Diagnosis

Ischemic colitis

Etiology

Cause [sww]

• Elderly:

  • Atherosclerotic vascular disease

  • Congestive heart failure

  • Recent aortic or cardiopulmonary bypass surgery

  • Hypotension

• Younger patients:

  • Hypercoagulable states --> Thromboembolism

  • Collagen vascular diseases

  • Long-distance running

  • Cigarette smoking

  • Constipation

  • Drugs (oral contraceptives, neuroleptics)

Pathophysiology [mc6][sac]

1. The intestine is mainly supplied by 2 major arteries:

   • Superior mesenteric artery (SMA)

   • Inferior mesenteric artery (IMA)

2. Oxygen extraction is low from the intestinal arteries (permits the liver to receive enough oxygen through the portal vein)

3. Regulatory mechanisms:

   • Postprandial intrinsic autoregulation

   • Vasodilation of collateral circulation

   • Increased oxygen extraction

4. The 'watershed' areas (a region between 2 major arteries) prone to ischemia:

   • Splenic flexure (Griffiths point)

   • Rectosigmoid junction (Sudek's point)

5. Hypoperfusion in blood supply below that required for the metabolic needs

   • Occlusive disease (atherosclerosis/thrombosis, embolism, venous thrombosis)

   • Intestinal hypoperfusion or nonocclusive mesenteric ischemia (heart failure, shock)

6. The duration and severity of hypoperfusion will determine the colonic injury

   • Mucosal ulceration, inflammation, and hemorrhage

Risk factors

• Old age

• Female

• Hypertension

• Diabetes

• Dardiovascular disease

• Chronic kidney disease

• Atrial fibrillation

• Coagulation disorders,

• Hypotension

• Postsurgical abdominal aortic aneurysm repair or post cardiac surgery with extracorporeal circulation

• Hypercoagulable states (COVID-19)

Complications [mc6][sac]

• Gangrenous and necrotic bowel

• Intestinal perforation

• Sepsis

• Toxic megacolon

• Multiple organ failure

• Fibrosis

• Fistula

• Colonic stricture

• Pelvic abscess

Epidemiology

Incidence per 100.000 [sww][d3c][e5e][ez7]

Approach

• Blood test

• Blood gas

• ECG

• CT abdomen

• Colonoscopy

• Biopsy

Treatment

Treatment depending on the severety of the ischemia: [dtn][mc6][sac]

1. Stage I: Ischemia limited to the mucosa: Erosions, and smaller ulcerations

   Supportive treatment:

   • IV fluid resuscitation

   • Optimizing cardiac output

   • Oxygen

   • Bowel on rest (parenteral nutrition)

   • Broad-spectrum antibiotics to cover both aerobic and anaerobic coliform bacteria

2. Stage II: Larger/deeper ulcerations with ischemia limited to the submucosa

   • Colonoscopy: Hemoclipping, epinephrine injection, hemostatic powder

3. Stage III: Necrotic, gangrenous, and/or perforated colon due to transmural injury

   • Surgery:

     • Colectomy with ileostomy or colostomy

     • Embolectomy

     • Mesenteric bypass

   • Endovascular intervention:

     • Mechanical thrombectomy

     • Catheter-directed thrombolysis

     • Balloon Angioplasty with/without stent

Differential diagnoses

Abdominal abscess, Acute pancreatitis, Adhesion, Aortic dissection, Appendicitis, Benign neoplasm of the small intestine, Celiac disease, Cholangitis, Cholecystitis, Cholelithiasis, Colorectal cancer, Crohn disease, Diabetic gastroparesis, Diverticulitis, Drug side effects, Femoral hernia, Foreign body, Gastric cancer, Gastroenteritis, Gastrointestinal obstruction, Hypokalemia, Incisional hernia, Infectious colitis, Inguinal hernia, Intussusception, Irritable bowel syndrome, Liver abscess, Lymphoma, Meckels diverticulum, Myocardial infarction, Ovarian torsion, Pancreatic cancer, Perforated ulcer, Peutz-Jeghers syndrome, Postoperative paralytic ileus, Pyelonephritis, Radiation enteritis, Ruptured aortic aneurysm, Ruptured ectopic pregnancy, Small bowel cancer, Spontaneous bacterial peritonitis, Toxic megacolon, Tuberculosis, Ulcerative colitis, Ulcer disease, Umbillical hernia, Urolithiasis, Viral hepatitis, Volvulus