Clinical Characteristics and Neurophysiologic Findings of Postural Orthostatic Tachycardia Syndrome in Pediatric Patients

Baek, Jong Geun; Kim, Young Soo; Park, Ki Jong; Yeom, Jung Sook; Park, Ji Sook; Park, Eun Sil; Seo, Ji Hyun; Lim, Jae Young; Park, Chan Hoo; Woo, Hyang Ok; Youn, Hee Shang

Abstract

PURPOSE
No domestic report has been published on postural orthostatic tachycardia syndrome (POTS) in adolescents, although it has been increasingly studied in adolescents since first reported in 1999. This study analyzed the clinical characteristics and neurophysiologic findings of POTS in Korean pediatric patients.
METHODS
We reviewed the medical records of pediatric patients (<18 years) with POTS who visited Gyeongsang National University Hospital in Jinju between January 2008 and March 2010. All patients underwent tilt-table and autonomic function tests.
RESULTS
We identified 18 patients (72.2% male, mean age 13.6 +/- 2.1 years). The mean orthostatic heart rate increment was 43.0 +/- 9.1 beats/min. Most patients (83.3%) had mild autonomic dysfunction, and three (16.6%) had moderate autonomic dysfunction. Half of patients had sudomotor abnormalities in the lower limbs, implying peripheral postganglionic sympathetic denervation in the legs. Of these patients, 66.6% also had adrenergic impairment. The degree of autonomic dysfunction correlated with the orthostatic heart rate increment (P=0.047). Patients needing pharmacologic treatment had a higher orthostatic heart rate increment (P=0.017), composite autonomic severity score (P=0.002), and sudomotor score (P=0.006), compared with non-pharmacologically treated patients.
CONCLUSION
Autonomic dysfunction or autonomic neuropathy seems to be the main pathophysiology of POTS in pediatric patients, especially adolescents. Further, the degree of autonomic dysfunction influenced the prognosis of POTS. Additionally, unlike previous adult series, most of our patients were male. This male predominance in adolescents suggests that the growth spurt is an important factor triggering POTS at this age.