Ischemic Colitis

Published on 19/07/2015 by admin

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Last modified 22/04/2025

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 Emboli to SMA from cardiac sources most commonly

image Affects right colon ± small bowel
image CT findings often subtle (ileus, lack of mucosal enhancement, no wall thickening acutely)
• Mesenteric venous thrombosis

image Thrombosis or filling defect in SMV
image Marked submucosal edema of affected colon (right > left) ± small bowel
image Marked infiltration of mesentery ± ascites
• Hypoperfusion ischemia

image Elderly, cardiac patients; recent hypotensive episode
image Affects “watershed” areas of colon (splenic flexure and descending colon > sigmoid)
image Rectum is rarely affected by ischemic colitis

TOP DIFFERENTIAL DIAGNOSES

• Diverticulitis
• Infectious (including Clostridium difficile) colitis
• Granulomatous colitis (Crohn disease)

PATHOLOGY

• Hypoperfusion: Predisposing factors

image Hypotensive episodes: Hemorrhagic, cardiogenic, or septic shock
image CHF, arrhythmia, drugs (e.g., digitalis), trauma

CLINICAL ISSUES

• Major predisposing cause in elderly: Nonocclusive vascular disease (hypoperfusion)

image Most common cause of colitis in elderly, often self-limiting
• Presentation: Bloody diarrhea, hypotension
image
(Left) Graphic shows luminal narrowing and wall thickening image near the splenic flexure, a “watershed” area between the vascular distribution of the SMA and IMA.

image
(Right) This 89-year-old man had pain and bloody diarrhea several hours after a hip arthroplasty procedure. Coronal reformatted CECT shows wall thickening and mucosal and mesenteric hyperemia affecting the descending colon image. Incidental renal allograft noted image.
image
(Left) Axial CECT in the same case shows submucosal edema and luminal narrowing of the descending colon image. The SMA and SMV are patent.

image
(Right) Another CT section in this patient shows wall thickening and pericolonic stranding of the descending colon image, whereas the remaining colon is normal. The rectum (not shown) was normal. These are classic clinical and CT features of ischemic colitis due to a hypotensive episode in an elderly patient.

TERMINOLOGY

Definitions

• Compromise of mesenteric blood supply leading to colonic injury

IMAGING

General Features

• Best diagnostic clue

image Symmetric, long segmental colonic wall thickening on CT
image Pneumatosis, mesenteric venous gas; more definitive but less common findings
• Location

image Watershed segments of colon

Radiographic Findings

• Radiography

image Supine abdominal films

– Normal or nonspecific ileus
– “Thumbprinting” (submucosal edema or hemorrhage)
– Luminal narrowing or transverse ridging (spasm)

Fluoroscopic Findings

• Barium enema

image Hallmark: Serial change on studies performed over days, weeks, or months
image “Thumbprinting”

– Usually within 24 hours after onset
– Thickened, nodular transverse folds (submucosal edema or hemorrhage)
– Most consistent and characteristic finding (75% of cases)
image Ulceration: Mucosal sloughing

– Usually 1-3 weeks after onset
– Longitudinal or discrete, superficial or deep, small or large collections of barium
image Stricture: 12% of cases heal with stricture formation
image Intramural barium: Rare, due to sloughing of necrotic mucosa

CT Findings

• NECT

image Circumferential, symmetric wall thickening ± “thumbprinting”

– Hypoattenuation of bowel wall: Submucosal or diffuse edema
– Hyperattenuation of bowel wall: Submucosal hemorrhage
image Luminal narrowing or dilatation, and air-fluid levels
image Pneumatosis: intramural gas in circumferential or band-like collections
image Gas in mesenteric and portal veins

– Tends to collect in periphery of liver (unlike biliary gas)
• CECT

image Findings vary by acuity, etiology, and severity
image Acute arterial thromboembolic

– Emboli to SMA from cardiac sources most commonly

image e.g., prosthetic cardiac valves, prior myocardial infarction, atrial fibrillation
image Symptoms are more likely to be acute and severe
– Occlusion or filling defect in lumen of superior mesenteric artery (SMA)
– Affects right side of colon ± small bowel
– CT findings often subtle (ileus, lack of mucosal enhancement)

image No bowel wall edema or mesenteric infiltration until reperfusion occurs
image Pneumatosis ± portal venous gas: Late findings of frank infarction
image Mesenteric venous thrombosis

– Often in hypercoagulable patients
– Thrombosis or filling defect in SMV
– Results in marked submucosal edema of affected colon (right > left) ± small bowel
– Marked infiltration of mesentery ± ascites
– Mucosal enhancement is often normal or increased
– Onset of symptoms more likely to be subacute and less severe
image Hypoperfusion ischemia

– Usually in elderly, cardiac patients; those with recent hypotensive episode
– Affects “watershed” areas of colon

image Splenic flexure: Junction of SMA and inferior mesenteric artery (IMA) (Griffith point)
image Left colon: Typical in elderly with decreased perfusion
image Sigmoid colon: Junction of IMA and hypogastric artery (Sudeck point)
– Rectum is rarely affected by ischemic colitis

Ultrasonographic Findings

• Color Doppler

image Hypoechoic bowel wall thickening
image Absent arterial flow in colon wall

Imaging Recommendations

• Best imaging tool

image CECT with multiplanar reformations

– Mucosal enhancement & submucosal edema are better seen without use of enteric contrast media
image Single-contrast barium enema for chronic disease (stricture detection)

DIFFERENTIAL DIAGNOSIS

Diverticulitis

• Long segment (usually sigmoid) involvement
• Diverticula and soft tissue density wall thickening
• Pericolonic infiltration ± extraluminal gas and fluid
• Sigmoid mesocolic vascular engorgement

Infectious (Including

• Usually pancolitis including rectum
• CECT: Marked submucosal edema (accordion sign)
• Mucosal hyperenhancement
• Ascites is common

Ulcerative Colitis

• Acute

image Distal rectosigmoid > pancolonic
image ± “backwash ileitis”
image Mucosal and mesenteric hyperemia
image Not as much colonic wall thickening as with infectious colitis
• Chronic

image Colonic foreshortening and loss of transverse folds

– “Windowpane” or “lead pipe” appearance
image Mucosal sloughing evolving into pseudopolyps

Granulomatous Colitis (Crohn Disease)

• Acute

image Favors distal small bowel ± colon
image Mucosal and mesenteric hyperemia
image Submucosal edema, luminal narrowing
image Mesenteric adenopathy
• Chronic

image Luminal strictures
image Mesenteric fibrofatty proliferation

Colon Carcinoma

• Soft tissue density, short segment, wall thickening
• Luminal narrowing or obstruction (especially for distal colonic tumors)

image Bulky, nonobstructing masses in ascending colon
• Adjacent lymphadenopathy ± transmural tumor extension
• Liver metastases

PATHOLOGY

General Features

• Etiology

image Most common vascular disorder of GI tract
image 90% of cases are segmental or pancolitis
image Hypoperfusion: Predisposing factors

– Hypotensive episodes

image Hemorrhagic, cardiogenic, or septic shock
image CHF, arrhythmia, drugs (e.g., digitalis), trauma
– Arteriosclerotic disease, chronic renal failure
– Upstream of colonic obstruction 

image Cancer or volvulus

Gross Pathologic & Surgical Features

• Segmental or focal; localized or diffuse
• Thickened bowel wall; dark red or purple discoloration

image Hemorrhagic, ulcerated mucosa

Microscopic Features

• Mucosal erosions, ulcerations, necrosis; submucosal edema, hemorrhage

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image Mild to severe abdominal pain
image Rectal bleeding, bloody diarrhea, hypotension
• Lab data

image ↑ leukocytosis, positive guaiac stool test
image Negative blood cultures; EKG changes may be seen

Demographics

• Age

image Usually elderly 

– > 60 years old
• Gender

image M = F
• Epidemiology

image Major predisposing cause in elderly: Nonocclusive vascular disease (hypoperfusion)

– Most common cause of colitis in elderly, often self-limiting

image Mortality rate estimated at 7%

Natural History & Prognosis

• Complications

image Reversible or transient ischemic is common
image Colonic stricture, gangrene of colon, perforation
image Transmural bowel infarction may cause perforation or even death
• Prognosis

image Transient, mucosal ischemia: Good
image Transmural infarction: Poor

Treatment

• Partial mural ischemia (nonocclusive)

image Conservative medical treatment; fluid resuscitation
• Transmural infarction

image Surgical resection of ischemic colon

DIAGNOSTIC CHECKLIST

Consider

• Consider history of cardiac, bowel, renal problems and hypotensive medication use in elderly

Image Interpretation Pearls

• Segmental bowel wall thickening in watershed areas
• “Thumbprinting,” pneumatosis, portal venous gas

image
(Left) This 69-year-old woman has aortic stenosis and was receiving medication for hypertension. She had sudden onset of abdominal pain and hematochezia. CT shows wall thickening in the proximal descending colon image, whereas the more proximal colon is gas-distended with a normal wall.
image
(Right) Axial CECT section in this case shows massive wall thickening (“thumbprinting”) of the sigmoid colon image. The rectum image is spared. Ascites image is noted. These are classic clinical and CT features of ischemic colitis.
image
(Left) This elderly patient has severe atherosclerosis and presents with abdominal pain and hypotension. NECT shows gas within the wall of the ascending colon image, which is otherwise relatively normal in appearance.

image
(Right) Coronal NECT in the same patient shows gas within the wall of the distal small bowel image as well as the ascending colon. Portal venous gas image is also present. These are typical features of thromboembolic occlusion of the SMA.
image
(Left) This man had abdominal pain and hematochezia following resuscitation for cardiac arrest during dialysis. CT shows mural thickening with submucosal edema throughout the ascending image and transverse colon (not shown).

image
(Right) Coronal CT in the same patient shows mural thickening and edema of the small bowel image, whereas the distal colonic wall image is normal. This distribution of ischemic injury likely resulted from a combination of atherosclerotic narrowing of the SMA and the hypotensive episode.
image
Axial NECT with rectal contrast shows ischemic colitis of the sigmoid colon. Note the prominent thumbprinting image due to submucosal hemorrhage.

image
Axial CECT of bowel ischemia shows the thickened colon wall with a thumbprinting appearance image.
image
Axial CECT in the same patient demonstrates thickening of the small intestine wall image and focal pneumatosis image.
image
Axial CECT shows acute IMA ischemia. The descending and sigmoid colon are both thick-walled with a small amount of pericolonic infiltration image. Note the abrupt transition to normal sigmoid colon image.
image
Coronal reformatted CT in the same patient better depicts the extent of the disease, which corresponds to inferior mesenteric artery vascular distribution image. Ischemia was confirmed endoscopically.
image
Axial NECT shows chronic ischemic colitis. Note the marked mural thickening of the sigmoid colon image.
image
Endoscopic image of the sigmoid colon in the same patient demonstrates extensive areas of denuded mucosa image.
image
Single-contrast BE in this elderly patient with heart disease shows the narrowed lumen of the splenic flexure with “thumbprinting” (thickened haustral folds) due to submucosal edema or hemorrhage.
image
Single-contrast BE in a 60-year-old man with chronic heart disease shows strictures of the distal transverse + proximal descending colon due to subacute colonic ischemia.
image
Axial CECT in a 60-year-old patient with subacute colonic ischemia shows wall thickening image, submucosal edema, and luminal narrowing of the colon.
image
Axial CECT of a patient 24 hours post abdominal trauma (motor vehicle crash) shows portal venous gas image.
image
Axial CECT shows intramural and mesenteric venous gas. At surgery this patient had “degloving” injury (serosal tear + devascularization) with cecal infarction.
image
Axial CECT shows a mass in the pancreatic head with a biliary stent image. The superior mesenteric artery and vein image are encased and narrowed. Gas is present in the colon wall.
image
Axial CECT in a patient with pancreatic cancer shows intramural and mesenteric venous image gas present due to colon infarction.

SELECTED REFERENCES

1. Sise, MJ. Acute mesenteric ischemia. Surg Clin North Am. 2014; 94(1):165–181.

2. Raman, SP, et al. MDCT and CT angiography evaluation of rectal bleeding: the role of volume visualization. AJR Am J Roentgenol. 2013; 201(3):589–597.

3. Tadros, M, et al. A review of ischemic colitis: is our clinical recognition and management adequate? Expert Rev Gastroenterol Hepatol. 2013; 7(7):605–613.

4. O’Neill, S, et al. Systematic review of the management of ischaemic colitis. Colorectal Dis. 2012; 14(11):e751–e763.

5. Green, BT, et al. Ischemic colitis: a clinical review. South Med J. 2005; 98(2):217–222.

6. Korotinski, S, et al. Chronic ischaemic bowel diseases in the aged—go with the flow. Age Ageing. 2005; 34(1):10–16.

7. Ripolles, T, et al. Sonographic findings in ischemic colitis in 58 patients. AJR Am J Roentgenol. 2005; 184(3):777–785.

8. Sreenarasimhaiah, J. Diagnosis and management of ischemic colitis. Curr Gastroenterol Rep. 2005; 7(5):421–426.

9. Wiesner, W, et al. CT of acute bowel ischemia. Radiology. 2003; 226(3):635–650.

10. Horton, KM, et al. Volume-rendered 3D CT of the mesenteric vasculature: normal anatomy, anatomic variants, and pathologic conditions. Radiographics. 2002; 22(1):161–172.

11. Horton, KM, et al. Multi-detector row CT of mesenteric ischemia: can it be done? Radiographics. 2001; 21(6):1463–1473.

12. Horton, KM, et al. CT evaluation of the colon: inflammatory disease. Radiographics. 2000; 20(2):399–418.

13. Balthazar, EJ, et al. Ischemic colitis: CT evaluation of 54 cases. Radiology. 1999; 211(2):381–388.

14. Iida, M, et al. Ischemic colitis: serial changes in double-contrast barium enema examination. Radiology. 1986; 159(2):337–341.

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