Chronic bowel obstruction

Bowel obstruction, which is also called intestinal obstruction, is not a disease but a condition marked by difficult passing of the intestinal contents due to some kind of a blockage that may be present either in the intestine or outside of it. When the blockage is within the intestine, it is usually either a tumor or swelling that fills and obstructs the normal passing of the digestive contents.

On the other side, if the adjacent organs or tissues make excessive pressure on the intestine, it may also cause the problematic passing of the digestive contents through the intestine. The intestinal obstruction may be total or partial, and it may occur either in the small intestine or, on the other side, in the large intestine.

Small and large bowel obstructions are responsible for approximately 15% of hospital admissions for acute abdominal pain in the USA and ~?20% of cases needing acute surgical care. Starting from the analysis of a common clinical problem, we want to guide primary care physicians in the initial management of a patient presenting with acute abdominal pain associated with intestinal obstruction.

Bowel obstruction is an important cause of morbidity and mortality accounting for nearly 30,000 deaths and more than $3 billion per year in direct medical costs; it is responsible for approximately 15% of hospital admissions for acute abdominal pain in the USA and ~?20% of cases needing acute surgical care.
Bowel obstruction etiology is based on a mechanical intrinsic luminal obstruction or extrinsic compression. Adynamic ileus and colonic pseudo-obstruction are caused by a lack of enteric propulsion. Colonic pseudo-obstruction and an adynamic ileus can be caused by drugs, trauma, the postoperative period, metabolic disturbance, and other different basis.
In 90% of cases, small bowel obstruction is caused by adhesions, hernias, and neoplasms. Adhesive small bowel obstruction represents 55–75% of small bowel obstruction cases while hernias and small bowel tumors account for the remainder. Large bowel obstruction is provoked by cancer in about 60% of cases; volvulus and diverticular disease are responsible for the other 30%.
In bowel obstruction, abdominal pain is classically a colic onset due to an increase in motility to overcome occlusion. This is later replaced by continuous pain attributable to reduced peristalsis and dilation. Pain can be intense and untreatable with analgesics in case of ischemia (small bowel/large bowel volvulus) or perforation.
Each hernia orifice (umbilical, inguinal, femoral) and all laparotomic/laparoscopic incision scars should be carefully examined. Digital rectal examination and rectoscopy can be useful in patients to detect blood or a rectal mass suggestive of colorectal malignancy.
Abdominal plain X-ray is the first level radiologic study. In small bowel obstruction, plain abdominal radiographic findings are diagnostic in 50–60%, inconclusive in 20–30%, and misleading in 10–20% of patients.
Small bowel obstruction can be diagnosed with ultrasound if there are >?2.5-cm dilated loops of the bowel that are proximal to collapsed loops of bowel and if there is decreased or absent peristalsis activity. Using ultrasound for small bowel obstruction diagnosis has 90% sensitivity and 96% specificity.
To minimize the burden of ionizing radiation in children and pregnant women, magnetic resonance imaging is a valid alternative examination to computed tomography scan for bowel obstruction: prospective study demonstrated a sensitivity of 95% and a specificity of 100%.
The role of colonoscopy is limited to the diagnosis of large bowel obstruction. The goal is to exclude other causes for obstruction. Biopsy should be performed in cases of suspected malignancy when emergency surgery has not been indicated or endoscopic stent placement can be expected.

Bowel obstruction is a common and challenging surgical emergency. Further studies are needed to evaluate more precisely the role of conservative treatment in adhesive small bowel obstruction and its length. Moreover, a great debate is underway about laparoscopic adhesiolysis potentialities against possible severe technical complications. Both issues are critical to decrease the well-known adhesive small bowel obstruction recurrence risk. Stents will probably become the mainstay of cancer large bowel obstruction transforming emergency operations in elective cases decreasing complications and stomas.

✓ Fact confirmed: Bowel obstruction: a narrative review for all physicians Fausto Catena, Belinda De Simone, Federico Coccolini, Salomone Di Saverio, Massimo Sartelli & Luca Ansaloni; 29 April 2019

Common Causes of Obstruction in the Small Intestine

Adhesions, hernia, and tumors are some of the most usual reasons for the occurrence of obstruction of the small bowel.

Adhesions represent a kind of scar and they refer to the regions of tough and fibrous connective tissues. Adhesions frequently appear outside of the intestine after surgery on pelvic organs, appendix, and colon.

Sometimes it happens that the part of the small bowel protrudes through the weakened area on the abdominal muscle wall. This part of the small intestine is called a hernia and it is possible that the bowel obstruction appears in the hernia if it is tightly pinched.

Cancerous tumors may also lead to the incidence of blockage in the small intestine. In most cases, the small intestine does not develop cancer within itself, but it gets affected by metastatic cancer that comes from some adjacent organ.

Common Causes of Obstruction in the Large Intestine

The most common culprits for the appearance of obstruction of the large bowel are colorectal cancer, volvulus, and diverticular disease.

When colorectal cancer is not diagnosed in early stages, or when it is left untreated, it leads to the narrowing of the large bowel, which eventually causes bowel obstruction.

Volvulus is the medical term for the condition featured by the abnormal twisting of the part of the intestine around itself. It mainly occurs in elderly people who are suffering from constipation for a long time.

Diverticulitis refers to the infection of diverticula, which are found in the wall of the intestine. The scar can slowly lead to the tightening and narrowing of the intestine, thus resulting in bowel obstruction.