Every Patient Tells a Story (33 page)

With years of experience under his belt, Podell knew that when a patient has already been to a slew of specialists before arriving at your door, you need to approach the case with a different mind-set—with different assumptions. You know, for example, that whatever this patient has, it isn’t going to be obvious. Maybe it’s an unusual disease, known best by specialists—like scleroderma—or perhaps it’s an unusual presentation of a more common illness. In any case, it won’t be routine. In such situations, he knew, you had to start from scratch even if the patient comes to you with a diagnosis already made. He asked the woman to continue with her story, apologizing because he knew she had told and retold it so many times already in the past year.

She said that until that morning a year ago she had always been healthy. But the burning pain in her legs had been so intense that now she could hardly walk. And she had felt weak—especially in her left leg. She went to her regular doctor, but he didn’t know what to make of her symptoms and sent her to a neurologist. He examined her, sent off a dozen blood tests, and got a CT scan of her head and spine before sending her back to her internists, still undiagnosed.

Then she developed a cough. It was usually a dry, irritating cough, but occasionally she coughed up blood. Recently she felt out of breath with even slight exertion. This morning, she told Podell, she had to stop and rest during the short walk from the parking lot to his office. Her internist sent her to a pulmonologist because her lungs seemed clearly involved. He got a chest X-ray, then a chest CT, more blood tests, even a biopsy. The chest X-ray proved that her lungs were involved. In the normally black areas of the image over the air-filled lung tissue, there were faint patches of white. The biopsy showed inflammation but nothing more specific. He wasn’t sure what this was. He tried her on a variety of antibiotics. Finally he sent her back to her internist, suggesting the possibility of scleroderma.

Eventually her internist sent her to Podell, who is a rheumatologist—a
specialist in diseases of connective tissues. Because connective tissues are found throughout the body, complex, multisystem illnesses are the rheumatologists’ bread and butter.

The patient was a slender woman with a mass of straight dark hair streaked with gray. Her skin was clear, but her eyes were puffy with fatigue, and she looked older than her fifty-three years. Examining her, Podell found few obvious signs of disease. Despite the cough and breathing problems, her lungs sounded clear. She had some mild weakness in her left hip, but other than that, her joints, skin, and muscles were all normal.

Podell could see why the previous doctors were puzzled. Her symptoms suggested that her illness involved the nervous system and the pulmonary system, which is an unusual pairing. Although scleroderma can affect both nerve and lung tissue, Moity didn’t have the classic thickening of the skin that is the hallmark of that disease. Could this be an atypical form of scleroderma? Or was it something else altogether?

Could this be Sjögren’s syndrome, a disease in which the immune system mistakenly attacks a patient’s fluid-producing glands? Sjögren’s can affect the lungs and sometimes spreads to the nervous system. Patients with Sjögren’s usually complain of painful eyes or a dry mouth, and this patient had mentioned that her mouth was dry.

Podell ordered blood tests to look for evidence of Sjögren’s. He assured the patient that he would do all he could to figure out what was going on, but that it would take a bit more time. Looking defeated, Graciela Moity made an appointment to return in a couple of weeks and trudged out toward the parking lot.

Podell wanted to examine the patient’s extensive medical record, especially the tests and results obtained by the other doctors. He didn’t read the records in advance in complicated cases. He felt it was important to take in the information without any preconceived notions about what was going on. But at the end of the day Podell sat down with her thick chart and went through every page. When you are the last in a string of practitioners, one of your most important jobs is to review each piece of the puzzle with fresh eyes, questioning every assumption and double-checking the reported
results. In complex cases like this, the answer is sometimes already there, just waiting to be noticed.

A long list of blood tests had been done. Several suggested an inflammatory process, but none identified the cause. The patient also had MRIs of her head and spine, as well as a CT scan of the chest. Podell was particularly interested in the chest CT, which showed something he could not have detected in his physical exam: faint, cloudy patches throughout both lungs. He wasn’t an expert in interpreting CT scans, so he called in a radiologist to look them over. But the colleague merely confirmed what Podell could already see: cloudy areas showed the presence of fluid in both lungs. Etiology: unknown.

The patient had also had a lung biopsy. The pathology report said there was evidence of inflammation but, like the blood tests, revealed nothing of the cause. But, again, Podell sought an expert opinion—in this case from the pathologist Tom Anderson. Podell and Anderson sat at a double-headed microscope in the pathology lab, scanning slides that held the biopsy samples. The first slide showed evidence of extensive inflammation, Anderson agreed, but nothing more. As he zipped across the second slide, Anderson reported that again he saw lots of inflammation. Suddenly he stopped. He quickly flipped the microscope lens to zoom in tight on one group of cells that formed a cluster, quite different in appearance from the cells around it.

“That looks like a granuloma,” he said.

These distinctive cell formations are characterized by groups of giant cells up to a hundred times larger than normal cells. They are seen in the lungs only in a few diseases—most commonly sarcoidosis (known more commonly as sarcoid) and tuberculosis. Podell almost laughed out loud. At last, the needle had fallen from the haystack. He picked up the phone and called the patient.

“I know what’s going on,” he told her. “I can explain everything.”

The culprit, Podell explained, was almost certainly sarcoid, a mysterious chronic disease characterized by inflammation of tissues that often display the unusual granuloma collections of cells. The disease usually affects the lungs, but in one third of cases can attack other parts of the body as well,
including (rarely) the nervous system. He told her she would need to be tested for tuberculosis, as that disease can also cause granulomas, but he was confident that’s not what she had. She had none of the common symptoms of TB such as night sweats, weight loss, or fever. No, Podell said, this is overwhelmingly likely to be sarcoid.

Podell started the patient on the corticosteroid prednisone, which is a highly effective anti-inflammatory medicine. Almost immediately her breathing became easier and the cough disappeared. Within a few days she was walking up and down stairs, something she hadn’t been able to do for more than a year. The damage to the nerves in her legs would take longer to treat and may not be completely reversible, but with the diagnosis now clear and effective treatments known, the prognosis for a full recovery was excellent.

Dr. Podell wasn’t born an excellent diagnostician. He didn’t always know to check and double-check the work of other doctors earlier in the “train” for any particular patient. He learned this and many other invaluable lessons about diagnosis over the course of a long career. And that, in the end, is why we can be hopeful that doctors and other health care providers can avoid or even eliminate the types of cognitive errors we have encountered in this chapter. Yes, doctors are human beings and, thus, are prone to biases, distortions of perspective, and blind spots. But doctors have the capacity to learn from their mistakes, overcome built-in biases, and guard against the kinds of thinking errors that in other professions might only be an annoyance.

I recall a rather mortifying moment in my own learning curve. I was in my third year of medical school. I was given a very simple task by an experienced doctor: to intubate an unconscious patient. Intubation is to medicine what boiling water is to cooking—one of the most basic techniques you can think of. And yet I blew it. Because both the trachea (the tube for air) and the esophagus (the tube for food) diverge at the back of the throat, it is relatively easy to slide the breathing tube into the esophagus. Doing so, of course, is a potentially deadly mistake. Students are therefore repeatedly taught to listen to the lungs for sounds of air movement after placing the breathing tube. If you’ve accidentally put the tube into the stomach, the
lungs will be silent. When I listened I heard the terrible silence that means you’ve made this basic error. Under the gaze of my supervising doctor, I removed the tube and tried again, feeling extremely embarrassed in the process. But the doctor was not annoyed or disappointed. And what he said next has always stuck with me.

“There’s no shame in intubating the esophagus,” he said. “But there
is
shame in not checking or catching the error.”

His point was that errors themselves are unavoidable. Mistakes will always happen—all types of mistakes, from the technical to the cognitive. But that doesn’t mean we throw up our hands in helplessness. The key is designing our systems, our procedures, our protocols, and our own thinking processes to minimize mistakes as much as possible and then to
catch
mistakes when they are made.

Medicine is not the only field in which mistakes can be deadly. The airline industry, to take just one example, has had to put into place many systems for preventing and catching human errors. In the 1930s, following a crash in which a test pilot and crewman were killed due to “pilot error,” the air force responded by requiring every pilot and copilot to complete a pre-takeoff checklist before each flight. The rate of accidents plummeted, and eventually this became standard practice for military and commercial pilots. Most airlines also now require pilots and crew to review the flight plan just before takeoff. This is done as a group and anyone in the crew, from pilot to steward, can bring up any problems they see or anticipate. Pilot and crew are drilled on safety procedures for a wide variety of problems, often using flight simulators to make the experience as real and useful as possible. These basic steps are part of a broader movement that has dramatically improved air travel safety.

There is a national effort now being made to eliminate many of the errors in medicine, to implement layers of checks and double checks to catch errors before they happen. Many of the strategies developed by the airline industry have been adapted and incorporated into hospitals and operating rooms throughout the United States. For example, there is an effort to require surgeons to complete a pre-surgical checklist with all the members of the surgical team. Before any operation, the team meets and anyone, from
the anesthesiologist to the scrub nurse, can bring up any problem they see or anticipate. A recent study in the
New England Journal of Medicine
showed that the use of a nineteen-item surgical safety checklist decreased mortality by nearly 50 percent and the rate of complications overall by a third. A recent study showed that the use of a checklist before certain procedures in the ICU can also reduce medical errors by 80 percent and save lives.

Most of this effort has been directed at system errors—when the wrong drug is given or the wrong type of blood transfused. When the wrong leg is amputated. These were the errors identified in a report by the Institute of Medicine (IOM),
To Err Is Human
, published in 2000. Hospitals have been in the forefront of this movement and there are efforts to punish hospitals that have been slow to address these problems.

Diagnostic error, however, hasn’t been part of that effort. In fact, when one researcher searched the text of the IOM report, the term “medication error” came up seventy times but the term “diagnostic error” came up only twice. This was true even though the study that this report was based on found that diagnostic errors accounted for 17 percent of all the errors made.

Research into the cause and solution of diagnostic error is in its infancy. Most of the focus in the area of diagnostic errors is aimed at addressing one of the most fundamental cognitive limitations that doctors must deal with: the limited capacity of our own brains. Medical knowledge has grown so vast that no single human can know it all—no matter how much experience they have, no matter how many patients they’ve seen, and no matter how many textbooks they’ve read, no matter how many journals they keep up with. Some classes of cognitive errors are rooted in this limitation—you can’t see what you don’t know to look for. And even if you know about an illness, you may not think of it if a patient presents with an unusual version of the disease.

One obvious solution to this dilemma is for doctors to augment their own, personal neural computers with actual computers, which don’t get tired, don’t get confused, and have memory capacities that far outstrip that of any single human brain. But, as we will see, this “obvious” solution has not been nearly as easy to implement as many medical professionals once believed.

CHAPTER TEN
Digital Diagnosis

I
n 1976, Peter Szolovits had a vision of the future. He had a newly minted doctorate in information sciences from Caltech. He was in the vanguard of the computer-savvy. And he had a dream: that joining the data-gathering skills of the physician with the almost limitless memory and data-crunching ability of the computer would allow unprecedented accuracy in the physician’s art of diagnosis.

Szolovits came of intellectual age in a time of heady optimism about the capacity of these marvelous inventions. It was the dawn of the modern computer era. Microcomputers were the cutting edge. These computers were the size of a desk rather than the room-sized mainframes that had been the previous state of the art. The personal computer—one that ordinary people could use in their homes—was still just a dream in a Palo Alto garage. Data was still stored on enormous reels of electromagnetic tape. The newly invented LP-sized disk drives were marvels of data storage technology because they could hold 7 megabytes of information.