Teaching Case

A 73-year-old female patient with past surgical history of partial colectomy due to an ischaemic colitis and multiple autoimmune diseases such as dermatosclerosis, Raynaud’s syndrome and hypothyroidism, presented to the Emergency Department afebrile with lack of appetite, nausea and worsening abdominal pain with distention. No laboratory abnormalities were found.

An anteroposterior plain abdominal radiograph was performed and revealed a suboclusive ileus with large bowel distention as well as some dilated loops of the small intestine (Fig. 1a)

In concordance with the plain abdominal radiograph, a contrast-enhanced abdominal CT in the portal phase confirmed the suspected diagnosis. Twirling of the transverse mesocolon was identified (‘Whirlpool sign’) (Fig. 3a) with collapsed descending colon (Fig. 2a and 2b) and calibre change in transverse colon (‘Bird’s Beak’ sign) (Fig. 3b)

For teaching purposes, a volumetric reconstruction of the colon was made (Fig. 1b) exhibiting colon distention with change of calibre in the transverse colon.

Volvuli of the transverse colon were firstly described in 1932 by Kallio and despite their low incidence (2-4%), are related with higher mortality rates compared to the more prevalent sigmoid or caecal volvuli [1, 2]. As they are very uncommon, a high index of suspicion and awareness is required to reach a proper diagnosis. This is the reason why the vast majority of cases are diagnosed intraoperatively [3].

The most common underlying aetiology is redundancy due to dolicocolon in elderly patients [4, 5]. While the ascending and descending segments of the colon are fixed; the cecum, transverse colon and sigma are mobile tethered by their respective parts of the mesentery. This additional looseness combined with the colonic redundancy contributes to volvuli occurring in these specific regions. Other possible causes include adhesions from previous surgeries, Chilaiditi’s syndrome, congenital malrotation and C. difficile pseudomembranous colitis among others.

The presentation can be acute or subacute. Acute fulminating volvuli present with less abdominal distention but greater pain and leukocytosis attributable to early ischaemic changes [6]. On the other side, subacute volvuli as seen in our patient, present with larger abdominal distention and no significant changes in the leukocyte count.

The clinical presentation and plain abdominal radiographs can guide the clinician toward the diagnosis. However, computed tomography (CT) scan is advised in the subacute type in order to detect the presence of complications and the location of the volvulus before surgery [7].

The most significant radiological signs on CT indicating colonic volvulus are the ‘Whirlpool’ and ‘Bird’s beak’ signs (Fig. 3a and 3b) which indicate the exact point of mesenteric twisting and obstruction respectively. On the other hand, the abdominal plain radiograph will show a generalized distention of large bowel reflecting some degree of obstructive ileus.

With regard to the management of these patients, the treatment of choice consists in colectomy. Colonoscopic decompression would delay the surgery and hence is not recommended given the risk of infarction and necrosis [8]. Our patient was treated with partial colectomy and recovered successfully.

Considering the low incidence and high mortality rates of transverse colon volvuli, a deep understanding of its radiological signs is crucial in order to guide the clinician toward the correct diagnosis.