SMALL BOWEL OBSTRUCTION

Topic discussion : Acute Abdomenนศพ. ณัฐรกิา กานาค ชัน้ปีท่ี 4

Small Bowel Obstruction

• Clinical manifestation• Epidemiology• Pathophysiology• Type• Complication• Diagnosis• Management

Clinical manifestation• The 4 cardinals signs

• Abdominal colicky pain• Vomiting• Abdominal distension• Absolute constipation (Obstipation)

Epidemiology• Intraluminal

• Foreign bodies• Bezoars• Gallstones• Parasites

• Extramural• Bands/adhesions• Hernia

• Intramural• Stricture• Crohn’s disease• Malignancy• Intussusception• Volvulus

Epidemiology

Pathophysiology• The distension proximal to an obstruction is caused by

two factors:• Gas: there is a significant overgrowth of both aerobic and

anaerobic organisms, resulting in considerable gas production. Following the reabsorption of oxygen and carbon dioxide, the majority is made up of nitrogen (90 per cent) and hydrogen sulphide.

• Fluid: this is made up of the various digestive juices (saliva 500 mL, bile 500 mL, pancreatic secretions 500 mL, gastric secretions 1 litre – all per 24 hours). This accumulates in the gut lumen as absorption by the obstucted gut is retarded.

Pathophysiology

Pathophysiology

Pathophysiology• Dehydration and electrolyte loss are therefore due to:

• reduced oral intake• defective intestinal absorption• losses as a result of vomiting• sequestration in the bowel lumen• transudation of fluid into the peritoneal cavity

Type• Proximal or Distal• Partial (incomplete) or Complete• Simple or Strangulation• Mechanical or Functional

SBO : Strangulation

SBO : Strangulation• Localized abdominal tenderness• Constant pain, severe pain• Fever• Tachycardia• Leukocytosis• Acidosis

Diagnosis

• History• Physical

examination• Acute abdomen

series• Dilated small

bowel loop• Air-Fluid Level• Absent or

decrease large bowel gas

Diagnosis

• History• Physical

examination• Acute abdomen

series• Dilated small

bowel loop• Air-Fluid

Level• Absent or

decrease large bowel gas

Diagnosis

• History• Physical

examination• Acute abdomen

series• Ultrasound• CT scan• Small bowel

series or Enteroclysis

ManagementSupportive Tx• NPO• Fluid Resuscitation & urine output monitoring• Pass NG tube( diagnostic/therapeutic purpose)• I.V antibiotics if indicated : Enteric Gram-negative bacilli,

anaerobes, enterococci

Symptomatic Tx• Analgesia after confirming diagnosis

Specific Tx• Surgery

Management

ManagementImmediate operation• Complete SBO• SBO with

• Peritoneal sign• Suspected or confirm Strangulation• Incarcerated strangulated hernia• Closed loop obstruction

ManagementMore conservative (Nonoperative management)• Early postoperative bowel obstruction • Inflammatory bowel • Infectious small bowel disease – Patients who present

with a partial small bowel obstruction due to tuberculosis may improve with medical management, although, similar to Crohn’s disease, delayed diagnosis is more likely to require surgery.

• Colonic diverticular disease causing small bowel obstruction – Antibiotic therapy reduces peridiverticular inflammation and may relieve obstructive symptoms.