Rare Brain-Destroying Amoeba Causes Toddler's Death, Highlights Diagnostic Gaps

A previously healthy toddler in Washington state abruptly became ill, presenting with vomiting, lethargy, right-side weakness, headache, fever, and swallowing problems, followed by brief unresponsiveness and breathing pauses. After admission, his condition worsened and doctors eventually diagnosed an ultra-rare brain-destroying amoeba, a pathogen first identified in a San Diego Zoo monkey in 1986 and linked to roughly 200 human cases globally, about 90% of which are fatal.

The diagnosis took more than 30 days, by which time the child suffered severe, irreversible brain injury and his parents chose to remove the breathing tube to end his suffering. Autopsy findings showed a massive stroke, necrotic brain vessels, and heavy amoeba presence. Seattle Children’s Hospital clinicians detailed the diagnostic challenges in a BMJ Case Reports case study, hoping the shared information will enable quicker identification in future patients. The boy’s parents consented to publicizing the case to aid medical awareness.