Medical Health Cluster

4 abril, 2021

Why Do Some COVID-19 Tests Hurt So Much?

The one time I got tested for COVID-19, I wound up in the emergency room — but not because I tested positive. During the test, as the technician kept inching the swab deeper and deeper inside my nose, I felt a bit of discomfort. Afterward, I left the facility with a shrug, thinking it wasn’t so bad. I didn’t suspect it would trigger the worst headache I’ve ever had. I’ve had migraines for years, so I know from headaches. This felt exponentially worse, like a terrifying vise. Hours later, after over-the-counter pain medications didn’t even take the edge off, I let my husband call an ambulance.

I’m far from alone in having a COVID test with an ugly aftermath. Hattey Lennerman, a nurse in Lexington, KY, has to get monthly tests because of her work. At her very first one back in April 2020, “I felt a sharp pain and my eyes watered. I wound up gripping the chair, reeling back from the pain,” she says. She had a burning sensation and pain in her jaw. Within 15 minutes, she had the worst headache she’d had in years. “I had to turn out the lights in my office and just sit there. Ibuprofen didn’t touch it.” And at her second test, Lennerman’s nose bled.

Aside from headaches, teary eyes, and nosebleeds, some people have fainted. Others describe the test as feeling “like I was cleaned from behind my eyeball,” “wild painful,” and as if it “reached to the back of my skull and then went back for more.” One person’s eye started twitching, and another said she thought she was being lobotomized.

The Nasopharyngeal Swab

Hundreds of millions of COVID tests have been done in the U.S. over the last year. Tests using the nasopharyngeal swab — the one that feels like it might scrape your brain — are considered the gold standard.

“Think about the millions who’ve been swabbed — you hear about every one that has a bad experience,” says Andrew Lane, MD, director of the Johns Hopkins Sinus Center. “It’s extremely, extremely rare.”

Those bad experiences can stem from several issues, thanks to the number of things involved. People tolerate pain differently and have different perceptions of stimuli. And human anatomy varies widely — your nasal passages may be broader or narrower than the person standing next to you, or you may have a deviated septum. Another factor: the skill of the technician doing the test. Because testing ramped up so quickly, you’ll find a range of training and experience levels.

The premise of the test itself is another part of the problem. “The body doesn’t like foreign objects entering the nose. It’s an open path from the outside world that goes directly to your windpipe and your lungs. And your nasal cavity is adjacent to your eye and your brain,” Lane says. “That’s a high-priority territory to defend.”

To do the test, a technician inserts a flexible, soft-tipped, 6-inch swab into your nostril. They’ll guide it to the back of your nose until it reaches the nasopharynx — the area where your nasal cavities meet your throat — and swirl it gently. They may leave it there for a few seconds to collect secretions. If the first nostril doesn’t provide enough, they may repeat the process in the other nostril.

Explaining Those Reactions

The challenge, according to Lane, is that no two noses are the same. ˙The goal with the swab should be to get to the nasopharynx without hitting anything along the way,” he says. “Unfortunately, the geometry of the nasal passages is different from person to person.”

The mucous membrane that lines your nose has a lot of nerve endings. “In general, the body’s pretty tolerant the first couple centimeters — as far as you can stick your finger in. Beyond that, the mucous membrane reacts to being touched.” Lane says.

That activates involuntary, hard-wired reflexes. Depending on how strongly your body responds, the result can be discomfort, teary eyes, pain, and other reactions. “Some people get gagging, coughing, sneezing — it’s all part of the same reflex,” he says. For people who are more prone to get headaches, it can trigger a whopper.

As for nosebleeds, that membrane (called the mucosa) is delicate and has lots of blood vessels, says Philip Chen, MD, an associate professor of otolaryngology — head and neck surgery at the University of Texas Long School of Medicine. “Nosebleeds would occur if the swab irritated and broke the surface of the mucosa,” he said in an email. “This might be more likely in really dry climates, at altitude, and if the person has a very narrow nose.”

Fainting has an equally straightforward explanation: “It’s what’s called a vasovagal event. This can occur whenever the body has a very strong response to a situation such as emotional distress or pain,” says Chen. “For some people, the anxiety of having the procedure or the actual pain can result in fainting.”

Scraping the Brain?

Although some say the test feels like having your brain tickled or stabbed, the swab can’t actually get near your grey matter.

“There are three layers of protection in the nose. There’s the mucosal lining, which covers the inside of the nose. There’s the olfactory epithelium (involved in sense of smell). The inside, the dura mater, which means ‘tough mother,’ is a tough lining of skin around the brain. It’s hard to penetrate through (it) without something sharp,” Shawn Nasseri, MD, an ear, nose, and throat surgeon in Los Angeles, told USA Today.

In a very small number of cases around the world, testing has led to leaking cerebrospinal fluid. At least one of those was found to be due to a previously unknown birth defect. “I suspect the people who have this happen had an abnormality, a protrusion of brain tissue through a hole in the bone,” says Lane. The swab itself is flexible, so it’ll bend before getting into bone.

“It’s such a low risk, I wouldn’t be frightened,” he says. “Your risk of having COVID and not knowing is much higher.”

There is one group that may be at a higher risk for this kind of trouble: “People who have had extensive sinus surgery should not be tested with nasopharyngeal swab,” says Chen. He’s the lead author of a study that looked at the need for warning such patients. That kind of surgery often involves removing a bone between the nasal cavity and the base of the skull, which might allow the swab to get through.

Tips for a Pain-Free Swab

Because anatomy and pain tolerance vary, there’s no way of knowing if you’re likely to have a bad experience. But these suggestions may lessen your discomfort:

  • If you’ve got a stuffy nose, try a spray decongestant like Afrin, Lane suggests. That can help clear a path and make it less likely that the swab will bump into anything on its way to your nasopharynx. Lie down and put one drop in each nostril, 30-60 minutes before the test.

  • Pay attention to the technician’s instructions. Position your head as directed, so they can place the swab at the correct angle. And once they start, don’t move! “Wherever they tell you to put your head, put your head in that spot and keep it there,” says Lane.

 
Sources:
Hattey Lennerman, Lexington, KY.
Business Insider: “A doctor explains why some people faint when they get a coronavirus test.”
CDC: “COVID Data Tracker: United States Laboratory Testing,” “Interim Guidelines for Collecting and Handling of Clinical Specimens for COVID-19 Testing.”
Nature: “Equivalent SARS-CoV-2 viral loads by PCR between nasopharyngeal swab and saliva in symptomatic patients.”
Andrew Lane, MD, professor of otolaryngology — head and neck surgery, Johns Hopkins University School of Medicine; director, Johns Hopkins Sinus Center.
Philip Chen, MD, associate professor, Department of Otolaryngology — Head and Neck Surgery, UT Health San Antonio Long School of Medicine.
USA Today: “Fact check: No, the COVID-19 nasal test doesn’t swab the blood-brain barrier.”
Fox San Antonio: “San Antonio woman leaks spinal fluid after receiving Covid nasal swab.”
JAMA Otolaryngology Head & Neck Surgery: “Cerebrospinal Fluid Leak After Nasal Swab Testing for Coronavirus Disease 2019,” “Assessment of Available Online Information About Nasopharyngeal Swab Testing in Patient Instructions for Sinus and Pituitary Surgery.”
The Asthma Center: “Taking the Pain Out of Coronavirus Testing.”

 


Créditos: Comité científico Covid

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