Intestinal ObstructionEdit

Intestinal obstruction refers to a blockage that prevents the normal passage of contents through the intestines. It can be mechanical, where a physical barrier blocks the lumen, or functional, where the intestine fails to propel contents despite an open lumen. The mechanical category includes adhesions, hernias, tumors, and volvulus, while functional obstructions—often termed ileus—reflect a temporary disruption of intestinal motility, frequently after surgery or a severe illness. In many health systems, timely recognition and treatment of obstruction are major concerns for patients and physicians alike, given the potential for rapid deterioration if blood flow to the bowel is compromised or perforation occurs.

In adults, the leading mechanical cause is adhesions from prior abdominal surgery or inflammatory processes; hernias and tumors are common alternatives, and less frequently, volvulus or inflammatory strictures can play a role. Functional ileus can accompany nearly any major illness or operation and, although not a true blockage, can produce similar symptoms and require careful management. Early and clear recognition improves outcomes, whereas delays can raise the risk of bowel necrosis or perforation. For more context on related conditions, see adhesions, small bowel obstruction, and ileus.

Causes

Mechanical causes

Adhesions: bands of scar tissue that form after prior surgery or infection and can twist or compress loops of bowel. Adhesions are a leading cause of intestinal obstruction in developed health systems and frequently determine whether a patient will require surgery. See adhesions.
Hernias: a loop of bowel may become trapped in a defect in the abdominal wall or diaphragm, causing a closed-loop obstruction that can rapidly progress to ischemia if not treated. See hernia.
Tumors and inflammatory masses: growths or inflammatory tissue can physically block the lumen or compress nearby segments. See tumor or neoplasm.
Volvulus and other rarer mechanical causes: twisting of a loop of bowel or internal herniation can create an abrupt blockage. See volvulus.
Other obstructions: strictures from Crohn’s disease or radiation, intussusception in certain age groups, and other less common problems. See Crohn's disease and intussusception.

Functional causes (ileus)

Postoperative ileus: temporary cessation of coordinated bowel movement after abdominal or pelvic surgery, common enough to demand standardized postoperative care pathways. See postoperative ileus.
Medication- or illness-induced ileus: certain drugs (notably some narcotics) and systemic illnesses can reduce gut motility.
Critical illness and metabolic disturbances: sepsis, electrolyte imbalances, or severe trauma can impair intestinal movement even without a fixed blockage.

Presentation and diagnosis

Patients with obstruction often present with cramping abdominal pain that may become more constant, along with vomiting, abdominal distension, and a failure to pass stool or gas (obstipation). The pattern of pain may differ by location and cause; for example, high-grade small bowel obstruction can produce rapid vomiting and dehydration, while large bowel obstruction tends to cause more progressive distension. A thorough examination, including a history of prior surgeries or known hernias, is essential. See abdominal pain, vomiting, and obstipation.

Physical examination may reveal abdominal tenderness, guarding if there is concern for perforation, and signs of systemic stress if strangulation or sepsis develops. Laboratory tests are useful for assessing dehydration, electrolyte imbalance, and possible complications; they do not reliably establish the presence or site of an obstruction on their own, but they help guide management. Imaging is central to diagnosis: - Plain abdominal X-ray can show dilated loops of bowel and air–fluid levels and is often a first step in evaluation. See X-ray. - Computed tomography (CT) scan provides more detailed information about the site, cause, and signs of compromised blood supply, and is widely used to differentiate mechanical obstruction from ileus and to assess for strangulation. See CT scan. - Ultrasound can be helpful in certain populations or when evaluating specific etiologies, such as gallstone ileus or pediatric cases. See ultrasound.

Timely assessment is critical, because signs of strangulation (tender, rigid abdomen, fever, tachycardia, rising white blood cell count) or peritonitis usually necessitate urgent surgical exploration. See surgery and emergency surgery.

Management

Initial management emphasizes stabilization and accurate assessment. General steps include: - NPO (nothing by mouth) and secure intravenous access for fluids and electrolyte correction. See intravenous therapy. - Nasogastric decompression to relieve vomiting and reduce distension. See nasogastric tube. - Careful monitoring for signs of deterioration, ongoing assessment of vital signs, urine output, and laboratory values. See monitoring (medicine). - Broad-spectrum antibiotics are reserved for suspected or confirmed perforation, ischemia, or contamination. See antibiotics.

Decisions about nonoperative versus operative management depend on the cause and the clinical status: - Nonoperative (conservative) management: In selected cases of suspected small bowel obstruction without signs of strangulation or peritonitis, close observation with serial exams, fluid management, and repeat imaging can lead to resolution without surgery. This approach must balance the desire to avoid unnecessary procedures with the risk of delayed intervention in evolving stricture or strangulation. See Small bowel obstruction. - Operative management: Indications for urgent or emergent surgery include signs of strangulation or perforation, a closed-loop obstruction, clear radiographic or clinical evidence of ongoing ischemia, and failure of nonoperative management within a reasonable time frame. Surgical options range from adhesiolysis (removal of adhesions) to bowel resection when necrotic tissue is present. See adhesiolysis, surgery, and bowel resection.

Surgical approaches vary with patient factors and surgeon preference: - Open surgery and laparoscopic approaches are both used, with laparoscopy offering potential benefits in reduction of postoperative adhesions and faster recovery in suitable cases. See laparoscopic surgery. - Intraoperative decisions may involve resection of nonviable bowel and restoration of continuity, along with measures to reduce recurrent obstruction, such as meticulous handling of bowel and consideration of temporary stomas in selected situations. See resection and stoma.

Prevention of adhesive disease where possible is a priority in surgical practice. Techniques to minimize adhesion formation, as well as the use of adhesion barriers in certain settings, are topics of ongoing discussion among surgeons and policymakers. See adhesions and adhesion barrier.

Controversies and policy debates

In discussions about intestinal obstruction, several debates reflect broader policy and clinical viewpoints: - Timing of intervention and resource use: Proponents of disciplined resource management argue for careful patient selection for nonoperative management to avoid unnecessary hospital stays and procedures, while caution is advised to prevent delays in recognizing strangulation. The balance between watchful waiting and early surgery is a central point of practice variation and guideline development. See guidelines and medical guidelines. - Imaging and diagnostic pathways: There is ongoing tension between reducing unnecessary imaging to lower costs and radiation exposure, and using high-quality imaging to correctly identify the obstruction’s cause and risk of strangulation. CT scan often provides critical detail, but some clinicians advocate more selective use of imaging. See radiology and medical imaging. - Defensive medicine and malpractice reform: Critics contend that medico-legal concerns drive excessive testing or hospitalization, raising costs without improving patient outcomes. Advocates for reform argue that improved liability protections and sensible limits could reduce waste while preserving patient safety. See medical malpractice and tort reform. - Access to care and outcomes: In systems with multiple payers or varying coverage, access to timely emergency care for obstruction can depend on insurance status and hospital resources. Proponents of market-based reforms emphasize competition and efficiency, while opponents warn of disparities in urgent treatment. See healthcare reform and emergency medical services. - Prevention of adhesions: Reducing adhesion formation remains a topic of technical debate, including the choice between open and laparoscopic techniques and the use of barrier methods. Advocates for practice improvements point to reduced reoperation rates, while others stress that evidence must guide widespread use. See adhesions and laparoscopic surgery.

Prognosis

The outcome for intestinal obstruction depends on the cause, speed of diagnosis, and timeliness of treatment. Mechanical obstructions that are relieved promptly without complications have good prospects, but delays or strangulation can lead to bowel necrosis, perforation, sepsis, and higher mortality. Early recognition and appropriate surgical or medical management are associated with better outcomes, and advances in imaging and perioperative care continue to improve prognosis. See prognosis and mortality.