From the Guidelines
To assess for intestinal obstruction, a computed tomography (CT) scan with intravenous contrast is the most accurate diagnostic tool, offering superior sensitivity and specificity compared to conventional abdominal radiography and ultrasound. When evaluating a patient for intestinal obstruction, it is essential to begin with a thorough history and physical examination, focusing on symptoms like abdominal pain, vomiting, constipation, and abdominal distension 1. Ask about previous surgeries, hernias, or inflammatory bowel disease. During examination, check for abdominal tenderness, distension, visible peristalsis, and listen for high-pitched or absent bowel sounds. Perform a digital rectal examination to check for masses or impacted stool.
Some key points to consider when assessing for intestinal obstruction include:
- Order plain abdominal X-rays to look for dilated bowel loops and air-fluid levels, which are classic signs of obstruction 1
- CT scan with oral contrast is the gold standard diagnostic test, offering detailed information about the location and cause of obstruction 1
- Laboratory tests should include complete blood count to assess for infection or inflammation, electrolytes to check for imbalances from vomiting, and lactate levels which may be elevated in cases of bowel ischemia
- While waiting for diagnostic confirmation, place a nasogastric tube to decompress the stomach, maintain nil by mouth status, provide IV fluids for hydration, and administer pain medication as needed 1
It is crucial to note that early diagnosis is vital as intestinal obstruction can lead to serious complications including bowel ischemia, perforation, and sepsis if not promptly identified and treated 1. The use of CT scan with intravenous contrast can provide accurate information about the underlying cause of obstruction, identify potential complications, and guide preoperative planning 1.
From the Research
Assessment of Intestinal Obstruction
To assess for intestinal obstruction, the following steps can be taken:
- Clinical presentation: The clinical presentation generally includes nausea and emesis, colicky abdominal pain, and a failure to pass flatus or bowel movements 2, 3, 4.
- Physical examination: Classic physical examination findings include abdominal distension, tympany to percussion, and high-pitched bowel sounds 2, 4.
- Laboratory evaluation: Laboratory evaluation should include a complete blood count, metabolic panel, and serum lactate level 4.
- Radiologic imaging: Radiologic imaging can confirm the diagnosis, and can also serve as useful adjunctive investigations when the diagnosis is less certain 2. Abdominal CT with oral and intravenous gastrografin contrast is highly sensitive and specific in detecting/characterizing SBO 3.
Diagnostic Criteria
The diagnosis of intestinal obstruction can be suggested by the following:
- Abdominal pain, nausea and emesis, abdominal distention, and constipation-to-obstipation, which is the classical clinical tetrad 3.
- Severe direct tenderness, involuntary guarding, abdominal rigidity, and rebound tenderness suggest advanced SBO 3.
- Marked leukocytosis, neutrophilia, bandemia, and lactic acidosis also suggest advanced SBO 3.
Imaging Studies
Imaging studies that can be used to assess for intestinal obstruction include:
- Abdominal radiography: Although radiography is often the initial study, it may not be sufficient to confirm the diagnosis 2.
- Non-contrast computed tomography: Recommended if the index of suspicion is high or if suspicion persists despite negative radiography 2.
- Abdominal CT with oral and intravenous gastrografin contrast: Highly sensitive and specific in detecting/characterizing SBO 3.