Enema in Acute Intestinal Obstruction
Enemas (barium or water-soluble contrast) are not recommended as primary treatment for acute intestinal obstruction, but water-soluble contrast enemas have diagnostic value and potential therapeutic benefits in specific cases of adhesive small bowel obstruction. 1
Diagnostic Value of Contrast Enemas
- Water-soluble contrast enemas have high diagnostic accuracy with 96% sensitivity and 98% specificity in diagnosing large bowel obstruction, making them a valid alternative when CT is unavailable 1, 2
- Water-soluble contrast studies can help distinguish mechanical obstruction from pseudo-obstruction, potentially preventing unnecessary surgery 3
- Small bowel follow-through with water-soluble contrast is widely used in adhesive small bowel obstruction for diagnostic purposes and can predict the need for surgery 1
- If contrast has not reached the colon on abdominal X-ray 24 hours after administration, this strongly indicates non-operative management failure 1
Therapeutic Role in Adhesive Small Bowel Obstruction
- Water-soluble contrast administration correlates with a significant reduction in the need for surgery in patients with adhesive small bowel obstruction 1
- The administration of water-soluble contrast can lead to a significant reduction in time to resolution and length of hospital stay 1
- Water-soluble contrast agents may have an active therapeutic role in adhesive small bowel obstruction, though evidence remains controversial and uncertain 1
Safety Considerations and Contraindications
- Potential life-threatening complications of water-soluble contrast include aspiration pneumonia and pulmonary edema 1
- To minimize complications, contrast medium should only be administered after adequate stomach decompression through a nasogastric tube 1
- Water-soluble contrast agents may further dehydrate patients due to their high osmolarity, shifting fluids into the bowel lumen 1
- In some children and elderly adults, the loss of plasma fluid may be sufficient to cause a shock-like state 1
- Rare anaphylactoid reactions following oral contrast media use have been reported 1
- Caution is warranted in patients at high risk of gastropathy 1
- Barium enemas should be avoided due to risk of barium inspissation causing obstruction, as documented in case reports 4
Administration Protocol
- The contrast medium may be administered at a dosage of 50-150 ml, either orally or via nasogastric tube 1
- It can be given both at immediate admission or after an initial 48-hour conservative treatment attempt 1
- Administering water-soluble contrast at 48 hours may reduce both aspiration pneumonia and dehydration risks, as the patient should be adequately rehydrated by then 1
- In this situation, the contrast material can be diluted with water 1
Role in Different Types of Obstruction
- For large bowel obstruction, CT with IV contrast is the preferred initial imaging modality, with water-soluble contrast enema as a valid alternative 5, 2
- For sigmoid volvulus without ischemia or perforation, endoscopic detorsion is recommended rather than enema 5
- For malignant large bowel obstruction, self-expanding metallic stents are preferred to enemas for both palliation and as a bridge to elective surgery 1, 5
Limitations and Alternative Approaches
- Enteroclysis (small bowel contrast study) is not useful in acute obstruction situations when the patient is ill due to its invasive nature 1
- CT with intravenous contrast is superior to contrast enemas for determining the cause and site of obstruction and for detecting complications 5, 2
- Plain abdominal X-rays have limited sensitivity (74-84%) and specificity (50-72%) and should only be used when other modalities are unavailable 2