Clinical Cases - Peritoneal Cavity & Intestines

A fifty-four year old woman presents to your clinic with complaints of cramping, "colicky" abdominal pain, nausea and vomiting, severe constipation (obstipation), dizziness, and a fever for the past two days. Previous surgical history includes an appendectomy. On physical exam you note that her blood pressure is 75/40, heart rate 130, and her temperature is 102. Her abdomen is distended, and auscultation reveals intermittent high-pitched bowel sounds. On light palpation, peritoneal irritation is demonstrated by the presence of involuntary guarding and rebound tenderness. You order a CBC (complete blood count) which demonstrates a white blood cell count of 14,000. You also order an abdominal X-ray which reveals a small bowel obstruction with dilated small bowel loops (greater than 3 cm in diameter), multiple air-fluid levels within the small bowel and a lack of gas in the distal colon and rectum. The diagnosis of a small bowel obstruction is made, and the patient is sent to surgery for evaluation .

Questions to consider:
  1. What is small bowel obstruction?
    Mechanical obstruction of the bowel lumen, resulting in hyperactivity proximal to the obstruction and inactivity distal to the obstruction; with collection of gas and fluid proximal to the obstruction.
  2. What are some common causes of small bowel obstruction?
    Three types of causes may be identified:
    1) Mechanical: Due to tumors, intussusception (telescoping), impacted feces, and bezoars.
    2) Intrinsic: Congenital strictures and inflammatory diseases.
    3) Extrinsic: Due to postoperative adhesions, hernias, and neoplasms.
  3. What clinical findings are suggestive of small bowel obstruction?
    Crampy, "colicky" abdominal pain, nausea and vomiting, constipation, abdominal distension, the variable bowel sounds and the inflammatory signs of fever with subsequent tachycardia and hypovolemia suggested by the lowered blood pressure.
  4. What radiographic findings support the diagnosis of small bowel obstruction?
    The appearance of both air-fluid levels and the dilation of the small bowel loops proximal to the obstruction, with a lack of air distal to the obstruction within the colon.
  5. What is the accumulated gas visualized on the X-ray film?
    Nitrogen is not absorbed by the gastric mucosa and therefore moves through the GI tract during normal motility. The nitrogen is trapped proximal to the site of any luminal obstruction.
  6. What is the difference between simple and strangulating bowel obstruction?
    A simple bowel obstruction implies that the lumen itself is occluded; a strangulating lesion involves a segment of bowel looped back onto itself with a subsequent compression of the vasculature which supplies that region of bowel.