June 22, 2018

“How Did That Get There?” - Foreign Objects in the Brain

The brain is our inner sanctum, containing every experience of consciousness, sensation, and memory. It’s cradled in the skull, meninges and dura mater, as well as aggressively defended by a special wing of the immune system. There is no way that anything should get in (or out). However, because of this very organ, humans are ingenious creatures and always can find ways to do incredibly stupid things. This article is not for the faint of heart.

“But I saw it on the internet….”
As I was researching this article, I quickly learned (to slight disappointment) that many stories entitled ‘Man or Woman had XYZ in Brain’ had pretty dodgy concepts of anatomy. We will start with the obvious: the brain is encased in the skull, and has no immediate access to the outside world. Some routes may be shorter than others, like the thin sheet of bone above the nasal cavity, but without blunt trauma they’re tightly sealed.
For example (apologies in advance to all arachnophobes), spiders can very easily wander into or lay eggs in your ears. However, to make it to the brain, they would have to make a hole in the eardrum, wander all the way through the cochlea and somehow squeeze their way along the auditory nerve. So the stories that you may hear about referring to ant colonies growing in an individual’s brain? Undoubtedly fake.

Misplaced Objects
As one might suspect, a lot of foreign objects find their way into the brain via tragic or unfortunate circumstances. For example, two Turkish neurologists reported a seemingly normal man who was discovered late in life to have three needles in his brain. His only symptom? A few headaches. The authors suspected that the needles were from a failed homicide attempt when the man was an infant. He survived the removal surgery, and presumably went on with his life [1].
As with other types of surgeries, it is also possible for tools, gauze, or other implements to be left behind in the brain. Tissue grows around these foreign bodies, and infection or abscesses may occur if not caught in time (usually by neurological symptoms). Most (but not all!) of the time these remnants can be removed, and one may assume that a malpractice lawsuit soon follows.
One of the more famous examples of foreign objects in the brain came from a man named Dante Autullo in 2012 [2]. He was using a nail gun to fix a shed, and somehow misfired it into his own head. His friend cleaned up what looked like a surface wound, and they continued building. The next day Autullo was feeling slightly nauseous, and a trip to the doctor ended with him getting a nail removed from his brain. He survived without further impairment. Compare this with the very famous case of railroad worker Phineas Gage, who took an iron rod to the head. He, too, survived without neurological symptoms, but his peers noticed a massive change in personality until he died twelve years after the accident [4].


Radiology Picture of the Day, Courtesy Dr. Laughlin Dawes. Pictured is a CT scan of a patient who pushed a ballpoint pen through the eye socket (and survived).


Squirm-Inducing
Apart from trauma, there is a more insidious and infinitely more gross way that things can get into your brain: parasites. For example, the pork tapeworm Taenia solium can enter the bloodstream from poorly-cooked food, and invade the skin, eyes, and brain. The danger here is not acute, but rather builds up over time as the body forms cysts trying to isolate the parasite from brain tissue [3]. Depending on where these cysts develop, this can cause seizures or other neurological complications. In developing countries, it is estimated that up to a relatively high percentage of the general population is a carrier of the tapeworm, but the fraction of those burden with neurological problems is unknown. Treatment of these brain invaders is also complicated, as the most common antiparasitic drugs cause severe tissue inflammation, which in the brain can be fatal. Often, surgical excision of the cysts is the only option [5].

The brain lesion was... moving.

But for the maximum gross-out factor, let’s also spend a moment talking about larger critters. In 2010, a British man visited the doctor complaining of headaches, strange smells, pain and other vague symptoms. He was tested for just about every neurological disease under the sun, including dozens of brain scans, but doctors couldn’t figure out what was wrong. It was only when a neurologist compared the scans over time that they noticed that a small brain lesion was… moving. Yes. He had a living worm in his brain. It turned out to be a rare type of frog parasite, and was genotyped in the hope of better diagnosing infected patients in the future [6]. Cases like his are (thankfully!) extremely rare, but do still pop up from time to time...

No Entry
In short, having anything in your brain besides neurons, glia and supportive cells is bad news. It takes a keen eye and a good neurologist to spot and deal with the problem, and all of us are better off avoiding these situations all together. So, keep pointy objects away from your head and cook your food well.
Oh, and don’t believe everything that you read online.

Constance Holman
PhD Student, AG Schmitz

[1] Pelin and Kaner, Neurol Int 2012
[2] https://bit.ly/2jNy3vL
[3] https://bit.ly/2rxLsvq
[4] https://bit.ly/2L4vhPc
[5] White, J Infect Dis 2009
[6] Bennett et al., Genome Biol 2014



Like what you see? Interested in contributing? We are always looking for new authors and submission on anything related to the topic of (neuro)science. Pitch us an article, or send us some beautiful shots from your microscope, poems to claudia.willmes@charite.de!   

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