Bowel Obstruction Clinical Features

Bowel Obstruction

• Small bowel obstruction causes periumbilical pain and cramp with paroxysms of pain occurring every four or five minutes.
• Focal and constant pain may indicate peritoneal irritation related to complications (ischemia, bowel necrosis).
• Proximal small bowel obstruction can cause severe nausea and vomiting.
• Large bowel obstruction presentation depends on the location and etiology of the obstruction.
• Tumor (Colonic adenocarcinoma) is the most common cause of large bowel obstruction, followed by adhesive disease and volvulus.

Clinical Features

• Dehydration is a hallmark feature of bowel obstruction, characterized by tachycardia, orthostatic hypotension, and reduced urine output.
• Fever may be associated with infection or complications of obstruction.
• Hematochezia can be a sign of tumor, ischemia, or inflammatory mucosal injury, or intussusception.
• Abdominal inspection reveals distention, surgical scars, and abdominal wall hernia.

Diagnosis

• History and examination confirm the diagnosis, with plain radiography and CT of the abdomen being the most practical and useful diagnostic tools.
• Plain radiographs are used to quickly confirm a diagnosis, while CT of the abdomen characterizes the nature, severity, and potential etiologies of the obstruction.

Pathophysiology

• Luminal obstruction leads to progressive dilation of the intestine proximal to the blockage, while distal to the blockage the bowel decompresses as luminal contents pass.
• Swallowed air and gas from bacterial fermentation can accumulate, adding to bowel distention.
• The bowel wall becomes edematous, normal absorptive function is lost, and fluid is sequestered into the bowel lumen.

Risk Factors

• Prior abdominal or pelvic surgery
• Abdominal wall or groin hernia
• Intestinal inflammation
• History of or increased risk for neoplasm
• Prior abdominal or pelvic irradiation
• History of foreign body ingestion

Clinical Presentation

• Abrupt sudden onset of abdominal pain, nausea, vomiting, and abdominal distention
• Intermittent, acute symptoms that resolve only to recur again
• Some patients with chronic, partial obstruction may develop superimposed symptoms and signs of acute bowel obstruction

Symptoms

• Abdominal pain in 70-92% of patients
• Vomiting in 77-82% of patients
• Absence of passage of flatus in 90% or stool in 81% of patients

Differential Diagnosis

• Nausea and vomiting may be a manifestation of many disorders
• Bowel obstruction is uncommon relative to all possible causes of nausea and vomiting and abdominal pain
• Pain often precedes vomiting when associated with an acute surgical etiology

Adynamic (Paralytic) Ileus

• Causes include post-operative complications, peritonitis, trauma, intestinal ischemia, and medications
• Exacerbated by electrolyte disorders, particularly hypokalemia
• Initial return of bowel function and oral intake, followed by nausea, vomiting, abdominal pain, and distention, indicates mechanical bowel obstruction

Intestinal Pseudo-Obstruction

• A chronic condition characterized by symptoms of recurrent abdominal distention associated with nausea, vomiting, and diarrhea
• The colon is generally affected more than the small intestine
• No mechanical cause can be demonstrated, and the patient frequently has a history of several previous operations for bowel obstruction during which no cause for obstruction could be found.

Learn about the clinical features of small bowel obstruction including periumbilical pain, cramping, and complications like ischemia and necrosis. Understand the presentation of large bowel obstruction based on location and etiology.