Stellate Ganglion Block for COVID-induced Parosmia

Summary

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 Recent research by our group (unpublished data) and suggests that parosmias, moreso than hyposmias, can result in increased rates of anxiety, depression, and even suicidal ideation.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.

Conditions

• COVID-19-Induced Parosmia

Interventions

DRUG

Stellate Ganglion Block

The stellate ganglion will be identified using ultrasound guidance, and after negative aspiration, 6-8 mL of 1% mepivacaine will be injected near the stellate ganglion.

DRUG

Placebo Sham Injection

The stellate ganglion will be identified using ultrasound guidance, and after negative aspiration, 6-8 mL of 0.9% saline will be injected near the stellate ganglion.

Sponsors & Collaborators

• Washington University School of Medicine

  lead OTHER

Principal Investigators

• Nyssa Farrell, MD · Washington University School of Medicine

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

PARALLEL

Eligibility

Min Age

18 Years

Max Age

70 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-10-25

Primary Completion

2024-09-16

Completion

2024-09-16

FDA Drug

Yes

Countries

• United States

Study Locations