How Doctors Think (17 page)

God, You answered my prayer.

Shira received her morning feeding through the tube, and then Rachel went to the end of the hospital corridor to a pay phone. She called one of her closest friends from her congregation and told her the news.

"It's so wonderful," her friend exclaimed. But then there was a long silence.

Rachel wondered what was wrong.

"Turn on your TV."

Rachel stood frozen in the room and felt as if her heart, so full of joy, were being torn. At the moment she celebrated Shira's restored life, thousands were likely dead in the attack on the World Trade Center.
How can I rejoice when God's creatures are dying?

Forty-five days after Rachel and Shira went to the Children's Hospital ER, mother and daughter left for home. It was Friday, just hours before the onset of the Sabbath. When Rachel turned the key and entered her apartment in Brookline, she could smell the meal left by friends. Two candles stood ready to be lit, two fresh challahs ready to be savored. Rachel held Shira after lighting the candles. The soft glow of the flames played off her daughter's face. It was the day of rest and of peace, the day when all woes were meant to cease, the day that Rachel had not truly had for more than six weeks.

At each step, Rachel had not been sure whether she would find the strength she needed to endure, and the courage to question. Silently, she again thanked God for creating all human beings with such remarkable reservoirs of resilience. She thought how the Sabbath was the time when these reservoirs were refilled. She prayed that during this first Sabbath after 9/11 her country would find the strength and courage to defend itself and to care, with a full heart, for the families who had lost loved ones.

Rachel's reverie was broken by Shira fussing in her arms. It was time for her feeding, time to replenish whatever nutrients must have been missing in the food in the orphanage in Vietnam that caused her immune deficiency. "Enjoy, sweet thing. Enjoy," Rachel said as the formula flowed in.

In May 2002 in Boston, Shira's case was presented at a clinical conference at Children's Hospital. Its purpose was to educate the staff about a diagnosis that had not been seriously considered, and if not made, could have led to a disastrous bone marrow transplant. The young doctor leading the conference, and the ICU and bone marrow transplant teams, of course knew the outcome of Shira's case. But the larger audience did not. So her story was presented from the start, as if each doctor listening had been at the bedside and required to make decisions from the first harrowing moments in the ER.

"What is your differential diagnosis?" the young doctor asked the audience. "List the possible causes for this set of signs and symptoms in our patient." The consensus was SCID.

Then, in a dramatic flourish, a slide was projected on a large screen:

PATIENT DID NOT HAVE SCID.

The doctor presenting the case switched to the next slide, which detailed how malnutrition is a leading cause of immune deficiency worldwide. The most common form of malnutrition and immune deficiency in poor countries is due to the lack of ade quate protein, as in severe starvation. This did not seem to be the cause in Shira's case, since her muscles were well formed. But during the intervening months since her discharge, the team of doctors had found scientific articles that reported on how the deficiency of even a single vitamin could impair immune function. Other articles reported on deficiencies of metals like zinc, iron, and magnesium in children that resulted in decreases in T-cell numbers and T-cell function. These were all very rare but well-documented instances. Still, no one could say for sure what accounted for Shira's immune deficiency.

In the stylized speech of the clinical world, the presenter brought the audience up to date: "Patient discussed has been followed since discharge, and her immune function remains normal. The patient is growing well and meeting milestones."

The kind of conference where Shira Stein's case was discussed occurs at every teaching hospital in the country. And in community hospitals that do not have medical students or interns, there are similar forums where intriguing and unusual clinical problems are discussed among the senior staff. These conferences, whether at the academic centers or community institutions, are of great value in educating even the most experienced doctors about arcane and important disorders. But what is generally lacking at the conferences is an in-depth examination of why the diagnosis was missed—specifically, what cognitive errors occurred and how they could have been remedied. There is rarely an explicit dissection of which heuristics were used and where they fell apart.

Understanding the medical context in which Shira Stein was treated is essential to identifying the cognitive biases that almost had her undergo a debilitating, perhaps fatal bone marrow transplant. As Rachel Stein repeatedly told me, and as I well know (because Children's Hospital, by way of full disclosure, saved the life of my oldest child), the institution is among the very best in the world in pediatric care. The physicians there have considerable expertise in SCID and other genetic abnormalities that cause severe immunodeficiency. Laboratories at the hospital study how deranged genes paralyze T cells and other key components of immune defense. Clinicians have refined treatment protocols to administer standard and experimental medications and to maximize success in restoring the body's immunity. Since many cases of SCID are routinely diagnosed and treated at the institution, not only the senior attendings but the interns and residents as well are thoroughly familiar with the disorder.

Because of this expertise and familiarity, a "prototype" SCID child is established in the minds of the staff. And there is a natural cognitive tendency to zero in on certain characteristics of a patient like Shira and match them to the prototype. Familiarity breeds conclusions and sometimes a certain degree of contempt for alternatives. A maxim that I repeatedly heard during my training was "If it looks like a duck, walks like a duck, and quacks like a duck, then guess what? It's a duck." But it isn't always a duck.

Physicians should caution themselves to be not so ready to match a patient's symptoms and clinical findings against their mental templates or clinical prototypes. This is not easy. In medical school, and later during residency training, the emphasis is on learning the typical picture of a certain disorder, whether it is a peptic ulcer or a migraine or a kidney stone. Seemingly unusual or atypical presentations often get short shrift. "Common things are common" is another cliché that was drilled into me during my training. Another echoing maxim on rounds: "When you hear hoofbeats, think about horses, not zebras."

Rachel Stein, trawling through the long list of causes of Pneumocystis pneumonia, found a zebra. A nutritional deficiency can cause impaired immune defense and provide fertile ground for this infection. With his characteristic élan, Pat Croskerry, at Dalhousie University in Halifax, has coined the phrase "zebra retreat" to describe a doctor's shying away from a rare diagnosis. Powerful forces in modern medicine discourage hunting for them. Often the laboratory tests and procedures needed to pin down an arcane diagnosis are hard to perform, highly specialized, and expensive. In an era of cost containment, when insurers and managed care plans scrutinize how much physicians spend on any one patient, doctors have a strong disincentive to pursue ideas that are "out there." In fact, some physicians are called to account for ordering too many tests because they may turn up only one correct diagnosis out of twenty-five, fifty, a hundred, or five hundred, and because the money would be better spent on something else. Unless, of course, that one zebra case turned out to be the bean counter's own child.

To add to that pressure, doctors who hunt zebras are often ridiculed by their peers for being obsessed with the esoteric while ignoring the mainstream. Zebra hunters are said to be showoffs. As an intern on rounds, I often heard senior residents call them "flamers."

There is yet another psychological reason for a physician's "zebra retreat." Because a doctor usually lacks personal experience with the very arcane case, knowing about it only from his reading or a single encounter over years of work, he often lacks the courage of his convictions. He is uncertain of how far to press the hunt.

Participants in the conference on Shira Stein's case at Children's Hospital listed many nutritional inadequacies that result in immune deficiency. I would wager that very few on the staff would know how to identify them. I admit that I don't; I would have to find a specialist or look up the answers, which are not readily available in medical textbooks. Furthermore, aside from relatively common dietary deficiencies—lack of vitamin BE causing pernicious anemia, or insufficient vitamin C giving rise to scurvy—little is known about the effects of nutrition on many bodily functions. This absence of general clinical knowledge prompted physicians to dismiss Rachel Stein's repeated suggestions that her daughter might be lacking some nutrient. Why pursue such a far-out and vague idea? Shira didn't fit the prototype of the malnourished child.

In addition to forming mental prototypes and retreating from zebras, Shira's doctors made a third cognitive mistake, called "diagnosis momentum." Once a particular diagnosis becomes fixed in a physician's mind, despite incomplete evidence—or, in Shira's case, discrepancies in evidence, like the rising T-cell numbers and the rarity of SCID among girls—the first doctor passes on his diagnosis to his peers or subordinates. This, of course, plagued Anne Dodge for fifteen years. Here, the ICU attending became convinced that Shira had SCID. This powerful belief was passed on to his interns and residents and then to the bone marrow transplant team when Shira was moved out of the ICU. Every morning on rounds when Shira's case was reviewed, the opening statement was "Shira Stein, a Vietnamese infant girl with an immune deficiency disorder consistent with SCID..." Diagnosis momentum, like a boulder rolling down a mountain, gains enough force to crush anything in its way.

Rachel Stein was not an expert in cognitive psychology and did not study errors in medical decision-making. She was a desperate and frightened mother. But she found the strength to educate herself about her child's plight. And when she found inconsistencies in the many doctors' reasoning, she politely but persistently refused to be deterred. She diverted the boulder.

I have made the same cognitive errors that Shira's doctors did, despite all my training and all my good intentions. When all the pieces of the clinical puzzle did not fit tightly together, I moved some of those that didn't to the side. I made faulty assumptions, seeking to make an undefined condition conform to a well-defined prototype, in order to offer a familiar treatment.

One year after Rachel got word from the adoption agency that an infant awaited her in Vietnam, I took my daughter Emily, then twelve years old, to visit Rachel and Shira. They live on a shaded street in an apartment on a lower floor of an old stone building. I had seen them in synagogue a few times, and commented on how healthy and robust Shira looked. But Rachel and I had not discussed her story in depth. I told Rachel that I was trying to understand how she had been able to think clearly and challenge the many doctors' logic.

She shook her head as she listened. Then she explained how she saw the world: "God is like a best friend for me." A best friend. A friend you can always call upon. A friend who never deserts you. A friend who offers wisdom and resources without question. A friend you can bounce ideas off of with complete trust in his integrity. A friend you can reveal feelings to without fear that he might exploit your vulnerability.

This was the friend who steadied her time and again through the tempest of Shira's illness. This was the friend who held her back from breaking. This was the friend who helped Rachel think clearly, assimilate information, ask questions when she spoke with her sister in Los Angeles and with the many doctors and nurses caring for Shira. Drawing strength and inspiration from this friend, Rachel used all of her intellectual, social, and spiritual resources to press the request that ultimately led to the correct diagnosis.

Typically, my patients look to their faith for solace during a trying time. Some pray for God's intervention, believing as many do that there are moments when His grace enters human lives in a di rect and personal way. They pray for a miracle, for God to steer events away from debility or death. Others simply ask for the strength to endure. After hearing Rachel's story, I saw a third way in which faith can function.

Those who read the Bible, cynics say, are merely reading fairy tales. But astute psychologists counter that whatever the reader believes about the literal truth of Scripture, the Bible offers profound insights into human character. No one in its stories, despite his knowledge and power, and despite his good intentions, is perfect, infallible. Everyone is flawed at some time, in thought or in deed, from Abraham to Moses to the Apostles.

In their
Handbook of Religion and Health,
Koenig, Larson, and McCullough review the arguments, pro and con, about how faith influences the ill. One school of thought holds that religion makes people passive, accepting the course of events as God's will. Such patients, these critics assert, relegate their personal responsibility for choices and action to an imagined force outside themselves, thus further infantilizing their part in an already overly paternalistic relationship with their physicians. This view is a corollary of Karl Marx's famous assertion that religion "is the opium of the people," a pacifier of both the individual and the society. For Rachel it was quite the opposite: faith can make a person a productive partner in the uncertain world of medicine. Faith, a well-recognized source of solace, of strength to endure, can also give people the courage to recognize uncertainty, acknowledge not only their own fallibility but also their physicians', and thereby contribute to the search for solutions.