A new treatment could help long-term Covid patients suffering from parosmia regain a functional sense of smell.
- Parosmia, a condition where the sense of smell no longer functions properly, is a known symptom of Covid-19.
- Researchers have found that a procedure, called a stellate block, can relieve this symptom.
- This involves making an injection of anesthetic into the stellate ganglia which are located on each side of the neck.
Up to 60% of Covid-19 patients have been affected by parosmia, distortion of one odor towards another, according to recent studies. While most patients recover their sense of smell over time, some with long Covid continue to present this symptom for months, even years, after infection. American researchers claim to have found a treatment allowing patients to smell good perfumes again or to avoid ghost odors. It will be presented at the annual meeting of the Radiological Society of North America (RSNA), organized from November 26 to 30, 2023.
Loss of smell: stellar ganglia targeted by researchers
To treat patients with post-Covid parosmia, scientists have become interested in stellate ganglia. They are located on either side of the neck and are part of the autonomic nervous system. They regulate involuntary processes like heart rate, blood pressure, breathing and digestion. They also deliver certain signals to the head, neck, arms and part of the upper chest.
The team wanted to see if the stellate block – a treatment which consists of injecting a local anesthetic into the stellate ganglion – could be beneficial for the loss of smell. This procedure, which lasts about ten minutes, is already used in the treatment of certain conditions, including cluster headaches, phantom limb pain, Raynaud’s syndrome and Ménièreangina pectoris and cardiac arrhythmia.
Post-Covid parosmia: promising results
The preliminary results of this study are encouraging. Of the 37 patients with post-Covid parosmia treated with stellate block, 22 reported significant improvement in their symptoms one week after the injection. Of these, 18 observed additional progress one month later. After one trimester, there was an average 49% improvement in symptoms among participants.
26 patients agreed to have a new injection in the other side of the neck. “While 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 reported further progress after the next injection. . No complications or adverse events have been reported.”specify the authors in a communicated.
“The initial patient had an extremely positive outcome, almost immediately, with continued improvement to the point of symptom resolution at four weeks”adds lead author Dr. Adam Zoga of Jefferson Health in Philadelphia. “We were surprised by some results, including almost 100% resolution of phantosmia (a form of olfactory hallucination) in some patients, throughout the trial.”
