A Distended Abdomen

A 39-year-old woman presented to an Urgent Care clinic with abdominal distension. She reported that her bowels had not opened for two weeks. The distension had developed over the past four days, and she had vomited once the previous day. She was still passing flatus but described crampy abdominal pain.

Eight days earlier she had been seen at the same clinic by another doctor with a diagnosis of constipation that was not improving despite laxatives and a Microlax enema. At that time she was still passing flatus. Blood tests were arranged, she was given another fleet enema, and advised to follow up with her GP or return if symptoms worsened. Blood results were all normal.

She had no past surgical history, no significant medical history, no family history and was not taking regular medications. On examination she appeared well and hydrated. Her observations were temperature 37°C, blood pressure 145/91, and heart rate 98. Her abdomen was severely distended and hard, though non-tender. No bowel sounds were heard and there was no fluid thrill. Digital rectal examination revealed an empty rectum with no palpable masses.

The clinical impression was of bowel obstruction. An abdominal X-ray showed dilated large bowel loops with a transverse diameter of 9 cm at the proximal transverse colon

She was referred urgently to general surgery and admitted to hospital, where she was diagnosed with a large bowel obstruction caused by a recto-sigmoid mass. She underwent an emergency laparotomy with a right hemi-colectomy.

Learning Nuggets

*This is an uncommon presentation in this age group. Colorectal cancer (CRC) is more common over the age of 50.

*Large bowel obstruction (LBO) only represents about 20% of intestinal obstruction presentations and only 25% of CRC presents with LBO. CRC is however the most common cause of LBO (50-60% cases).

*At first sight it may seem that the management on initial presentation to the clinic was inadequate or that the diagnosis had been missed. However this highlights the challenges in the early diagnosis of CRC and LBO especially in younger people.

*CRC can present with a more insidious onset with symptoms such fatigue, anaemia, anorexia, weight loss and rectal bleeding, change in bowel habit (CIBH) or as with this patient, a rapid development of LBO.

*A CIBH can be very insidious in onset with constipation and alternating with diarrhoea and could be easily confused with irritable bowel syndrome or simple constipation. The report of passage of flatus was falsely reassuring.¹

*There is a lack of consensus worldwide regarding referral guidelines for CIBH. A 2019 Swedish study² was undertaken to evaluate CIBH as a sole alarm symptom for CRC. Of 628 patients there were no cases of CRC under age 55 in the CIBH only group. According to current guidelines on Auckland Health Pathways suspicion of colorectal cancer is defined as “either palpable or visible rectal mass or unexplained rectal bleeding and either iron deficiency anaemia or alter bowel habit for more than six weeks age 50 or over”.⁴ In Auckland it is unlikely that this patient would have qualified for urgent investigation had she not developed LBO. This is concerning considering the incidence of CRC in young adults is increasing and that New Zealand has one of the highest bowel cancer incidence rates worldwide.³

*There is a significant risk that these type of patients could be lost to follow-up in the current setting of healthcare in New Zealand where patients are finding it very difficult to see their GP in a timely fashion. Many people do not have private health insurance and so a person under the age of 55 in Auckland would be most likely looking at an non-urgent DHB gastroenterology referral and perhaps having a delayed diagnosis.

*Although CRC is the most common cause of LBO, there are many other causes. The second commonest cause is sigmoid acute diverticulitis and especially in younger patients we need to consider e.g. endometriosis, congenital bands, migration of IUDs, ovarian CA and body packing.^1,5

The 3-6-9 rule is an aide memoire for the upper limit of normal bowel dimensions of small bowel, large bowel and caecum respectively.⁶

References

1. Lieske B, Marietta M, Meseeha M. Large bowel obstruction. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025. Available from: http://www.ncbi.nlm.nih.gov/books/NBK441888/
2. McCulloch SM, Aziz I, Polster AV, Pischel A, Stålsmeden H, Shafazand M, et al. The diagnostic value of a change in bowel habit for colorectal cancer within different age groups. UEG Journal [Internet]. 2020 Mar;8(2):211–9. Available from: https://onlinelibrary.wiley.com/doi/10.1177/2050640619888040
3. Waddell O, Pearson J, McCombie A, Marshall H, Purcell R, Keenan J, et al. The incidence of early onset colorectal cancer in Aotearoa New Zealand: 2000–2020. BMC Cancer [Internet]. 2024 Apr 12;24(1):456. Available from: https://bmccancer.biomedcentral.com/articles/10.1186/s12885-024-12122-y
4. HealthPathways [Internet]. Available from: https://aucklandregion.communityhealthpathways.org/index.htm
5. Jones J. Large bowel obstruction | Radiology reference article | Radiopaedia.org. Radiopaedia. Available from: https://doi.org/10.53347/rID-6335
6. Hacking C. 3-6-9 rule (Bowel) | Radiology Reference Article | Radiopaedia.org. Radiopaedia. Available from: https://doi.org/10.53347/rID-66259