Normal Bowel Patterns in Sedentary Patients

Introduction

One of the difficulties with abdominal plain film image interpretation is that a normal appearance of the bowel can show considerable variability. This can be attributed to congenital differences, variable amounts of bowel gas, surgical and other interventions and differences associated with activity levels of the patient. Elderly and disabled patients who are sedentary tend to show similar bowel patterns on plain film as discussed below.

Pattern Recognition

Patients who are sedentary will often show

•gas-filled bowel

•large bowel septa are thin, smooth and sharply marginated. (Stephen R. Baker, The Abdominal Plain Film, Appleton and Lange, 1990)

	This is a supine abdominal plain film(left) of an elderly sedentary patient. Compare the appearance of the large bowel with that shown below. The sedentary patient's large bowel, particularly evident in the right colon, is sharply marginated and demonstrates very thin septa (white arrow). This is in contrast to the classic appearance of haustra and plicae semilunaris as shown below.
	The referring doctor was concerned about the large amount of bowel gas and requested an erect abdominal view. The patient was unable to adopt the erect position and the radiographer performed a left lateral decubitus view in lieu of the erect view. The decubitus image (left) does not demonstrate air-fluid levels.

Case 1

There are a variety of conditions that can cause this distinctive appearance of the large bowel. This is a young 18 year old girl with anorexia nervosa. The large bowel has the classic three features smooth walled sharply marginated thin septa This appearance is often assumed to be abnormal and a request for an erect abdominal film may follow. In this case, I suspect this is not an acutely abnormal appearance of the bowel. You could add gas-filled as a fourth feature to this list. The bowel (large and small) has an evenly gas-filled look about it that is reminiscent of generalised adynamic ileus.

Comment

The distinctive appearance of the bowel in sedentary patients should not be confused with pathological appearances. This appearance is not unique to sedentary patients (refer to Stephen Baker's book- The Abdominal Plain Film). It is not uncommon for this appearance to be mistaken for a motility disorder requiring additional imaging such as an erect abdominal image to check for air/fluid levels. Radiographers who are familiar with this pattern may be able to save an elderly frail patient from the discomfort associated with an erect or decubitus position when it is not required.

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