Acute presentation of intestinal malrotation in adults: a report of two cases

Abstract

Introduction

Intestinal malrotation is a rare developmental abnormality occurring as a result of incomplete rotation during fetal life. It usually presents in the first few weeks of life, but may persist unrecognised into adult life. We report two interesting cases in elderly patients both characterised by a significant diagnostic challenge due to atypical clinical and radiological signs and in one case an unusual complication following laparotomy.

Case Reports

The first case was a 64-year-old man initially treated for diverticulitis but at laparotomy was found to have malrotation of the midgut and a perforated left-sided appendicitis. The second case was a 76-year-old woman admitted with multiple fractures and increasing abdominal distension following a fall. Ten days after admission, she underwent right hemicolectomy to treat faecal peritonitis due to multiple caecal perforations complicating volvulus in the presence of midgut malrotation.

Conclusions

These cases illustrate challenges associated with managing patients with undiagnosed intestinal malrotation. Delayed diagnosis is a common feature in several case reports describing atypical presentation of appendicitis in patients with malrotation. While abdominal CT scan can remove much of the diagnostic uncertainty, the diagnosis of malrotation can be missed unless there is a high index of suspicion.

Intestinal malrotation is a developmental abnormality occurring as a result of failure of normal intestinal rotation and fixation during weeks 5–10 of fetal life. Whilst this is a well described cause of neonatal bowel obstruction, it is being increasingly recognised that its persistence unrecognised into adult life can cause diagnostic uncertainty.¹ In adults, malrotation may present acutely to the general surgeon with conditions related to the abnormality such as caecal volvulus and band obstruction (Ladd band), or incidentally, as a result of unrelated abdominal pathology such as acute appendicitis.² Appendicitis is notoriously difficult to diagnose in such patients because of its abnormal position. We report two interesting cases in elderly patients both characterised by a significant diagnostic challenge due to atypical clinical and radiological signs and in one case an unusual complication following laparotomy.

Case one

GL, a 64-year-old man, was an emergency admission with a 3-day history of left iliac fossa (LIF) pain associated with nausea but no vomiting and no change in bowel habit. He did not have any significant medical history and no history of abdominal surgery. On examination he was pyrexial with a temperature of 38ºC, tachycardic (110/min) and normotensive (122/78 mmHg). Abdominal examination revealed tenderness in the LIF, normal bowel sounds and a normal digital rectal examination. Urinalysis was normal. Laboratory tests showed a raised white cell count (13.3 × 10⁹ cells/l) and a raised C-reactive protein concentration (130 mg/l). Abdominal X-ray was unremarkable (Fig. 1). He was commenced on intravenous antibiotics for presumed acute diverticulitis. Following 5 days of treatment without improvement, an abdominal computed tomography (CT) scan was performed that revealed features compatible with midgut malrotation (Fig. 2). In addition, there was evidence of an inflammatory process in the LIF but no cause for this was identified. Emergency laparotomy performed through a midline incision confirmed midgut malrotation with the small bowel lying in a ‘peritoneal pouch’ on the right side and a perforated appendix lying in the LIF. An appendicectomy was performed with no attempt made at correcting the mal-rotation. GL developed obstructive symptoms on the third postoperative day and a repeat laparotomy was performed. An obstructing kink in the small bowel as it emerged from behind its peritoneal covering on the right side was corrected. A re-look laparotomy 24 h later confirmed viable small bowel. GL made a good postoperative recovery and was discharged on the tenth postoperative day.

Figure 1.

Abdominal plain film with ‘unremarkable’ gas pattern (on retrospective review, the caecal shadow is seen lying in the left iliac fossa).

Figure 2.

Abdominal CT with oral contrast in coronal section. Small bowel is seen lying entirely on right side of abdomen. Colon (C) is seen lying in the left hemi-abdomen. Abnormal relationship of great vessels with aorta positioned to the right of the inferior vena cava.

Case two

AS, a 76-year-old woman, presented with neck, limb and abdominal pain to the emergency department after having sustained a fall down 10 steps at her home. Her initial injuries were type 2 ondontoid peg fracture (fracture line runs through the base of the dens of the second cervical vertebra) and also a fracture dislocation of her right elbow. Her abdomen was mildly distended and soft but tender in the LIF. A CT abdomen was performed and reported as normal ‘the large and small bowel appear unremarkable’. She was admitted under the care of the orthopaedic team, who subsequently contacted the general surgical team for input in her management. On assessment by the surgical team, AS was stable but had a distended abdomen. Abdominal X-ray revealed a dilated centrally located large bowel loop

that raised the suspicion of caecal volvulus, but this was reported by the radiology registrar as dilated sigmoid colon (Fig. 3). Given the gas pattern on a repeat abdominal X-ray and passage of flatus in an immobilised elderly woman, a diagnosis of pseudo-obstruction was made and AS was managed conservatively. She appeared to improve, continued to pass flatus and open her bowels; however, she developed abdominal pain 10 days after admission. On examination, she had a distended and markedly tender abdomen. A repeat abdominal X-ray was difficult to interpret and, upon the advice of a gastrointestinal radiologist, a further abdominal CT scan was performed. This revealed a distended centrally placed caecum with small bowel in the right iliac fossa and extensive free intra-abdominal gas indicating perforation (Fig. 4). Emergency exploratory laparotomy showed malrotation of the mid gut, generalised faecal peritonitis due to two large ischaemic perforations secondary to caecal volvulus. A right hemicolectomy was performed and she was transferred to the intensive care unit postoperatively. Her recovery was complicated by severe wound infection requiring vacuum-assisted closure dressings.

Figure 3.

Abdominal plain film showing dilated caecum.

Figure 4.

Abdominal CT sowing abnormal position of superior mesenteric vein (outline blue arrow) lying anterior to superior mesenteric artery (outline red arrow) and a dilated caecum and free intra-peritoneal air.

Discussion

Of patients with congenital malrotation, 85% present in the first two weeks of life, usually with intestinal obstruction.³ Some afflicted people, however, do not present at this time and may remain asymptomatic throughout the rest of their life. The lack of autopsy studies in this area makes estimation of adulthood prevalence of malrotation difficult.

Case one is unusual in two respects. First, acute appendicitis is less common in the elderly⁴ hence the index of suspicion is lower. Even more unlikely is a diagnosis of ‘left-sided appendicitis’ in a patient not previously known to have bowel malrotation. Delayed diagnosis is a common feature in several case reports describing atypical presentation of appendicitis in patients with malrotation.^2,5–12 Given an age of 64 years, the initial working diagnosis of diverticulitis was reasonable.¹³ The patient’s failure to respond to antibiotics after a few days prompted further investigations which clinched the diagnosis of congenital malrotation. Second, although for 64 years GL did not have any problems related to his malrotation with all of the small bowel trapped underneath the parietal peritoneum extending from the ascending colon, 3 days after laparotomy (during which a few centimetres of bowel was withdrawn and examined), he developed small bowel obstruction due to a kink at the entrance into the ‘pouch’. Whether the peritoneal sac should have been completely laid open during the initial laparotomy is debatable.

Case two demonstrates that the diagnostic challenge posed by adult manifestation of malrotation extends to radiologists as well as surgeons. Despite a CT abdomen on admission, this finding was not diagnosed, probably because of the low prevalence of malrotation in the adult population.¹⁴ The diagnosis of malrotation was also missed on the second abdominal CT scan and it was only on retrospective review that the features became apparent (Fig. 4). Her clinical course would suggest that the patient was probably experiencing intermittent caecal volvulus throughout her admission though its causal relationship to the initial fall is not known. The signs and symptoms of caecal volvulus secondary to malrotation in adults are often intermittent and notoriously difficult to diagnose.^1,2,12 The abnormal position of the caecum made interpretation of the abdominal X-ray difficult. This, combined with a distracting history of trauma led the clinical team to treat her initially for pseudo-obstruction. A more timely consideration of malrotation in this case might have resulted in definitive treatment before the intra-abdominal catastrophe of caecal perforation.

Conclusions

Because malrotation is rarely seen in the adult population, diagnosing its presentation can be difficult. The major challenge in managing adult patients presenting with complications of midgut malrotation is the difficulty of diagnosis. Whereas features suggestive of ‘left-sided appendicitis’ in young patients would arouse suspicion of malrotation and trigger further investigations (imaging); elderly patients would be thought to suffer from diverticulitis and mostly treated with antibiotics. A careful approach to diagnosis, treatment and regular review will identify patients not responding to treatment in the usual way. Such patients should then proceed to further imaging. While abdominal CT scan can remove much of the diagnostic uncertainty as demonstrated in case one, the diagnosis of malrotation can be missed unless there is a high index of suspicion (case two). These reports should increase the index of suspicion about the problems associated with incomplete rotation of the gut.