Worms in Spanish man's brain puzzle doctors as no clear cause is revealed

A Spanish man started experiencing severe headaches over two weeks and also reported changes in his behaviour. Doctors thought he was suffering from brain cancer. Turns out, he had worms in his brain. Neurological tests showed that, barring a mild delay in movements, there were no other problems. His blood work was fine except for a spike in IgE, which shows that the body had had an immune response to allergies, autoimmune disease, and parasitic infections. A CT scan showed lesions in his brain accompanied by swelling. More analysis revealed that he was not immunocompromised and had never travelled internationally. This led the doctors to assume that he was possibly suffering from metastatic cancer.

The case has been detailed in Emerging Infectious Diseases. He was given an anti-inflammatory corticosteroid for the pain. More extensive tests followed, including a whole-body, contrast-enhanced CT scan, a colonoscopy, and a hybrid positron emission tomography/CT scan. But they did not reveal any malignancies. An MRI gave a better look and revealed that the lesions weren’t tumours, but encapsulated tapeworm larvae, with their heads clearly visible.

The study states that tapeworms aren't endemic to Spain. However, findings have shown that certain tapeworms are found in the country. But in the case of this 60-year-old man, suspicion fell on his construction, from which he had retired 10 years ago. A lot of his co-workers were from regions where pork tapeworms (Taenia solium) are endemic. He is suspected of having picked them up through shared meals and bathrooms, and one of them likely had a tapeworm infection. But this is only an assumption, and the case remains conclusively unexplained.

How do tapeworms spread

Taenia solium infects people in two ways: through undercooked meat or by ingesting eggs through faecal contamination. Pigs ingest the eggs from faeces, which hatch in their guts, enter the intestine and the bloodstream, and reach other parts of the body where they turn into encapsulated larvae called cysticerci. When a human eats undercooked meat containing cysticerci, the larvae enter the body and develop into adult tapeworms in the intestinal tract. The eggs are released in the faeces, and if they spread around and reach a person's mouth, they can enter the bloodstream and reach various tissues and organs.

“Our case emphasises that the absence of travel history should not preclude NCC from the differential diagnosis of multiple ring-enhancing brain lesions, even in regions where metastatic cancer is statistically much more likely,” the researchers said.