When the 25-year-old woman arrived at the emergency room, she was weak, dizzy and experienced shortness of breath. But her doctor immediately zeroed in on a lot more regarding symptoms.
"She looked physically blue," said Otis Warren, an emergency medical doctor who treated the woman last year on Rhode Island.
The woman's skin and nails had taken on a bluish hue – a common sign that the body is not getting enough oxygen – and her blood had also become unusually dark, according to a report published in Thursday's issue of the New England Journal of Medicine .  Fortunately, doctors knew exactly what was wrong.
The symptoms pointed to a rare and potentially fatal condition called acquired methemoglobinemia, where exposure to certain chemicals or drugs changes the shape of a person's hemoglobin molecules, causing the blood to stop releasing oxygen into the surrounding tissue, Warren said. As a result, the tissues turn blue and the blood that now "selfishly sticks to oxygen" darkens from a "bright glowing red color" to a "chocolate brown," he said. Metemoglobinemia can also be transmitted through families, although this form is much rarer.
In this case, the doctors say that the woman's condition was triggered by a reaction to a topical pain medication she used to soothe a toothache. The drug contained benzocaine, the active ingredient in a number of anesthetic ointments without a counter. Benzocaine is also often used by doctors and nurses to kill patients' noses and throats during procedures. There have been more than 400 reported cases of benzocaine-associated methemoglobinemia since 1
The morning after using the drug, the woman, who is not named in the report, told the doctors that she woke up feeling short of breath, Warren said.
Then she looked in the mirror, became "very worried" and rushed to the hospital, he said.
"" I'm blue, "the woman informed medical personnel about the arrival, according to Warren. Her blood tests also showed the failing discoloration, he said. Warren emphasized that the woman's blood was brown, not dark blue, as other media have reported. Throughout his career, Warren said, he has only seen one other patient with the disease but still remembers the living signs.
That's the type that gets stuck with you, he said. in the dots and administered the really called antidote, methylene blue, Warren said, Methylene blue returns the altered hemoglobin to its normal form, restoring the blood's ability to deliver oxygen.
patients with levels greater than 50 percent may be at risk of heart failure, coma or "And with death," Warren said.
"She was on that case, for sure," he said.
In a 2018 communication on the dangers of benzocaine products and methemoglobinemia, the FDA noted that it identified 119 reports of the condition in the past decade, most of which were serious and required treatment. Of these cases, four people died, including one infant. The federal agency warned that all oral drugs containing benzocaine should not be used to treat infants and children younger than 2 years, a demographic that is particularly susceptible to blood disease, Warren said.
"These products have serious risks and offer little to no benefits for treating oral pain, including sore gums in infants due to dental care," the FDA wrote.
It's unclear how much benzocaine the woman used, but Warren said even small amounts can be dangerous depending on the person.
"This is a drug that is usually used without problems all the time," he said. "There are some people out there who have this idiosyncratic reaction, and you don't know it until it happens."
The woman received two doses of methylene blue administered through an IV and responded well to the treatment, Warren said. She spent one night in the hospital before her symptoms cleared and she was released with a referral to the dentist.
Warren said that he and another doctor decided to publish the details of the woman's experience on Thursday given its rarity, adding that it was a "very interesting physiological case."
"I may work another 20 years and may never see anything like it again," he said.