Teaching Case

A 68-year-old female presented with a history of localised left-sided abdominal pain and tenderness for two days. She experienced intermittent abdominal cramping pain every few weeks for the past few years. Laboratory tests showed elevated C-reactive protein, white blood cell count and neutrophil count. Haemoglobin and transferrin saturation were decreased. Otherwise, laboratory findings were within normal limits.

A contrast-enhanced CT scan showed outpouching, round, thick-walled structures containing fluid with gas at the mesenteric border of the jejunum, along with perienteric fat stranding (Figures 1, 2 and 6). Additionally, there was underlying small bowel diverticulosis (Figures 3 and 6) and colonic diverticulosis as well (Figures 4 and 6).

Background

Small bowel diverticulosis (SD) is relatively rare, with a prevalence rate of about 2% in the population [1]. Unlike Meckel’s diverticulum, SD is characterised by herniation of only mucosa and submucosa through weaker-site of the muscle layer. Most are located on the mesenteric border where the mesenteric vessels enter the bowel wall [1,2]. The disease typically peaks in incidence during the sixth and seventh decades of life, with a higher prevalence in males [3]. The pathophysiology of small bowel diverticulosis is believed to result from a combination of congenital and acquired factors. Congenital weakness in the muscular layer of the small bowel predisposes to diverticula formation, while acquired factors such as increased intraluminal pressure, dysmotility, and chronic inflammation contribute to their progression [4].

Clinical Perspective

Small bowel diverticulosis is usually asymptomatic, but chronic abdominal symptoms such as abdominal pain, nausea, diarrhoea, and malabsorption have been described in some reports [3,5,6]. However, SD can also present more acutely with severe complications. Major complications include diverticulitis, haemorrhage, intestinal obstruction, and acute perforation [5,6]. Therefore, it is critical to keep the possibility of small bowel diverticulosis in mind when evaluating cases of malabsorption, chronic abdominal pain, repeated unexplained bleeding, perforation, and intestinal obstruction, especially in patients with connective tissue disorders, a family history of diverticula and a personal history of colonic diverticulosis [6].

Imaging Perspective

The diverticula are commonly seen as round, oval, or flask-shaped structures protruding from the mesenteric border of the small bowel. The most reliable method of diagnosis is to demonstrate mucosa leading into the neck of individual diverticula [2,7]. The differential diagnosis includes small bowel perforation, inflammatory bowel disease making large small bowel ulcers, or necrotic change of small bowel tumours [6,7]. What is observed on the mesenteric border can be differentiated from Crohn’s disease or Meckel’s diverticulum. The barium study may allow visualization of small bowel diverticulosis, small bowel fistula and stenosis. Furthermore, the CT scan may allow for visualisation of the complication of SD, such as thickening of the diverticular wall, and the infiltration through the peridiverticular mesenteric fat, intraperitoneal micro-air bubble and enlarged mesenteric lymph nodes may be seen [6–8].

Outcome

The consensus in treatment of complicated SD is a small bowel resection with primary anastomosis [6]. However, as these patients are often elderly and their symptoms respond well to antibiotics and anti-inflammatory drugs, surgery is usually not necessary in most cases. Furthermore, non-surgical methods such as angiography with ultra-selective embolisation in bleeding complications, argon plasma coagulation and endoclip placement via deep enteroscopy have also been described [4]. In the case of our patient, symptoms have disappeared since broad-spectrum antibiotics and anti-inflammatory drugs. Iron supplementation was also initiated, as laboratory findings suggested iron deficiency anaemia. A repeat CT scan after 7 days with intravenous antibiotics (Figure 5) showed a resolution of inflammatory changes.

Take Home Message / Teaching Points

The possibility of small bowel diverticulitis should be kept in mind. As the presentation is often similar to other pathologies such as acute appendicitis, pancreatitis, or acute cholecystitis, careful analysis of the imaging landmarks can be helpful in the early stages of detection.