The sight of blood can make many people feel queasy, but one woman’s blood is likely to make you double-take.
A 25-year-old woman in Rhode Island was rushed to hospital after she became short of breath and her skin started to turn blue.
When she arrived, doctors discovered that it wasn’t just her skin - her blood had also turned dark blue.
According to her case report, which is published in the New England Journal of Medicine, doctors discovered that this strange colouring was the result of the toothache medication she was on.
Eating cheese can help to protect your blood vessels, study reveals
The night before she went to hospital, the woman had used a ‘large amount’ of a topical toothache pain reliever that contained a local anaesthetic called benzocaine.
At the hospital, tests revealed that oxygen saturation levels in her blood were at a very low 88%. For comparison, healthy levels are 97-100%.
Worryingly, supplemental oxygen didn’t help, and her saturation levels plummeted to 67%.
The doctors discovered that the woman had acquired methemoglobinemia - a blood disorder in which too little oxygen is delivered to your cells.
Healthline explained: “Oxygen is carried through your bloodstream by haemoglobin, a protein that’s attached to your red blood cells.
“Normally, haemoglobin then releases that oxygen to cells throughout your body. However, there’s a specific type of haemoglobin known as methemoglobin that carries oxygen through your blood but doesn’t release it to the cells.
“If your body produces too much methemoglobin, it can begin to replace your normal haemoglobin. This can lead to not enough oxygen getting to your cells.”
Oxygenated blood is a brighter red colour than deoxygenated blood, explaining why this woman's blood had turned so dark.
While it remains unclear why the benzocaine had this effect on the woman, thankfully she made a full recovery.
