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His sudden seizures were a mystery. Then doctors saw a tapeworm in his brain from 20 years ago

· Nov 16, 2021
Doctors were stumped as to what the diagnosis could be - that is, until a CT scan of his head showed that the man’s brain had unwanted company. After finding three brain lesions, doctors dia ...

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When a 38-year-old man fell from his bed during a violent seizure, his wife found him shaking and “speaking gibberish” on their bedroom floor at 4 a.m. After he arrived at Massachusetts General Hospital in Boston, the man, who was reported to be in good health and had no history of related symptoms, suffered another seizure.

Doctors were stumped as to what the diagnosis could be - that is, until a CT scan of his head showed that the man’s brain had unwanted company. After finding three brain lesions, doctors diagnosed the man with neurocysticercosis after they concluded that larval cysts from a tapeworm had migrated to his head 20 years ago and embedded into parts of his brain, according to a case study.

The findings, which were published in the New England Journal of Medicine on Thursday, show that the 38-year-old, who was not publicly identified by researchers, had lived in a rural part of Guatemala before immigrating to the United States. It remains unclear how the man ended up hosting a parasite in several parts of his brain, but doctors noted that he probably ate a meal made by someone who had a tapeworm. Parasite-related illness is endemic in the area of Guatemala where he lived, the study says.

"On the basis of the features of the patient's presentation, the fact that he had been healthy the day before the seizure, and his history of living in a rural area of Guatemala, neurocysticercosis is the most likely diagnosis in this case," wrote Andrew Cole, the study's lead author.

Edward Ryan, the director of global infectious diseases at Massachusetts General Hospital and one of the study’s co-authors, said the man’s case was fascinating because the tapeworm in his brain was long dead but still set off seizures.

"This gentleman was a little atypical, but not amazingly rare, in that his parasites were dead and calcified and there was no living parasite in his brain for one or two decades," Ryan said. "The infection was long gone, but part of his brain was scarred - and that scarred area was leading to the seizures."

While having a parasitic infection in the brain is rare in the United States, some medical mysteries in recent years have ended with tapeworms in the cerebrum. New York doctors in 2019 discovered that a woman undergoing surgery to remove a mass from her brain did not have a tumor but instead a baby tapeworm. That year, a man living in Texas who suffered from headaches and fainting spells was diagnosed with neurocysticercosis in a case that doctors said could have ended in death if he had not been treated quickly.

Eating undercooked pork and being around unsanitary conditions are two of the most common ways to get a tapeworm. But when it comes to neurocysticercosis, a person could have swallowed "microscopic eggs passed in the feces of a person who has an intestinal pork tapeworm," according to the Centers for Disease Control and Prevention.

"Once inside the body, the eggs hatch and become larvae that find their way to the brain," the CDC says.

Tapeworms infect the central nervous system after they make their way through muscles and tissues, Ryan said, and they often take a round shape. After they die in five to 10 years, the dead parasites can cause inflammation throughout the body, leading to symptoms such as headache, soreness or seizure.

In the case of the Massachusetts man, Boston doctors saw a case of a tapeworm that was still affecting him decades later.

"He's not the only person this has happened to, but he's in the minority of individuals we see," said Ryan, who did not treat the man.

When the 38-year-old patient was stabilized with anti-seizure medication, doctors treated him with two antiparasitic drugs as well as an anti-inflammatory drug, according to the study. He was released from the hospital five days later without any symptoms or additional seizures, researchers said.

Doctors have followed up with the man over the course of three years, the study says. The swelling around the largest lesion in his brain had gone down, according to the study, and he had not had seizures while on the medication.

“He seems to be doing fine,” Ryan said.