Doctors have identified a treatment for people whose sense of smell and taste was warped by Covid.
The 10-minute procedure sees a doctor inject a steroid into a collection of nerves at the base of the neck, which jumpstarts the nervous system.
Researches are not exactly sure how it works, but the treatment has been used to treat PTSD, migraines and other issues involving the circulatory system.
In a study of 54 patients with persistent post-COVID parosmia, or distorted sense of smell, the injection provided them with some relief from their distorted sense of smell.
Doctors are not certain why exactly this procedure was so effective for regaining sense of smell, but there is a prevailing hypothesis that injecting and numbing some of the sympathetic nerve tissue recalibrates the body’s nervous system to pre-Covid condition. Photo courtesy of Nevada Comprehensive Pain Center
You can’t walk past a bakery without gagging, the smell of onions makes you physically sick and even brushing your teeth is unbearable. It sounds unthinkable, yet that’s the reality for tens of thousands of people with parosmia after getting Covid
An estimated 20million Americans have been affected by a loss or distortion of their taste or smell, often leaving them put off food and drinks they used to enjoy.
Doctors have found people with Covid lose their sense of smell because the virus damages the receptor nerve endings or supporting cells within their nose.
The scent-detecting nerve endings tell the brain how to interpret the chemical information that makes up a smell, and when damaged or if they heal incorrectly, this can lead to parosmia.
Loss of taste and smell were more common earlier in the pandemic, when up to three in five sufferers were estimated to have the symptom.
But amid vaccination and the spread of new variants, the symptoms have become less common.
Its mechanism of action is largely unknown but it is possible that blocking the nerve in the neck could alter the way the brain interprets smells coming in through the nose.
Parosmia, where the damaged nerves try to regenerate but send confused messages to the brain, distorting the sense of smell and taste, can be debilitating.
Parosmia is not a new phenomenon. It can be caused by damage to olfactory nerve cells following a head injury or sinus problems. But it also occurs following viral infections affecting the upper airway.
It has been known to cause severe nausea and disgust around food that could progress to an eating disorder as people suddenly cannot stomach basic nutrition.
The condition is not known to be a permanent after-effect of Covid, though millions of people still have not seen their symptoms subside completely over a year after getting sick in the first place.
To determine whether a stellate ganglion block (SGB) used for the treatment of pain could work for problems with sense of smell, radiologists recruited 54 test subjects who had been referred to them by ear, nose, and throat doctors after suffering from the condition for at least six months after their Covid infection.
The procedure itself saw the doctor inject an anesthetic mixed with a steroid at the base of the neck where the cluster of nerves is situated on either side of the voice box where it delivers signals to the head, neck, arms, and chest.
Dr Adam Zoga, a musculoskeletal radiologist at Jefferson Health in Philadelphia who led the study, said: ‘Parosmia has previously been reported as a rare disorder occurring after brain trauma, brain surgery, stroke, viral syndromes, and with some head and neck tumors.
‘We were not entirely confident that the procedure would work for parosmia.’
The team’s reasoning for choosing SGB as a possible treatment was not explained, though there is a general hypothesis that this type of injection into the tangle of nerves can recalibrate the part of the nervous system that handles unconscious tasks to its pre-Covid infection state.
The early results showed the procedure was largely successful. Out of the 37 patients who provided follow-up information, 22 people reported their smell had improved one week after injection.
And 18 of 22 people said their symptoms had improved significantly after one month.
Dr Zoga said: ‘The initial patient had a tremendously positive outcome, almost immediately, with continued improvement to the point of symptom resolution at four weeks.
‘Other treatments have failed to date. This injection is working.’
The research team’s findings will be presented in full next week at the Radiological Society of North America’s annual meeting.
SGB has been shown in previous research to improve smell loss symptoms. For instance, a study out this year in the journal Local and Regional Anesthesia found that performing SGBs for long covid symptoms helped about 87 percent of people recover their lost or distorted sense of smell.
In a separate case study series, researchers found that SGB helped five out of six patients in Florida with long covid-linked smell and taste problems.