midgut volvulus occurs when there is a rotation of small bowel around its mesenteric vascular pedicle . it is more commonly seen in the pediatric population , with approximately 85% of malrotation cases presenting in the first 2 weeks of life , and more than 90% of patients will present by their 1st birthday , . in adults , midgut volvulus is a rare surgical disease , with reported incidences between 0.00001% to 0.19% . despite its rarity , midgut volvulus remains an important cause of small bowel obstruction and more importantly it can compromise blood supply to the small intestine resulting in mesenteric ischemia and infarction . as such , it requires a high index of clinical suspicion and a low threshold for operative intervention to prevent or treat the development of intestinal ischemia and/or gangrene , as this scenario carries a high morbidity and mortality rate . those without any underlying or identifiable cause can be classified as primary cases , and are even less commonly seen . in this case report , we present a rare case of adult primary midgut volvulus mimicking acute appendicitis . a 35-year - old chinese male presents with 1-day history of intermittent and worsening right iliac fossa pain . past medical history includes renal stones previously treated in japan with shock wave lithotripsy a few years ago . he denies any previous surgeries . on examination , he was afebrile , and haemodynamically normal ( blood pressure 123/79  mm hg , heart rate 68/min , oxygen saturation 98% on room air ) . chest radiograph did not reveal any free air under diaphragm , excluding a possibility of a perforated viscus . the patient was clinically diagnosed to have acute appendicitis , and appendectomy was promptly arranged . after an incision was made in the mcburney s area , a moderate amount of serous fluid and dilated small bowel loops were seen on entry into the peritoneal cavity . the appendix only appeared mildly inflammed , and upon running the bowel a jejunal volvulus was noted ( fig . 1 , fig . this appeared secondary to extensive adhesions between the small bowel loops , and extensive adhesiolysis was performed . the frequency and mode of presentation for midgut volvulus in adults differ by geography . in western countries , the annual incidence of midgut volvulus has been estimated to be about 1.75.7 per 100,000 population , and 36% of patients present with intestinal obstruction ( io ) . in africa and asia , about 2460 per 100,000 population suffer from midgut volvulus annually , with 2050% of these presenting with io . to understand intestinal rotation and its anomalies the embryo s gut is formed as a straight tube in the fourth week of fetal life . during the fifth week , a vascular pedicle develops . the superior mesenteric vessel supplies the midgut , and is defined by a rapidly enlarging loop with the superior mesenteric artery running out to its apex . the cephalad portion of the loop gives rise to the first 20 feet of small bowel , and the remainder of the loop forms the distal small bowel and colon up to the splenic flexure . intestinal rotation primarily involves the midgut . during the development of the intestine , rotation of the intestine stage i occurs in weeks 510 , involving midgut extrusion into the extra - embryonic cavity , a 90 counter - clockwise rotation , and return of the midgut into the fetal abdomen . stage ii occurs in week 11 and involves further counterclockwise rotation within the abdominal cavity completing a 270 rotation , bringing the duodenal loop behind the superior mesenteric artery with the ascending colon to the right , the transverse colon above , and descending colon to the left . stage iii involves fusion and anchoring of the mesentery , where the cecum descends , and the ascending and descending colon attach to the retroperitoneum , . stage i anomalies include omphaloceles caused by failure of the gut to return to the abdomen . stage iii anomalies include an unattached duodenum , mobile cecum , and an unattached small bowel mesentery . primary midgut volvulus is more common in children and young adults , and can not be attributed to any predisposing anomaly found intra - operatively . in a previous study of midgut volvulus , the small bowel in high - risk populations were shown to have a corresponding longer mesentery , with deficient mesenteric fat , and has a narrower insertion . a fiber - rich diet has also been implicated , particularly a large amount , with resultant forceful small bowel peristalsis and eventual volvulus , . in this case report , our patient did not have any of these known predisposing factors , with the midgut volvulus likely secondary to congenital adhesion bands . other predisposing conditions that could increase the likelihood of small bowel volvulus include a narrow mesenteric root , malrotation , internal hernias , diverticulosis , congenital bands , jejunal lipomatosis , colostomy , fistula , meckel s diverticulum , calcified mesenteric lymph nodes , mesenteric lipomas , pregnancy , endometriosis , abscess , mycobacterial disease , aneurysms , and hematomas , and tumors such as mesenteric lymphangiomas or jejunal adenocarcinomas , , . midgut volvulus in adults can present with acute colicky abdominal pain usually in the peri - umbilical or epigastric regions . they may then develop small bowel obstruction and present with nausea , vomiting and/or abdominal distension . in patients without prior history of abdominal surgery or other obvious causes like hernias , there should be a high index of suspicion of midgut volvulus as a cause of the intestinal obstruction . patients at risk of midgut volvulus such as those with congenital midgut malrotation are usually asymptomatic . many remain so , with the anomaly discovered only at autopsy or incidentally during ct scans performed for another indication . however , some may have chronic and unexplained abdominal discomfort , and even fewer may report acute episodes of severe abdominal pain , . localization of small intestinal loops predominantly in the right side or absence of cecal gas shadow should arouse suspicion of malrotation ; this was not present in our patient . ultrasonography has been reported to be helpful in diagnosis of intestinal malrotation in the literature , with the classically described  whirpool sign . standard upper gastrointestinal series may show a vertical duodenum not crossing the midline , with the entire small bowel found in the right half of the abdomen . the gold standard of diagnosis is a computed topography ( ct ) scan of the abdomen . malrotation can be diagnosed with ct with the anatomic location of a right - sided small bowel , a left - sided colon , an abnormal relationship of the superior mesenteric vessels , and aplasia of the uncinate process . whirpool sign is also visible on ct imaging in patients with or without malrotation signifying volvulus . diagnostic imaging should not be considered in a distressed patient with a rigid abdomen , as further delay will increase the likelihood or worsen any developing bowel ischemia , causing unnecessary morbidity . in our case , we elected to operate on the patient immediately with a clinical diagnosis of appendicitis . to our surprise a delay in operative intervention by performing a ct imaging might have compromised blood flow to bowel and could have resulted in bowel ischemia necessitating bowel resection . the classic treatment for incomplete intestinal malrotation is the ladd s procedure , which entails division of ladd s bands and mobilization of the duodenum , division of adhesions around the sma to broaden the mesenteric base , placing the small bowel primarily to the right and the large bowel to the left of the midline , and an appendectomy . these principles have remained the same since ladd s address to the new hampshire medical society in 1936 . recently reported a series of malrotation patients managed laparosopically . in patients with volvulus secondary to other causes , the principles of management include early surgical intervention to decompress bowel , resection of non - viable bowel and addressing the underlying cause , e.g. adhesiolysis for adhesions . the frequency and mode of presentation for midgut volvulus in adults differ by geography . in western countries , the annual incidence of midgut volvulus has been estimated to be about 1.75.7 per 100,000 population , and 36% of patients present with intestinal obstruction ( io ) . in africa and asia , about 2460 per 100,000 population suffer from midgut volvulus annually , with 2050% of these presenting with io . the embryo s gut is formed as a straight tube in the fourth week of fetal life . during the fifth week , a vascular pedicle develops . the superior mesenteric vessel supplies the midgut , and is defined by a rapidly enlarging loop with the superior mesenteric artery running out to its apex . the cephalad portion of the loop gives rise to the first 20 feet of small bowel , and the remainder of the loop forms the distal small bowel and colon up to the splenic flexure . intestinal rotation primarily involves the midgut . during the development of the intestine , rotation of the intestine stage i occurs in weeks 510 , involving midgut extrusion into the extra - embryonic cavity , a 90 counter - clockwise rotation , and return of the midgut into the fetal abdomen . stage ii occurs in week 11 and involves further counterclockwise rotation within the abdominal cavity completing a 270 rotation , bringing the duodenal loop behind the superior mesenteric artery with the ascending colon to the right , the transverse colon above , and descending colon to the left . stage iii involves fusion and anchoring of the mesentery , where the cecum descends , and the ascending and descending colon attach to the retroperitoneum , . stage i anomalies include omphaloceles caused by failure of the gut to return to the abdomen . stage iii anomalies include an unattached duodenum , mobile cecum , and an unattached small bowel mesentery . primary midgut volvulus is more common in children and young adults , and can not be attributed to any predisposing anomaly found intra - operatively . in a previous study of midgut volvulus , the small bowel in high - risk populations were shown to have a corresponding longer mesentery , with deficient mesenteric fat , and has a narrower insertion . a fiber - rich diet has also been implicated , particularly a large amount , with resultant forceful small bowel peristalsis and eventual volvulus , . in this case report , our patient did not have any of these known predisposing factors , with the midgut volvulus likely secondary to congenital adhesion bands . other predisposing conditions that could increase the likelihood of small bowel volvulus include a narrow mesenteric root , malrotation , internal hernias , diverticulosis , congenital bands , jejunal lipomatosis , colostomy , fistula , meckel s diverticulum , calcified mesenteric lymph nodes , mesenteric lipomas , pregnancy , endometriosis , abscess , mycobacterial disease , aneurysms , and hematomas , and tumors such as mesenteric lymphangiomas or jejunal adenocarcinomas , , . midgut volvulus in adults can present with acute colicky abdominal pain usually in the peri - umbilical or epigastric regions . they may then develop small bowel obstruction and present with nausea , vomiting and/or abdominal distension . in patients without prior history of abdominal surgery or other obvious causes like hernias , there should be a high index of suspicion of midgut volvulus as a cause of the intestinal obstruction . patients at risk of midgut volvulus such as those with congenital midgut malrotation are usually asymptomatic . many remain so , with the anomaly discovered only at autopsy or incidentally during ct scans performed for another indication . however , some may have chronic and unexplained abdominal discomfort , and even fewer may report acute episodes of severe abdominal pain , . localization of small intestinal loops predominantly in the right side or absence of cecal gas shadow should arouse suspicion of malrotation ; this was not present in our patient . ultrasonography has been reported to be helpful in diagnosis of intestinal malrotation in the literature , with the classically described  whirpool sign . standard upper gastrointestinal series may show a vertical duodenum not crossing the midline , with the entire small bowel found in the right half of the abdomen . the gold standard of diagnosis is a computed topography ( ct ) scan of the abdomen . malrotation can be diagnosed with ct with the anatomic location of a right - sided small bowel , a left - sided colon , an abnormal relationship of the superior mesenteric vessels , and aplasia of the uncinate process . whirpool sign is also visible on ct imaging in patients with or without malrotation signifying volvulus . diagnostic imaging should not be considered in a distressed patient with a rigid abdomen , as further delay will increase the likelihood or worsen any developing bowel ischemia , causing unnecessary morbidity . in our case , we elected to operate on the patient immediately with a clinical diagnosis of appendicitis . to our surprise a delay in operative intervention by performing a ct imaging might have compromised blood flow to bowel and could have resulted in bowel ischemia necessitating bowel resection . the classic treatment for incomplete intestinal malrotation is the ladd s procedure , which entails division of ladd s bands and mobilization of the duodenum , division of adhesions around the sma to broaden the mesenteric base , placing the small bowel primarily to the right and the large bowel to the left of the midline , and an appendectomy . these principles have remained the same since ladd s address to the new hampshire medical society in 1936 . generally , symptomatic patients with malrotation should have surgical intervention . recently reported a series of malrotation patients managed laparosopically . in patients with volvulus secondary to other causes , the principles of management include early surgical intervention to decompress bowel , resection of non - viable bowel and addressing the underlying cause , e.g. adhesiolysis for adhesions . adult midgut volvulus is a rare cause of small bowel obstruction but has the potential for morbidity and mortality if not diagnosed early with intestinal ischaemia and related sequlae . as such , clinicians should maintain a reasonable index of suspicion and in diagnostic dilemmas , we recommend performing a contrast ct scan early . written informed consent was obtained from the patient for publication of this case report and accompanying images . a copy of the written consent is available for review by the editor - in - chief of this journal on request .
highlightsadult midgut volvulus is a rare but important cause of small bowel obstruction.our patient , 35 year old male , was clinically suspected to have acute appendicitis.intra-operatively , we found a normal appendix and jejunal volvulus with adhesions.if in doubt , early contrast ct scan should be performed.delay to diagnosis and surgical intervention may result in bowel ischemia .