3 Bowel Obstruction

Types of bowel obstruction

A bowel obstruction is a blockage or marked slowing of intestinal contents. Mechanical obstruction is caused by a physical narrowing or blockage. Paralytic ileus is a functional problem: peristalsis, or intestinal movement, is reduced or absent without a physical blockage. Both conditions can cause abdominal distention, nausea, vomiting, and inability to pass stool or gas, and both require prompt clinical evaluation.

Causes and risk contexts

Mechanical obstruction may be partial or complete and may affect either the small or large bowel. Common causes include postoperative adhesions, hernias, and tumors. Other causes include volvulus, in which the bowel twists; intussusception, in which one segment telescopes into another; inflammatory narrowing; and fecal impaction. A strangulated obstruction is especially dangerous because pressure or twisting can compromise blood flow to the bowel.

Paralytic ileus occurs when the bowel does not propel contents normally. It may follow abdominal surgery or anesthesia, occur with severe illness or electrolyte abnormalities, or result from medicines that slow motility, including opioids and anticholinergics. Unlike mechanical obstruction, ileus has no physical point of blockage.

Assessment findings

Symptoms vary with the obstruction’s location, severity, and duration. Findings can include cramping or colicky abdominal pain, nausea, vomiting, abdominal distention or bloating, constipation, and inability to pass flatus. Obstipation means inability to pass both stool and gas, though a partial obstruction may still allow some stool or liquid to pass.

Bowel sounds may be high-pitched or frequent early in mechanical obstruction and later become diminished or absent. Ileus often presents with minimal or absent bowel sounds. Bowel sounds alone cannot establish the diagnosis. Vomiting and fluid shifts into the bowel can contribute to dehydration and reduced urine output.

Evaluation and monitoring

Ask about the last bowel movement and passage of flatus, prior abdominal surgery or obstruction, hernias, relevant illnesses, and medicines that affect bowel motility. Examine the abdomen as directed by clinical protocol and promptly report concerning changes.

Evaluation commonly includes blood tests for fluid and electrolyte status, kidney function, and signs of infection, as well as imaging. CT can help identify the obstruction’s location and cause and detect complications such as ischemia or perforation. Clinical assessment and imaging help distinguish mechanical obstruction from ileus; history or bowel sounds alone do not confirm the cause.

Complications and urgent signs

A blockage can cause fluid and electrolyte losses, dehydration, and impaired kidney function. Increased pressure may compromise bowel blood flow and lead to ischemia, bowel necrosis, perforation, peritonitis, or sepsis. These complications can be life-threatening.

Immediately report worsening or severe continuous pain, guarding or rebound tenderness, fever, tachycardia, hypotension, increasing distention, bloody stool, or sudden deterioration. These findings may indicate ischemia, perforation, infection, or shock and require urgent evaluation.

Treatment approach

Management depends on the cause, severity, and presence of complications. Suspected acute obstruction requires hospital assessment and early surgical consultation. Initial treatment commonly includes bowel rest (NPO), IV fluids, correction of electrolyte abnormalities, and nasogastric decompression for significant vomiting or distention. Antibiotics may be ordered when ischemia, perforation, or infection is suspected.

Some partial mechanical obstructions can resolve with close monitoring and supportive care. Complete obstruction, failure to improve, or evidence of ischemia, strangulation, or perforation may require surgery. Paralytic ileus is generally managed by addressing its underlying cause, supporting hydration and electrolytes, reducing or stopping contributing medicines when clinically appropriate, and allowing motility to recover. Ileus and mechanical obstruction do not necessarily require the same definitive treatment.

Nursing priorities

Nursing priorities are early recognition of deterioration, maintaining fluid balance, symptom relief, and preparing for treatment.

• Monitor and communicate: Trend vital signs, pain, abdominal distention, nausea and vomiting, passage of stool or flatus, and bowel sounds. Promptly escalate new or worsening findings, especially signs of peritonitis or shock.

• Maintain fluid balance: Keep accurate intake and output. Monitor urine output, ordered laboratory results, and nasogastric drainage. Administer prescribed IV fluids and electrolyte replacement, and report concerning changes.

• Support decompression and comfort: Maintain NPO status as prescribed. If a nasogastric tube is ordered, verify and maintain it according to policy, document drainage, and provide frequent oral and nasal care. Give prescribed symptom relief and use appropriate nonpharmacologic comfort measures.

• Prevent avoidable harm: Follow aspiration precautions as indicated and assist with mobility when safe and appropriate. Review medicines that may slow motility with the care team. Do not give food, drink, laxatives, or medications by mouth unless specifically authorized by the treating clinician.

• Prepare and educate: Facilitate ordered imaging, laboratory tests, and surgical evaluation. Explain the reason for bowel rest and monitoring. Resume oral intake only when approved, advancing the diet as ordered and tolerated.