Colon

Blood supply of colon and rectum.

Vancomycin enemas can also be used if the patient has an ileus

Fecal enemas from a donor (fecal transplant) for patients with recurrent or drug-resistant C. difficile

High relapse rate (15%) after adequate therapy

Consider a subtotal colectomy if the patient has worsening sepsis despite adequate medical treatment

Other surgical indications include toxic megacolon, peritonitis, and organ failure

High surgical mortality rate

Clostridium difficile colitis is associated with the use of all antibiotics including metronidazole, clindamycin (most common), penicillins, and cephalosporins.

A 38-year-old male with AIDS presents with lower Gastrointestinal (GI) bleeding. What is the most common cause for this bleeding?

Immunocompromised patients such as HIV and transplant patients are at risk for opportunistic infections. In the GI system, the most common opportunist is cytomegalovirus (CMV), causing colitis.

Lower GI Bleeding

Etiologies include:

Anatomic: Diverticulosis, Meckel diverticulum, hemorrhoids

Vascular: Angiodysplasia, ischemia, radiation-induced

Inflammatory: Inflammatory bowel disease (IBD), idiopathic

Infections: C. difficile colitis, hemorrhagic E. coli

Neoplastic

Most common cause is diverticular disease (30% to 50%), yet only 15% of patients with diverticulosis will have bleeding

Most diverticular bleeds occur in the absence of diverticulitis and resolve spontaneously

Caused by disrupted vasa recta arterial bleeding

The most common cause of massive LGI bleeding is diverticulosis

50% to 90% of diverticular bleeds occur on the right side while most diverticular disease is on the left side

Angiodysplasia (Arteriovenous malformation, or AVM) is the most common cause of bleeding in elderly patients

Most common in cecum or ascending colon

Usually venous source

Bleeding usually self-limited

80% re-bleed if untreated

20% to 30% patients also have aortic stenosis (Heyde syndrome).

Treatment of bleeding includes argon plasma coagulation, endoscopic coagulation, injection sclerotherapy, or definitive surgical resection

While treatment should be individualized, broad indications for surgery include:

Transfusion of 4U PRBC within a 24-hour period

Persistent bleeding after 72 hours

Re-bleeding within 1 week of an initial episode

Remember that upper GI bleeding can cause lower GI bleeding. In fact, up to 15% of patients with lower GI bleeding have an upper GI source.

Workup of lower gastrointestinal (GI) bleeding.

An 82-year-old man underwent a hip replacement 8 days ago and now has a massively distended, non-tender abdomen. An abdominal X-ray (AXR) confirms marked colonic distension with a cecum measuring 9 cm and no obstruction seen on a gastrografin enema imaging study. What is the most likely diagnosis?

While identifying a possible source of obstruction is the first thought in any patient with a massively dilated colon, elderly patients without an obstruction are known to develop colonic pseudoobstruction, also known as Ogilvie syndrome.

Ogilvie Syndrome

Massive dilation of colon without mechanical obstruction

Common in elderly patients who are debilitated or have had recent surgery or trauma

Must rule out mechanical obstruction with a water-soluble contrast enema or CT with rectal contrast

Treatment

Most (85%) resolve with conservative treatment

Bowel rest

Correct fluid-electrolyte imbalances

Avoid narcotics and anticholinergics

Rectal tube decompression

If above measures fail or cecum is >10 to 12 cm:

Consider a cholinesterase inhibitor (IV neostigmine)

Neostigmine increases acetylcholine activity to induce coordinated colon propulsion

90% success rate but 25% will recur

Neostigmine is contraindicated in patients with cardiovascular disease, asthma, or on beta-blockers

Must administer in a monitored setting with atropine available, as patients can become profoundly bradycardiac

Consider colonoscopic decompression in patients who fail or have contraindications to neostigmine

Cecostomy is an option if the patient fails the above measures

Surgery is generally reserved for perforation or ischemia (rare)

Procedure of choice is subtotal colectomy with end ileostomy

A 90-year-old female from a nursing home was noted to have obstipation and a significant increase in her abdominal girth. She is brought to the hospital where an AXR demonstrated large loops of redundant colon in the left lower quadrant. She has no peritoneal signs. What is the next step in management?

Unless the patient already meets criteria for a surgical resection (worsening sepsis, perforation, etc.), a rigid or flexible sigmoidoscopy should be performed for immediate decompression of a sigmoid volvulus.

Sigmoid volvulus. (With permission from Mulholland MW, Lillemoe KD, Doherty GM, Maier RV, Upchurch GR, eds. Greenfield’s Surgery. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.)

Sigmoid Volvulus

Sigmoid colon is the most common site for colonic volvulus

Notorious in bedridden, institutionalized patients with neurologic or psychiatric conditions

Risk factors: Redundant sigmoid colon, bedridden patients, chronic constipation

Differential diagnosis includes obstructing colorectal cancer, cecal volvulus, and Ogilvie syndrome

AXR shows dilated redundant colon and “bent inner tube” sign, which can extend anywhere from the pelvis to the RUQ

Obtain a barium enema if AXR is equivocal

A classic “bird’s beak” points to the site of obstruction

Treatment is sigmoidoscopy to decompress and detorse the volvulus

Success rate 85%

Patients with perforation, peritonitis, hematochezia, gangrene or those who fail detorsion or fail to improve should undergo rapid resuscitation and surgical resection

60% of patients will have a recurrence after endoscopic detorsion and patients should undergo elective resection (sigmoid colectomy) during the same hospitalization. These patients should be nutritionally optimized and undergo full colonoscopy in the interim.

A 55-year-old woman presents with severe abdominal pain. Physical exam reveals a distended abdomen that is tympanitic and diffusely tender. She has a marked leukocytosis. AXR shows a dilated cecum extending to the left upper quadrant. A gastrografin enema confirms the diagnosis of cecal volvulus. What is the next step?

An ileocecectomy or right colectomy to include the involved area is indicated.

Cecal Volvulus

Less common than sigmoid volvulus

Differential diagnosis is the same as that for sigmoid volvulus

Treatment is resection with right hemicolectomy

Despite higher risk of recurrence, cecopexy can be considered in:

Poor medical candidates with a short life expectancy, with viable bowel

Patients with mild symptoms caused by cecal bascule (chronic intermittent obstruction caused by a floppy cecum that folds on itself leading to obstruction)

There is no role for neostigmine in the management of volvulus.

A 78-year-old man is found to have a stricture in the sigmoid colon on contrast studies. He has a history of multiple attacks of diverticulitis. What is the next step in his management?

A stricture often recurs following endoscopic dilatation. Surgical resection of the stricture with primary colon anastomosis is the definitive treatment and will rule out neoplasia.

Relation of diverticula to blood vessels. (With permission from Mulholland MW, Lillemoe KD, Doherty GM, Maier RV, Upchurch GR, eds. Greenfield’s Surgery. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.)

Diverticular Disease

“False” diverticula—involve herniation of the mucosa through the muscularispropria

90% of diverticular disease involves the sigmoid

35% of patients have disease outside the sigmoid

Incidence rises with age; 30% to 50% by age 60, 80% by age 85

Most patients are asymptomatic

One-third of patients present with complications (bleeding, abscess, stricture, or acute perforation)

Surgery is only indicated for patients with diverticular complications, recurrent bleeding, or multiple hospitalizations

One-third of patients require an operation

A 67-year-old woman presents with a 1-day history of fever, left lower quadrant pain, and leukocytosis. AXR shows significant free air. What is the most likely diagnosis?

Perforated diverticulitis is a common cause of sudden left lower quadrant pain and free air.

Diverticulitis

A CT scan with oral and IV contrast helps establish the diagnosis

Right-sided (atypical) diverticulitis is more common in younger and Asian patients

Hinchey classification

Stage I: Confined pericolic abscess

Stage II: Distant abscess (retroperitoneal or pelvic)

Stage III: Purulent peritonitis due to rupture of pericolonic/pelvic abscess but without communication with bowel

Stage IV: Fecal peritonitis due to free perforation of diverticulum with communication with bowel

Treatment

Mild diverticulitis: A course of oral broad-spectrum antibiotics and a low-residue diet

Must cover E. coli and Bacteroides fragilis

Severe diverticulitis: IV antibiotics, IV fluids, bowel rest and analgesics

If an abscess is seen, percutaneous drainage followed by elective resection in 6 to 12 weeks

Patients with generalized peritonitis and fecal contamination or worsening sepsis (Stage III or IV) require immediate surgery

All patients should undergo colonoscopy 6 weeks after episode of diverticulitis to rule out neoplasia

High recurrence rate

30% recur after first episode and 30% recur after second episode, however complications are most likely to occur with first episode

Elective resection recommended for patients with uncomplicated diverticulitis when the frequency and severity of episodes impact quality of life

Elective resection recommended after the first episode in immunosuppressed due to higher recurrence and complication rates

Elective operation is a simple resection with primary anastomosis

Choice of operation in an emergent situation depends on degree of inflammation and contamination

Anastomosis of severely inflamed/contaminated ends of bowel should be avoided given the risk of non-healing and subsequent leakage

Emergency operation choices include:

Hartmann procedure (resection of involved colon with the proximal end brought out as an end colostomy)

Resection with primary anastomosis ± proximal diversion with a “protective” diverting loop ileostomy

Placement of large external drains at the site of perforation ± proximal diversion with an ostomy (useful choice when dissection is very dangerous)

4% to 10% can recur even after surgical resection, especially when a portion of sigmoid colon is left in place

The choice to perform a diverting ostomy depends on the bowel tissue integrity and the degree of inflammation and contamination.

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Apr 20, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Colon

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