CHICAGO – Using a minimally invasive, image-guided procedure, researchers can restore the sense of smell in patients who have suffered from long COVID, according to research to be presented at the annual meeting of the Radiological Society of North America (RSNA).
Parosmia , a condition in which the sense of smell no longer functions properly, is a known symptom of COVID-19 . Recent research has found that up to 60% of COVID-19 patients have been affected. While most patients regain their sense of smell over time, some long COVID patients continue to have these symptoms for months, or even years, after infection, negatively affecting their appetite for food and quality of life. life in general.
" Post-COVID parosmia is common and increasingly recognized," said the study’s senior author, Adam C. Zoga, MD, MBA, professor of musculoskeletal radiology at Jefferson Health in Philadelphia, Pennsylvania. "Patients may develop a dislike for foods and beverages they previously enjoyed."
The distorted sense of smell can also affect the perception of smell, and some patients may suffer from phantosmia , a condition that causes people to detect odors (bad or pleasant) that are not found in their environment.
To evaluate a possible treatment for patients with long-term post-COVID parosmia, researchers analyzed the potential benefits of CT-guided stellate ganglion block . The stellate ganglia, which are part of the autonomic nervous system, which regulates involuntary processes such as heart rate, blood pressure, breathing and digestion, are nerves on each side of the neck. They send certain signals to the head, neck, arms, and part of the upper chest.
Infographic : New treatment restores the sense of smell in patients with long COVID
The research team used a stellate ganglion block, which involves injecting anesthetic directly into the stellate ganglion on one side of the neck to stimulate the regional autonomic nervous system. The minimally invasive procedure lasts less than 10 minutes and does not require sedation or intravenous analgesia. Stellate ganglion block has been used with varying degrees of success to treat a number of conditions, including cluster headaches, phantom limb pain, Raynaud and Meniere syndromes, angina, and cardiac arrhythmia.
"Parosmia has previously been reported as a rare disorder that occurs after brain trauma, brain surgery, stroke, viral syndromes, and some head and neck tumors," Dr. Zoga said. "We weren’t completely sure the procedure would work for parosmia."
For the study, 54 patients were referred by an otolaryngologist after at least six months of post-COVID parosmia resistant to pharmaceutical and topical therapies.
CT guidance was used to place a spinal needle at the base of the neck for injection into the stellate ganglion. The researchers added a small dose of corticosteroid to the anesthetic in the drug preparation, suspecting that the COVID virus could be causing inflammation of the nerves.
"The initial patient had a tremendously positive outcome, almost immediately, with continued improvement to the point of resolution of symptoms at four weeks," Dr. Zoga said. "We have been surprised by some results, including close to 100% resolution of phantosmia in some patients, throughout the trial."
Follow-up was obtained for 37 patients (65%), and 22 (59%) of the 37 reported improvement in symptoms one week after injection. Of these 22, 18 (82%) reported significant progressive improvement at one month after the procedure. At three months, there was a mean 49% improvement in symptoms (range 10% to 100%) among the 22 patients.
Twenty-six patients returned for a second injection on the other (contralateral) side of the neck after at least a six-week interval. Although the second injection was not effective in patients who did not respond to the first injection, 86% of patients who reported some improvement after the first injection reported further improvement after the contralateral injection. No complications or adverse events were reported.
"Other treatments have failed to date," Dr. Zoga said. "This injection is working."
Co-authors are Sarah I. Kamel, MD, T. Rohan, MA Moriarty, Johannes B. Roedl, Ph.D., MD, Vishal Desai, MD, and Jeffrey A. Belair, MD
