Stellate Ganglion Block for COVID-induced Parosmia
Completed · Phase 2 · Has a placebo group
Conditions studied: COVID-19-Induced Parosmia
In brief
Chronic olfactory dysfunction, both hyposmia and parosmia, from the COVID-19 pandemic is a growing public health crisis with up to 1.2 million people in the United States affected. Olfactory dysfunction impacts one's quality of life significantly by decreasing the enjoyment of foods, creating environmental safety concerns, and affecting one's ability to perform certain jobs. Olfactory loss is also an independent predictor of anxiety, depression, and even mortality. Recent research by our group (unpublished data) and suggests that parosmias, moreso than hyposmias, can result in increased rates of anxiety, depression, and even suicidal ideation. While the pandemic has increased the interest by the scientific community in combating the burgeoning health crisis, few effective treatments currently exist for olfactory dysfunction. Persistent symptoms after an acute COVID-19 infection, or "Long COVID" symptoms, have been hypothesized to be a result of sympathetic positive feedback loops and dysautonomia. Stellate ganglion blocks have been proposed to treat this hyper-sympathetic activation by blocking the sympathetic neuronal firing and resetting the balance of the autonomic nervous system. Studies prior to the COVID-19 pandemic have supported a beneficial effect of stellate ganglion blocks on olfactory dysfunction, and recent news reports and a published case series have described a dramatic benefit in both olfactory function and other long COVID symptoms in patients receiving stellate ganglion blocks. A previous pilot study using stellate ganglion blocks of 20 participants with persistent COVID-19 olfactory dysfunction resulted modest improvements in subjective olfactory function, smell identification, and olfactory-specific quality-of-life, but it lacked a control group. Therefore, we propose a double-blinded, placebo-controlled randomized clinical trial assessing the efficacy of a stellate ganglion block versus saline injection in a total of up to 140 participants with persistent COVID-19-associated olfactory dysfunction.
Key facts
- Study ID
- NCT06253806
- Run by
- Washington University School of Medicine
- People needed
- 48
- Starts
- 2023-10-25
- Expected to finish
- 2024-09-16
- Last updated by the study team
- 2025-11-10
Who can join
Age: 18 and older, up to 70. Sex: any. Healthy volunteers: not accepted.
You may qualify if…
- Adults age 18 to 70
- Diagnosis of COVID at least 6 months prior to study enrollment with self-reported parosmia
- Ability to read, write, and understand English
- Score of at least 40 on DiSODOR during screening and at least 25 during Visit 1
You may not qualify if…
- History of smell loss or change prior to COVID-19 infection
- History of conditions known to impact olfactory dysfunction
- Chronic rhinosinusitis
- History of prior sinonasal or skull base surgery
- Neurodegenerative disorders (Parkinson's disease, Huntington's disease, Amyotrophic Lateral Sclerosis, Lewy body dementia, frontotemporal dementia)
- Currently using concomitant therapies specifically for the treatment of olfactory dysfunction
- Inability to tolerate a needle injection into the neck
- History of coexisting conditions that make SGB contraindicated:
- Unilateral vocal cord paralysis
- Severe COPD (FEV1 between 30-50% of predicted)
- Recent myocardial infarction within the last year
- Glaucoma
- Cardiac conduction block of any degree
- Currently taking blood thinners or antiplatelet agents, including aspirin >81mg.
- Allergy to local anesthetic
- Inability to extend the neck for any reason (e.g., severe arthritis)
- History of prior stellate ganglion block
Where it is running
- Nyssa Fox Farrell — St Louis, Missouri, United States
Full record on ClinicalTrials.gov
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