Cervicothoracic Sympathetic Block Evaluation for Post COVID Condition

Post-COVID Condition (PCC) affects roughly 2.1 million Canadians, carrying an annual economic burden of CAD $7.8-50.6 billion. It presents across multiple organ systems with symptoms including fatigue, brain fog, palpitations, and orthostatic intolerance, at an annual cost of CAD $1,675-$7,340 per case. A key mechanism underlying many treatment-resistant PCC symptoms appears to be dysautonomia abnormal autonomic nervous system function driven by immune-mediated sympathetic overactivity. Persistent inflammation (cytokine storms, T/B-cell dysfunction, microclots) sustains sympathetic hyperactivity, which in turn perpetuates systemic inflammation and "sickness behaviors" resembling PCC symptoms. Current treatments including beta blockers, ivabradine, fludrocortisone, and rehabilitation are limited by variable responses, side effects, and the complication of post-exertional symptom exacerbation. Emerging therapies (SSRIs, low-dose naltrexone, antihistamines, HBOT) show promise but lack robust trial evidence. Cervicothoracic sympathetic chain block (CSB) a local anesthetic block of the cervical and upper thoracic sympathetic ganglia is a promising intervention that reduces sympathetic outflow, improves cerebral blood supply, and lowers pro-inflammatory cytokines. Small observational studies (16 studies, 224 patients) show benefit for PCC symptoms, but all lack placebo controls and have significant methodological heterogeneity. The proposed study aims to fill this gap with a double-blind, placebo-controlled RCT to rigorously evaluate CSB's efficacy, magnitude of benefit, and durability in PCC patients.

Inclusion criteria 1. Age 18 years or older 2. PCC following COVID-19 infection with symptoms lasting for at least three months 3. Ability to read, write, and understand English 4. Quantified autonomic symptoms from at least one domain as reported by the patient on the screener Composite Autonomic Symptom Score (COMPASS-31), i.e. a COMPASS-31 score greater than 0. COMPASS-31 assesses 6 domains of autonomic symptoms: Orthostatic Intolerance, Vasomotor, Secretomotor, Gastrointestinal, Bladder, and Pupillomotor. 5. Patients should be stable on any PCC-related medications for at least four weeks. Exclusion criteria 1. History of co-existing conditions that are a contraindication for SGBCSBCSB: 1. Unilateral vocal cord paralysis; Severe chronic obstructive pulmonary disease (FEV1 between 30-50% of predicted value) 2. Recent myocardial infarction (within the last one year), Cardiac conduction block of any degree 3. Glaucoma 4. Infection or mass at injection site, bleeding disorders 2. Comorbid conditions that could confound study results, such as: 1. Active autoimmune disorders 2. Pre-existing autonomic dysfunction (e.g. POTS, IST, and CRPS) prior to COVID-19 3. Untreated psychiatric conditions (e.g. severe anxiety or PTSD requiring medication adjustments during the study period) 3. Recent history of major surgery or cerebrovascular events within the last three months 4. Allergy to local anesthetic; Inability to extend the neck for any reason (e.g. severe arthritis) 5. History of prior stellate ganglion block