Body mass index is decreased in children and adolescents with postural tachycardia syndrome.

Lin J, Zhao H, Ma L, Jiao F. Body mass index is decreased in children and adolescents with postural tachycardia syndrome. Turk J Pediatr 2019; 61: 52-58. Our intent was to explore the predictive value of body mass index (BMI) in differentiating between vasovagal syncope (VVS) and postural tachycardia syndrome (POTS) in children and adolescents. A total of 111 children and adolescents with POTS and 154 children and adolescents with VVS were included in our study. The control group included 82 healthy children and adolescents. Height and weight were measured in all participants. The headup tilt test was performed in participants in all groups (POTS, VVS, and control). BMI was significantly lower in children and adolescents with POTS (18.3±3.4) than in children and adolescents with VVS (20.3±4.2) and the control group (20.5±2.9). The receiver operating characteristic curve was performed to determine the predictive value of BMI differentiation between POTS and VVS and showed that a BMI of 19.30 was the cutoff value for the probability of distinction. However, the results (BMI of 19.30) produced unsatisfactory sensitivity (57.1%) and specificity (28.8%) rates of correctly discriminating between patients with POTS and patients with VVS. Children and adolescents with POTS have a lower BMI compared with healthy peers or children and adolescents with VVS.

Pathogenesis and Individualized Treatment for Postural Tachycardia Syndrome in Children.

OBJECTIVE: Postural tachycardia syndrome (POTS) is one of the major causes of orthostatic intolerance in children. We systematically reviewed the pathogenesis and the progress of individualized treatment for POTS in children. DATA SOURCES: The data analyzed in this review are mainly from articles included in PubMed and EMBASE. STUDY SELECTION: The original articles and critical reviews about POTS were selected for this review. RESULTS: Studies have shown that POTS might be related to several factors including hypovolemia, high catecholamine status, abnormal local vascular tension, and decreased skeletal muscle pump activity. In addition to exercise training, the first-line treatments mainly include oral rehydration salts, beta-adrenoreceptor blockers, and alpha-adrenoreceptor agonists. However, reports about the effectiveness of various treatments are diverse. By analyzing the patient's physiological indexes and biomarkers before the treatment, the efficacy of medication could be well predicted. CONCLUSIONS: The pathogenesis of POTS is multifactorial, including hypovolemia, abnormal catecholamine state, and vascular dysfunction. Biomarker-directed individualized treatment is an important strategy for the management of POTS children.

POTS following traumatic stress: interacting central and intracardiac neural control?

Cardiovascular autonomic dysfunction is one of the most overlooked complications in patients with diabetes. We report the case of a 19-year-old woman with a 4-year history of diabetes referred due to palpitations and light-headedness following traumatic stress. Rise of heart rate and blood pressure during tilt table testing indicated hyperadrenergic postural orthstatic tachycardia syndrome (POTS). Elevated blood pressure variability, an indirect parameter of increased sympathetic activity, remained almost stable during orthostatic stress. Short-term treatment with ivabradine in combination with psychosocial support alleviated POTS-related symptoms. Our findings suggest that traumatic stress in patients with type 1 diabetes mellitus might translate into disturbed neural heart rate control due to a central, ephemeral alteration in autonomic balance.

Risk factors for postural tachycardia syndrome in children and adolescents.

BACKGROUND: Postural tachycardia syndrome (POTS) is prevalent in children and adolescents and has a great impact on health. But its risk factors have not been fully understood. This study aimed to explore possible risk factors for children and adolescents with POTS. METHODS AND FINDINGS: 600 children and adolescents (test group) aged 7-18 (11.9 ± 3.0) years old, 259 males and 341 females, were recruited for identifying its risk factors. Another 197 subjects aged from 7 to 18 (11.3 ± 2.3) years old were enrolled in the validation group. Heart rate (HR) and blood pressure (BP) were monitored during upright test. Risk factors were analyzed and sensitivity and specificity for predicting POTS were tested via receiver operating characteristic curve. Among 600 subjects, 41 were confirmed with POTS patients (6.8%) based on clinical manifestation and upright test. The results showed a significant difference in daily water intake, the daily sleeping hours, supine HR, HR increment and maximum HR during upright test between POTS and the unaffected children (P<0.05). Likelihood of POTS would increase by 1.583 times if supine HR was increased by 10 beats/min (95%CI 1.184 to 2.116, P<0.01), by 3.877 times if a child's water intake was less than 800 ml/day (95%CI 1.937 to 7.760, P<0.001), or by 5.905 times (95%CI 2.972 to 11.733, P<0.001) if sleeping hours were less than 8 hours/day. Supine HR, daily water intake and sleeping hours showed the capability of predicting POTS in children and adolescents with an AUC of 83.9% (95% CI: 78.6%-89.1%), sensitivity of 80.5% and specificity of 75%. Furthermore, in validation group, predictive sensitivity and specificity were 73.3% and 72.5%. CONCLUSION: Faster supine HR, less water intake and shorter sleeping hours were identified as risk factors for POTS.

Addressing the confounding role of joint hypermobility syndrome and gastrointestinal involvement in postural orthostatic tachycardia syndrome.

Quantitative and qualitative abnormalities in visceral function have been demonstrated in postural orthostatic tachycardia syndrome. Joint hypermobility is frequently associated with both postural orthostatic tachycardia syndrome and gastrointestinal symptoms. Future studies in this area should appropriately and systematically control for the presence of joint hypermobility syndrome.

Small-fiber neuropathy with cardiac denervation in postural tachycardia syndrome.

INTRODUCTION: Postural tachycardia syndrome (POTS) is a disorder of orthostatic intolerance characterized by excessive tachycardia of unknown etiology. Our objective in this study was to evaluate the correlation between C-fiber involvement as shown by skin biopsy and adrenergic cardiac metaiodobenzylguanadine (MIBG) uptake in POTS patients. METHODS: Skin biopsies of 84 patients with POTS were examined by Protein Gene Product 9.5 (PGP9.5) immunohistochemistry and were compared with MIBG myocardial scintigraphy imaging data. RESULTS: Mean intraepidermal nerve fiber (IENF) density was in the lower normal age-adjusted range, 7.2 ± 2.9/mm (normal ≥ 7/mm), and was slightly below the normal range in 45% of POTS patients. MIBG uptake was reduced in 21% of patients. Low IENF density correlated with reduced cardiac MIBG uptake (r = 0.39, P = 0.001). CONCLUSIONS: A subset of neuropathic POTS patients may harbor mild small fiber neuropathy with abnormalities of unmyelinated nerve fibers in the skin associated with reduced myocardial postganglionic sympathetic innervation.

Manometric abnormalities in the postural orthostatic tachycardia syndrome: a case series.

BACKGROUND: Postural orthostatic tachycardia syndrome (POTS) is a rare disease that is believed to be mediated by dysautonomia. Gastrointestinal complaints in POTS patients are common and disturbing but not well characterized. AIMS: We hypothesized that gastrointestinal dysmotility may be contributory to these symptoms. METHODS: We studied 12 POTS patients who presented with gastrointestinal symptoms to a tertiary referral center. Gastrointestinal symptoms were quantified using a previously validated symptom questionnaire. All patients underwent gastroduodenal manometry (GDM); select patients also underwent further testing including esophageal manometry (EM), anorectal manometry (ARM), plain abdominal radiography (AXR), abdominal computed tomography (CT), gastric emptying studies (GES), and colonic transit time (CTT) studies. RESULTS: The four most common symptoms were bloating, constipation, abdominal pain, and nausea/vomiting, all experienced by greater than 70 % of patients. On GDM testing, 93 % of patients demonstrated signs of neuropathy, and the most common abnormalities observed included bursts of uncoordinated phasic activity in both fasting (59 %) and post-prandial (42 %) states, low contractility in the post-prandial state (67 %), and lack of post-prandial pattern (42 %). A total of 67 % of patients undergoing EM and 86 % of those undergoing ARM demonstrated abnormalities consistent with dysmotility. On AXR or CT, 58 % demonstrated either dilated intestinal loops or air-fluid levels. On CTT 80 % demonstrated delayed colonic transit, while on GES 60 % demonstrated delayed gastric emptying. CONCLUSIONS: In this cohort of POTS patients with gastrointestinal symptoms, there is a high prevalence of abnormal manometric and radiographic findings suggestive of dysmotility.

Structural and functional small fiber abnormalities in the neuropathic postural tachycardia syndrome.

OBJECTIVE: To define the neuropathology, clinical phenotype, autonomic physiology and differentiating features in individuals with neuropathic and non-neuropathic postural tachycardia syndrome (POTS). METHODS: Twenty-four subjects with POTS and 10 healthy control subjects had skin biopsy analysis of intra-epidermal nerve fiber density (IENFD), quantitative sensory testing (QST) and autonomic testing. Subjects completed quality of life, fatigue and disability questionnaires. Subjects were divided into neuropathic and non-neuropathic POTS, defined by abnormal IENFD and abnormal small fiber and sudomotor function. RESULTS: Nine of 24 subjects had neuropathic POTS and had significantly lower resting and tilted heart rates; reduced parasympathetic function; and lower phase 4 valsalva maneuver overshoot compared with those with non-neuropathic POTS (P<0.05). Neuropathic POTS subjects also had less anxiety and depression and greater overall self-perceived health-related quality of life scores than non-neuropathic POTS subjects. A sub-group of POTS patients (cholinergic POTS) had abnormal proximal sudomotor function and symptoms that suggest gastrointestinal and genitourinary parasympathetic nervous system dysfunction. CONCLUSIONS AND RELEVANCE: POTS subtypes may be distinguished using small fiber and autonomic structural and functional criteria. Patients with non-neuropathic POTS have greater anxiety, greater depression and lower health-related quality of life scores compared to those with neuropathic POTS. These findings suggest different pathophysiological processes underlie the postural tachycardia in neuropathic and non-neuropathic POTS patients. The findings have implications for the therapeutic interventions to treat this disorder.

Postural orthostatic tachycardia syndrome: diagnosis and treatment.

BACKGROUND: Postural orthostatic tachycardia syndrome (POTS) is an autonomic disorder characterized by an exaggerated increase in heart rate that occurs during standing, without orthostatic hypotension. Women are most frequently affected, and may present with palpitations, chest discomfort, shortness of breath, weakness, exercise intolerance, lightheadedness, presyncope, and syncope. METHODS: We present three cases of POTS in otherwise healthy women, and discuss the clinical management of different types of this orthostatic intolerance. RESULTS AND CONCLUSION: The diagnosis was established with a tilt-table test in 1 patient who became symptom-free with ß-blockade and nonpharmacologic treatment, including fluid therapy, liberal sodium intake, support hose, and a reconditioning exercise program. The other 2 were diagnosed through a standing test, serum norepinephrine levels, and red-cell volumes. One patient had neuropathic POTS and partially responded to b-blockade and nonpharmacotherapy. The other patient had hyperadrenergic POTS and responded well to nonpharmacotherapy, a dualacting b-blocker, and a vasoconstrictor agent. Postural orthostatic tachycardia syndrome is not an uncommon clinical entity and making a correct diagnosis is crucial in providing appropriate treatment to restore patients' functional capability and quality of life.