What is Bowel obstruction - Meaning and definition

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: September 17, 2018.

Bowel obstruction is defined as the blockage of small or large bowel (partial or complete, mechanical or paralytic).

Causes.
Small bowel: strangulated hernia (40%), adhesions (30%), cancer, Crohn's disease
Large bowel: cancer (70%), volvulus, diverticulitis, fecal impaction

The symptoms of obstruction depend on the location and severity of the obstruction; the higher the level of obstruction, the more acute and rapid the onset of symptoms.

Small-bowel obstruction
- pain moderate to severe
- intermittent waves of pain; relative comfort between pain episodes
- vomiting frequent, violent, bilious when obstruction is high
- vomiting feculent when obstruction is lower
- abdominal bloating variable; prominent when obstruction is low
- reduced rectal gas and stool
- weakness

Large-bowel obstruction
- pain moderately severe (generally less acute than in small-bowel obstruction)
- colicky
- distension present, occurs early, may be severe
- vomiting usually late and infrequent, may be feculent
- reduced or absent rectal gas and stool
- sudden, severe pain characteristic of volvulus

Paralytic ileus
Obstruction of the bowel due to paralysis of the muscle of the bowel wall (causes: generalized peritonitis, acute inflammation of the abdomen, severe chest injury)
- major symptom is distension, resulting in moderate discomfort
- pain absent
- frequent vomiting or regurgitation of gastric contents
- "silent" distended abdomen on examination

Physical findings
- heart rate normal or increased
- respiration normal or increased
- blood pressure normal or low; postural blood pressure drop may be present
- patient pale, sweaty, anxious; he/she appears mildly to severely ill
- various degrees of abdominal distension
- hernia may be visible
- contractions of bowel wall (peristalsis) may be seen
- bowel sounds increased, in early stages
- peristaltic rushes, high-pitched tinkling sounds present
- later, bowel sounds are diminished or absent
- tenderness due to distension may be present
- tender localized mass or hernia may be present
- rebound tenderness and rigidity not present unless perforation, peritonitis, or strangulation have occurred
- rectal exam: blood or stool may be present, rectum may be empty
- examine all hernial orifices, including both femoral rings

Adapted from Clinical Practice Guidelines for Nurses in Primary Care. Gastrointestinal System. Internet. Accessed August 31, 2009.

Published by Roberto Wenk. Last updated date: May 29, 2016.

Bowel obstruction is defined as the blockage of small or large bowel (partial or complete, mechanical or paralytic).
Malignant bowel obstruction is a frequent complication of intra abdominal or pelvic cancers, occurring in up to 42% of patients with ovarian cancer and up to 24% in colorectal cancer.
The obstruction may be partial or complete, mechanical or adynamic.

Mechanical obstruction.
Extrinsic occlusion of the lumen: enlargement of the primary tumour or recurrence, mesenteric and omental masses, abdominal or pelvic adhesions, postirradiation fibrosis that cause bowel compression.
Intra-luminal occlusion of the lumen: results from tumour growth from within the bowel.
Intramural occlusion of the lumen: intestinal linitis plastica, tumour within the wall of the bowel resulting in poor motility.

Adynamic ileus or functional obstruction.
Intestinal motility disorders: tumor infiltration of the mesentery or bowel wall muscle and nerves, or malignant involvement of the celiac plexus.
Intestinal motility disorders: paraneoplastic neuropathy particularly in patients with lung cancer, chronic intestinal pseudo-obstruction (CIP), paraneoplastic pseudo-obstruction.

Common symptoms in patients with malignant bowel obstruction include nausea, vomiting, colicky or continuous pain, intermittent or complete constipation and overflow diarrhea.

Clinical practice recommendations for managing bowel obstruction in patients with end-stage cancer have been developed by the European Association of Palliative Care.
The recommendations are:
• A nasogastric tube should be used only as a temporary measure.
• Medical measures such as analgesics, anti-secretory drugs and antiemetics should be used alone or in combination to relieve symptoms.
• Surgery should not be undertaken routinely in patients with poor prognostic criteria, such as intra-abdominal carcinomatosis, poor performance status, and massive ascites.
• A venting gastrostomy should be considered if drugs fail to reduce vomiting to an acceptable level.
• Total parenteral nutrition should be considered only for patients who may die of starvation rather than from tumor spread.
• Parenteral hydration is sometimes indicated to correct nausea, whereas regular mouth care is the treatment of choice for a dry mouth.
• A collaborative approach involving both surgeons and physicians can offer patients an individualised and appropriate symptom management plan.

Mercadante S, Casuccio A, Mangione S. Medical treatment for inoperable malignant bowel obstruction: a qualitative systematic review. Journal of Pain Symptom Management; 2007 Feb; 33(2):217-223. Ripamonti CI, Easson AM, Gerdes H; Management of malignant bowel obstruction; European Journal of Cancer 2008; 44(8):1105-1115.

Bowel obstruction

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