ISCHEMIC
COLITIS
Epidemiology: Most prevalent form of GI ischemia
(50-60%). RISK FACTORS include: 1) age
>60, 2) male, 3) cardiovascular disease, DM, renal insufficiency, and
hematologic disorders.
Clinical
features: Varied and
non-specific. Broad spectrum of disease
from mild, sub-acute to fulminant septic shock.
1. SNS/SXS: crampy abd pain, diarrhea,
hematochezia.
2. EXAM: fever, mild focal tenderness, guiac +.
3. LABS: mild leukocytosis, significant blood
loss RARE.
Diagnostic
tests
1. KUB: used to screen for free air or air in
bowel wall.
2. Colonoscopy/bx: test of choice. Findings vary from palor, edema, submucosal
hemorrhage and ulceration (non-gangrenous form) to gray-green or black mucosa
(gangrenous form). Findings are
non-specific, but segmental distribution is suggestive and bx can r/o other
causes.
3. CT: non-specific bowel-wall thickening, but
distribution may be suggestive.
4. Barium enema: may show classic
“thumb-printing.” Now rarely used.
5. Angiography: usually negative. May be useful to r/o mesenteric ischemia.
DDx: mesenteric ischemia, IBD, diverticulitis,
infectious colitis, pseudomembranous colitis.
Pathophysiology: Supply and demand.
1. Colon has lowest blood flow/weight ratio of
entire gut.
2. Watershed areas:
a. rectosigmoid: 75% of cases
b. splenic flexure: 25% of cases
c. right colon: 10% of cases
ETIOLOGIES:
Occlusive
1. Large artery- thrombus, embolus, ligation
(post colon resection or aortic surgery)
2. Small vessel disease- DM, vasculitis, XRT,
amyloid.
3. Venous- hypercoagulable state, portal HTN,
pancreatitis.
4. Mechanical- tumor, adhesions, prolapse,
volvulus, diverticular disease.
Non-occlusive
1. Shock
2. Medications- digoxin, diuretics,
catecholamines, estrogens, danazol, gold, NSAIDS, neuroleptics.
Classification:
Prognostic and treatment significance.
1. Non-gangrenous (80-85%): involves only
mucosa/sub-mucosa, low mortality.
a. transient, reversible (50%)(
responds well to conservative medical management
b. chronic
i. chronic segmental colitis: difficult
to distinguish from IBD( usually requires surgical intervention.
ii. strictures( may require surgical
intervention.
1. Gangrenous (15-20%): transmural, 50-60%
mortality( requires early surgical intervention.
Treatment: Supply and
demand. With conservative medical
management, siginificant improvement usually occurs within several days,
complete resolution within 2 wks.
1. IVF
2. Broad spectrum, empiric abx to cover colonic
flora.
3. Maximize O2 and blood delivery.
4. Bowel rest.
5. Serial colonoscopy to document healing.
INDICATIONS FOR SURGICAL
INTERVENTION
1. Sepis refractory to medical management
2. Peritonitis
3. Free air
4. Gangrenous bowel
5. >14d of sxs with medical management
Gandhi et al. Dis Colon Rectum. 1996; 39: 88-100.
Bower. Surg Clin N America. 1993;73:
1037-1053.