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Large Bowel Obstruction

Large Bowel Obstruction is a mechanical or functional blockage of the colon that prevents the normal passage of intestinal contents, gas, and stool. It can become life-threatening when obstruction causes bowel ischemia, necrosis, or perforation

Also called

Colonic Obstruction

ICD-10

K56.609

Specialty

Gastroenterology

Onset

Acute

Reviewed

July 2026
On This Page

Overview

Large Bowel Obstruction is most commonly caused by:

  • Colorectal cancer
  • Volvulus
  • Benign strictures, such as those related to diverticular disease
  • Fecal impaction

The obstruction causes proximal accumulation of gas and intestinal contents, leading to bowel dilatation. If untreated, it may progress to ischemia, perforation, peritonitis, and sepsis.

Etiology & Risk Factors

Common causes of Large Bowel Obstruction include:

  • Colorectal cancer
  • Sigmoid volvulus
  • Cecal volvulus
  • Diverticular stricture
  • Fecal impaction
  • Benign colorectal strictures
  • Inflammatory bowel disease
  • Adhesions, less commonly than in small bowel obstruction

 

Risk Factors for Large Bowel Obstruction

  • Older age
  • Previous colorectal cancer
  • Diverticular disease
  • Chronic constipation
  • Previous abdominal or colorectal surgery
  • Neurological or psychiatric disorders predisposing to volvulus

Pathophysiology

Mechanical colonic blockage → accumulation of gas and fecal contents proximally → progressive colonic dilatation → increased intraluminal pressure → impaired venous and lymphatic drainage → mucosal ischemia → bowel necrosis → perforation → peritonitis and sepsis

Clinical Presentation

Symptoms

  • Abdominal distension

  • Colicky abdominal pain

  • Constipation

  • Obstipation

  • Failure to pass flatus

  • Nausea

  • Vomiting, usually later than in small bowel obstruction

  • Reduced appetite

 

Signs

    • Marked abdominal distension

    • Tympanic abdomen

    • Colicky abdominal tenderness

    • High-pitched or reduced bowel sounds

    • Dehydration

    • Visible peristalsis occasionally

Large Bowel Obstruction Overview
Tetanus Overview

History Taking

  • Onset and progression of abdominal pain
  • Abdominal distension
  • Constipation
  • Passage of flatus
  • Vomiting
  • Change in bowel habits
  • Rectal bleeding
  • Weight loss
  • Previous colorectal cancer
  • Diverticular disease
  • Previous abdominal surgery

Physical Examination

General Examination

  • Vital signs

  • Hydration status

  • General appearance

Look for:

  • Tachycardia

  • Fever

  • Hypotension

  • Dehydration

System-Specific Examination

    • Abdominal distension

    • Tenderness

    • Tympany

    • Bowel sounds

    • Guarding or rebound tenderness

    • Rectal examination for masses or fecal impaction

Investigations

Complete Blood Count

Useful when assessing:

  • Infection

  • Inflammation

  • Anemia

  • Possible bowel ischemia

 

Biochemistry / Specific Tests

  • Electrolytes

  • Urea and creatinine

  • Serum lactate when ischemia is suspected

  • C-reactive protein when clinically useful

  • Blood gas in severe illness

These help assess dehydration, renal impairment, and bowel ischemia.

 

Imaging

Abdominal X-ray

May show:

  • Dilated colon

  • Haustral markings

  • Obstructive pattern

CT Abdomen and Pelvis

The preferred imaging test in most adults with suspected Large Bowel Obstruction.

It helps identify:

  • Site of obstruction

  • Cause

  • Tumor

  • Volvulus

  • Ischemia

  • Perforation

  • Proximal bowel dilatation

Special / Confirmatory Tests

Colonoscopy

May be used in selected stable patients for:

  • Evaluation of suspected colorectal cancer

  • Diagnosis of the cause

  • Decompression of selected sigmoid volvulus

It is generally avoided when there is concern for perforation or severe peritonitis.

Diagnosis

-Diagnosis of large bowel obstruction is based on:

Abdominal distension + constipation/obstipation + colicky pain → imaging confirmation of colonic dilatation and a transition point → identify the underlying cause

CT abdomen and pelvis is generally the key diagnostic investigation.

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Management

1. First-Line / Emergency Management

Immediate management includes:

  • Urgent surgical assessment

  • Nil by mouth

  • IV fluid resuscitation

  • Correct electrolyte abnormalities

  • Analgesia and antiemetics

  • Urinary catheter when necessary

  • Nasogastric decompression if significant vomiting or proximal distension is present

  • IV antibiotics when ischemia, perforation, or infection is suspected

2. Definitive Treatment

Treatment depends on the cause.

Colorectal Cancer

  • Surgical resection when appropriate

  • Endoscopic stenting in selected patients, particularly some left-sided malignant obstructions

Sigmoid Volvulus

  • Endoscopic decompression if there is no ischemia or perforation

  • Definitive sigmoid colectomy because recurrence is common

Cecal Volvulus

  • Usually requires urgent surgery

Benign Stricture

  • Endoscopic or surgical treatment depending on the cause and severity

3. Medical Treatment

Medical treatment is mainly supportive:

  • IV fluids

  • Electrolyte replacement

  • Analgesia

  • Antiemetics

  • Antibiotics when infection, ischemia, or perforation is suspected

4. Surgical / Procedural Treatment

  • Resection of obstructed or ischemic bowel

  • Surgical treatment of volvulus

  • Colostomy or other diversion when required

Complications

  • Bowel ischemia
  • Bowel necrosis
  • Perforation
  • Peritonitis
  • Sepsis
  • Septic shock
  • Dehydration
  • Electrolyte abnormalities
  • Acute kidney injury
  • Aspiration
  • Death

Prognosis

-Prognosis depends mainly on:

  • Cause of obstruction
  • Duration of obstruction
  • Presence of ischemia
  • Perforation
  • Patient age and comorbidities
  • Speed of treatment

Early diagnosis and treatment generally lead to good outcomes, while ischemia and perforation significantly increase morbidity and mortality.

Key Points / Clinical Pearls

  • Large Bowel Obstruction is a mechanical blockage of the colon.
  • Common causes include colorectal cancer, volvulus, diverticular strictures, and fecal impaction.
  • Typical symptoms are abdominal distension, colicky pain, constipation, and obstipation.
  • Vomiting often occurs later than in small bowel obstruction.
  • Colorectal cancer is an important cause, particularly in older adults.
  • Sigmoid volvulus is an important cause of acute colonic obstruction.
  • Cecal volvulus usually requires urgent surgery.
  • Abdominal X-ray may show colonic dilatation.
  • CT abdomen and pelvis is the key imaging investigation in most adults.
  • Continuous severe pain, fever, peritonism, or raised lactate suggests ischemia or perforation.
  • Initial treatment includes bowel rest, IV fluids, electrolyte correction, and urgent surgical assessment.
  • Endoscopic decompression can be used for uncomplicated sigmoid volvulus.
  • Catena F, De Simone B, Coccolini F, et al. Bowel Obstruction: A Narrative Review for All Physicians. World J Emerg Surg. 2019;14:20. PubMed .
  • Vogel JD, Felder SI, Bhama AR, et al. The American Society of Colon and Rectal Surgeons Clinical Practice Guidelines for the Management of Colon Volvulus and Acute Colonic Pseudo-Obstruction. Dis Colon Rectum. 2021;64(9):1046-1057. PubMed .
  • Frago R, Ramirez E, Millan M, Kreisler E, del Valle E, Biondo S. Current Management of Acute Colonic Pseudo-Obstruction (Ogilvie's Syndrome). Cir Esp. 2014;92(10):711-717. PubMed .
  • National Library of Medicine (NIH). Large Bowel Obstruction . StatPearls.