Sniffing out better care

Researchers at St. Joseph’s Health Care London are testing a novel treatment for debilitating distorted smell triggered by COVID-19.

London, Ontario - When Rebecca Bruzzese lost her sense of smell and taste after a bout of COVID-19, it was disconcerting. But when it returned a week later, it was downright debilitating.

For over a year, Rebecca experienced what is called parosmia – a disorder that causes a distorted sense of smell, turning normal odors into a repulsive stench, and often creating disturbing, even frightening, phantom smells.

“Coffee was the worst,” says Rebecca. “It smelled like hot garbage.”

Ground beef frying on the stove smelled like “excrement in a pan” and tomatoes had a sharp acidic rancid smell.

The 32-year-old was so repulsed by food she lost 30 pounds. Causing even more havoc were the phantom smells – cigarette smoke and natural gas – which triggered great anxiety. She refers to them as scent hallucinations.

“Not having a reliable sense of smell was very disorienting and anxiety provoking,” says Bruzzese. “The natural gas smell was the worst. I live in a condo and would contact the building manager to investigate. I was borderline neurotic for a couple of months.”

Today, a normal sense of smell has returned to a relieved Bruzzese – restored by novel treatment being trialed at St. Joseph’s Health Care London (St. Joseph’s) by Dr. Leigh Sowerby, a surgeon with the Otolaryngology- Head and Neck Program and scientist with Lawson Health Research Institute. He is working in collaboration with anesthesiologists Dr. Geoff Bellingham, Medical Director of St. Joseph’s Pain Management Program, and Dr. Mohammad Misurati.

The randomized controlled trial is testing stellate ganglion block (SGB) – a procedure involving injecting a local anesthetic into the stellate ganglion, a collection of nerves in the neck. The stellate ganglion controls sympathetic signals to the head, neck, arms and part of the chest.

In an earlier survey by the study team, patient reports of temporarily blocking these sympathetic signals through an anesthetic injection showed promise in alleviating the distorted sense of smell. This initial study, conducted online and published in The Journal of Laryngology & Otology, involved patients who had experienced various treatment options for post-COVID parosmia, including SGB, to gather data about their experiences and outcomes.

The follow-up randomized clinical trial at St. Joseph’s with 44 patients is the next step and seeks to establish the efficacy of the SGB in treating post-COVID parosmia.

“The assumption for a lot of these patients is that there is nothing we can do,” explains Sowerby. “If the findings are positive, we’re hoping it will help advocate for more access to the procedure.”

It will also confirm the effect is not placebo, which will shed light on an intriguing neuronal pathway for olfaction (sense of smell), he adds.
“It’s an intriguing study because, based on our understanding of pathophysiology, the stellate ganglion should have no effect on olfaction,” he says. “Initial reports of benefit were met with great skepticism. We hope to validate the benefit.”

Patients who fit the study criteria are randomized to receive either saline (placebo) or lidocaine in a stellate ganglion block. It is a double-blind study, which means both the investigators and patients do not know what each individual receives. Currently, 14 patients have been enrolled in the study with recruitment ongoing. Participants will be followed for up to one year.

Bruzzese, who came down with COVID-19 in February 2023, received her injection at the end of March 2024. 

“Within two weeks I was mostly recovered. What Dr. Sowerby is doing is incredibly important. Being able to recognize smells is something we take for granted, until you can’t.”

Learn more.

Individuals experiencing distorted smell for more than six months after a COVID-19 infection may be eligible to take part in the study. Those interested can email @email for more information.

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Dr. Leigh Sowerby is available to speak to media Wed. Oct. 2. Rebecca Bruzzese as is also available for interviews.

For more information and to arrange an interview, contact:
Dahlia Reich, Communication Consultant
St. Joseph’s Health Care London
519 646-6100 ext. 65294, Cell: 519 619-0971
@email

About St. Joseph’s Health Care London

Renowned for compassionate care, St. Joseph’s Health Care London is a leading academic health care centre in Canada dedicated to helping people live to their fullest by minimizing the effects of injury, disease and disability through excellence in care, teaching and research. Through partnership with Lawson Health Research Institute and our collaborative engagement with other health care and academic partners, St. Joseph’s has become an international leader in the areas of chronic disease management; medical imaging; specialized mental health care; rehabilitation and specialized geriatrics; and surgery. St. Joseph’s operates through a wide range of hospital, clinic and long-term and community-based settings, including: St. Joseph’s Hospital; Parkwood Institute; Mount Hope Centre for Long Term Care; and the Southwest Centre for Forensic Mental Health Care. sjhc.london.on.ca.