“A green dinosaur is chasing me”: 16-year-old girl’s bizarre behavior... Thought to be mental illness, but a shocking twist [What happened to her body?]

[Financial News]  “Green dinosaurs are flying in the sky.”
The 16-year-old girl saw dinosaurs that did not exist. She trembled with fear that someone was chasing her and even heard terrifying voices telling her to hurt others. It was thought to be a simple mental illness. But the real cause was somewhere entirely unexpected: a rare disease called “autoimmune encephalitis,” in which the body’s own immune system destroys brain tissue.
On the 14th (local time), the U.S. science publication Live Science highlighted the remarkable medical case of a 16-year-old girl in California.
The life of the girl, who had always done well in school, began to unravel just 48 hours before she went to the emergency room. Brought in after suddenly suffering from auditory and visual hallucinations, she was trembling all over and gasping for breath. She acted as if there were a real dinosaur right in front of her.
The hospital was also at a loss. A brain CT scan and an EEG were performed, but the results were “normal.” As doctors struggled to find a clear cause, her condition deteriorated sharply on the second day of her hospital stay. She developed “catatonia,” stopped speaking, and became rigid. Tests of her cerebrospinal fluid and an MRI also showed no signs of infection. The situation was so dire that transferring her to a psychiatric ward was even considered.
The twist came with a “autoimmune test” conducted later.
Autoantibodies targeting “neuronal intermediate filaments (NIF),” which help maintain nerve cells in the brain, were detected in the girl’s body. This meant that, rather than an external virus, her own immune proteins were indiscriminately attacking her brain. It was an extremely rare form of autoimmune encephalitis in which NIF-related autoantibodies were found.
Once the medical team identified the exact enemy, they immediately counterattacked. Along with steroids and immunoglobulin, they also treated her with rituximab to suppress B lymphocytes. They additionally performed plasma exchange—directly filtering harmful autoantibodies from her blood—five times over the course of a month.
The grueling battle ended successfully. The girl was discharged after nearly two months in the hospital and gradually returned to daily life following more than a year of steady immunotherapy. She was also able to stop taking antipsychotic medication.
This case clearly shows how dangerous it is to diagnose a disease based only on outward symptoms. The medical team stresses that when sudden behavioral changes or hallucinations occur alongside fever or seizures, a neurological cause must be considered. The green dinosaur the girl saw was not just a hallucination. It was an urgent “call for help” from a brain in collapse.
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