A small triumph over a big sensory deficit post COVID-19

There might finally be relief for some people who still suffer from the long-term effects of the bizarre loss of smell and or taste acquired during a COVID-19 infection.

November 24, 2023 07:58 am | Updated 08:00 am IST

A loss or distortion of the sense of smell can be extremely damaging psychologically.

A loss or distortion of the sense of smell can be extremely damaging psychologically. | Photo Credit: Getty Images/iStockphoto

For months, after October 2021, Manish, a 35-year-old sales professional had completely no sense of smell. At least that was how it started. During the second wave of COVID-19, he had a bad bout of the infection, and among the first symptoms along with a high fever was the loss of smell. Others in his family also had COVID-19, but they seemed to have retained their sense of smell. Naturally, over time, he lost all taste, could not taste his favourite foods, started hating them, and even attempts to include pungent foods failed to stimulate his taste buds. But slowly, he entered what, in his opinion, was the worst phase of his long COVID battle — he could smell strange putrid smells that no one else could, or was he imagining them.

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He is by no means the only person who suffered from this common long COVID symptom. There might finally be some relief for all of them — people who still suffer from the long-term effects of the bizarre loss of smell and or taste acquired during a COVID-19 infection.

As per a note from the Radiological Society of America, a small 10-minute minimally invasive procedure could restore the sense of smell in patients with long COVID. The results of the study are to be presented at the upcoming meeting of the Society. “Post-COVID parosmia is common and increasingly recognised,” the Society’s note said, quoting the study’s lead author, Adam C. Zoga, M.D., M.B.A., professor of musculoskeletal radiology at Jefferson Health in Philadelphia, Pennsylvania. “Patients can develop a distaste for foods and drinks they used to enjoy.”

Long-term anosmia (partial or full loss of smell) and parosmia (distorted sense of smell, pleasant smells turning foul) are known as late sequelae of COVID-19. The authors of the study said while promising treatments for anosmia have evolved, similar success has evaded parosmia leading to mood disorders, weight loss, and decreased quality of life. 

Part of the autonomic nervous system, which regulates involuntary processes including heart rate, blood pressure, breathing and digestion, the stellate ganglia are nerves on each side of the neck. They deliver certain signals to the head, neck, arms and a portion of the upper chest. The stellate ganglion block has been used with varying degrees of success to treat a number of conditions, including cluster headaches, phantom limb pain, Raynaud’s and Meniere’s syndromes, angina and cardiac arrhythmia, according to the release.

Also Read | Long-term health issues following COVID-19 

54 patients were referred from an ENT olfactory subspecialist after at least 6 months of post-COVID parosmia, which was not resolved with drugs or topical therapies. The note recorded: ”The initial patient had a tremendously positive outcome, almost immediately, with continued improvement to the point of symptom resolution at four weeks,” Dr. Zoga said. “We have been surprised at some outcomes, including near 100% resolution of phantosmia in some patients, throughout the trial.”

At the follow-up, one week later, 59% of patients reported improvement in symptoms. Of this 82% reported significant progressive improvement by one month post-procedure. At three months, there was a mean 49% improvement in symptoms (range 10% to 100%) among the 22 patients.

While proof exists from a small study, more broad-based studies are required to establish the inconclusive efficacy of SGB for patients with parosmia. A highly specialised, skilled procedure, and doctors will have to be trained properly to execute it. Besides this, there are cost considerations too. However, every triumph of science over pathogens and the disastrous trail they leave behind ought to be celebrated, and there is no doubt this one is a true achievement too.

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