Common Findings in Ischemic Colitis
Ischemic colitis typically presents with the triad of abdominal pain, bloody diarrhea/hematochezia, and occurs predominantly in elderly patients (mean age ~65-75 years) with cardiovascular risk factors, most commonly affecting the left colon, particularly the descending colon and splenic flexure. 1, 2
Clinical Presentation
Demographics and Risk Factors
- Female predominance (3.5:1 female-to-male ratio) 2
- Elderly population: 65-75% of patients are ≥60 years old 1, 2
- Key comorbidities: Hypertension (most common), hyperlipidemia, coronary artery disease, diabetes mellitus, and cerebrovascular disease 1, 2
- Medication associations: Antihypertensive agents, antiplatelet drugs, statins, and hypoglycemic medications 2
Cardinal Symptoms
The classic triad consists of:
- Abdominal pain (present in 69.2% when combined with hematochezia) 2
- Hematochezia/rectal bleeding (86.9% in mild cases, but notably LESS common in severe cases at only 37.5%) 3
- Diarrhea 1, 4
Critical pitfall: The absence of hematochezia paradoxically predicts WORSE prognosis and should heighten concern for severe disease 3.
Laboratory Findings
Common Abnormalities
- Leukocytosis: Present in >90% of patients 5
- Elevated lactate: Found in 88% of cases; levels >2 mmol/L associated with irreversible ischemia (HR 4.1) 5
- Metabolic acidosis 5
- Elevated CRP: Correlates with clinical staging 2
- Anemia: More frequent in severe cases (37.5% vs 10.1% in mild cases) 3
- Hyponatremia: Associated with poor prognosis (46.6% in severe vs 14.9% in mild cases) 3
- D-dimer elevation: >0.9 mg/L has 82% specificity and 60% sensitivity; normal D-dimer essentially excludes intestinal ischemia 5
Important caveat: No laboratory test is sufficiently accurate alone to confirm or exclude ischemic bowel, but the CAR ratio (CRP/albumin ≥0.335) may serve as a marker for mild-to-moderate disease 2.
Imaging Findings
CT Findings (First-Line Imaging)
CTA should be performed as soon as possible when ischemic colitis is suspected 5. Triple-phase CT (non-contrast, arterial, portal venous) is the diagnostic investigation of choice 6, 7.
Common CT findings include:
- Bowel wall thickening (most common finding) 7, 8
- Pericolonic fat stranding 8, 9
- Involvement of watershed areas (splenic flexure, rectosigmoid junction) 8
- Variable bowel wall enhancement 6
- Bowel dilation 6
Plain Radiography
Limited diagnostic value in early ischemic colitis; only becomes positive when bowel infarction occurs with free intraperitoneal air 5. A negative radiograph does NOT exclude mesenteric ischemia 5.
Endoscopic Findings
Endoscopic visualization with histologic biopsy analysis is the gold standard for diagnosis 4.
Most Common Endoscopic Features
- Erythema 1
- Edema 1
- Erosions and ulcerations 1, 9
- Mucosal necrosis (in severe cases) 4
- Stenosis: Present in 66.6% of severe cases vs 17.3% of mild cases—a key predictor of poor prognosis 3
Anatomic Distribution
- Left colon involvement: 84.8% of cases 1
- Descending colon: Most commonly affected segment 1
- Rectum: Least commonly affected segment 1
- Pancolitis: Rare (only 1 case in 118 patients in one series) 1
Note: Endoscopic findings can mimic inflammatory bowel disease, pseudomembranous colitis, or even colorectal cancer, making histologic confirmation essential 9, 10.
Histologic Findings
- Mucosal ulceration 7
- Inflammation 7
- Hemorrhage 7
- Ischemic necrosis of variable severity 7
- Submucosal ischemic lesions 9
- Occasionally focal pseudomembranous areas (can mimic C. difficile colitis) 10
Poor Prognostic Indicators
Red flags for severe disease requiring surgery or associated with mortality (12.7% severe cases, 4.2% 30-day mortality) 1: