Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A1-G Surg Note Large Bowel > Toxic Megacolon > Flashcards

Toxic Megacolon Flashcards

1
Q

most commonly seen as a complication of

A
  • inflammatory bowel disease (IBD)
    more commonly ulcerative colitis (UC)
  • Clostridium difficile– associated (pseudomembranous) disease (CDAD).
  • In cases of IBD, toxic megacolon results as a progression from fulminant colitis.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fulminant colitis

A
  • severe inflammation of the colon with associated systemic toxicity with or without colonic dilatation.

in UC, fulminant colitis is diagnosed by the presence of

  • bloody diarrhea more than 10 times
  • heart rate higher than 90 beats/ min
  • temperature above 37.5 ° C
  • requirement of blood transfusion
  • erythrocyte sedimentation rate (ESR) more than 30 mm/ hr
  • with the presence of abdominal distension and tenderness on clinical examination, and dilated colon on x-ray.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

CDAD

A

CDAD severity, fulminant colitis is diagnosed by the presence of a

  • heart rate above 120 beats/ min
  • leukocytosis with more than 30% bands
  • severe oliguria
  • requirement of mechanical ventilator and vasopressors.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Toxic megacolon

A
  • segmental or total colonic distension of 6 cm or more in the presence of acute colitis with systemic toxicity.
  • Radiologically, it typically exhibits dilatation of the proximal colon with thickened inflamed distal colon and associated pneumatosis.
  • Unlike colonic obstruction, in which cecal dilation with perforation is a concern, the transverse colon is the most common area of dilatation in toxic megacolon.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Causes of Toxic Megacolon

A

Any inflammatory condition of the colon
-IBD, infectious causes including pseudomembranous colitis caused by C. difficile or other bacteria, such as Salmonella, Shigella, Campylobacter, or Entamoeba, and ischemic colitis

Chemotherapy Colonoscopy Barium enema Drugs that slow colonic motility (narcotics, antidiarrheal drugs, anticholinergic drugs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

pathogenesis of the toxic dilatation

A
  • Severe mucosal inflammation becomes transmural,
    extends into the smooth muscle layer > loss of motor tone and paralysis.
  • Severely inflamed smooth muscle produces nitric oxide, which is released into the colonic wall and further inhibits smooth muscle tone and causes dysmotility and atony.
  • Causes dilatation of the colon proximal to the colonic segment that is severely inflamed.
  • The toxic systemic response results from bacterial translocation and subsequent bacteremia.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

other factors that can affect colon motility

A

hypokalemia
hypomagnesemia
opiates
anticholinergic or antimotility agents
antidepressants
barium enemas
colonoscopy

may affect adversely colonic motility and exacerbate colon Dilatation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Diagnosis of Toxic mega Colon

A

Based in Clinical and Radiological findings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

diagnosis must be suspected in patients who have

A

diarrhea
abdominal distension
and signs of systemic toxicity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

patient’s history

A
  • Symptoms of severe colitis :
    severe diarrhea (usually bloody)
    abdominal pain
    fever, chills, and tachycardia.
    Hx of previous diagnosis of IBD
    medical therapy
    recent use of antibiotics
    other medications such as steroid, antimotility, and chemotherapeutic agents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

It is not uncommon that peritoneal signs maybe masked by

A

high dose steroid treatment typically used in IBD patients with fulminant colitis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Clinical criteria for the diagnosis of toxic megacolon

A
  • The Presence of three of the following for the clinical diagnosis:
    1- fever higher than 101.5 ° F (38.6 ° C)
    2- heart rate higher than 120 beats/ min
    3- white blood cell count above 10.5 (× 109/ L)
    4- anemia.
  • Should have one of the following criteria:
    1- dehydration
    2- mental changes
    3- electrolyte disturbances
    4- or hypotension.
  • Abdominal x-ray confirming the diagnosis of toxic megacolon > proximal colonic distention
    Dilatation of the ascending and transverse colon that varies from ( 6 cm up to 15 cm )
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What Radiological Sign may indicate for pending perforation ?

A

Transverse colon is dilated past 8 cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Other radiologic features include

A
  • Presence of air fluid levels
  • Loss of normal haustral pattern in the colon
  • Thickening and edema of colonic wall
  • Small bowel and gastric distension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

CT findings indicative of severe colitis

A
  • colonic wall thickening
  • submucosal edema
  • pericolic stranding
  • thickened haustra
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Laboratory tests are not specific, but include

A
  • leukocytosis
  • anemia
  • elevated ESR
  • serum C-reactive protein
  • electrolyte abnormalities with hypokalemia, hypomagnesemia, and hypoalbuminemia
  • Stool sample for culture, sensitivity, and C. difficile toxin assay
  • blood culture
17
Q

what is the two-stage test approach, and why used ?

A
  • Stool culture is highly sensitive but it does not differentiate between the presence of Clostridium bacteria and active infection.
  • Initial screening with glutamate dehydrogenase assay followed by confirmation of a positive test with cell cytotoxicity assay.
18
Q

In Patient not known to have IBD , What to do next ?

A
  • Limited endoscopy, proctoscopy, or sigmoidoscopy may be considered to determine the cause of toxic megacolon

pseudomembranes > CDAD
presence of inclusion bodies in the biopsies > (CMV) colitis

19
Q

How to Perform scope ?

A
  • extreme caution
  • without bowel preparation
  • minimal air insufflation
  • the endoscope should be advanced only as far as necessary to make a diagnosis.
  • Complete colonoscopy should not be performed because of the high risk of perforation.
20
Q

Medical Therapy

A
  • NO NGT
  • Frequent Position to redistribute the Air
  • Bowel Rest
  • IV Fluids
  • Correct electrolyte, Dehydration and Anemia
  • DC Meds That affect Motility
  • Start DVT Prophylaxis
  • Start Gastric Ulcer Prophylaxis
  • Start Abx
  • DC any agent that cause C.Diff
  • Frequent Clinical assesemnt
  • Physical exam
  • Serial Blood Counts and electrolytes
  • Abdominal Xrays
21
Q

Management algorithm for toxic megacolon.

A

see

22
Q

Management of Patients with Inflammatory Bowel Disease

A
  • High-dose intravenous steroid (hydrocortisone 100 mg every 6 hours) > Immediately to prevent progression to Toxic mega Colon
23
Q

If no response to Steroids ?

A
  • cyclosporine and antitumor necrosis factor-alpha (TNF-α) are immunosuppressant medications used in severe cases of UC.
  • Both medications are initiated if there is no response to high-dose intravenous steroids within 3 days.
24
Q

Which Drug Can reduce the need for Emergent Surgery

A

Some data suggests >
cyclosporin may have an initial effect in 80% of patients with severe fulminant colitis bordering on toxic megacolon and therefore may reduce the need for emergent surgery.

25
Q

Management of Patients with Clostridium difficile– Associated Disease

A
  • Antibiotics thought to have initiated the C. difficile infection should be withdrawn immediately
  • Oral vancomycin (125– 500 mg four times a day)
  • and/ or oral metronidazole (200– 500 mg four times a day, or 500 –750 mg three times a day) is initiated.
  • Intravenous metronidazole is also acceptable.
26
Q

If a patient cannot tolerate oral vancomycin because of severe ileus ?

A

it may be administered via an enema or nasogastric tube.

27
Q

Delay in surgical intervention carries a risk of developing

A

abdominal complications such as colonic Perforation and Abdominal Compartment Syndrome

Mortality increase to 50 %

28
Q

Absolute indications for Surgery

A
  • Progressive colonic dilatation
  • Uncontrolled hemorrhage
  • Complications such as Free perforation
  • General clinical deterioration such as
    Progressive sepsis with continued tachycardia, hypotension, or the need for presser agents.
  • Lack of improvement within 48 hours is also a relative indication for surgical intervention.
29
Q

Surgery typically is performed through an open approach, Why ?

A
  • The significant colon dilatation and friability of the colonic Wall
  • Patient usually unstable
30
Q

May go with Lap with fulminant colitis If

A
  • not progressed to toxic megacolon
  • colonic distention will not interfere with laparoscopic visibility
  • hemodynamically stable
  • not on any pressor medications
  • colonic wall does not appear significantly thinned or necrotic
31
Q

The current surgical standard of care for patients with toxic megacolon

A

total colectomy with end ileostomy.

RECTUM NOT RESECTED even IF IT IS INFLAMED

32
Q

During hepatic and splenic flexures mobilization

A

the colonic mesentery is divided close to the bowel wall to avoid damage to retroperitoneal structures.

33
Q

Difficult Rectal Stump

A
  • If the rectosigmoid junction appears too inflamed to hold staples or sutures, then the surgeon should leave a short segment of sigmoid colon to form a mucous fistula to decompress the remaining colon and rectum.
34
Q

In obese patients

A
  • The rectal stump may be brought through the inferior aspect of the midline fascial incision and left buried in the subcutaneous space.
  • This will be removed at time of stoma reversal, and if the stump blows out, it allows for decompression through the wound as opposed to in the peritoneal cavity.
35
Q

If a rectal stump is left in the peritoneal cavity

A
  • decompressed in the operating room with a rectal tube that is left in place to allow for further postoperative decompression and possible vancomycin enemas.
36
Q

When Rectal Stump Leak

A

A rectal stump leak typically occurs 5 to 10 days after surgery

therefore, if a patient manifests signs of peritonitis 5 to 7 days after surgery > high suspicion for rectal leak.

Emergent return to the operating room with washout and drainage is necessary.

37
Q

Postoperative care

A
  • Intensive care unit
  • Preoperative antibiotics are discontinued within 24 hours
  • Intravenous steroids are tapered to a maintenance dose (equivalent of 10– 20 mg of prednisone per day)
  • On restoration of gastrointestinal motility
    enteral feeding is given.
  • The rectal tube is removed on the fifth to seventh postoperative day.
38
Q

The mortality rate after colectomy for CDAD remains high 41.3%, What are the Predictors ?

A
  • Preoperative intubation
  • acute renal failure
  • multiorgan failure
  • and requirement of vasopressors

A1-G Surg Note Large Bowel (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions