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Bowel obstruction. By definition. is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion. Extrinsic lesions Adhesions 50-70% Hernia: internal or external 25% Volvulus 5% Masses Bowel wall lesions Neoplasm 5%
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By definition is a mechanical or functional obstruction of the intestines, preventing the normal transit of the products of digestion.
Extrinsic lesions Adhesions 50-70% Hernia:internal orexternal 25% Volvulus 5% Masses Bowel wall lesions Neoplasm 5% Inflammatory Vascular insufficiency Intramural hemorrhage Stricture ,atresia Luminal occlusion Swallowed (bezoar, gallstone, ascaris) Intussusception Tumor Small bowel obstruction
Small bowel obstruction • Plain film • >3 bowel loops • >3 cm 3-5 hr • Air-fluid level • Disparity in size between obstructed loops and contiguous loops beyond site of obstruction. • Little/no gas in colon 12-24hr • CT • Small bowel dilatation>2.5 cm • Small bowel feces • Transition zone
Small bowel obstruction • CT • Circumferential thickening of bowel wall, target sign. • Beaklike narrowing at the site of obstruction • Unusual course of mesenteric vessels • Specific enhancement patterns of the bowel wall • Mesenteric haziness • Engorgement of mesenteric vessels • Mesenteric fluid • Pneumatosis intestinalis • Portomesenteric venous gas
SBO-strangulation a 55-year-old woman presenting with features of intestinal obstruction shows dilated loops of the small bowel associated with thickened edematous valvulae conniventes and a strangulated left inguinal hernia (arrow).
Small bowel obstruction • Closed loop obstruction _U or C shaped dilated loops • Increasing intraluminal fluid • “Beak sign” • “Whirl sign”- twisting bowel and mesentery
SBO- closed loop obstructionThere is bowel wall thickening and mesenteric edema indicating ischemia
SBO-mass A CT scan of a 36-year-old woman. The axial contrast-enhanced CT scan through the midabdomen shows an extrinsic mass compressing a loop of small bowel.
Electrolytes- hypokalemia Ischemic event Medications (anticholinergic, antidepressants) Neuromuscular disorder (DM, porphyria, lead posisoning, hypothyroidism, amyloidosis, scleroderma, vagotomy etc.) Chest disease (LL pneumonia, pleuritis, MI, pericarditis, CHF) Retroperitoneal disease (hematoma, abscess). Post operative Visceral pain Intraabdominal inflammation Paralytic ileus
Paralytic ileus • Large + small bowel distention • Delayed but free passage of contrast material
Colonic obstruction • Extrinsic • Mass impression- endometriosis, abscess, tumor • Volvulus • Hernia • adhesions • Bowel wall lesions • Tumor (carcinoma) • Inflammtory • Infectious • Wall hematoma • Luminal obstruction • Fecal impaction • Intussusception
Colonic obstruction • Plain film • Dilated colon +/- small bowel dilatation • Gas fluid levels • 75%- the cecum is the most dilated portion. >10 cm high probability for perforation.
Acute colonic pseudoobstruction- Ogilvie syndrome • Metabolic imbalance • Drugs • Retropertoneal trauma • Abdominal/ cardiothoracic surgery • Age >60y • Massively dilated colon (Rt. hemicolon) • Normal haustral marking • Absence of obstructing lesion.
Acute fulminant colitis Neurogenic loss of motor tone Extensive colonic dilatation Systemic toxicity Profuse bloody diarrhea Mortality- 20% Etiology: UC, CD, IC Toxic megacolon
Toxic megacolon • Colonic ileus with marked dilatation of transverse colon • Air fluid levels • Loss of normal colonic haustra • Pneumatosis coli +/- pneumoperitoneum • Irregular mucosal surface