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Toddler's tragic death from brain-destroying amoeba offers lessons for doctors
Boy’s unusual symptoms could help identify the next case sooner.
A healthy toddler in Washington state fell ill abruptly. It began with vomiting, lethargy, and weakness on his right side. Then it progressed to a headache, fever, and trouble swallowing. At one point, he briefly became unresponsive, and he had episodes where he stopped breathing. Doctors admitted him to the hospital, but his condition only deteriorated.
The boy was infected with an ultra-rare amoeba known for ravaging the brain. The opportunistic pathogen was first identified in 1986 from the brain of a San Diego Zoo monkey, which died from the infection. Since then, only about 200 human cases have been recorded worldwide. About 90 percent of them have been fatal.
The initial symptoms can be vague and, given its rarity, the infection is notorious for being undiagnosed or misdiagnosed. Still, the scant medical literature does provide some telltale signs, clues of what it can look like on tests and scans. But for the toddler, the infection looked different, sending doctors down the wrong path.
It took over 30 days for his medical team to finally figure out what was going on. By then, it was too late. The boy had profound, irreversible brain injuries. After initial attempts at therapy had no effect, the boy’s parents made the heartbreaking decision to remove his breathing tube to end his suffering. A subsequent autopsy showed that he had had a severe stroke, the vasculature in his brain was necrotic, and his brain tissue was brimming with amoebas.
In a case report, published Wednesday in BMJ Case Reports, the toddler’s doctors at Seattle Children’s Hospital review how they were led in the wrong direction and how to prevent it from happening in the next case. They also report that the boy’s parents agreed to share his medical case in hopes that it can lead to earlier diagnoses.
One of the biggest missteps was a misdiagnosis early in his case. Often in these rare amoeba cases, the early symptoms are so vague that diagnoses are delayed. But in the boy’s case, doctors jumped to a diagnosis—the wrong one—based on an unusual presentation. When his parents brought him to an emergency room, his symptoms were vomiting, fatigue, lethargy, and weakness. A computed tomography (CT) scan showed he had a hemorrhage on his brain, requiring a shunt.
More imaging of his vasculature showed that some of his arteries were blocked or narrowed. This has not been reported with amoeba infections before. Doctors ended up diagnosing him with childhood Takayasu arteritis, a type of vasculitis. It’s a rare, systemic inflammatory condition that causes damage to large and medium arteries in the body. It wasn’t a perfect diagnosis, but it was the condition that fit best with what they could see. They treated the boy with immunosuppressive drugs, and his symptoms improved in the hospital. After about two weeks in the hospital, he went home.
However, a week later, he was back in an emergency department with vomiting. Doctors sent him home after tests found his shunt was working properly, suspecting it was likely a side effect of one of the medications for his inflammatory condition. But his parents brought him back two days later, this time with fever, lethargy, a headache, and trouble swallowing. He was re-admitted to the hospital, and his condition began to deteriorate. At this point, it had been 25 days since his first hospital visit. The next day, he needed to be intubated. Two days after that, day 28 of his illness, he became unresponsive, his eyes rolled upward with pinpoint pupils, and his muscles became floppy.
Doctors scrambled to figure out what was going on, running more tests. Imaging of his brain suggested his injuries were worsening. They upped his dose of immunosuppressive therapy, thinking it was due to his vasculitis. But it wasn’t helping as it did before, and they took him off it as they began to worry he could have a fungal infection.