One day, when I was driving home with my three-year-old son Brandon in the back seat of our car, I heard, “Mommy, my chest hurts.”

We had been well trained for this—as a toddler, Brandon had been diagnosed with severe asthma, a condition that didn’t seem to improve even with his daily doses of inhaled steroids and bronchodilators. I asked him quickly, “How bad is it? What kind of animal?”

“There’s a hippo on my chest.”

I slammed on the brakes, made an illegal U-turn towards the local emergency room, and parked half on, half off the sidewalk outside the hospital doors. Snatching Brandon from the back seat, I ran into the ER, shouting, “There’s a hippo on his chest. There’s a hippo on his chest.”

The triage nurse took him out of my arms. “I’ve got him. Go park and find us in the back,” she told me. When I returned a few minutes later, huffing from fear and the sprint from the parking lot, I found Brandon sitting on an examining table, swinging his legs and eating a cookie as he chatted away with the nurse.

“He’s fine,” she said. “No bronchial sounds, no symptoms.”

I asked him, “Does your chest still hurt?”

“Yes” he said, with a cookie-filled mouth.

The nurse turned to him and asked, “Do you have a hippo on your chest?”


She looked at me pointedly, then asked him, “Brandon, how big is the hippo?”

Brandon held up his thumb and forefinger about an inch apart. “This big.”

Brandon’s tiny hippo wasn’t just the product of an imaginative kid. It was a blaring announcement that perhaps we were treating something that didn’t exist. For over a year I had watched him carefully, jumped at every cough, and trained him to report any new symptoms.

And he was ill. He just didn’t have asthma.

My son was one of the more than 12 million Americans who experience a diagnostic error each year, a number equivalent to the combined populations of New York and Los Angeles. According to a report published by the Institute of Medicine in September, almost everyone in the U.S. “will experience at least one diagnostic error in their lifetime, sometimes with devastating consequence.” Those numbers are based on a 2014 study that found that around one out of every 20 outpatient experiences results in a misdiagnosis—people receive the wrong information about the cause of their illness, or they have treatment delayed because of an error, or they’re treated for something they don’t have.

Experts agree that these estimates are likely conservative. Other studies have shown error rates from 10 to 48 percent, depending on the specialty. Because the diagnostic process can involve many players and moving parts, identifying the true rate of error is nearly impossible. “There are no health-care organizations tracking diagnostic errors that I know of, anywhere,” says Mark Graber, the president and founder of the Society to Improve Diagnosis in Medicine. “The tools that hospitals have aren’t set up to detect diagnostic errors.”

And the small amount of research that exists is almost entirely limited to adult patients—meaning that as little as we know about the full extent of misdiagnoses, we know even less about how they affect children’s health.

We do know this much: Misdiagnoses in kids happen fairly often—perhaps even more than in adults (according to the IOM report, children, like patients with mental illness, can be especially challenging for diagnosticians). While pediatricians aren’t sued for malpractice as often as most other specialists, they do get sued for misdiagnosis far more often than any other group. When The Doctors Company, a large medical-liability insurer, compiled its data from 2007 to 2013 for the IOM, it found that misdiagnoses accounted for an astonishing 61 percent of all malpractice suits against pediatricians. And in a 2010 survey of more than 1,300 pediatricians in the journal Pediatrics, 54 percent admitted to making a diagnostic error at least once or twice each month.

One potential factor may be the sheer breadth of knowledge that pediatricians need in order to practice: Besides assessing sick children, they have to know about the physical, neurological, and emotional development of children at every stage, from newborns to teens. They’re also gatekeepers to almost every other specialty.

“Medicine is too complicated for human beings,“ says Baltimore-based David Meyers, the former chief of the medical-practice division at EmCare, a staffing agency for emergency health-care providers. “There’s just too much information to process. The settings in which we do this … are full of distractions. We’re not sure how much weight to put on which pieces of information we get.”

In most cases, adults who have been healthy know their bodies well enough to easily tell when they’re ill. But unless it’s acute or sudden pain, fever, or injury, children don’t always know that something’s wrong—they may not know, for example, that they’re feeling more fatigued than they should, or that they’re not supposed to have headaches all day, every day. And even if they do recognize that they’re feeling off, they may very well lack the vocabulary to accurately communicate what’s happening.

“For pediatrics, the two big things that I encounter as a hospital-based physician are fever of unknown origin and then chronic abdominal pain,” says Geeta Singhal, an associate professor of pediatrics at Baylor College of Medicine. “The differentials [the list of possible causes] for both of those are huge.”  Either could be caused by something benign, like an upset stomach or teething, or something more serious requiring immediate attention—but kids may not be able to detect or describe the nuances that help doctors separate an ordinary occurrence from a true emergency.

Older children and teens present a different set of issues for physicians. Pediatricians tend to rely on parents’ observations to supplement whatever information they can learn in an exam room. But as kids age into adolescence, they often begin withholding information about their lives that can significantly affect their health. This can include more serious things, like drug use and sexual activity, but it can also be something as seemingly innocent as a head injury from sports, or cuts from horsing around, or that weird rash they presume is poison ivy. Doctors also have to factor in social pressures and stress, each of which can influence a diagnosis.

“With teenagers, of course, generally, we presume they’re not fully disclosing,” says John Hickner, the head of family clinical medicine at the University of Illinois College of Medicine. That’s why best practice is for the pediatrician or family practitioner to “try to interview teens without their parents in the room, so they hopefully will develop some trust and will be more forthcoming with their issues.”

Another particularly challenging group for pediatricians is chronically ill kids, who often don’t report a symptom unless it’s something new. If a child feels pain every day, that becomes the new normal, making it less likely that he’ll mention it to a parent or doctor.

This is especially true for younger kids like Brandon, who don’t understand context or scale when it comes to describing their chronic symptoms (or the size of a hippo). In retrospect, the keys to my son’s misdiagnosis should have been easy to recognize: He hadn’t improved despite the ever-increasing daily doses of medicine, and he hadn’t experienced the key symptom of bronchial sounds, even though he was still having trouble getting air.

Eventually, we brought Brandon to Yale Children’s Hospital for a second opinion. They were alarmed at the enlarged size of his lungs, which filled his chest cavity because of his constant struggle for oxygen. “He has the lungs of someone who’s climbed Mount Everest,” the pediatric pulmonologist told us after she ruled out cystic fibrosis. Finally, after a full day of exams, careful questioning, and tests—including a CAT scan—she found the answer: Every one of Brandon’s sinus cavities was filled with solid material. He was unable to get air because the path was completely blocked.

The cause? A series of under-treated ear and sinus infections. Instead of a lifetime spent constantly fighting for oxygen and taking more than a dozen doses of various medicines each day, Brandon was healed by a simple 35-day course of antibiotics.