CT colonography (CTC) of NSAID induced diaphragm disease (DD) of the colon

Five patients, between the ages of 56 - 68, presented to their local gastroenterology services. Four of these were female, the fifth was male. One patient complained of bloody diarrhoea, while another presented with weightless and early satiety, the other three were referred for workup of anaemia. Notably, all five patients had a history of chronic NSAID use. All five patients displayed iron deficiency anaemia on investigation. All patients underwent colonoscopy and CT colonography as part of their work-up. All identified lesions were biopsied and followed up to ensure stability.

CASE 1 (Figures 1-5)
CTC showed a focal area of pinhole narrowing at the hepatic flexure with a shelf-like appearance in keeping with an NSAID induced stricture.
CASE 2 (Figures 6-8)
CTC showed a colonic stricture at the mid-transverse colon extending to the splenic flexure and a more distal stricture in the proximal descending colon suggestive of NSAID induced disease.
CASE 3 (Figures 9 & 10)
CTC showed eccentric distal thickening proximal to the splenic flexure with marked focal narrowing suggestive of NSAID induced disease of the colon.
CASE 4 (Figures 11 - 13)
CTC showed a smooth, plate-like stricture of the ascending colon with pin-hole lumen approximately 10cm distal to the ileocaecal valve. A follow-up CTC two years later, following cessation of NSAIDs showed no change in the lesion.
CASE 5 (Figures 14 - 16)
CTC showed two separate, segmental areas of focal narrowing and associated thickening in the transverse colon in keeping with NSAID induced disease of the colon.

- Background
Since the synthesis of aspirin in 1899, nonsteroidal anti-inflammatory drugs (NSAIDs) have been one of the most widely prescribed drugs in the world for defervescence, analgesia, and the therapy of inflammatory conditions, including osteoarthritis and rheumatoid arthritis [1]. It has been well known that NSAIDs could cause gastrointestinal (GI) inflammation, ulceration, bleeding, and perforation [2]. But it has not been widely recognised that NSAIDs can also cause other types of lesions, for example, formation of diaphragm-like stricture [2, 3], a phrase which was first coined by Lang et al, in 1998 [4]. The first report of NSAID-induced colonic DD was a letter by Sheers and Williams in 1989 [5]. A recent study by Wang et al, 2016, also demonstrates that over 90% of colonic DD occur in the right colon and are mainly located in the ascending colon [6].
- Clinical perspective & Outcome
In a review of the published cases of small bowel and clonic strictures it was felt that DD is more common in middle-aged and elderly patients because they are the most likely to take NSAIDs, the mean age at presentation was 65 ± 11 years in that study [6]. The disease has an obvious female preponderance with ratio of 3:1 presumably due to their higher incidence of chronic diseases requiring long-term analgesic and anti-inflammatory therapy, such as rheumatoid arthritis and osteoarthritis [7]. Our own case series is in line with this, with four of our five patients being female.
Clinical manifestations of the DD are nonspecific and insidious, including abdominal pain, vomiting and other obstructive symptoms, loss of blood and protein (overt GI bleeding, anaemia, positive faecal occult blood, hypoalbuminaemia, and protein-losing enteropathy), diarrhoea, constipation, changes in bowel habits, and weight loss [8].
- Take-home points/teaching points
Traditionally, diagnosis of DD has been difficult and is often made following extensive workup including bloods, endoscopy, diagnostic radiology and laparotomy. Conventional gastrointestinal radiological investigations have been felt to be inaccurate [6]. Barium studies may show the diaphragms [7], but they are as easily overlooked as the thin-walled diaphragms resembling exaggerated plicae circulares [9]. CTC is a valuable diagnostic tool for this uncommon entity and allows characterisation of the strictures and the involved segment of colon. DD is characterised by the presence of multiple (occasionally single [10]), thin, concentric, circumferential, and diaphragm-like mucosal projections narrowing the intestinal lumen from an approximately normal diameter to a pinhole causing varying degrees of obstruction and dividing the bowel lumen into a series of short compartments [6].
Written informed patient consent for publication has been obtained.