Neck injection may help patients regain smell after COVID-19

Key takeaways:

• Overall, 22 of 37 participants reported improved symptoms 1 week after injection.
• Of those who responded to the injection after 1 week, there was a mean 49% improvement in symptoms at 3 months.

A minimally invasive, CT-guided procedure was linked to a restored sense of smell among patients with long COVID, according to results of a small study presented at the annual meeting of the Radiological Society of North America.

In a previous study, 60.5% of adults with COVID-19 said they lost their sense of smell, a condition known as parosmia. Among them, about 25% partially regained their sense of smell and 3.7% never did.

“Post-COVID parosmia is common and increasingly recognized,” Adam C. Zoga, MD, MBA, a professor of musculoskeletal radiology at Jefferson Health, said in a press release. “Patients can develop a distaste for foods and drinks they used to enjoy.”

For the current study, Zoga and colleagues assessed the effectiveness of CT-guided stellate ganglion block among 54 patients who had post-COVID parosmia for at least 6 months. The patients had a mean age of 46 years, and 74% were women.

Of 37 patients who had follow-up data, 22 (59%) reported improved symptoms 1 week after the injection. Among these 22 patients, 18 (82%) reported a significant improvement after 1 month. By 3 months, there was a mean improvement of 49%, ranging from 10% to 100%.

“The initial patient had a tremendously positive outcome, almost immediately, with continued improvement to the point of symptom resolution at 4 weeks,” Zoga said. “We have been surprised at some outcomes, including near 100% resolution of phantosmia in some patients, throughout the trial.”

Zoga and colleagues noted that 26 participants — eight and 14 of whom reported no or some improvement 1 week after the first injection, respectively — returned for a contralateral injection with at least a 6-week interval. Among these participants, all of whom reported no improvement after the first injection similarly reported no improvement after the contralateral injection. However, 86% of patients who reported some improvement after the first injection reported additional improvement after the contralateral injection.
the researchers confirmed that Horner's syndrome occurred in 95% of all injections, and symptoms resolved within 30 minutes after the injection.

“Other treatments have failed to date,” Zoga said. “This injection is working.”

References:

• New treatment restores sense of smell in patients with long COVID. https://www.eurekalert.org/news-releases/1007873. Published Nov. 20, 2023. Accessed Nov. 20, 2023.
• Zoga A, et al. Stellate ganglion block with CT guidance for post-COVID parosmia. Presented at: Radiology Conference & Annual Meeting; Nov. 26-30, 2023; Chicago.