Medical Author: Jay W. Marks, MD
During my medical school training, I remember being counseled by one of my instructors; "In the practice of medicine, it doesn't matter what you do, it's how you do it." I thought she was being facetious, and I didn't give her advice much thought. Now, after years of practice, I understand what she was saying, and the truth of what she said was reinforced recently.
I was asked by a physician to see a patient in consultation who had been having episodic abdominal pain every few weeks for at least five years. She had undergone a hysterectomy (removal of the uterus) followed by radiation therapy for cancer of the uterus. The pain began a few months after the radiation. All types of testing had been done, including x-rays of the small intestine, to diagnose the cause of the pain but no cause had been identified. Almost in desperation, she underwent abdominal surgery to remove scar tissue (adhesions) between several loops of the intestines. (Adhesions often cause abdominal pain.) Even surgery was to no avail, and within two weeks of the surgery she was having pain again. I was seeing her two years after this latter surgery.
I took a careful history and examined her. She was a very good observer and could describe the progression of a typical episode of pain in detail. To me, it sounded like she was having intermittent obstruction of the small intestine. Taking x-rays of the small intestine after drinking barium is one of the best ways of diagnosing intestinal obstruction, and, indeed, she had such an x-ray prior to her most recent surgery. The x-ray was sent to me, and I reviewed it. There was nothing abnormal about it. I asked her if the x-ray was taken at a time when she was having an episode of pain. It was not.
I then discussed the situation with a radiologist who had particular expertise and extensive experience with gastrointestinal x-rays. We arranged for the patient to be seen by the radiologist urgently when she next developed an episode of pain so that another small intestinal x-ray could be done. Several weeks later, an episode occurred and the x-ray was completed. I reviewed it. There was a narrowing of the intestine (medically known as a stricture, a common cause of obstruction) that was so obvious on the x-ray that a second year medical student could have made the diagnosis.
Why hadn't the diagnosis been made previously? The narrowing certainly had been present when the prior x-ray had been done. Why wasn't it seen? The radiologist and I discussed possible explanations.
During a small intestinal x-ray, patients drink barium, a substance that blocks x-rays. The intestines fill with barium and appear on x-rays as a twisting, solid-looking, white tube outlined by "blackness." (The blackness occurs wherever x-rays do not encounter the barium and instead penetrate the tissues of the abdomen and reach the x-ray film behind the patient.) The small intestine is coiled within the abdomen, and loops of intestine lie on top of one another. X-rays are able to outline the top-most loop well, but since few or no x-rays penetrate the top-most loops, the deeper loops cannot be outlined by x-rays. As a result, it may be difficult or impossible to see the deeper loops.
After patients finish drinking the barium, single x-ray films of the abdomen are obtained by a technician intermittently (e.g., every 15 minutes) until the barium has traveled through the entire small intestine. This often takes an hour and a half.
How had my gastrointestinal radiologist performed his intestinal x-ray? First, he had used a barium that was thinner and less dense than the usual barium. This allowed some x-rays to penetrate the top-most loops and reach the deeper loops. Therefore, the deeper loops could be seen. Moreover, the radiologist stayed with my patient after she had swallowed the barium, frequently checking with x-rays as the barium progressed through the intestine. Thus, he was able to recognize the narrowing in the intestine as soon as the barium reached it and could examine the narrowing more closely before all of the overlapping loops of intestine filled with barium and made observation more difficult.
What happened to my patient? Reluctantly, she agreed to surgery, underwent removal of the narrowed intestine, and recovered uneventfully from the surgery. Two months have gone by, and she has had no further abdominal pain. According to the patient, for the first time in five years she feels normal.
So how does this experience reinforce my instructor's counsel? I've learned that there often is more than one way to reach a diagnosis. For example, one might choose x-rays or one might choose a CT scan. WHAT procedure you choose is important but may not be critical; however, HOW you perform the procedure always is critical. My patient did her part by being a good observer. This allowed me to suspect the diagnosis. I did my part by ordering the proper study at the proper time. But the real credit goes to the gastrointestinal radiologist for how he performed the x-rays.