Intestinal Obstruction

Intestinal obstruction is a blockage that prevents food or liquid from passing through your small intestine or large intestine (colon). This can be a medical emergency requiring immediate treatment.

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. Always consult with a healthcare provider for diagnosis and treatment.

Table of Contents

Overview

Intestinal obstruction is a serious medical condition where a blockage prevents the normal flow of digestive contents through the intestinal tract. This blockage can occur in either the small intestine or the large intestine (colon) and can be partial or complete. When left untreated, intestinal obstruction can lead to serious complications, including tissue death, perforation of the intestinal wall, and severe infection.

The condition can develop suddenly (acute) or gradually over time (chronic). Acute intestinal obstruction is a medical emergency that requires immediate attention, as it can rapidly progress to life-threatening complications. The intestines are responsible for digesting food, absorbing nutrients, and eliminating waste. When blocked, these vital functions are disrupted, leading to a buildup of food, fluids, gastric acids, and gas above the obstruction site.

There are two main types of intestinal obstruction: mechanical and functional. Mechanical obstruction occurs when something physically blocks the intestines, such as scar tissue, tumors, or hernias. Functional obstruction, also called paralytic ileus or pseudo-obstruction, happens when the intestines don't work properly due to muscle or nerve problems, even though there's no physical blockage. Understanding the type and location of the obstruction is crucial for determining the appropriate treatment approach.

Symptoms

The symptoms of intestinal obstruction can vary depending on the location and severity of the blockage. Symptoms typically develop rapidly in complete obstructions and may be more gradual in partial obstructions. Recognizing these symptoms early is crucial for prompt medical intervention.

Common Symptoms

  • Sharp abdominal pain - Severe, crampy pain that comes in waves, often described as colicky
  • Nausea - Persistent feeling of sickness that often precedes vomiting
  • Vomiting - May progress from stomach contents to bile, and in severe cases, fecal matter
  • Stomach bloating - Visible abdominal distention and feeling of fullness
  • Constipation - Complete inability to pass stool or gas in complete obstruction

Less Common Symptoms

  • Retention of urine - Difficulty urinating due to pressure on the bladder
  • Burning abdominal pain - May indicate complications or tissue damage
  • Pain of the anus - Can occur with lower intestinal obstructions
  • Fever - May indicate infection or perforation
  • Rapid heart rate - Sign of dehydration or systemic infection

Symptom Progression

In the early stages, patients typically experience intermittent crampy abdominal pain. As the obstruction progresses, the pain may become more constant and severe. Vomiting often follows, initially consisting of stomach contents, then bile, and in advanced cases, feculent material. The inability to pass gas or have bowel movements is a hallmark sign of complete obstruction. Abdominal distention develops as gas and fluids accumulate above the blockage site.

The location of the obstruction influences symptom presentation. High small bowel obstructions typically cause early and frequent vomiting with less distention, while lower obstructions may present with more pronounced abdominal distention and later onset of vomiting. Partial obstructions may allow some passage of gas and liquid stool, leading to intermittent symptoms that can delay diagnosis.

Causes

Intestinal obstruction can result from various mechanical or functional causes. Understanding the underlying cause is essential for proper treatment and prevention of recurrence.

Mechanical Causes

Adhesions: The most common cause of small bowel obstruction in developed countries. These bands of scar tissue form after abdominal surgery, inflammation, or infection and can trap or twist portions of the intestine.

Hernias: When a portion of intestine protrudes through a weak spot in the abdominal wall, it can become trapped (incarcerated) or lose its blood supply (strangulated), causing obstruction.

Tumors: Both benign and malignant tumors can block the intestinal lumen. Colorectal cancer is a common cause of large bowel obstruction in adults.

Intussusception: A condition where one segment of intestine telescopes into another, more common in children but can occur in adults with tumors or other lead points.

Volvulus: Twisting of the intestine around itself, cutting off blood supply and causing obstruction. More common in the sigmoid colon and cecum.

Functional Causes

Paralytic ileus: Temporary cessation of intestinal peristalsis following surgery, infection, or metabolic disturbances. The intestines don't move contents forward despite no physical blockage.

Medications: Certain drugs, particularly opioids, anticholinergics, and some antidepressants, can slow intestinal motility and cause functional obstruction.

Electrolyte imbalances: Abnormal levels of potassium, sodium, or calcium can affect intestinal muscle function, leading to decreased motility.

Other Causes

  • Crohn's disease - Can cause strictures and inflammation leading to obstruction
  • Diverticulitis - Inflammation can cause scarring and narrowing
  • Foreign bodies - Swallowed objects or bezoars can block the intestines
  • Gallstones - Large stones can cause gallstone ileus
  • Inflammatory conditions - Such as radiation enteritis or ischemic strictures

Risk Factors

Several factors can increase the likelihood of developing intestinal obstruction. Understanding these risk factors can help identify high-risk individuals and implement preventive measures.

Surgical History

Previous abdominal or pelvic surgery is the most significant risk factor for adhesion-related obstruction. The risk increases with multiple surgeries, extensive procedures, and complications such as infection or bleeding. Common surgeries associated with adhesion formation include appendectomy, colorectal surgery, gynecologic procedures, and exploratory laparotomy.

Medical Conditions

  • Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
  • Previous radiation therapy to the abdomen or pelvis
  • Hernias - Both internal and external
  • History of diverticulitis or diverticular disease
  • Colorectal or other gastrointestinal cancers
  • Congenital abnormalities of the intestines

Lifestyle and Demographic Factors

Age plays a role, with certain causes more common in specific age groups. Intussusception is more common in children, while cancer-related obstructions increase with age. Geographic factors matter too - volvulus is more common in areas with high-fiber diets. Certain medications, particularly chronic opioid use, increase the risk of functional obstruction. Dehydration and electrolyte imbalances can precipitate ileus, especially in elderly or debilitated patients.

Diagnosis

Accurate and timely diagnosis of intestinal obstruction is crucial for appropriate management and prevention of complications. The diagnostic process involves clinical evaluation, laboratory tests, and imaging studies.

Clinical Evaluation

The initial assessment includes a detailed medical history focusing on previous surgeries, underlying conditions, and symptom progression. Physical examination reveals important signs including abdominal distention, abnormal bowel sounds (high-pitched, tinkling, or absent), tenderness, and signs of peritonitis. The presence of surgical scars, hernias, or masses guides further evaluation.

Laboratory Tests

Blood tests help assess the severity and complications of obstruction:

  • Complete blood count - May show elevated white blood cells indicating infection or inflammation
  • Electrolyte panel - Reveals dehydration and electrolyte imbalances from vomiting
  • Kidney function tests - Assess dehydration and prerenal azotemia
  • Lactate levels - Elevated in bowel ischemia or perforation
  • Arterial blood gas - May show metabolic acidosis in severe cases

Imaging Studies

Plain abdominal X-rays: Initial imaging showing dilated bowel loops, air-fluid levels, and absence of gas in the rectum in complete obstruction. May identify free air indicating perforation.

CT scan with contrast: The gold standard for diagnosing intestinal obstruction. Provides detailed information about the location, cause, and complications. Can differentiate between mechanical and functional obstruction and identify transition points.

Contrast studies: Water-soluble contrast enemas or small bowel follow-through can help in equivocal cases and may have therapeutic benefits in adhesive obstructions.

Ultrasound: Useful in pregnant patients and children, can identify fluid-filled dilated loops and assess peristalsis.

Treatment Options

Treatment of intestinal obstruction depends on the cause, location, completeness of obstruction, and presence of complications. Management ranges from conservative measures to emergency surgery.

Conservative Management

Initial treatment for uncomplicated obstructions often begins with conservative measures:

  • Bowel rest: Nothing by mouth (NPO) to reduce intestinal stimulation
  • Nasogastric decompression: Tube placement to remove gas and fluids, relieving distention
  • Intravenous fluids: Aggressive hydration to correct dehydration and electrolyte imbalances
  • Pain management: Careful use of analgesics avoiding medications that slow motility
  • Monitoring: Serial examinations and imaging to assess response to treatment

Medical Treatment

Specific medical interventions based on the underlying cause:

  • Discontinuation of offending medications in drug-induced ileus
  • Correction of metabolic abnormalities and electrolyte imbalances
  • Prokinetic agents for functional obstruction once mechanical causes are ruled out
  • Antibiotics if infection is suspected or for prophylaxis
  • Corticosteroids for inflammatory strictures in Crohn's disease

Surgical Treatment

Surgery is indicated for:

  • Complete mechanical obstruction that doesn't resolve with conservative management
  • Signs of strangulation, ischemia, or perforation
  • Failure of conservative treatment after 48-72 hours
  • Specific causes requiring surgical correction (hernias, tumors, volvulus)

Surgical approaches include adhesiolysis for adhesions, hernia repair, tumor resection, reduction of intussusception or volvulus, and bowel resection for nonviable segments. Minimally invasive laparoscopic techniques may be appropriate for selected cases, offering faster recovery and reduced adhesion formation.

Post-treatment Care

Recovery involves gradual diet advancement from clear liquids to regular food, monitoring for recurrence, management of underlying conditions, and nutritional support for prolonged cases. Long-term follow-up addresses the underlying cause and implements preventive strategies.

Prevention

While not all cases of intestinal obstruction can be prevented, certain measures can reduce the risk, especially in high-risk individuals.

Surgical Considerations

For those requiring abdominal surgery, minimally invasive techniques when appropriate can reduce adhesion formation. Careful surgical technique, use of adhesion barriers, and prompt treatment of post-operative complications help minimize risk. Early mobilization and return of bowel function after surgery are important preventive measures.

Medical Management

  • Proper management of inflammatory bowel disease to prevent strictures
  • Regular screening for colorectal cancer in high-risk individuals
  • Prompt treatment of hernias before they become complicated
  • Careful medication management, especially with drugs affecting motility
  • Maintaining proper hydration and electrolyte balance

Lifestyle Modifications

Dietary measures include adequate fiber intake to prevent constipation, proper chewing to avoid food bolus obstruction, and avoiding foods that form bezoars in susceptible individuals. Stay well-hydrated, maintain regular bowel habits, and seek prompt medical attention for persistent abdominal symptoms. Those with a history of obstruction should be aware of warning signs and have a low threshold for seeking medical evaluation.

When to See a Doctor

Intestinal obstruction can be a medical emergency. Immediate medical attention is necessary for certain symptoms and situations.

Seek Emergency Care For:

  • Severe, persistent abdominal pain that worsens over time
  • Inability to pass gas or have bowel movements for more than 2-3 days
  • Persistent vomiting, especially if it becomes bilious or feculent
  • Significant abdominal distention with pain
  • Signs of shock: rapid pulse, low blood pressure, confusion, cold extremities
  • Fever above 101°F (38.3°C) with abdominal symptoms
  • Blood in vomit or stool

Schedule Medical Consultation For:

  • Recurrent episodes of crampy abdominal pain
  • Chronic constipation with new onset of symptoms
  • Previous history of obstruction with returning symptoms
  • Unexplained weight loss with digestive symptoms
  • Changes in bowel habits lasting more than two weeks

Individuals with risk factors such as previous abdominal surgery, hernias, or inflammatory bowel disease should have a lower threshold for seeking medical evaluation when experiencing abdominal symptoms.

Frequently Asked Questions

Can intestinal obstruction resolve on its own?

Partial obstructions and some adhesive obstructions may resolve with conservative treatment including bowel rest and decompression. However, complete mechanical obstructions typically require medical intervention, and some cases need surgery. Never attempt to wait out severe symptoms without medical evaluation.

How long can you live with a bowel obstruction?

Untreated complete intestinal obstruction is life-threatening and can lead to bowel perforation, sepsis, and death within days. With proper medical treatment, most patients recover fully. The timeline depends on the cause, severity, and how quickly treatment is received.

What foods should I avoid if I'm prone to obstruction?

Those with a history of obstruction should avoid foods that don't digest well, including tough meats, foods with skins or seeds, popcorn, nuts, and raw vegetables with tough fibers. Chew food thoroughly and stay well-hydrated. Work with a dietitian for personalized recommendations.

Can you have a bowel movement with an obstruction?

With a complete obstruction, you cannot pass stool or gas. However, with a partial obstruction, you may pass some liquid stool or gas. The presence of any bowel movement doesn't rule out obstruction, especially if accompanied by other symptoms.

What's the difference between obstruction and constipation?

Constipation is difficulty passing stool but material can still move through the intestines. Obstruction is a physical or functional blockage preventing passage. Obstruction causes severe symptoms like vomiting, severe pain, and complete inability to pass gas, while constipation symptoms are generally milder.

References

  1. Gore RM, et al. "Bowel Obstruction." Radiologic Clinics of North America. 2015;53(6):1225-1240.
  2. Catena F, et al. "Adhesive small bowel obstruction (ASBO): Evidence based guidelines." World Journal of Emergency Surgery. 2019;14:42.
  3. Paulson EK, Thompson WM. "Review of small-bowel obstruction: the diagnosis and when to worry." Radiology. 2015;275(2):332-342.
  4. Mayo Clinic. "Intestinal obstruction - Symptoms and causes." Mayo Clinic Website. Accessed 2024.
  5. National Institute of Diabetes and Digestive and Kidney Diseases. "Intestinal Pseudo-obstruction." NIDDK Website. Updated 2023.
  6. American College of Gastroenterology. "Small Bowel Obstruction." ACG Clinical Guidelines. 2020.