26/06/2022
Intestinal obstruction (Bowel Obstruction)
Bowel obstruction refers to the interruption of the normal passage of bowel contents through the bowel, either due to a functional or mechanical obstruction.
Functional bowel obstruction, or paralytic ileus, is a temporary disturbance of peristalsis in the absence of mechanical obstruction.
Mechanical bowel obstruction is the interruption of normal passage through the bowel due to a structural barrier.
Mechanical bowel obstruction can be classified as either a small bowel obstruction (SBO) or large bowel obstruction (LBO) according to its location, and, depending on the extent of the obstruction, as either partial or complete.
Postoperative bowel adhesion is the most common cause of SBO and malignancy is the most common cause of LBO.
Regardless of the cause, bowel obstruction typically manifests with nausea, vomiting, abdominal pain, abdominal distention, and constipation or obstipation.
Bowel sounds are increased and high-pitched in the early phases of bowel obstruction and decreased or absent in the later stages.
Bowel distention leads to third-space volume loss, resulting in dehydration and electrolyte abnormalities.
The symptoms of bowel obstruction are typically less severe in partial bowel obstruction than in total bowel obstruction.
A diagnosis of bowel obstruction should be confirmed on radiological imaging
Typical findings include dilated bowel loops proximal to the obstruction, collapse of bowel loops distal to the obstruction, and multiple air-fluid levels.
Laboratory tests are needed to assess severity (e.g., metabolic acidosis and elevated serum lactate suggest bowel ischemia) and identify acid-base and electrolyte imbalances.
A trial of nonoperative management (NOM), which includes bowel rest and supportive care (such as IV fluids, analgesics, antiemetics, and, if needed, antibiotics) can be considered in patients with simple bowel obstruction with no evidence of complications.
Surgery is indicated for complicated bowel obstruction, closed-loop bowel obstruction, or if there is no clinical improvement following NOM for simple bowel obstruction.
The underlying cause of bowel obstruction should be sought for and managed appropriately.
