First, in one of the comments it was said that the CT ordered was unnecessary. Not so. In a patient with a history of colon/rectal cancer complaining of abdominal pain and constipation a CT is prudent. Even though I was and am firmly of the opinion that he knew he was merely constipated I am not omniscient. Cancer patients do relapse and it would be negligent on my part to ignore his complaint. While there are definitely occasions when it is both necessary and right to call a patient on their mendacity, this was not IMHO one of them.
Second, should I have ignored him and he be found later to have relapsed, his disease would have had time to progress and he could possibly be too sick to fix.
Third, I would be at risk of losing my livelihood to the nearest ambulance chaser if he were actually ill. Without tort reform practicing defensive medicine is necessary. Anyone, (MD, APN, RN, EMT-P) anyone who is in the medical field now practices defensive medicine, or doesn't practice long. That doing so is occasionally a benefit to the patient is a bonus. Most of the time it simply adds to the cost of medical care.