Every so often, doctors encounter a patient with a problem so unusual they decide to publish a case report. Case reports are meant to add to scientific research, or help other doctors who might encounter the same strange symptoms in the future.
But to those who aren't doctors, case reports illuminate the limits and the mysteries of the human body.
LiveScience searched the medical literature to find some of the weirdest medical cases on record. From a man who nearly died of an overdose of a common condiment to a woman who ended up with a toothpick in an unlikely body part, here's a look at 14 cases that may tell you more about the human body than you may want to know.
Editor's Note: This article was first published on July 2, 2013, at 3:45 p.m. ET.
A frustrated man in India went to doctors complaining that he got a headache every time he watched pornography. The pain started five minutes into a video, and peaked after eight to 10 minutes.
Sex headaches are both mysterious and somewhat rare, said Dr. Amy Gelfand, a neurologist at the University of California, San Francisco School of Medicine. One percent of the population may suffer from so-called primary sex headaches at one point in life, she told LiveScience.
Most sufferers develop a sudden headache at the point of orgasm. Less often, the primary sex headache will emerge slowly as sexual arousal heightens. But the man in India had quite the unusual case because his sex headaches only appeared while watching videos, not during masturbation and not during sexual activity, according to the case report published in 2012 in the journal Archives of Sexual Behavior.
Doctors think that muscle contractions in the neck and jaw may trigger primary sex headaches. Others theorize nerves or blood vessels in the head become overly sensitive to the sexual response. However, the cause remains a mystery.
Risky drinking games usually involve alcohol, but one teen learned not to swig soy sauce, either. A 19-year-old man in Virginia drank a quart of soy sauce on a dare.
He first started twitching, and then had seizures and eventually landed in the hospital in a three-day coma. Doctors diagnosed him with hypernatremia, or dangerous levels of salt in the bloodstream.
One quart of soy sauce can contain as much as a third of a pound (150 grams) of sodium. Excess sodium in the bloodstream pulls water out of nearby tissues by a process called osmosis, which equalizes the concentrations of salt across cells. Hypernatremia can extract so much water from the brain that it starts to shrink and bleed.
It took doctors about five hours and 1.5 gallons (5.7 liters) of sugar water pumped into the teen's body to get his sodium levels back to normal, according to the report, published in the Journal of Emergency Medicine in June.
Surprisingly, he survived with no long-term neurological damage.
An 87-year-old woman in Switzerland sought medical help when she developed painful spasms every time she swallowed. Imaging and X-rays revealed her esophagus twisted up like a corkscrew whenever she ate. The condition caused her to lose 11 pounds (5 kilograms) over the course of several months, according to the case report, published in the New England Journal of Medicine in May.
Specialists in the United States told LiveScience that while the twisting esophagus was odd, the condition is not unknown.
Muscle spasms are to blame for this type of pain. Instead of contracting and relaxing in a series from the mouth to the stomach, the muscles within this woman's esophagus contracted simultaneously, said Dr. John Pandolfino of Northwestern Memorial Hospital in Chicago.
There is no cure for the condition.
Sometimes, cartoons get it right. A punch to the head left one man in Austria with an actual star in his eye, according to a report published in April in the New England Journal of Medicine.
A strong hit to the face from balls, punches or even airbags can send shockwaves through the eye strong enough to damage the lens and cause a cataract. Doctors say the cataract that appeared in the 55-year-old's eye was only strange because of the intricate star shape.
"Nature has made a beautiful cataract," said Dr. Mark Fromer, an ophthalmologist at Lenox Hill Hospital in New York.
Usually, such cataracts appear as a white-yellow cloud, not a star. In these types of cases, cataract surgery can restore a person's vision.
Your eyeball is certainly one place you don't want to grow hair. A young Iranian man knew that since birth, he had a benign tumor on his eye, just below his pupil. But by the time he was 19, the tumor had grown to about a quarter inch thick (0.64 centimeters), and started sprouting hair.
The tumor was a limbal dermoid. Although this type of tumor isn't typically cancerous, it can grow cartilage, hair and sometimes even sweat glands. Not everyone with these tumors wants or needs them removed.
However, doctors did remove the hairy tumor from the man's eye, according to the case report published in January in the New England Journal of Medicine.
A young man's tattoo idea went terribly wrong when it left him with a permanent erection. The 21-year-old in Iran paid a tattoo artist to put the letter M, for his girlfriend's last name, and the Persian phrase for "Good luck with your journeys" on his penis.
According to the doctors who treated him, the man felt pain for eight days after the tattoo. Then, his penis became permanently semierect. He lived with the condition for three months before getting medical help, according to the report.
Doctors tried shunting the penis to drain excess blood, but it didn't work. Ultimately, the patient decided he was fine with the condition and declined further treatment, according to the case report published in 2012 in the Journal of Sexual Medicine.
Ever wonder what would happen if you were to drink soda — and only soda — for a long time? A woman in Monaco did just that for 15 years.
The 31-year-old was sent to the hospital after she fainted. Tests found she had severely low potassium levels and an irregular heartbeat, but no hormone problems or family history of heart problems. She did, however, admit to drinking 2 liters (about a half gallon) of cola and no other liquids every day since the age of 15.
Doctors said the cola could draw excess water into the bowels, causing diarrhea and leaching potassium from the body. High amounts of caffeine in the cola could also interfere with potassium reabsorption. Low levels of potassium are known to cause heart rhythm problems.
One week after dropping her soda habit, the woman's heartbeat and potassium levels returned to normal, according to the report, presented in June at a heart doctors' meeting in Athens, Greece.
Forget watermelon seeds or gum. Don't ever swallow a toothpick.
In a recent case, a 45-year-old woman became gradually weaker over several months before being admitted to the hospital for vomiting and low blood pressure.
At first, doctors thought she had an infection, but tests showed a 1-inch-long (2.5 cm) puss-filled cavity in her liver. Surgery later showed it was a toothpick she had swallowed; it had somehow moved from her digestive track and lodged itself in her liver, according the report, published in the journal BMJ Case Reports in 2012.
Doctors have published at least 17 cases of patients who swallowed a whole toothpick that migrated to the liver.
A 67-year-old retired teacher in Kentucky was on the verge of asking for an exorcism after she started seeing oblong faces with large teeth, eyes and ears hovering over her.
Doctors confirmed she wasn't on drugs, and wasn't losing her mind. The woman said she knew the hallucinations were not really there, and they didn't speak to her.
In fact, the woman's macular degeneration had triggered a peculiar condition called Charles Bonnet syndrome, which causes some people suffering from eye disease to start to see animals, creepy faces or other illusions.
"When [the brain] expects sensory input and receives nothing, it often creates its own input," said Dr. Bharat Kumar, an internal medicine resident at the University of Kentucky who treated the woman.
Oftentimes, the hallucinations stop once the brain gets used to less visual input, according to the case report, published in February in the journal Age and Aging.
In a cat rescue mission gone wrong, a teenager in the Netherlands was left with a large, black open wound, which took multiple doctors several weeks to find its rare cause.
The kitten that the 17-year-old girl rescued from drowning in a ditch was sick and died the following day. Over the next several days the teenager developed a red wound on her wrist that blistered and then turned black. She also developed painful red bumps on her arm, spanning from the wound on her wrist up to her armpit.
After the antibiotics didn’t work, doctors began to suspect that the wound was caused by the cowpox virus.
"The girl had been treated by different doctors for about 13 days by then," said Dr. Jojanneke Heidema, a specialist in pediatric infectious disease at St. Antonius Ziekenhuis Hospital in Nieuwegein, Netherlands, who reported the case published Sept. 2 in the journal BMJ Case Reports.
After another week, the girl got better on her own, and the wound healed within two months, leaving a scar.
Cowpox is a self-limiting disease, meaning it usually doesn't need medical treatment if the patient has a healthy immune system, Dr. Heidema told LiveScience. [Image: the blackened, open wound]
A 49-year-old man in Brazil survived a stroke but underwent a strange personality change afterward -- he developed "pathological generosity," according to a report of his case.
The man began to give away money, and bought candies for children he met on the street, his wife told the doctors. He was unable to manage his financial life, and would have gone into debt if it were not for his wife's attention, the researchers said.
The stroke apparently left the man with "excessive and persistent generosity," the researchers said in the report published Aug. 20 in the journal Neurocase.
The doctors evaluated the patient, by didn't find any evidence of manic symptoms or dementia that could explain his excessive generosity.
A CT scan showed low blood flow to several brain regions, including areas in the frontal lobe. These regions may not be directly damaged by the bleeding in the man's brain during his stroke, but are connected with that region by neural pathways. Damage in these pathways might have had a role in changing patient’s personality, the researchers said. [Image: MRI scan of the bleed]
In a strange case, a woman developed "hyper empathy" after having a part of her brain called the amygdala removed in an effort to treat her severe epilepsy, according to a report of her case.
The amygdala is involved in recognizing emotions, and removing it would be expected to make it harder rather than easier for a person to read others' emotions, according to the researchers who reported her case, published Aug. 14 in the journal Neurocase. [Image: Patient's MRI Scan after Removing Amygdala]
The woman reported experiencing a new, spectacular emotional arousal and feeling physical effects along with her emotions, such as a "spin at the heart" or an "esophageal unpleasant feeling" when experiencing sadness or anger.
The researchers evaluated her psychological condition and found she performed exceptionally well on standard tests of empathic abilities.
The researchers said that perhaps, even though the amygdala was gone, other brain regions and newly organized connections among them, were responsible for driving stronger empathy.
An 8-year-old boy in Australia had high levels of lead in his blood for more than two years for unexplained reasons, until doctors found lead pellets in his body, trapped in an unlikely place, according to a report of his case published in Aug. 8 issue of the New England Journal of Medicine.
When the boy developed a stomachache and was admitted to the hospital, the doctors did an x-ray, which revealed a large number of small round objects in the boy's abdomen, appearing to be inside the digestive tract. The doctors immediately gave the boy a bowel washout, which should have cleared any object within his digestive tract, but a second x-ray showed the objects had not moved.
The doctors suspected the unlikely scenario – the objects had to be lodged in the boy's appendix.
In surgery, the doctors removed the boy’s appendix, and found it weighed five times heavier than normal. When they cut it open, they found 57 lead pellets trapped inside.
It turned out, the boy’s family had hunted for food with a gun that fired such pellets, and the boy had consumed them while playing a game with his siblings.
One man's irrepressible body odor was the result of a bacterial infection of his armpit hair, according to a recent report of the case.
The 40-year-old man told his doctors he'd had armpit odor and "dirty" armpit hair for the last four years. There was a "creamy yellow" substance on the man's armpit hairs.
The doctors diagnosed the man with trichomycosis axillaris, which is an infection of hair shafts caused by the bacteria Corynebacterium tenuis.
The man had his armpit hair shaved, and was treated with aluminum chloride (used to treat sweating) as well as the antibiotic erythromycin. The odor went away several weeks later, his doctors said.
The report was published Oct. 30 in the New England Journal of Medicine.
Surfer's eye is an eye problem in which fibrous tissue grows over the surface of the eye. To treat this condition, surgeons often cut out the tissue with scissors.
But one adventurous surfer in Hawaii chose to let the force of water take care of his eye, by dipping his head into the rushing water while surfing a 30-foot (10 meters) wave, according to a report of his case published in 2014 in the journal BMJ Case Reports.
Apparently, the blunt force of water ripped off the irritating fibrous tissue, but doctors said the man was lucky the water didn't damage his eye.
A young man in Brazil who suffered from throbbing headaches and vision problems for 10 years turned out to have stonelike buildups of calcium in his brain.
The stones were likely a rare complication of the man's celiac disease, a digestive condition that the man didn't know he had, according to a report of his case published in 2014 in the New England Journal of Medicine.
Celiac disease is an autoimmune disorder that, over time, can damage the lining of the small intestine and prevent the body from absorbing nutrients.
It is unclear how exactly celiac disease resulted in calcification in the brain, but researchers said it is possible that the patient's lowered ability to absorb iron may have had a role.