Intestinal Obstruction: Clinical Presentation
Subjective Complaints
Patients with intestinal obstruction typically present with colicky abdominal pain, nausea, vomiting, and inability to pass flatus or stool. 1
Key Symptoms to Elicit:
- Abdominal pain: Colicky, intermittent cramping pain that comes in waves 1, 2
- Nausea and vomiting: Progressive emesis that may become feculent in prolonged cases 1, 2
- Constipation: Failure to pass flatus or bowel movements (obstipation) 1
- History of prior abdominal surgery: Most reliable historical finding, as adhesions cause 70-90% of small bowel obstructions 3, 2
- Abdominal distension: Patient-reported bloating or visible enlargement 1, 2
Red Flag Symptoms Suggesting Strangulation or Ischemia:
- Fever 2
- Continuous severe pain (rather than colicky) suggesting ischemia 3
- Hemodynamic instability (hypotension, tachycardia) 2
- Diffuse abdominal pain with peritoneal signs 2
Objective Findings
Physical examination should focus on identifying abdominal distension, abnormal bowel sounds, peritoneal signs, and examination of all hernial orifices. 3
Critical Physical Examination Findings:
- Abdominal distension: Visible enlargement with tympany to percussion 1, 3
- Bowel sounds: High-pitched, hyperactive "tinkling" sounds in early obstruction; absent sounds suggest ileus or late-stage obstruction 1
- Hernial examination: Mandatory examination of inguinal, femoral, umbilical, and incisional sites for incarcerated hernias 3
- Peritoneal signs: Rebound tenderness, guarding, and rigidity indicate perforation or ischemia requiring immediate surgery 3, 2
Laboratory Abnormalities Indicating Complications:
- Leukocytosis with left shift: Suggests peritonitis or intestinal ischemia 3
- Elevated lactate: Strong indicator of bowel ischemia 3
- Elevated C-reactive protein: May indicate inflammation or ischemia 3
- Electrolyte disturbances: Hypokalemia, hypochloremia from vomiting and third-spacing 3
- Elevated BUN/creatinine: Indicates dehydration and renal injury 3
Diagnostic Imaging Findings
Computed tomography with intravenous contrast is the preferred imaging modality, with high sensitivity and specificity for diagnosing intestinal obstruction and identifying complications. 3
CT Findings:
- Transition point: Identifies exact location where dilated bowel becomes decompressed 3
- Degree of obstruction: Distinguishes complete from partial obstruction 3
- Cause identification: Adhesions, hernias, masses, volvulus 3
- Signs of ischemia: Bowel wall thickening, pneumatosis, portal venous gas, lack of enhancement 3
- Free air: Indicates perforation requiring immediate surgery 3
- Closed-loop obstruction: Two transition points with fluid-filled loop, high risk for strangulation 3
Plain Radiograph Findings (Limited Utility):
Clinical Pitfalls to Avoid
- Do not rely on plain radiographs alone: They miss 30-40% of obstructions; proceed to CT if clinical suspicion remains high 3
- Do not delay imaging in suspected strangulation: Peritonitis, fever, elevated lactate, or continuous pain mandate immediate CT and surgical consultation 3, 2
- Do not miss hernias: Examine all potential hernial sites including femoral canals in women and prior surgical incisions 3
- Recognize "virgin abdomen" obstruction: Adhesions occur in 1-10% of patients without prior surgery from congenital bands or inflammation 3