CASE 8696 Published on 29.12.2010

Imaging of caecal volvulus in pregnancy

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Haworth AE1, Kibriya N1, Young S1, Massey G2.
1. Royal Liverpool University Hospitals NHS Trust, UK
2. St Helens and Knowsley University Hospitals NHS Trust, UK

Patient

21 years, female

Categories
Area of Interest Colon ; Imaging Technique MR
Clinical History
A 22-year-old 19-week primigravida presented to the obstetric department with recurrent, worsening abdominal pain, vomiting and constipation, previously treated with laxatives for presumed constipation.
Clinically she had a globally tender, distended abdomen with pain localising in the left upper quadrant. Laboratory results showed raised inflammatory markers and white cells.
Imaging Findings
In view of the pregnancy, a limited plain X-ray of the abdomen was obtained in accident and emergency using a lead shield (Fig. 1). This showed distended loops of bowel in the left upper quadrant, however, given the non diagnostic nature of this radiograph, the presumed obstructive cause it implied and the patient’s deteriorating clinical condition, a discussion between radiologist, clinician and the patient over the risks and benefits of MR, CT and surgical exploration during the second trimester was conducted.
With consent an MRI was performed with T1W, T2W and FLAIR sequences using standard protocols. The MR demonstrated malrotation of the gut with probable axial caecal volvulus and impending caecal perforation (Figs. 2-5).
At surgery, small bowel was noted in the right colic gutter and large bowel in the left colic gutter. A grossly distended, mobile intraperitoneal caecum was noted with a serosal tear and mucosal necrosis, the cause being a 360° rotation at the caeco-colic junction.
The patient underwent a limited right hemicolectomy with primary anastomosis and recovered well. The pregnancy completed term and she delivered without further complication
Discussion
Approximately 10% of the population (US) have a developmental failure of peritoneal fixation, enabling malrotation of the gastrointestinal tract from a freely mobile proximal colon. Caecal volvulus accounts for 11% of all intestinal volvulus, of which ~3% lead to intestinal obstruction. Men are at slightly higher risk, peaking between 20-40 years [1, 2].

Two types of caecal volvulus are seen radiologically although the management is identical:
Axial torsion: a twist of 180-360° along the longitudinal axis of the ascending colon results in a distended loop of large bowel progressing from the RLQ to the LUQ (the commonest site to which the caecum is displaced). The distended caecum may be seen anywhere in the abdomen [1, 3]. This obstructive process is associated with vascular compromise that can lead to gangrene and perforation, hence the higher mortality rate [3].
Bascule: the caecum folds anteriorly without any torsion of the ileum (no small bowel obstruction). A gas-filled appendix is usually seen in an unusual location attached to a distended caecum, typically in the centre of the abdomen [1, 2, 3].

A history of previous abdominal surgery, pelvic masses (in particular a third trimester pregnancy), colonoscopy, violent coughing and travel in unpressurised aircraft all increase the risk of developing caecal volvulus [1, 2].

Symptoms typically consist of sudden onset, severe colicky abdominal pain, nausea, vomiting and constipation [1, 2]. Pregnant women are at increased risk of caecal volvulus and can present with vague symptoms which are generally regarded as pregnancy-related and treated conservatively as in our patient’s case. This often delays diagnosis and plays a crucial role in the associated increased mortality rate during pregnancy [4]. In addition, abdominal organs are commonly displaced in pregnancy, resulting in atypical symptoms which compound the delay in diagnosis [5, 6].

Imaging typically involves a plain AXR. A grossly gas-distended bowel lies in the LUQ with the haustral pattern maintained and the distal colon collapsed [2, 3]. In our case an unshielded AXR should have been performed with consent as this may have provided enough evidence to initiate surgery.

Pelvic CT may account for doses up to 50 mGy which can double the risk of childhood cancer [7, 8], therefore CT and fluoroscopy are not ideal imaging modalities.
There are few literature reports on the use of MRI in diagnosis of an acute abdomen during pregnancy. Research has shown no adverse effects of static fields (1T) on foetal development, inconclusive findings on noise exposure and minor risk from time varying gradient fields and RF pulses (teratogenic heating effects), leading the MHRA to conclude that the decision to scan should be made between the clinician, patient and MR radiologist with formal consent, weighing up risks and benefits. The MR sequences used should be the minimal required under standard operating conditions [9].

Conservative management with endoscopic decompression is associated with a high recurrence rate and right hemicolectomy (or caecostomy if very unstable) is the treatment of choice.

In conclusion: abdominal pain in pregnancy should raise a high degree of clinical suspicion to avoid overlooking serious pathology.
Differential Diagnosis List
Caecal volvulus (Axial).
Final Diagnosis
Caecal volvulus (Axial).
Case information
URL: https://www.eurorad.org/case/8696
DOI: 10.1594/EURORAD/CASE.8696
ISSN: 1563-4086