oral contrast, ultrasound, and computed tomography (CT). Ultrasound and CT are the preferred options. The findings indicate an inversion of the SMA/SMV relationship, with the SMA located on the right and the SMV on the left, absence of a retro-mesenteric (retro-peritoneal) D3 segment of the duodenum, a duodenojejunal junction inferior to the duodenal bulb in the right abdomen, large bowel predominantly on the left, and small bowel predominantly on the right [10]. In this instance, the combination of supportive clinical and sonographic findings, in addition to the patient’s young age, led us to proceed directly to surgery without additional imaging. However, a preoperative CT scan would have confirmed IM, allowing us to position ourselves on the right side of the patient from the start of the operation, thus saving operating time.

The management of IM is dependent upon the presenting symptoms. Several studies indicate that the risk of midgut volvulus in asymptomatic adults is low. While some authors support prophylactic Ladd procedures, others caution that surgical risks can outweigh potential benefits in patients who have remained symptom-free for years [15]. Management should be individualized, taking into account patient age, comorbidities, and overall risk profile. However, in the event of midgut volvulus, Ladd’s procedure is indicated. It consists of 4 stages: counterclockwise detorsion of the volvulus, division of Ladds bands, broadening of the narrow small bowel mesentery, and division of adhesions around the SMA. In addition, the small bowel is frequently placed along the right lateral gutter and the colon along the left, and an incidental appendectomy is also performed.

Conclusions

Intestinal malrotation can remain undiagnosed into adulthood and may be discovered incidentally during surgery for an unrelated condition. Awareness of this anomaly is crucial for surgeons to avoid misidentification of structures and ensure safe and effective surgical management. Surgical intervention in adults is only required in symptomatic cases. Future studies should explore optimal management strategies for asymptomatic malrotation in adults and the role of preoperative imaging in the acute setting.