Exam 2 - Bowel Obstruction Flashcards
What is the difference between a partial and complete bowel obstruction?
Partial - fluid/air continue to pass
Complete - cessation of passage of stool or flatus
What are the three major causes of bowel obstruction?
- Extrinsic/Extra-luminal (external to bowel)
- Intrinsic (within wall of bowel)
- Intraluminal (defect that prevents passage of GI contents)
What is the pathophysiology behind a bowel obstruction?
Obstruction leads to bowel dilatation and retention of fluid within lumen proximal to obstruction, while distal to obstruction, bowel decompresses
What is the pathophysiology behind the complications of a bowel obstruction?
Excessive dilatation can compromise vascular supply leading to poor perfusion which can result in complications of: Ischemia –> Necrosis –> Perforation
What is the most common etiology/risk factor for a mechanical small bowel obstruction?
What are two other main causes?
Adhesions from prior abdominal/pelvic surgery
Hernia and Neoplasm
What clinical presentation is associated with a small bowel obstruction?
- Abdominal pain (periumbilical, intermittent, “cramping”)
- Abdominal bloating/distention
- Anorexia
- Nausea/Vomiting
- Constipation
- Obstipation (inability to pass flatus or stool)
- Possible hematochezia, fever/chills
Your patient presents with periumbilical, intermittent, “cramping” abdominal pain along with other symptoms which makes you concerned for a small bowel obstruction. Their pain has now become more focal and constant. What should you be concerned for now?
Peritonitis
What may be found on physical exam, including red flags, in a patient with a small bowel obstruction?
- Lying motionless (red flag)
- Abdominal distention
- High pitched “tinkling” bowel sounds (early phase) or hypoactive/absent (late phase)
- Diffuse or localized abdominal tenderness
- Peritoneal signs (red flag)
What will be seen on a supine and upright abdominal x-ray in a patient with a small bowel obstruction?
Dilated loops of bowel with air fluid levels
Why would you obtain a chest x-ray in a patient with possible small bowel obstruction?
Look for free air under diaphragm consistent with a perforation
What will be seen on a CT abdomen in a patient with a small bowel obstruction?
- Dilated proximal bowel with distal collapsed loops
- Bowel wall thickening > 3 mm
- Submucosal edema
What is the non-surgical management of a small bowel obstruction?
- Admit with general surgery/GI consult
- NPO
- Volume resuscitation (IV fluids and electrolyte replacement/management
- Bowel decompression with NG tube
- Anti-emetics, Analgesics, +/- Antibiotics
- Serial clinical monitoring over next 2-5 days (improvement marked by decrease in distention, passage of flatus/stool, decrease in NG output)
What are some indications for surgical exploration of a small bowel obstruction?
Complicated bowel obstruction (ischemia, necrosis, perforation)
- Evidenced by worsening pain, fever, tachycardia, leukocytosis, metabolic acidosis, peritonitis
Intestinal Strangulation
Worsening symptoms or unresolved symptoms with NG tube and bowel rest
What are causes of intestinal strangulation?
- Strangulated hernia
- Volvulus
- Intussusception (rare in adults, almost always associated with a tumor)
What is an ileus?
Hypomotility of GI tract in absence of mechanical bowel obstruction (loss of peristalsis)
What is the most common cause of an ileus?
What are some other causes?
Postoperative abdominal surgery (results from inflammatory response to intestinal manipulation/trauma)
Use of hypomotility agents (opioids, antispasmodics, anticholinergics)
How does a patient present clinical with an ileus?
Abdominal pain, distention, bloating, “gassiness”, nausea, vomiting, inability to tolerate PO (similar to SBO)
What will be seen on a 3-way abdominal x-ray series in a patient with an ileus?
- Dilated loops of bowel BUT air is present in both small and large bowel.
- NO air fluid levels
What is the management for an ileus?
- IV fluids and electrolyte replacement
- Pain management with NSAIDs (avoid narcotics)
- Bowel rest (NPO/clear liquid diet)
- Bowel decompression with NG tube if persistent nausea/vomiting
What is the most common etiology of a large bowel obstruction?
What are some other common causes?
Adenocarcinoma (colon and rectum)
Volvulus (sigmoid), fecal impaction
What is a volvulus?
Abnormal twisting of a portion of the GI tract, usually the intestine, which can impair blood flow
What will be seen on an abdominal x-ray that is consistent with a large bowel obstruction?
Dilated bowel proximal to obstruction
What are risk factors for sigmoid volvulus?
- Chronic constipation
- Redundant sigmoid colon
- Colonic dysmotility
- Hypomotility agents
What diagnostic studies are considered for possible sigmoid volvulus?
- Upright abdominal x-ray
- CT scan
- Contrast enema (diagnostic and therapeutic)
What is the management for sigmoid volvulus?
- Flex Sig to decompress and de-rotate
- Surgery to resect redundant sigmoid colon and prevent recurrence
What diagnostic studies are considered for possible cecal volvulus?
- Upright abdominal x-ray (dilated cecum typically displaced medially superiorly)
- CT scan (diagnostic)
What is the management of cecal volvulus?
Surgery
