Ischaemic colitisBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i6600 (Published 22 December 2016) Cite this as: BMJ 2016;355:i6600
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We thank Dr. Joseph and colleagues’ for their interest in this article, and for highlighting points of interest. The issues raised in this response are, firstly, that published guidance from the USA is not directly relevant to UK practice, and, secondly, that this clinical update overstates the diagnostic role of CT in Ischaemic colitis (IC) and unduly dismisses ultrasonography (USS) despite evidence of its usefulness.
With regard to best practice guidance from the American Collage of Gastroenterology being not applicable to UK practice, we do not feel that this is correct. There is a lack of formal UK guidance and the North American specialty association who published this guidance collated the information from international peer reviewed publications. Thus it represents an appropriate summary of the evidence to date. Furthermore, IC presents the same way in the USA as it does in the rest of the world, and hence evidence based best practice guidance offers more of an international flavour to best practice.
We concur with the response that USS can give useful diagnostic information regarding bowel pathology when performed by consultant radiologists. It is clear that the author was able to provide this in their practice previously. However, it must be noted in the first paragraph this clinical update aims to provide “practical advice to non-specialists regarding the diagnosis, management, and guideline recommendations for ischaemic colitis in the acute setting”. Detailed information on all modalities available is suited to publication in specialist Journals. Here we have sought to give clear and concise information on the radiological investigation of choice for IC, which is CT. Patients with IC present at all times of day, systemically unwell with tender abdomens. It is the job of the admitting clinical team to resuscitate, arrive at a diagnosis and make prompt a decision on treatment. Dependence on an USS specialist in GI imaging is therefore not always accessible even if available. In the case of IC this includes an expedient decision of whether an emergency laparotomy is required. This is a decision that is frequently required out of hours. The admitting team need definitive information on whether such a patient has IC, colonic malignancy, complicated diverticulitis, full thickness colonic ischaemia, localized perforation or other pathology that can present in a similar fashion to IC, in an unstable patient. All secondary care trusts make provision for CT out of hours with either reporting from home, resident middle grade radiology or distant reporting. Whilst we acknowledge that an USS may be of benefit in the hands of a specialist radiologist, it is not conceivable that a 24 hours provision of such is appropriate in current health care settings.
CT has the advantage of being a non-dynamic investigation which is not operator dependent, where images can be easily reviewed by specialist GI radiologists not available at the time of admission. As stated in the update, patients with acute IC may often need serial imaging so progress can be assessed, something not as robust with the few recorded still images on USS compared with CT.
In summary, we reject the assertion that following evidence based guidance from the USA is some way not relevant to the presentation of an identical condition in the UK. We agree that USS has been shown to be of use in IC but maintain it is not initial investigation of choice. We agree that Doppler sonography may have a larger role to play in IC management, and as such the update states this as an area for further research without going into detail not appropriate for the generalist audience of The BMJ.
Competing interests: No competing interests
Clinical update should be a more balanced presentation.
It is with some concern we note the comments made in the article Ischaemic Colitis (IC). There is a failure to tackle this problem in a realistic clinical context adopting a more routine diagnostic pathway appropriate for patients with this condition who present acutely with abdominal pain in a British hospital. The diagnostic pathways have been based on what may be a more likely scenario in the American context. This is borne out by stated reliance on guidance from the American College of Gastroenterology.
Comments such as, ‘There is no role for abdominal plain radiographs or ultrasonography in diagnosing ischaemic colitis’, is misleading to say the least. There is however a throw away concession ‘though these investigations (are) often used in practice in the assessment of abdominal pain. They can give some information about ischaemic colitis such as thumb printing on X ray or mural thickening on ultrasonography’. Although ultrasound may not be the first choice in the investigation of ischaemic colitis it will be conceded by the authors that ultrasound is often the initial procedure in the investigation of abdominal pain. It is in this context the role of ultrasound should be considered. The ultrasound features described in the text is grossly inadequate and there is no mention of the fact that thumb printing may also be identified with ultrasound. (Thumb printing noted on US and radiographs is the result of marked inflammation and oedema of the inter haustral fold leading to the narrowing of the haustral and central lumen of the colon. The inflamed oedematous inter haustral fold is outlined by the echogenic content of the colon or the air in the colonic lumen). It is worth bringing to the attention of your readers the results of a study by Ripolles et. al. In a study 0f 58 patients with proven IC, sonography was 93.5% sensitive in characterisation of colonic abnormalities including segmental involvement in 57 patients, left sided colitis in 81%, Absence of or barely visible Doppler flow in thickened bowel wall was recorded in 80% patients. (p=0.004). Sonography was also helpful in following up patients1.
It is therefore of great importance that the investigators should be fully conversant with the findings of IC to be able to detect or suspect this condition in the investigation of abdominal pain. There does not appear to be significant radiological input.
The other worrying aspect is that this paper is one of the many which give the impression that ultrasound contributes little to the detection of bowel related pathology including malignancy or inflammatory bowel disease. Clinicians such as these authors belittle ultrasound to the extent that I have been told by consultant radiologists that all too often they do not bother to examine the bowel since clinicians may pay little attention to bowel abnormalities reported on ultrasound. It may be far too much for the authors to be told that ultrasound not uncommonly detects inflammatory bowel disease not commented on CT scans, picked up on routine US examination or that ultrasound may be used to evaluate appearances not categorised by CT or even MRI. CT and MR have their limitations when the use of contrast agents is not advisable.
There is also a clinical implication. Findings on imaging should be interpreted on the basis of clinical presentation. A radiologist performing ultrasound is in a relatively advantageous situation in that there is the opportunity to relate the findings to the history directly obtained from the patient, and the signs and symptoms rather than on the details provided by the clinicians. In the case of ischaemic colitis the ultrasound findings correlated with acute onset of pain, blood PR and diarrhoea of sudden onset or a sudden urge to pass stools with little outcome or perhaps a small quantity of blood stained stools could raise a strong suspicion of IC.
I (AEJ) must take this opportunity to thank gastroenterological colleagues (three of them are co-authors) for the opportunities they provided me and the trust they placed on ultrasound findings. Radiologists are only as good as the diagnostic demands placed on them by the clinicians. There is also a need for radiologists in training and in their later routine practice to make every effort to develop expertise in bowel ultrasound.
One may conclude that the authors have generalised on the basis of their experience and their own practice. Reports of the use of ultrasound in bowel disease started appearing since 1976 (Holms et.al.) and there is now a wealth of information in the literature.
BMJ readers pay special attention to articles that are of educational value and hence papers published in the BMJ should ensure a more balanced view than demonstrated in this Clinical Update on Ischaemic Colitis.
1. Ref Ripolles T, Simo L, Martinez-Perez MJ et al. Sonographic findings in Ischemic colitis in 58 patients. Am J Radiology 2005;184(3)777-85.
Competing interests: No competing interests