Colitis, ischemic K55.9

Ischemic colitis (IC) refers to changes in the colon caused by complete or incomplete ischemia of the intestinal wall. The pattern of damage ranges from a pure mucosal lesion to transmural necrosis (Remmele 1996).

Together with Clostridioides difficile colitis, IK is one of the non-occlusive diseases of the colon (Böhm 2025).

Ischemic colitis can present as:

• Transient ischemic colitis. This occurs in approx. 80 % of those affected.
• Gangrenous ischemic colitis. This form is found in approx. 20 % (Hauser 2018)
• Stenosing colitis (Fleischmann 2020).

A distinction is also made between the acute and chronic forms of ischemic colitis (Fleischmann 2020).

Ischaemic colitis is one of the most common forms of gastrointestinal ischaemia (Fleischmann 2020). Reliable figures on the frequency are not available, as the number of unreported cases is estimated to be very high (Remmele 1996).

Ischaemic colitis is caused by a generalized reduced perfusion, in contrast to mesenteric ischaemia. Compression of the mucosa by intraluminal stool masses is thought to be a further pathogenesis factor (Hauser 2018).

Ischemic colitis occurs preferentially in older people. Patients are generally > 65 years of age (Herold 2023)

Acute colicky abdominal pain (Herold 2023) and hemorrhagic diarrhea occur from a feeling of well-being. The full picture is an acute abdomen (Hauser 2018).

The diagnosis depends on the severity of the clinical findings. If the severity is mild to moderate, a colonoscopy is recommended for diagnosis. However, if the full picture of an acute abdomen is present, an emergency laparotomy is indicated after basic diagnostics (e.g. laboratory, abdominal X-ray) (Hauser 2018).

Colonoscopy

Colonoscopy reveals segmental, sharply defined whitish lesions. The left hemicolon, the right colonic flexure and the recto-sigmoid junction are predominantly affected (Hauser 2018). In a severe form of IC, however, ulcerations with black or greenish discoloration of the mucosa can be seen (Kasper 2017).

Computer tomography

This reveals segmental wall thickening of the colon (Hauser 2018).

• Acute mesenteric ischemia
• Acute or chronic colitis (Hauser 2018)

In the case of transient ischemic colitis, treatment consists of abstinence from food, fluid replacement and, if necessary, supportive antibiotics (Hauser 2018).

In the presence of gangrenous ischemic colitis, an emergency laparotomy is indicated (Hauser 2018), as is stenosing colitis (Fleischmann 2020).

The extent of the resection depends on the extent of the bowel damage. A decision can only be made intraoperatively as to whether continuity restoration with an upstream ileostomy is possible or whether the operation should be ended with a Hartmann discontinuity resection (Hauser 2018).

Transient ischemic colitis usually has a good prognosis, while the gangrenous form is always fatal without surgical treatment (Hauser 2018).

1. Böhm G. (2025) Ischemic and pseudomembranous colitis from a surgical perspective. Coloproctology 47 , 121 - 128 https://doi.org/10.1007/s00053-025-00862-9
2. Fleischmann T, Hohenstein C (2020) Clinical Emergency Medicine: Volume I Knowledge. Emergency Medicine according to the EU curriculum. Elsevier Urban and Fischer Publishers Germany 124
3. Hauser H, Buhr H J, Mischinger H J (2018) Acute abdomen: diagnosis - differential diagnosis - initial treatment - therapy. Springer Verlag Vienna 434
4. Herold G et al. (2023) Internal medicine. Herold publishing house 484, 818
5. Kasper D L, Fauci A S, Hauser S L, Longo D L, Jameson J L, Loscalzo J et al. (2015) Harrison's Principles of Internal Medicine. Mc Graw Hill Education 1980
6. Remmele W (1996) Pathology 2: Digestive tract. Springer Verlag Berlin / Heidelberg / New York 553