Correspondence (reply): In Reply

K H Haegler raises the important issue of additional, contrast medium-related, renal damage. If a patient meets the risk profile for mesenteric ischemia, rapid contrast-enhanced CT is the top priority. Existing renal damage is often subsequent to dehydration and should be treated in parallel by using infusion therapy. In patients with known compensated renal failure, possible additional damage owing to contrast medium with a deterioration in renal function should be accepted. K H Haegler weights the problem correctly: if in doubt, choose contrast-enhanced CT, even if there is a risk for the renal failure to worsen.

I thank K Lehman for her comments on intestinal angioedema as a differential diagnosis to acute mesenteric ischemia. Our article aims at providing a very clear description of mesenteric ischemia; the objective was to reduce the persistent high mortality by rapid exclusion and speedy detection of mesenteric vascular occlusion. If the patient fits the profile and clinical presentation of possible mesenteric ischemia, then triphasic, contrast-enhanced CT should be undertaken without delay. If this shows that the vessels are clear, the remaining differential diagnoses can be narrowed down without putting the patient at risk. Intestinal angioedema is one such differential diagnosis.

R Sen Gupta points out that overdosage of digitalis medication is of particular etiological relevance as a cause of nonocclusive mesenteric ischemia. We agree. In the overview “Clinical manifestation, risk factors, and classification of acute mesenteric ischemia” (Box) we included digitalis medication among the risks. Overdosage is not easily confirmed in the emergency setting. For us it was important to emphasize that every patient taking digitalis medication should be assessed precisely with regard to NOMI.

T Bein and colleagues in their letter focus on contrast-enhanced sonography as an innovative diagnostic approach for detecting mesenteric ischemia. The publication by Hamada et al cited in the letter (Br J Radiol 2007) has prospectively evaluated this approach. The study included 50 patients who were admitted to hospital with a diagnosis of ileus. Contrast-enhanced sonography aims to detect flow signals in the distended intestinal wall. Where intestinal wall perfusion was not confirmed, the researchers concluded that ischemia was present. The sensitivity of this approach is 94.1%. Visualizing the large mesenteric arteries and veins was not the study’s objective. By contrast, the main objective of our article was to shorten the time to the eventual diagnosis of mesenteric ischemia. The triphasic contrast-enhanced CT or angiography that we recommended have the advantage of very detailed imaging of the large mesenteric vessels, together with the anatomical structure of the perfusion problem, in order to set out an optimal treatment concept consisting of radiological intervention, lysis, or surgery. By comparison, contrast-enhanced ultrasonography provides insufficient information compared with the therapeutic algorithm we presented in our article. The only way to lower the persistently high mortality of mesenteric ischemia is by shortening the time from initial manifestation to therapy. Contrast-enhanced sonography entails an extension of the time taken to diagnosis. In future, we will be successful in treating mesenteric ischemia only if we make the diagnosis in the shortest possible amount of time, by using a single, easily available diagnostic tool that enables comprehensive interpretation. Each further investigation that precedes contrast-enhanced CT or angiography is a step in the wrong direction. We dealt with the problem of contrast medium in our response to the first reader’s letter.

In conclusion I thank the correspondence authors for dealing with our publication in such detail. This has helped clarify further important aspects of the symptoms.