“Look at this,” Harris panted, pulling her sheet aside so we could see her legs. “My ankles are fine now, but I’m hurting in my wrists—I can barely move my hands. And my knees, look how puffy!”

Dan, the resident, listened to her heart, his brow furrowed in concentration. “Her heart sounds different,” he said. “It’s weird. She has a bunch of new murmurs.” Before, the lub-dub of her heart had been clear; now, all I could hear were loud whooshing sounds.

I was stunned. Dan and I were thinking the same thing: It had to 
be bacterial endocarditis. In endocarditis, small masses of bacteria form on the surface of a heart valve, and these little infected clumps—septic emboli—can slip off into the bloodstream. Depending on where they settle, they can cause major problems: abscesses, strokes, kidney disease, blood clots, and, by interfering with a heart valve’s normal function, congestive heart failure.

I asked the student to draw some more blood to culture again for bacteria and to order another echocardiogram, which would show whether bacteria had built up on a valve.

We were flabbergasted when the echocardiogram results came in that afternoon. It looked like another patient’s heart, and a really bad heart at that. The mitral valve no longer leaked a small amount; now a jet of blood regurgitated backward into the left atrium with each beat. And it wasn’t only the mitral valve. The aortic valve also spewed blood in the wrong direction. The valves were damaged, but the echocardiogram showed no bacterial clumps. This didn’t seem to be bacterial endocarditis. So why were Harris’s heart valves worsening before our very eyes?

Dan wondered if we were missing a clue in her medical history. “New murmurs, the ankle pain that went to her wrists and knees, congestive heart failure. . . . Could she be having another bout of rheumatic fever?” he asked.

Because it had happened so many years earlier, we hadn’t given much thought to her history of rheumatic fever, an inflammatory disease that can affect the heart, joints, and central nervous system.

“Interesting thought,” I said to Dan. “But something would have triggered it. And she said she’d been fine except for the congestive heart failure two weeks ago.”

“That’s true,” Dan said. “But what if she had something minor, like a sore throat, and didn’t get treated for it?”

Rheumatic fever is a complication of something astonishingly basic: an untreated strep throat infection. When a particular type of strep bacterium—the group A beta-hemolytic streptococcus—infects the throat and isn’t treated promptly, it can trigger an autoimmune response, causing the body to turn on itself.

One of the proteins on the strep bacterium’s surface, the M protein, structurally resembles certain heart proteins. The body’s natural response to a bacterial infection is to create antibodies to fight it; in the case of this particular streptococcus, the antibody to the M protein also works against the body’s own heart proteins. The result: autoimmune destruction of some heart tissue and the heart valves. Damage to the valves can lead to permanent and often serious rheumatic heart disease.

The prevalence of rheumatic fever and rheumatic heart disease has plummeted in the past century in the United States and other industrialized countries, thanks to antibiotics and improved living conditions. In 1994, the last year the Centers for Disease Control and Prevention tracked the incidence of acute rheumatic fever, there were just 112 cases in the country.

Only a small number of sore throats in adults are caused by the strep bacterium that can, if untreated, trigger rheumatic fever. And most of us don’t think about getting a culture every time we have a sore throat, since most are caused by viruses. But in people with a history of acute rheumatic fever, it’s a different story. They are prone to significant risk from strep throat, especially if their original bout of rheumatic fever affected their heart.

We had to go back to Harris for that missing piece of the puzzle.

She stared out the window and thought back over the previous few months. At first she couldn’t recall being sick, but then she remembered. Back in January, she said, she’d had a sore throat and fever.

“I thought I had the flu,” she said. “It lasted a couple days, and then I started to feel better.”

That was the clue we were looking for. We sent off one more test that might give us the answer, a blood test for an antibody signifying recent exposure to strep.

The next day the puzzle was solved. Harris had recurrent rheumatic fever.

The original damage her mitral valve sustained as a result of her childhood rheumatic fever wasn’t too serious. But the immune response to her strep throat in January had been dramatic, with a new wave of antibodies eventually wreaking havoc on her heart valves. It’s a condition I had only read about and have never seen since.

The response to treatment—at least for the joint pains—can be magical. Penicillin and high-dose aspirin erased Harris’s discomfort in less than 24 hours. The damage to her valves, unfortunately, was permanent. Although we could control her symptoms with diuretics and other medications, and although antibiotics stopped the strep bacteria’s destructive barrage, we could not repair the heart itself.

Because rheumatic fever is such an uncommon disease in the United States, nobody had educated Harris about the importance of promptly evaluating a sore throat. It simply wasn’t something that most doctors—including me—thought about anymore.

Our patient was better for now. We were finally treating the infection that was weakening her heart valves. If she hadn’t been treated, she probably would have suffered additional valve damage and ended up with more advanced congestive heart failure. She might have needed more medication and, perhaps, surgery to replace the damaged valves.

None of us would ever forget how dangerous an untreated strep throat infection could be, nor how a missing clue could so easily hide in plain sight.