SMALL-BOWEL OBSTRUCTION
I. Definition
A. Blockage of the lumen of the intestine that prevents normal functioning and results in distention and tremendous losses of fluid into the gut
B. Necrosis with toxicity and possible perforation may occur with strangulation.
II. Etiology
A. Adhesions—most common
B. Hernias—external and internal
C. Volvulus—twisting of the bowel on itself, causing obstruction
D. Strictures—due to
1. Crohn’s disease
2. Radiation
3. Ischemia
E. Hematomas—related to
1. Trauma
2. Anticoagulants
F. Intussusception—slipping of one part of an intestine into another part just below it
G. Feces (impaction)
H. Tumors
I. Foreign bodies
IV. Laboratory/diagnostic findings
A. Leukocytosis may be present.
B. Hemoconcentration and electrolyte imbalances
C. Supine and upright abdominal x-rays
1. Ladder-like pattern of dilated bowel with air-fluid levels
2. Little or no air in the colon or rectum with complete obstruction
3. Thickening or “thumbprinting” of the intestinal wall with strangulation
D. Transabdominal ultrasonography
1. Noninvasive, radiation-free method
2. Well tolerated by patients with acute abdominal symptoms
3. Accurate and highly specific in the diagnosis of SBO
E. Barium radiography confirms the diagnosis if there is uncertainty.
F. CT
1. Shows abdomen in cross section to uniquely diagnose
2. Used to decide the level and cause of obstruction when undetermined by x-ray
3. Superior to ultrasound and x-ray, with 94% accuracy in diagnosing SBO
G. Small bowel feces sign
1. Found in 82% of patients
2. Solid material containing gas bubbles found in a segment of dilated bowel
3. Be careful not to mistake feces in the cecum for SBO at the ileocecal valve.
H. A key diagnostic sign is a finding of a discrete transition point between dilated SBO and collapsed, nondistended SBO; this localizes the point of obstruction.
V. Management
A. IV fluids and electrolyte replacement as indicated
B. Nasogastric tube (NGT) to lower wall suction
C. Initiate broad-spectrum antibiotics if strangulation is suspected (e.g., cefoxitin [Mefoxin], 1-2 g every 6 to 8 hours IV piggyback, cefotetan [Cefotan]).
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