General and Colorectal

CASE 15: abSolute ConStipation

history

A 70-year-old man presents with a 4-day history of colicky lower abdominal pain. He has been vomiting for the past 2 days and last opened his bowels 3 days ago. He has been unable to pass flatus for the past 24 h. He reports a 2-stone weight loss in the past year but is otherwise fit with no other past medical history of note. He currently lives on his own and leads an active life, walking his dog every day.

examination

He is afebrile with a pulse rate of 100/min and a blood pressure of 100/50 mmHg. Cardiovascular and respiratory examinations are unremarkable. The abdomen is distended and tympanic to percussion with lower abdominal tenderness. The bowel sounds are ‘tinkling’. The hernial orifices are empty and digital rectal examination reveals an empty rectum.

INVESTIGATIONS

an x-ray of the abdomen is performed and is shown in Figure 15.1.

Figure 15.1 plain x-ray of the abdomen.

Questions

•What is the likely diagnosis?

•What are the possible causes?

•Which further investigations are required?

29

100 Cases in Surgery

ANSWER 15

The x-ray demonstrates large-bowel obstruction. Large-bowel obstruction classically presents with lower abdominal pain, abdominal distension and absolute constipation. Vomiting is a late feature. The common causes of large-bowel obstruction are listed below:

•Carcinoma: approximately 15 per cent of colorectal cancers present with obstruction and roughly 25 per cent are found to have distant metastases at the time of presentation

•Diverticulitis: repeated episodes of diverticulitis can lead to fibrosis and narrowing of the colonic lumen

•Volvulus: sigmoid volvulus typically occurs in older individuals with a history of constipation and straining, whereas caecal volvulus is seen in younger patients and is associated with a congenital defect in the peritoneum, resulting in inadequate fixation of the caecum

•Intussusception: intussusception is most commonly seen in children; approximately 70 per cent of adult intussusceptions are caused by tumours

•Colonic pseudo-obstruction: pseudo-obstruction or Ogilvie syndrome is seen most often in the elderly patient with chronic or severe illness

In approximately 20 per cent of patients, the ileocaecal valve is competent resulting in a ‘closed-loop’ obstruction which does not allow decompression into the small bowel. The large bowel gradually dilates with maximal dilatation occurring in the caecum. Gross dilation (>10 cm) with tenderness over the caecum is a sign of impending perforation and requires prompt treatment. Decompression of the large bowel with either a colonic stent or defunctioning loop colostomy may be required. More definitive surgery can then be planned after optimization and further imaging.

A contrast enema or contrast CT can be used to determine the level of the obstruction and if it is complete. If the patient is stable and is suspected of having a tumour, then histology should be gained and staging completed by computerized tomography of the chest, abdomen and pelvis prior to definitive surgery.

The barium enema demonstrates a stenosis at the rectosigmoid junction secondary to a tumour (arrow in Figure 15.2).

Figure 15.2 barium enema demonstrating a stricture at the rectosigmoid junction (arrow).

30

General and Colorectal

KEY POINTS

Causes of large-bowel obstruction are:

•Carcinoma

•Diverticulitis

•volvulus

•intussusception

•Colonic pseudo-obstruction

31

This page intentionally left blank