Plain abdominal radiographs in acute medical emergencies: an abused investigation?

• acute medical emergencies
• abdominal radiographs

I read the article on plain abdominal radiographs in acute medical emergencies with interest,¹ and I agree in many respects about the unnecessary use of abdominal radiographs, especially if the diagnosis is clear. I would, however, like to address a few points with regards to the article.

• I note that the abdominal radiographs were performed on patients admitted under a general medical on-call with acute medical emergencies. It is unusual, in my experience, for patients with medical disorders to have abdominal radiography unless an acute abdomen is suspected. In this situation, the patient would have a surgical abdomen. In this case an abdominal radiograph may be necessary to exclude/confirm obstruction and perforation by demonstrating Rigler’s sign. Consequently, I would say that the plain abdominal film is not an abused investigation as it may determine quite rapidly whether the patient has emergency surgery or medical treatment.

• The indications for a plain abdominal radiograph as described by the Royal College of Radiologists were mentioned. Examining the request forms table (table 3), it would appear that 58% of abdominal radiographs were requested for one of the guidelines determined by the Royal College of Radiologists and presumably the doctor on-call considered these as part of the differential diagnosis in patients presenting with abdominal pain.

• I note that for acute pancreatitis, abdominal radiographs were requested. Could it be that this is probably due to standard medical teaching which instructs on the ability of a plain abdominal radiograph to reveal features suggestive of acute pancreatitis (for example, sentinel loop, loss of psoas shadow)?

• An abdominal radiograph may be required to exclude or confirm one of several differential diagnoses if the clinical problem is not apparent. It may be one of the reasons why abdominal films were requested in this cohort. Consequently, I would argue that in this situation, plain films are not an unnecessary investigation.

• Of the 45 patients with a diagnosis that was not stated, what was the eventual clinical impression? Could it be that in this subgroup, the acquisition of a plain abdominal radiograph may have resulted in the correct diagnosis being reached and therefore managed appropriately?

• Also I would say that an abdominal radiograph in an elderly patient with rebound tenderness in the right iliac fossa and signs and symptoms suggestive of pseudo-obstruction may be necessary to determine caecal size. How many of the patients had this presumptive diagnosis and had an abdominal radiograph?

• Pre-registration house officers may have ordered the largest number of abdominal radiographs, but how many of these films were requested after discussion with a senior on-call (senior house officer or registrar)? Do the authors have data that give this information?

• It may be essential to do a plain abdominal radiograph to narrow down the diagnosis in an acute abdomen. In this case, radiation dose may be minimised by ordering a single supine plain film, rather than the standard erect and supine set of radiographs for the abdomen. Were erect and supine abdominal radiographs obtained in the study?