Objective:

To characterize the neuropathic subtype of Postural Orthostatic Tachycardia Syndrome (POTS) in the pediatric population.

Background:

Neuropathic Postural Orthostatic Tachycardia Syndrome (POTS)is suggestive of small fiber neuropathy (SFN) involving autonomic and somatosensory nerve dysfunction. Recent studies have associated neuropathic POTS with altered immune function affecting the peripheral nervous system in the adult population. Despite increasing recognition of POTS in the pediatric population, limited data exists regarding the prevalence of neuropathic POTS and its potential association with immune dysfunction in this group. We hypothesized that immune function dysregulation would correlate with the presence of neuropathic POTS among the pediatric population.

Design/Methods:

We conducted a retrospective chart review of 123 pediatric patients aged 14-18 years evaluated for POTS via tilt table testing (TTT) between January 2015 and December 2024 at our single tertiary care center. Patients with positive TTT were divided into SFN(+) and SFN(-) groups based on quantitative sudomotor axon reflex testing (QSART). Serum markers of inflammation, autoimmune dysautonomia, and pre-existing autoimmune comorbidities were recorded and compared between the two groups. One-sample t-test and Wilcoxon rank-sum test were used to analyze prevalence and inflammation/autoimmune markers, respectively.

Results:

Among the 123 patients, 73 had positive TTT. Sixty-one of those patients underwent QSART with an SFN prevalence of 22.9% (14/61). No significant differences were observed between inflammatory and autoimmune markers SFN(+) and SNF(-), including CRP, ESR, celiac markers, anti-ENA panel, TPO, and ANA. Additionally, presence ofpre-existing autoimmune comorbidities did not differ significantly between the two groups.

Conclusions:

Our preliminary findings indicate that neuropathic POTS presents differently inpediatric patients compared to adults (33%). Additionally, we examined no significant relationship to immune system dysfunction. By expanding our sample size and further examining immune markers, we aim to uncover clinically relevant insights that may improve treatment strategies for pediatric patients with SFN-POTS.