Stellate Ganglion Block - a potential treatment for “Long-Covid 19” patients suffering with Anosmia and Ageusia: A Case Report

Stellate Ganglion Block - a potential treatment for “Long-Covid 19” patients suffering with Anosmia and Ageusia: A Case Report



Background:

Long COVID or Post Acute Sequelae of SARS-CoV-2 infection (PASC) has been described as a constellation of symptoms seen after initial infection with COVID-19 virus in both asymptomatic and symptomatic COVID-19 positive individuals. These long COVID symptoms include fatigue, dyspnea, chest pain, cough, memory or concentration issues, insomnia, muscle pain, headaches, post-exertional malaise, GI symptoms, tachycardia, anosmia, ageusia, depression, anxiety, and orthostatic intolerance (Liu et al., 2022). This case report demonstrates a Long COVID patient with anosmia and ageusia which improves significantly following bilateral  Stellate Ganglion Blocks. Although the exact pathophysiology of Long COVID is currently unknown, The response to Stellate Ganglion Blocks may suggest that an excessive and chronic inflammatory response from unabated production of pro-inflammatory cytokines leads to aberrant sympathetic nervous system response (Dantzer et al., 2008) that a Stellate Ganglion Block may help reset.


Purpose/Objectives:

Patient was administered the University of Pennsylvania Smell Identification Test (UPSIT) which is a trusted, reliable, and accurate test that assess the function of the olfactory system. A stellate ganglion block is a chemical sympathectomy of the entire cervical sympathetic chain with injection of local anesthetic near the ganglion. A successful block will demonstrate typical signs of ipsilateral miosis, ptosis, anhidrosis, facial flushing, and an elevated temperature of the ipsilateral upper extremity. The cervical sympathetic chain provides sympathetic innervation to head, neck, upper limbs, thymus, lungs, heart, and to the lacrimal, salivary, pineal, and thyroid glands. The stellate ganglion block has been used for many decades for reflex sympathetic dystrophy (now known as CRPS). The blocks ability to reduce sympathetic tone and improve blood flow allows it to be used to be used in treatment of Raynaud’s phenomenon and hyperhidrosis of the upper limbs. Stellate ganglion blocks are also useful for phantom limb pain, peripheral vascular disease, intractable angina, and psychiatric disorders including PTSD (Kerzner et al., 2021).



Method:

A 31 yo previously vaccinated male with no significant past medical history presented to ENT clinic on January 7, 2022 with altered sense of taste and smell status/post COVID-19 infection. He initially tested positive for COVID-19 in January 2021. His course was non-critical and developed anosmia and ageusia about 3 weeks into the illness. He reports his sense of smell and taste partially returned by July 2021 but both were still significantly altered. He had muted tastes of sweetness, saltiness, spiciness and intermittent ability to test other flavors such as sour, garlic, and other specific flavors. From June 2021 to August 2021, He reported a constant old milk and grease smell. He also reported inability to correctly match smells (i.e. milk would smell like peppermint).  After 6 months, His initial anosmia transitioned into parosmia.

He subjectively reports faint intermittent smells and has undergone smell retraining therapy with essential oils since August 2021. No head trauma or early onset of dementia in family. He has associated altered taste as well. No recent infections, sinusitis, or allergy history. He was noted with Nasal passage blockage with stuffiness. No sinus pressure, lymphadenopathy, dysphagia, odynophagia, vertigo, or balance issues. No cancer history or tobacco use. He only reports occasional alcohol use. Endoscopic evaluation of nasal passages revealed only hypertrophic turbinates. No masses or lesions were found. No deviated septum. The exam was otherwise normal. He was administered the University of Pennsylvania Smell Identification Test (UPSIT) which is a trusted, reliable, and accurate test that assess the function of the olfactory system (Doty et. Al., 1989). His score was 13/40, which was consistent with anosmia. ENT recommended Budesonide and NaCl/BiCarb rinses twice a day and plan to continue smell retraining therapy. He returned on follow up in Feb 2022 to ENT with some mild symptomatic improvement in smell. He still had persistent chronic rhinitis and anosmia. His sense of smell and taste remain altered but mildly improved. He UPSIT score was 17/40, still consistent with anosmia. He was referred to Interventional Pain Management for consideration of Stellate Ganglion Blocks.

Patient presented to NMCP Pain Management Clinic on March 22 2022 with persistent anosmia and partial ageusia for consideration of Stellate Ganglion Block. Nasal steroid washes and smell therapy subjectively helped improve his ageusia stating he can now taste salt garlic and pepper. However, he still reports difficulty differentiating fine notes and intensity of flavor. He report additional long COVID symptoms of chronic fatigue and sleep dysfunction. Denies any pain or physical limitations. Patient was set up with an ultrasound guided Right Stellate Ganglion block on 4/22/22 and an ultrasound guided Left Stellate Ganglion Block on 4/29/22. Patient reports significant improvement with return of both sense of tastes and smells. His UPSIT score was now 31/40, consistent with mild microsmia.



Results:

This case report illustrates a case of a patient with Long COVID with anosmia and ageusia with significant improvement in taste and smell following bilateral stellate ganglion blocks. There was 35% improvement in sense of smell as demonstrated by the patients improvement on the UPSIT test. This suggests that a component of the pathophysiology of some of the Long COVID symptoms may be due to dysautonomia from aberrant excessive sympathetic mediated processes. The stellate ganglion sympathetic blockade with local anesthetic seems to help reset the dysregulation and imbalance of the parasympathetic/sympathetic nervous systems to improve long COVID symptoms such as sense of taste and smell. The Stellate Ganglion Blocks offers to be a new promising therapeutic modality in the treatment of Long COVID and anosmia/ageusia. 



Conclusions: Moon HS, Chon JY, Lee SH, Ju YM, Sung CH. Long-term Results of Stellate Ganglion Block in Patients with Olfactory Dysfunction. Korean J Pain. 2013;26(1):57-61. doi:10.3344/kjp.2013.26.1.57

Barizien N., Le Guen M., Russel S., et al. Clinical characterization of dysautonomia in long COVID-19 patients. Sci. Rep. 2021;11:14042. doi: 10.1038/s41598-021-93546-5. PMID: 34234251; PMCID: PMC8263555.

Liu LD, Duricka DL. Stellate ganglion block reduces symptoms of Long COVID: A case series. J Neuroimmunol. 2022;362:577784. doi:10.1016/j.jneuroim.2021.577784

Dani M., Dirksen A., Taraborrelli P., Torocastro M., Panagopoulos D., Sutton R., Lim P.B. Autonomic dysfunction in ‘long COVID’: rationale, physiology and management strategies. Clin. Med. (Lond) 2021 Jan;21(1):e63–e67. doi: 10.7861/clinmed.2020-0896. Epub 2020 Nov 26. PMID: 33243837; PMCID: PMC7850225.

Kerzner J, Liu H, Demchenko I, et al. Stellate Ganglion Block for Psychiatric Disorders: A Systematic Review of the Clinical Research Landscape. Chronic Stress (Thousand Oaks). 2021;5:24705470211055176. Published 2021 Dec 8. doi:10.1177/24705470211055176

Doty RL, Frye RE, Agrawal U. Internal consistency reliability of the fractionated and whole University of Pennsylvania Smell Identification Test. Percept Psychophys. 1989;45(5):381-384. doi:10.3758/bf03210709

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