Familial Dysautonomia Clinical Trials

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.