0071643192.pdf

ABDOMINAL AND GASTROINTESTINAL

EMERGENCIES

TABLE 11.9. Common Causes of Large Bowel Obstruction

ETIOLOGY PATHOPHYSIOLOGY DIAGNOSIS/TREATMENT

Colorectal cancer Most common cause of LBO; history Diagnosis can be made with contrast enema or

may reveal change in bowel habits, colonoscopy. CT may be helpful in evaluating extension

rectal bleeding, weight loss and metastases. Treatment in cases of LBO is resection

of involved segment.

Diverticulitis Second most common cause of LBO; CT is diagnostic.

infection of the walls of diverticuli leads Treatment is conservative and includes broad spectrum

to bowel edema and secondary obstruction; antibiotics, NPO, NGT decompression, and fluid,

second most frequent cause of large-bowel electrolyte repletion.

obstruction

Occurs in 10–25% of pts with

diverticuli; incidence increases with age.

Right-sided diverticular disease is more

common in pts of Asian and African descent.

Sigmoid volvulus Rotation of a segment of bowel on an axis AXR: A single distended loop of bowel is seen rising out

formed by its mesentery; older pts, of the pelvis. Contrast enema: A dilated bowel loop

bedridden pts, and those w/ psychiatric with bird’s beak shape. CT is also diagnostic.

illness taking anticholinergic medications Treatment: Decompression with a scope or rectal tube

are at risk for sigmoid volvulus; history of may be successful. Resection and fixation are indicated for

constipation unsuccessful attempts and strangulation.

Cecal volvulus Congenital defect in the peritoneum AXR or contrast enema is diagnostic: Distended ovoid

resulting in the twisting of the mobile cecum that takes a “coffee bean” shape.

segment of the cecum; most common in Treatment is surgical.

younger men and gravid females

Intussusception Proximal segment of bowel invaginates Contrast enema is diagnostic and therapeutic in

into more distal segment; primarily a 60–80% of cases

disease of children Diagnosis may also be made with abdominal ultrasound

or CT; unsuccessful reduction with enema or

evidence of perforation treated with operative resection

Acute colonic Seen in elderly patients hospitalized with CT is diagnostic; correct underlying precipitating

pseudo-obstruction severe illness; massive dilatation (>10 cm disorder. Initial conservative management with bowel

(Ogilvie syndrome) in diameter) usually of the cecum and right rest, hydration and correction of electrolyte

colon in the absence of a mechanical abnormalities; avoid medications that slow colonic

obstruction;often an underlying surgical motility; pharmacologic treatment with neostigmine or

disorder or precipitated by a medical colonoscopic decompression may be effective in cases

disorder that do not resolve with conservative management

Surgical intervention is reserved for refractory cases or cases

complicated by perforation.

■ Emergent surgical consultation is imperative as operative management

is often necessary. Management may vary depending on etiology. (See

Table 11.9.)

■ Antibiotic regimens include tazobactam-piperacillin, cefotetan, ertape-

nam, or combination of a fluoroquinolone and metronizadole.