Mesenteric ischemia

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In medicine, mesenteric ischemia or mesenteric vascular occlusion is "obstruction of the flow in the splanchnic circulation by atherosclerosis; embolism; thrombosis; stenosis; trauma; and compression or intrinsic pressure from adjacent tumors. Rare causes are drugs, intestinal parasites, and vascular immunoinflammatory diseases such as periarteritis nodosa and thromboangiitis obliterans."[1]

Ischemic colitis is ischemia of the colon.

Diagnosis

Signs and symptoms

Three progressive phases of ischemic colitis have been described:[2][3]

  • A hyperactive phase occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase.
  • A paralytic phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel motility decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam.

Symptoms of mesenteric ischemia vary and can be acute (especially if embolic)[4], subacute, or chronic[5].

Case series report prevalence of clinical findings and provide the best available, yet biased, estimate of the sensitivity of clinical findings[6][7]. In a series of 58 patients with mesenteric ischemia due to mixed causes[7]:

  • abdominal pain was present in 95% (median of 24 hours duration). The other three patients presented with shock and metabolic acidosis.
  • nausea in 44%
  • vomiting in 35%
  • diarrhea in 35%
  • heart rate > 100 in 33%
  • 'blood per rectum' in 16% (not stated if this number also included occult blood - presumably not)
  • constipation 7%

In the absence of adequate quantitative studies to guide diagnosis, various heuristics help guide diagnosis:

  • Mesenteric ischemia "should be suspected when individuals, especially those at high risk for acute mesenteric ischemia, develop severe and persisting abdominal pain that is disproportionate to their abdominal findings"[8]
  • Regarding mesenteric arterial thrombosis or embolism: "...early symptoms are present and are relative mild in 50% of cases for three to four days before medical attention is sought"[9].
  • Regarding mesenteric arterial thrombosis or embolism: "Any patient with an arrhythmia such as auricular fibrillation who complains of abdominal pain is hghly suspected of having embolization to the superior mesenteric artery until proved otherwise"[9].
  • Regarding nonocclusive intestinal ischemia: "Any patient who takes digitalis and diuretics and who complains of abdominal pain must be considered to have nonocclusive ischemia until proved otherwise"[9].

Blood tests

In a series of 58 patients with mesenteric ischemia due to mixed causes[7]:

  • White blood cell count >10.5 in 98% (probably an overestimate as only tested in 81% of patients)
  • Lactic acid elevated 91% (probably an overestimate as only tested in 57% of patients)

Plain x-ray

Plain X-rays are often normal or show non-specific findings.[10].

Computed tomography

Computed tomography (CT scan) is often used.[11][12] The accuracy of the CT scan depends on whether a small bowel obstruction (SBO) is present [13].

SBO absent

SBO present

Findings on CT scan include:

  • Mesenteric edema[11]
  • Bowel dilatation[11]
  • Bowel wall thickening[11]
  • Intramural gas[11]
  • Mesenteric stranding[14]

Devices for Diagnosis During Endoscopy

A number of devices have been used to assess the sufficiency of oxygen delivery to the colon. The earliest devices were based on tonometry, and required time to equilibrate and estimate the pHi, roughly an estimate of local CO2 levels. The first device approved by the U.S. FDA (in 2004) used visible light spectroscopy to analyze capillary oxygen levels. Use during Aortic Aneurysm repair detected when colon oxygen levels fell below sustainable levels, allowing real-time repair. In several studies, specificity has been 83% for chronic mesenteric ischemia and 90% or higher for acute colonic ischemia, with a sensitivity of 71%-92%. This device must be placed using endoscopy, however.[15],[16],[17]

References

  1. ↑ Anonymous (2024), Mesenteric vascular occlusion (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. ↑ Boley, SJ, Brandt, LJ, Veith, FJ. Ischemic disorders of the intestines. Curr Probl Surg 1978; 15:1.
  3. ↑ Hunter G, Guernsey J (1988). "Mesenteric ischemia.". Med Clin North Am 72 (5): 1091–115. PMID 3045452.
  4. ↑ Oldenburg WA, Lau LL, Rodenberg TJ, Edmonds HJ, Burger CD (2004). "Acute mesenteric ischemia: a clinical review". Arch. Intern. Med. 164 (10): 1054–62. DOI:10.1001/archinte.164.10.1054. PMID 15159262. Research Blogging.
  5. ↑ Font VE, Hermann RE, Longworth DL (1989). "Chronic mesenteric venous thrombosis: difficult diagnosis and therapy". Cleveland Clinic journal of medicine 56 (8): 823–8. PMID 2691119.
  6. ↑ Levy PJ, Krausz MM, Manny J (1990). "Acute mesenteric ischemia: improved results--a retrospective analysis of ninety-two patients". Surgery 107 (4): 372–80. PMID 2321134.
  7. ↑ 7.0 7.1 7.2 Park WM, Gloviczki P, Cherry KJ, Hallett JW, Bower TC, Panneton JM, Schleck C, Ilstrup D, Harmsen WS, Noel AA (2002). "Contemporary management of acute mesenteric ischemia: Factors associated with survival". J. Vasc. Surg. 35 (3): 445–52. DOI:10.1067/mva.2002.120373. PMID 11877691. Research Blogging.
  8. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named pmid10784595
  9. ↑ 9.0 9.1 9.2 Cope's Early Diagnosis of the Acute Abdomen by Zachary Cope and William Silen (2005) - Oxford University Press, USA ISBN 019517545X
  10. ↑ Smerud M, Johnson C, Stephens D (1990). "Diagnosis of bowel infarction: a comparison of plain films and CT scans in 23 cases.". AJR Am J Roentgenol 154 (1): 99–103. PMID 2104734.
  11. ↑ 11.0 11.1 11.2 11.3 11.4 Alpern M, Glazer G, Francis I (1988). "Ischemic or infarcted bowel: CT findings.". Radiology 166 (1 Pt 1): 149–52. PMID 3336673.
  12. ↑ Taourel P, Deneuville M, Pradel J, Régent D, Bruel J (1996). "Acute mesenteric ischemia: diagnosis with contrast-enhanced CT." (PDF). Radiology 199 (3): 632–6. DOI:10.1148/rg.243035084. PMID 8637978. Research Blogging.
  13. ↑ Staunton M, Malone DE (2005). "Can acute mesenteric ischemia be ruled out using computed tomography? Critically appraised topic". Canadian Association of Radiologists journal = Journal l'Association canadienne des radiologistes 56 (1): 9–12. PMID 15835585.
  14. ↑ Pereira JM, Sirlin CB, Pinto PS, Jeffrey RB, Stella DL, Casola G (2004). "Disproportionate fat stranding: a helpful CT sign in patients with acute abdominal pain". Radiographics : a review publication of the Radiological Society of North America, Inc 24 (3): 703–15. DOI:10.1148/rg.243035084. PMID 15143223. Research Blogging.
  15. ↑ Lee ES, Bass A, Arko FR, et al. (2006). "Intraoperative colon mucosal oxygen saturation during aortic surgery." 136 (1): 19–24. PMID 16978651.
  16. ↑ Friedland S, Benaron D, Coogan S, et al. (2007). "Diagnosis of chronic mesenteric ischemia by visible light spectroscopy during endoscopy.". Gastrointest Endosc 65 (2): 294–300. DOI:10.1016/j.gie.2006.05.007. PMID 17137857. Research Blogging.
  17. ↑ Lee ES, Pevec WC, Link DP, et al. (2008). "Use of T-Stat to predict colonic ischemia during and after endovascular aneurysm repair.". J Vasc Surg 47 (3): 632–634. DOI:10.1016/j.jvs.2007.09.037. PMID 18295116. Research Blogging.
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