Assessment of comorbid symptoms in pediatric autonomic dysfunction

PURPOSE

Pediatric patients with autonomic dysfunction and orthostatic intolerance (OI) often present with co-existing symptoms and signs that might or might not directly relate to the autonomic nervous system. Our objective was to identify validated screening instruments to characterize these comorbidities and their impact on youth functioning.

METHODS

The Pediatric Assembly of the American Autonomic Society reviewed the current state of practice for identifying symptom comorbidities in youth with OI. The assembly includes physicians, physician-scientists, scientists, advanced practice providers, psychologists, and a statistician with expertise in pediatric disorders of OI. A total of 26 representatives from the various specialties engaged in iterative meetings to: (1) identify and then develop consensus on the symptoms to be assessed, (2) establish committees to review the literature for screening measures by member expertise, and (3) delineate the specific criteria for systematically evaluating the measures and for making measure recommendations by symptom domains.

RESULTS

We review the measures evaluated and recommend one measure per system/concern so that assessment results from unrelated clinical centers are comparable. We have created a repository to apprise investigators of validated, vetted assessment tools to enhance comparisons across cohorts of youth with autonomic dysfunction and OI.

CONCLUSION

This effort can facilitate collaboration among clinical settings to advance the science and clinical treatment of these youth. This effort is essential to improving management of these vulnerable patients as well as to comparing research findings from different centers.

Creating a data dictionary for pediatric autonomic disorders

PURPOSE

Whether evaluating patients clinically, documenting care in the electronic health record, performing research, or communicating with administrative agencies, the use of a common set of terms and definitions is vital to ensure appropriate use of language. At a 2017 meeting of the Pediatric Section of the American Autonomic Society, it was determined that an autonomic data dictionary comprising aspects of evaluation and management of pediatric patients with autonomic disorders would be an important resource for multiple stakeholders.

METHODS

Our group created the list of terms for the dictionary. Definitions were prioritized to be obtained from established sources with which to harmonize. Some definitions needed mild modification from original sources. The next tier of sources included published consensus statements, followed by Internet sources. In the absence of appropriate sources, we created a definition.

RESULTS

A total of 589 terms were listed and defined in the dictionary. Terms were organized by Signs/Symptoms, Triggers, Co-morbid Disorders, Family History, Medications, Medical Devices, Physical Examination Findings, Testing, and Diagnoses.

CONCLUSION

Creation of this data dictionary becomes the foundation of future clinical care and investigative research in pediatric autonomic disorders, and can be used as a building block for a subsequent adult autonomic data dictionary.

Building a community-academic partnership to improve screening for intimate partner violence: Integrating advocates in healthcare clinic settings

AIMS

To develop an innovative community-academic partnership to advance, test and promote intimate partner violence screening and referral protocols by comparing the effect of integrating intimate partner violence advocates versus enhancing medical training in medical clinic settings serving women from vulnerable populations. Detecting intimate partner violence in healthcare settings allows for survivors to connect to safety and referral resources prior to violence escalating. Screening for intimate partner violence and connecting patients to referral resources requires creating a safe and trusting relationship between healthcare providers and patients. Developing screening and referral protocols responsive to survivors' needs requires involvement of clinic staff, survivors and community agencies that support survivors.

DESIGN

Three phases of the project include Discovery, Implementation and Dissemination. Mixed-methodology will help in understanding current practices and effects of interventions.

METHODS

Actions included in each phase: Discovery: 1) nurse-led focus groups of clinic staff, providers and survivors to understand current clinic practices; 2) retrospective chart review of the number of screens performed, positive screens detected and interventions performed.

IMPLEMENTATION

1) randomization of patients to be interviewed by a trained advocate or by healthcare provider with enhanced training; and 2) assess the number of screenings and referrals performed in each arm and 3) evaluate outcomes of intervention. Dissemination through: presentations, manuscripts and policy recommendations at the institutional and regional level. This IRB-approved proposal was funded in July 2021 by an Advancing a Healthier Wisconsin grant.

DISCUSSION

The partnership has improved channels of communication and understanding between diverse clinical care providers, survivors and community agency staff as they navigate the complex challenges to the development and integration of screening and referral protocols.

IMPACT

This project will provide evidence of the most effective intimate partner violence screening and referral methodology that can be utilized in a wide variety of medical settings.

Does Unconscious Bias Affect How Pediatricians Manage Their Patients?

BACKGROUND

Both implicit bias-referred to as unconscious bias-and explicit bias affect how clinicians manage patients. The Implicit Association Test (IAT) has incremental predictive validity relative to self-reports of unconscious bias. Few studies have uniquely specified the impact of unconscious bias in pediatric practices.

OBJECTIVE

We aimed to assess the influence of unconscious bias on decision-making in the faculty in a pediatric academic center using the IAT, in addition to and separately applying clinical vignettes with racial and socioeconomic class associations in both tools as it relates to clinicians' race, gender, years in practice, education achieved by the clinician's parents, and language spoken.

METHODS

We conducted a prospective quality control evaluation of faculty in an academic center's pediatrics department. An anonymous online tool was used to gather IAT responses, clinical vignette responses, demographics, and explicit bias questions.

RESULTS

Of 295 faculty members (73% females), 230 completed the questionnaire, at least in part. Faculty reported on the explicit bias questions, neutral feelings when comparing the demands of educated vs noneducated patients, African American vs European American patients, and patients in the upper vs lower socioeconomic class. Of the approximately two-thirds who answered the IAT, faculty showed preference for European American and upper socioeconomic class. However, the clinical vignettes revealed no differences in how faculty responded to patients based on race or socioeconomic status when stratified by factors listed above, except physicians who favor upper socioeconomic class over lower socioeconomic class were more likely to give a detailed explanation of options if the patient's parent was upper socioeconomic class (P = 0.022).

CONCLUSIONS

Pediatricians exhibit racial and socioeconomic unconscious bias that minimally affects decision-making, at least based on vignette responses.

Dietary sodium and health: How much is too much for those with orthostatic disorders?

High dietary salt (NaCl) increases blood pressure (BP) and can adversely impact multiple target organs including the vasculature, heart, kidneys, brain, autonomic nervous system, skin, eyes, and bone. However, patients with orthostatic disorders are told to increase their NaCl intake to help alleviate symptoms. While there is evidence to support the short-term benefits of increasing NaCl intake in these patients, there are few studies assessing the benefits and side effects of long-term high dietary NaCl. The evidence reviewed suggests that high NaCl can adversely impact multiple target organs, often independent of BP. However, few of these studies have been performed in patients with orthostatic disorders. We conclude that the recommendation to increase dietary NaCl in patients with orthostatic disorders should be done with care, keeping in mind the adverse impact on dietary NaCl in people without orthostatic disorders. Modest, rather than robust, increases in NaCl intake may be sufficient to alleviate symptoms but also minimize any long-term negative effects.

Non-pharmacologic management of orthostatic hypotension

Orthostatic hypotension (OH), a debilitating disorder characterized by a drop in blood pressure when in the upright position, may be treated through several pharmacologic and lifestyle modifications. The treatment is aimed at decreasing the symptoms, mainly the falls, increase the standing time, and improve the activities of daily life. A recent expert consensus outlined the management of orthostatic hypotension and included 4 sequential steps: 1) review medications and modify or remove those that may aggravate or cause OH; 2) non-pharmacologic measures; 3) pharmacologic measures and 4) treatment combinations. The aim of this manuscript is to review the non-pharmacological approach. In milder cases, this approach may suffice, but with more severe symptoms, such as falls, syncope or near-syncope, a pharmacological strategy is simultaneously employed. Furthermore, most non-pharmacological measures are combined. The non-pharmacological approach is aimed at optimizing blood volume, decreasing postural venous pooling, reducing heat and post-prandial induced vasodilation, emphasizing physical conditioning, and minimizing nocturnal diuresis.

Human papillomavirus (HPV) vaccine and autonomic disorders: a position statement from the American Autonomic Society

INTRODUCTION

Human papillomavirus (HPV) vaccination has been anecdotally connected to development of dysautonomia, chronic fatigue, complex regional pain syndrome and postural tachycardia syndrome.

OBJECTIVES

To critically evaluate a potential connection between HPV vaccination and above noted conditions.

METHODS

We reviewed the literature containing the biology of the virus, pathophysiology of infection, epidemiology of associated cancers, indications of HPV vaccination, safety surveillance data and published reports linking HPV vaccination to autonomic disorders.

RESULTS

At this time the American Autonomic Society finds that there are no data to support a causal relationship between HPV vaccination and CRPS, chronic fatigue, POTS or other forms of dysautonomia.

CONCLUSIONS

Certain conditions are prevalent in the same patient populations that are vaccinated with the HPV vaccine (peri-pubertal males and females). This association, however, is insufficient proof of causality.

Does maladaptive cardiovagal modulation extend to gastric modulation in women with chronic pelvic pain?

BACKGROUND

Women with chronic pelvic pain (CPP) have poor cardiovagal modulation. It is unclear whether this finding reflects a broader abnormality across many systems such as gastro-vagal modulation.

AIM

To determine if maladaptive cardiovagal activity in females with CPP is accompanied by maladaptive gastric myoelectric activity.

METHODS

A total of 36 health controls (HC) and 75 CPP underwent supine (10 min), then upright (tilted 70° head up; 30 min), and back to supine (10 min) positions. High-frequency heart rate variability (HF-HRV; 0.15-0.4 Hz) was measured as an index of cardiovagal activity. Cutaneous electrogastrography (EGG) assessed gastric myoelectric activity pre- and during-upright tilt. EGG measures from 16 HC and 31 CPP patients were available for analysis and included relative percentage of gastric activity within the normal (2-4 cpm) and tachygastria (4-10 cpm) ranges, plus ratio of normal/tachygastria.

RESULTS

HF-HRV was lower in CPP individuals at all time points (each p < .05). CPP individuals showed lesser decrease in HF-HRV from supine to upright, and poorer HF-HRV recovery from upright back to supine (F[1, 106] = 4.62, p = .034). HC showed increase in tachygastria activity (t[15] = -2.09, p = .054) while the CPP group showed no change in tachygastria activity from pre-upright to upright (t[30] = -0.62, p = .537).

CONCLUSIONS

Individuals with CPP going from supine to upright demonstrate an impairment in both tachygastria and the parallel decrement in HRV. These results support the hypothesis of a generalized blunting in the physiological modulation in CPP individuals affecting both cardiovascular and gastric systems.

Sensitivity of functional connectivity to periaqueductal gray localization, with implications for identifying disease-related changes in chronic visceral pain: A MAPP Research Network neuroimaging study

Previous studies examining the resting-state functional connectivity of the periaqueductal gray (PAG) in chronic visceral pain have localized PAG coordinates derived from BOLD responses to provoked acute pain. These coordinates appear to be several millimeters anterior of the anatomical location of the PAG. Therefore, we aimed to determine whether measures of PAG functional connectivity are sensitive to the localization technique, and if the localization approach has an impact on detecting disease-related differences in chronic visceral pain patients. We examined structural and resting-state functional MRI (rs-fMRI) images from 209 participants in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network study. We applied three different localization techniques to define a region-of-interest (ROI) for the PAG: 1) a ROI previously-published as a Montreal Neurological Institute (MNI) coordinate surrounded by a 3 mm radius sphere (MNI-sphere), 2) a ROI that was hand-traced over the PAG in a MNI template brain (MNI-trace), and 3) a ROI that was hand-drawn over the PAG in structural images from 30 individual participants (participant-trace). We compared the correlation among the rs-fMRI signals from these PAG ROIs, as well as the functional connectivity of these ROIs with the whole brain. First, we found important non-uniformities in brainstem rs-fMRI signals, as rs-fMRI signals from the MNI-trace ROI were significantly more similar to the participant-trace ROI than to the MNI-sphere ROI. We then found that choice of ROI also impacts whole-brain functional connectivity, as measures of PAG functional connectivity throughout the brain were more similar between MNI-trace and participant-trace compared to MNI-sphere and participant-trace. Finally, we found that ROI choice impacts detection of disease-related differences, as functional connectivity differences between pelvic pain patients and healthy controls were much more apparent using the MNI-trace ROI compared to the MNI-sphere ROI. These results indicate that the ROI used to localize the PAG is critical, especially when examining brain functional connectivity changes in chronic visceral pain patients.

A longitudinal analysis of urological chronic pelvic pain syndrome flares in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network

OBJECTIVE

To describe the frequency, intensity and duration of urological chronic pelvic pain syndrome symptom exacerbations ('flares'), as well as risk factors for these features, in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain Epidemiology and Phenotyping longitudinal study.

PARTICIPANTS AND METHODS

Current flare status ('urological or pelvic pain symptoms that are much worse than usual') was ascertained at each bi-weekly assessment. Flare characteristics, including start date, and current intensity of pelvic pain, urgency and frequency (scales of 0-10), were assessed for participants' first three flares and at three randomly selected times when they did not report a flare. Generalized linear and mixed effects models were used to investigate flare risk factors.

RESULTS

Of the 385 eligible participants, 24.2% reported no flares, 22.9% reported one flare, 28.3% reported 2-3 flares, and 24.6% reported ≥4 flares, up to a maximum of 18 during the 11-month follow-up (median incidence rate = 0.13/bi-weekly assessment, range = 0.00-1.00). Pelvic pain (mean = 2.63-point increase) and urological symptoms (mean = 1.72) were both significantly worse during most flares (60.6%), with considerable within-participant variability (26.2-37.8%). Flare duration varied from 1 to 150 days (94.3% within-participant variability). In adjusted analyses, flares were more common, symptomatic, and/or longer-lasting in women and in those with worse non-flare symptoms, bladder hypersensitivity, and chronic overlapping pain conditions.

CONCLUSION

In this foundational flare study, we found that pelvic pain and urological symptom flares were common, but variable in frequency and manifestation. We also identified subgroups of participants with more frequent, symptomatic, and/or longer-lasting flares for targeted flare management/prevention and further study.

Cardiovagal modulation in pediatric functional gastrointestinal disorders

BACKGROUND AND OBJECTIVES

Though reduced cardiovagal modulation accompanies adult IBS, adolescents with functional gastrointestinal disorders (FGID) have not been studied. We aim to investigate whether adolescents with FGID have reduced cardiovagal modulation.

METHODS

After 10-minute supine rest, we recorded ECG for 5-minute supine and 5-minute standing without support in healthy and FGID-affected adolescents. After analysis with Kubios 2.2 for high-frequency (hf) and low-frequency (lf) heart rate variability (HRV), Wilcoxon signed-ranks test compared individual paired supine and standing HRV data, while Kruskal-Wallis and Mann-Whitney U tests compared HRV across groups.

RESULTS

A total of 50 FGID subjects (90% females; median age 17 years [range 11-21]) and 22 healthy comparison group (HC) (59% females; median age 14 years [range 10-18]) participated. Both absolute and relative supine hfHRV exceeded standing in both groups. Absolute supine lfHRV was higher than standing in FGID patients and not in HCs, while relative supine lfHRV power was actually lower in both groups. Compared to HC, FGID group showed significantly lower absolute HRV, while relative HRV did not differ between groups.

CONCLUSIONS

Cardiovagal modulation is lower in adolescents with FGID. This difference impacts these subjects significantly. Whether this finding reflects a cause or a consequence of FGID is unknown.

The gastrointestinal symptoms present in patients with postural tachycardia syndrome: A review of the literature and overview of treatment

Orthostatic intolerance, including postural tachycardia syndrome, is often associated with gastrointestinal symptoms. In the vast majority of the cases, the gastrointestinal symptoms are not secondary to the orthostatic disorder, but rather just a comorbid condition. This concept is critical, since treatment aimed at the orthostatic condition will not improve the gastrointestinal symptoms. Only when the gastrointestinal symptoms develop in the upright position and improve or resolve in the supine position, they may be related to the orthostatic stress. The most common symptoms associated with orthostatic intolerance include nausea, dyspepsia, bloating and constipation. The majority of subjects do not have gastroparesis. The chapter discusses available treatments of these conditions.

Pediatric Disorders of Orthostatic Intolerance

Orthostatic intolerance (OI), having difficulty tolerating an upright posture because of symptoms or signs that abate when returned to supine, is common in pediatrics. For example, ∼40% of people faint during their lives, half of whom faint during adolescence, and the peak age for first faint is 15 years. Because of this, we describe the most common forms of OI in pediatrics and distinguish between chronic and acute OI. These common forms of OI include initial orthostatic hypotension (which is a frequently seen benign condition in youngsters), true orthostatic hypotension (both neurogenic and nonneurogenic), vasovagal syncope, and postural tachycardia syndrome. We also describe the influences of chronic bed rest and rapid weight loss as aggravating factors and causes of OI. Presenting signs and symptoms are discussed as well as patient evaluation and testing modalities. Putative causes of OI, such as gravitational and exercise deconditioning, immune-mediated disease, mast cell activation, and central hypovolemia, are described as well as frequent comorbidities, such as joint hypermobility, anxiety, and gastrointestinal issues. The medical management of OI is considered, which includes both nonpharmacologic and pharmacologic approaches. Finally, we discuss the prognosis and long-term implications of OI and indicate future directions for research and patient management.

Pediatric sleep and autonomic complaints

Objectives:

Little is known about the relationship between autonomic dysfunction and sleep disturbances. This study aimed to identify patterns of sleep disturbances and autonomic dysfunction in children.

Methods:

A retrospective chart review of 14 children who underwent sleep and autonomic testing was performed. Subjects were divided into three groups based on sudomotor Composite Autonomic Severity Score Scale score and postural tachycardia syndrome criteria. Sleep quality, sleep architecture, and number of comorbidities were analyzed.

Results:

There were no statistically significant differences between groups in measures of sleep quality, sleep architecture, and number of comorbidities.

Conclusion:

Patients with postural tachycardia syndrome and autonomic dysfunction experience multiple sleep-related complaints. The low power of our study did not allow firm conclusions, but there is no pattern to these abnormalities.

Sensory mapping of pelvic dermatomes in women with interstitial cystitis/bladder pain syndrome

AIM

To describe a sensory map of pelvic dermatomes in women with Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS). We hypothesized that if IC/BPS involves changes in central processing, then women with IC/BPS will exhibit sensory abnormalities in neurologic pelvic dermatomes.

METHODS

Women with IC/BPS and healthy controls underwent neurologic examination that included evaluation of sharp pain sensitivity and vibration in dermatomes T12, L1, L2, S1-5. Peripheral nervous system sensitivity to pressure, vibration, and pinprick were scored using numeric rating scales (NRS). Bilateral comparisons were made with Wilcoxon signed-rank test and comparisons between groups were made by the Mann-Whitney U-test.

RESULTS

Total of 74 women with IC/BPS and 36 healthy counterparts were included. IC/BPS and control groups had similar age (43.0 ± 14.1 and 38.6 ± 15.3 years, P = 0.14) and BMI (28.9 ± 8.0 kg/m² and 26.9 ± 8.4 kg/m² , P = 0.24), respectively. Women with IC/BPS reported hyperalgesia (elevated bilateral NRS pain intensity) in all pelvic dermatomes compared to healthy controls. S4-S5 region had the highest pain intensity in all participants. All IC/BPS participants exhibited vibration sensation hypoesthesia, at least unilaterally, in all of the pelvic dermatomes except L1 compared to healthy controls.

CONCLUSION

This detailed map of neurologic pelvic dermatomes in women with IC/BPS found hyperalgesia in all pelvic dermatomes, and some evidence of vibration sensation hypoesthesia, compared to healthy controls. These findings support the hypothesis that IC/BPS may involve changes in central signal processing biased towards nociception.

Unusual Structural Autonomic Disorders Presenting in Pediatrics: Disorders Associated with Hypoventilation and Autonomic Neuropathies

Structural autonomic disorders (producing structural damage to the autonomic nervous system or autonomic centers) are far less common than functional autonomic disorders (reflected in abnormal function of a fundamentally normal autonomic nervous system) in children and teenagers. This article focuses on this uncommon first group in the pediatric clinic. These disorders are grouped into 2 main categories: those characterized by hypoventilation and those that feature an autonomic neuropathy.

Benign Joint Hypermobility Minimally Impacts Autonomic Abnormalities in Pediatric Subjects with Chronic Functional Pain Disorders

OBJECTIVE

To determine if children with benign joint hypermobility (BJH) syndrome and chronic functional pain disorders have more autonomic dysfunction.

STUDY DESIGN

Retrospective chart review study of pediatric patients seen in the pediatric neurogastroenterology and autonomic clinic who underwent autonomic testing and had either a Beighton score of ≥6 and met Brighton criteria for BJH (with BJH) or a score of ≤2 (no BJH).

RESULTS

Twenty-one female subjects (10 without BJH) met inclusion criteria; 64% of BJH had diagnosis confirmed by genetics consultation. We evaluated for postural tachycardia syndrome, syncope, orthostatic intolerance, and orthostatic hypotension. None of these diagnoses, as well as baseline heart rate, peak heart rate in first 10 minutes of head up tilt (P = .35 and P = .61, respectively), and sudomotor index (suggestive of autonomic neuropathy) (P = .58), showed differences between the groups. Age of onset of symptoms was also similar (P = .61) (BJH vs without BJH: median [range]:15.6 years [12.9-17.5] vs 15.4 years [11.1-18.2]). There was no difference between groups in complaints of migraine, chronic nausea, chronic fatigue, lightheadedness, dizziness, fainting >3 times/lifetime, delayed onset of sleep, irritable bowel syndrome, dyspepsia, abdominal migraine, functional abdominal pain, constipation, or fibromyalgia.

CONCLUSIONS

Children with chronic functional pain disorders and BJH have autonomic testing findings and comorbid features compared with a similar cohort of subjects without BJH, suggesting that BJH is not the driver of the autonomic and comorbid disorders.

Autonomic Testing in Women with Chronic Pelvic Pain

PURPOSE

We determined whether abnormal autonomic nervous system innervation of the bladder underlies IC (interstitial cystitis)/BPS (bladder pain syndrome) differently than other chronic pelvic pain.

MATERIALS AND METHODS

In this institutional review board approved protocol 39 healthy controls and 134 subjects were enrolled, including 36 with IC/BPS, 14 with myofascial pelvic pain and 42 with IC/BPS plus myofascial pelvic pain. Three subjects were excluded from study. Autonomic nervous system evaluations included deep breathing, the Valsalva maneuver, and the tilt table and sudomotor tests. The latter evaluates autonomic neuropathy. A modified validated composite autonomic laboratory score was applied.

RESULTS

Median age in the IC/BPS group was 47.5 years (range 21 to 78), greater than in healthy controls (34 years, range 20 to 75, p = 0.006), the myofascial pelvic pain group (33 years, range 22 to 56, p = 0.004) and the IC/BPS plus myofascial pelvic pain group (38 years, range 18 to 64, p = 0.03). Body mass index did not significantly differ but the myofascial pelvic pain and IC/BPS plus myofascial pelvic pain groups had a higher body mass index than healthy controls (p = 0.05 and 0.03, respectively). Cardiovascular and adrenergic indexes did not differ. The tilt table test showed more orthostatic intolerance in all chronic pelvic pain groups. Tilt table test diagnoses (orthostatic hypotension, postural tachycardia syndrome and reflex syncope) were rare. Baseline heart rate was higher in all chronic pelvic pain groups (p = 0.004). Compared to healthy controls all myofascial pelvic pain groups showed significantly more clear-cut autonomic neuropathy, defined as a sweat score of 3 or greater (vs IC/BPS plus myofascial pelvic pain p = 0.007 and vs myofascial pelvic pain p = 0.03).

CONCLUSIONS

Some chronic pelvic pain types show autonomic neuropathy and some show vagal withdrawal. In all types orthostatic intolerance likely reflects central sensitization and perhaps catastrophizing. Some of these findings suggest novel therapeutic targets.

High Prevalence of Nausea among School Children in Latin America

OBJECTIVES

To evaluate the prevalence of nausea and its association with functional gastrointestinal disorders (FGIDs) in a large-scale, population-based study of Latin American school children.

STUDY DESIGN

This cross-sectional study collected data from children in 3 Latin American countries. A Spanish version of the Questionnaire on Pediatric Gastrointestinal Symptoms-Rome III Version (QPGS-III) was administered to school children in Central and South America. Subjects were classified into FGIDs based on Rome criteria (QPGS-III). Students from 4 public and 4 private schools in the countries of El Salvador, Panama, and Ecuador participated in this epidemiologic study.

RESULTS

A total of 1137 school children with mean age 11.5 (SD 1.9, range 8-15) years completed the QPGS-III (El Salvador n = 399; Panama n = 321; Ecuador n = 417). Nausea was present in 15.9% of all school children. Two hundred sixty-eight (24%) children met criteria for at least 1 FGID. Nausea was significantly more common in children with FGIDs compared with those without: El Salvador 38% vs 15% (P < .001); Panama 22% vs 7% (P < .001); Ecuador 25% vs 13% (P = .004). Among children with FGIDs, those with functional constipation had a high prevalence of nausea. Nausea was significantly more common in girls and children attending private schools.

CONCLUSIONS

Nausea is commonly present in Latin American school children. FGIDs are frequently associated with nausea.

Comorbid Conditions Do Not Differ in Children and Young Adults with Functional Disorders with or without Postural Tachycardia Syndrome

OBJECTIVE

To determine if several multisystem comorbid conditions occur more frequently in subjects with tilt-table defined postural tachycardia syndrome (POTS) compared with those without.

STUDY DESIGN

Retrospective chart review of 67 subjects aged 6-24 years, referred to a tertiary care neurogastroenterology and autonomic disorders clinic for a constellation of functional gastrointestinal, chronic pain, and autonomic complaints. All patients underwent formal autonomic testing, Beighton scores assessment for joint hypermobility (0-9), and fibromyalgia tender points (0-18) (43 subjects).

RESULTS

Twenty-five subjects (37%) met tilt table criteria for POTS. The median age of 16 years (range, 12-24 years) in the POTS group differed from 15 years (range, 6-21 years) in the no-POTS group (P = .03). Comorbidities including chronic fatigue, sleep disturbances, dizziness, syncope, migraines, functional gastrointestinal disorders, chronic nausea, fibromyalgia, and joint hypermobility did not differ between groups. All subjects with fibromyalgia by tender point-examination had a Beighton score ≥ 4 (P = .002).

CONCLUSIONS

Comorbid conditions are equally prevalent in children and young adults with and without tilt-table defined POTS, suggesting that POTS itself is not a cause of the other comorbidities. Instead, POTS likely reflects another comorbid condition in children with functional disorders. Dizziness and syncope, classically associated with POTS, are not predictive of a diagnosis of POTS by tilt table, a test that is still required for formal diagnosis. These results suggest a paradigm shift in the concept of POTS as the physiological basis of many functional symptoms.

Functional Gastrointestinal Disorders in a Primary Care Pediatric Clinic

Functional gastrointestinal disorders (FGIDs) are a common problem in pediatric patients and can affect quality of life. However, the extent of these disorders may vary in different subpopulations of children. This study investigated the prevalence of FGIDs in an inner-city primary care practice. Healthy patients between the ages of 9 and 17 were administered a validated questionnaire that assessed for FGIDs and other somatic complaints. Eleven of 145 patients (7.5%) met criteria for FGIDs based on Rome III Diagnostic Criteria. Raynaud-like symptoms tended to occur more often in patients meeting criteria for FGIDs, although this association was not statistically significant (P = .07). The lower prevalence of FGIDs in this population compared with earlier studies may suggest a link between socioeconomic status and the prevalence of FGIDs. Larger population-based studies consisting of a heterogeneous cohort from a variety of socioeconomic backgrounds are necessary to further elucidate the true connection between FGIDs and socioeconomic status.

Joint hypermobility: a common association with complex functional gastrointestinal disorders

OBJECTIVE

To evaluate the prevalence of joint hypermobility (JH) and comorbid conditions in children and young adults referred to a tertiary care neurogastroenterology and autonomic disorders clinic for functional gastrointestinal complaints.

STUDY DESIGN

This was a retrospective chart review of 66 new patients aged 5-24 years who fulfilled at least 1 pediatric Rome III criteria for a functional gastrointestinal disorder (FGID) and had a recorded Beighton score (n = 45) or fibromyalgia tender point score (n = 45) based on physician examination. Comorbid symptoms were collected and autonomic testing was performed for evaluation of postural tachycardia syndrome (POTS).

RESULTS

The median patient age was 15 years (range, 5-24 years), 48 (73%) were females, and 56% had JH, a significantly higher rate compared with population studies of healthy adolescents (P < .001; OR, 10.03; 95% CI, 5.26-19.13). POTS was diagnosed in 34% of patients and did not correlate significantly with hypermobility. Comorbid conditions were common, including sleep disturbances (77%), chronic fatigue (93%), dizziness (94%), migraines (94%), chronic nausea (93%), and fibromyalgia (24%).

CONCLUSION

JH and other comorbid symptoms, including fibromyalgia, occur commonly in children and young adults with complex FGIDs. POTS is prevalent in FGIDs but is not associated with hypermobility. We recommend screening patients with complex FGIDs for JH, fibromyalgia, and comorbid symptoms such as sleep disturbances, migraines, and autonomic dysfunction.

Interstitial Cystitis - Elucidation of Psychophysiologic and Autonomic Characteristics (the ICEPAC Study): design and methods

BACKGROUND AND PURPOSE

Interstitial cystitis/bladder pain syndrome (IC/BPS) is relatively common and associated with severe pain, yet effective treatment remains elusive. Research typically emphasized the bladder's role, but given the high presence of systemic comorbidities, the authors hypothesized a pathophysiologic nervous system role. This paper reports the methodology and approach to study the nervous system in women with IC/BPS. The study compares neurologic, urologic, gynecologic, autonomic, gastrointestinal, and psychological features of women with IC/BPS, their female relatives, women with myofascial pelvic pain (MPP), and healthy controls to elucidate the role of central and peripheral processing.

METHODS AND RESULTS

In total, 228 women (76 IC/BPS, 76 MPP, 38 family members, and 38 healthy controls) will be recruited. Subjects undergo detailed screening, structured neurologic examination of limbs and pelvis, tender point examination, autonomic testing, electrogastrography, and assessment of comorbid functional dysautonomias. Interpreters are blinded to subject classification. Psychological and stress response characteristics are examined with assessments of stress, trauma history, general psychological function, and stress response quantification. As of December 2012, data collection is completed for 25 healthy controls, 33 IC/BPS ± MPP, eight MPP, and three family members. Recruitment rate is accelerating and strategies emphasize maintaining and encouraging investigator participation in study science, internet advertising, and presentations to pelvic pain support groups.

CONCLUSION

The study represents a comprehensive, interdisciplinary approach to sampling autonomic and psychophysiologic characteristics of women with IC/BPS. Despite divergent opinions on study methodologies based on specialty experiences, the study has proven feasible to date and different perspectives have proved to be one of the greatest study strengths.

Chronic idiopathic nausea of childhood

OBJECTIVES

To compare children with primary, chronic idiopathic nausea to those with secondary nausea associated with functional abdominal pain.

STUDY DESIGN

Retrospective chart review of 45 children with a primary complaint of chronic nausea several times per week. Comparisons were made to prospectively collected data on 49 children with functional abdominal pain and comorbid nausea.

RESULTS

The majority of those affected were adolescent Caucasian females. Subjects with chronic nausea had a more severe presentation with daily 88% (vs 26%) and constant 60% (vs 10%) nausea (P < .001), one-half with peak morning intensity. In the chronic nausea group, 62% had migraines, and 71% (vs 22%) had familial migraines (P < .001), 36% had postural tachycardia syndrome and 27% cyclic vomiting syndrome. Both groups suffered comorbid symptoms (anxiety, dizziness, fatigue, and sleep problems). The chronic nausea cohort underwent extensive, negative medical evaluations.

CONCLUSIONS

Chronic idiopathic nausea of childhood is a poorly described symptom. Patients with primary (vs secondary) chronic nausea were more likely Caucasian, older adolescent females with severe, daily nausea and comorbid conditions such as anxiety, dizziness, and fatigue as well as significantly more migraine features. Chronic nausea is a major, disabling symptom that requires increased recognition as a separate functional entity. Future studies may need to focus on comorbid conditions including migraine and dysautonomia.

Adolescent fatigue, POTS, and recovery: a guide for clinicians

Many teenagers who struggle with chronic fatigue have symptoms suggestive of autonomic dysfunction that may include lightheadedness, headaches, palpitations, nausea, and abdominal pain. Inadequate sleep habits and psychological conditions can contribute to fatigue, as can concurrent medical conditions. One type of autonomic dysfunction, postural orthostatic tachycardia syndrome, is increasingly being identified in adolescents with its constellation of fatigue, orthostatic intolerance, and excessive postural tachycardia (more than 40 beats/min). A family-based approach to care with support from a multidisciplinary team can diagnose, treat, educate, and encourage patients. Full recovery is possible with multi-faceted treatment. The daily treatment plan should consist of increased fluid and salt intake, aerobic exercise, and regular sleep and meal schedules; some medications can be helpful. Psychological support is critical and often includes biobehavioral strategies and cognitive-behavioral therapy to help with symptom management. More intensive recovery plans can be implemented when necessary.

Chronic idiopathic nausea

Chronic nausea is a prevalent but poorly described symptom in adolescents. It often co-occurs with other functional gastrointestinal disorders (FGIDs) but may also present in isolation. A multitude of triggers and complex neural pathways underlie the sensation of nausea. These include gastrointestinal and blood-borne insults, dysmotility, vestibular or central nervous system pathways, an aberrant autonomic nervous system, and psychosocial factors. Although clinical algorithms are lacking, diagnosis is typically made on the basis of a thorough clinical history and without extensive testing. Treatment is mainly empiric and may be directed at comorbid symptoms such as migraine, delayed gastric emptying, orthostatic intolerance, and visceral hypersensitivity. Chronic idiopathic nausea is an increasingly prevalent symptom that needs careful clinical assessment and individualized treatment plans.

Intravenous dihydroergotamine therapy for pediatric abdominal migraines

Abdominal migraines present with debilitating symptoms in adolescence. At our institution, the gastroenterology, neurology, and autonomic departments collaborated in treating patients with such presentations. This case series describes 6 patients who were given intravenous dihydroergotamine (DHE) for presumed abdominal migraines. DHE was only used when other agents like amitriptyline, verapamil, topiramate, or depakote had proved ineffective. DHE was started at 0.5 mg dose and on average 7 to 9 mg were given on each hospitalization. Patient ages ranged from 13 to 19 years with the majority being female. One patient did not respond to treatment. One patient was admitted 4 times for symptoms of abdominal migraines resolving with DHE. The average time between symptom relapse was about 5 to 12 months. Five of our 6 patients responded to the infusion without significant side effects. Based on these case series, DHE may be a treatment option in children with intractable abdominal migraine.

Gastrointestinal manifestations of pediatric autonomic disorders

Functional gastrointestinal disorders (FGIDs) are currently classified under the Rome criteria based on symptoms and absence of organic disease. Preliminary studies have shown that FGIDs are probably not restricted to the GI tract, but may represent a systemic disorder with comorbidities affecting other parts of the body, including migraine, fatigue, aches and pains, etc. The autonomic nervous system (ANS) provides the extrinsic control of GI motility, secretions, and even immune response. The role of the ANS in the development of FGIDs and comorbidities is still unclear. Limited data demonstrate orthostatic intolerance such as reflex syncope and postural tachycardia syndrome in a large subset of subjects with FGIDs. Some studies have found improvement in the GI symptoms with treatment of the orthostatic intolerance it produces. Prospective studies are needed to determine the chronology of the development of the comorbidities, the triggers that induce these syndromes, and effective treatments. This chapter aims to review current understanding of the role of the ANS in FGIDs.

Co-morbidities of interstitial cystitis

Introduction: This study aimed to estimate the proportion of patients with interstitial cystitis/painful bladder syndrome (IC/BPS) with systemic dysfunction associated co-morbidities such as irritable bowel syndrome (IBS) and fibromyalgia (FM). Materials and Methods: Two groups of subjects with IC/BPS were included: (1) physician diagnosed patients with IC/BPS and (2) subjects meeting NIDDK IC/PBS criteria based on a questionnaire (ODYSA). These groups were compared to healthy controls matched for age and socio-economic status. NIDDK criteria required: pain with bladder filling that improves with emptying, urinary urgency due to discomfort or pain, polyuria >11 times/24 h, and nocturia >2 times/night. The ODYSA instrument evaluates symptoms pertaining to a range of disorders including chronic fatigue, orthostatic intolerance, syncope, IBS, dyspepsia, cyclic vomiting syndrome, headaches and migraines, sleep, Raynaud’s syndrome, and chronic aches and pains. Results: IC/BPS was diagnosed in 26 subjects (mean age 47 ± 16 years, 92% females), 58 had symptoms of IC/BPS by NIDDK criteria (mean age 40 ± 17 years, 79% females) and 48 were healthy controls (mean age 31 ± 14 years, mean age 77%). Co-morbid complaints in the IC/BPS groups included gastrointestinal symptoms suggestive of IBS and dyspepsia, sleep abnormalities with delayed onset of sleep, feeling poorly refreshed in the morning, waking up before needed, snoring, severe chronic fatigue and chronic generalized pain, migraines, and syncope. Discussion: Patients with IC/BPS had co-morbid central and autonomic nervous system disorders. Our findings mirror those of others in regard to IBS, symptoms suggestive of FM, chronic pain, and migraine. High rates of syncope and functional dyspepsia found in the IC/BPS groups merit further study to determine if IC/BPS is part of a diffuse disorder of central, autonomic, and sensory processing affecting multiple organs outside the bladder.

FGIDs in children are associated with many nonpsychiatric comorbidities: the tip of an iceberg?

Functional gastrointestinal disorders (FGIDs) are common. The poor health-related quality of life in FGIDs is a combination of gastrointestinal symptoms and comorbid conditions. We determined by using the Ohio Dysautonomia questionnaire the medical comorbidities in 38 children with FGID. Almost all of the subjects had a comorbid disorder, with orthostatic symptoms in 89%, fainted >3×/lifetime in 17%, headaches with migrainous features in 40%, other types of chronic pain in 50%, and fatigue lasting >6 months in approximately 33%. These findings constitute a critical first step in changing the paradigm of our approach to FGID as a broader systemic disorder, not one limited to the gastrointestinal tract.

Pediatric autonomic testing: retrospective review of a large series

OBJECTIVE. To describe the reasons for referral, autonomic diagnoses, test results, and patient management in a large pediatric population referred for testing for an autonomic disorder. DESIGN. The authors reviewed autonomic testing data and medical records for patients aged 18 years and younger who underwent testing between 1993 and 2007 and who had adequate clinical data. Relevance of test results to clinical symptoms was ranked on a 3-point scale. Treatments were noted and their benefit ranked on a 5-point scale. RESULTS. Among 142 pediatric patients identified, postural tachycardia syndrome was most common (71%) while orthostatic hypotension was rare (5%). Testing provided relevant information regarding the patient's symptoms in 88% of the cases. Beta-blockers were the most commonly prescribed medication (59%); 73% improved. CONCLUSIONS. Postural tachycardia syndrome was common in this large pediatric population, whereas orthostatic hypotension was infrequent. The symptomatic improvement in the majority bears an unclear relationship to treatment. Prospective studies are needed.

Implications of tilt-table induced faint time in patients with reflex syncope

OBJECTIVE

The aim of this study was to determine whether patients who faint earlier in the course of a tilt table study represent a separate population with a poorer prognosis or different pathophysiology. We analyzed differences across patients with different syncopal times on the tilt-table study to answer this question.

METHODS

This was a retrospective, approved, chart review. From our database of over 6000 patients, we identified 1222 patients with syncope. After excluding patients with orthostatic hypotension, postural tachycardia syndrome and diabetes, we were left with 131 patients with pure reflex syncope. We divided fainters into an early (<20 minutes) and late (>20 minutes) faint times. Along with the tilt table test all patients underwent heart rate response for deep breathing, Valsalva maneuver and quantitative sudomotor axon reflex tests.

RESULTS

By 10 minutes in the tilt study, only 18% of subjects had fainted, 65% by 20 minutes, 92% by 30 minutes and 96% by 35 minutes. Age was evenly distributed across all syncopal times. Neither the 14 abnormal cardiac responses to deep breathing nor the 20 abnormal Valsalva maneuvers, nor the 28 abnormal axon reflex responses clustered with an early or late faint time.

CONCLUSION

A 10-minute tilt will miss 82% of syncopal episodes, while a 30- minute tilt increases the yield 10-fold, missing only 8%. Patients with early faint times did not differ from patients with late fainting times with regard to age or autonomic test abnormalities. Timing of syncope during the tilt table test does not associated with more severe dysautonomia. A prospective study is needed to confirm these observations.

Comorbidities in pediatric patients with postural orthostatic tachycardia syndrome

OBJECTIVE

To investigate the frequency of various nonorthostatic complaints in children with postural orthostatic tachycardia syndrome (POTS).

STUDY DESIGN

We used our autonomic laboratory database to identify all pediatric patients with traditionally defined POTS who had completed the Ohio Dysautonomia Survey (ODYSA). The responses of the patients to questions targeting various autonomic complaints, including syncope, gastrointestinal symptoms, sleep disturbances, headaches, urinary symptoms, chronic pain, and Raynaud-like symptoms, were collected and analyzed.

RESULTS

A total of 53 pediatric patients completed the ODYSA questionnaire. The participants reported high frequencies of sleep abnormalities, chronic pain, Raynaud-like symptoms, and gastrointestinal abnormalities, with lower rates of headaches, syncope, and urinary complaints.

CONCLUSIONS

Our findings demonstrate the occurrence of various nonorthostatic symptoms in pediatric patients with POTS. These findings suggest the need for an interdisciplinary approach to the treatment and management of POTS, as well as for further investigation into the mechanisms that lead to the concurrent presentation of both orthostatic and nonorthostatic symptoms in these patients.

Orthostatic syndromes differ in syncope frequency

BACKGROUND

There are conflicting opinions on whether postural tachycardia syndrome predisposes to syncope. We investigated this relationship by comparing the frequency of syncope in postural tachycardia syndrome and orthostatic hypotension.

METHODS

We queried our autonomic laboratory database of 3700 patients. Orthostatic hypotension and postural tachycardia syndrome were defined in standard fashion, except that postural tachycardia syndrome required the presence of orthostatic symptoms and a further increase in heart rate beyond 10 minutes. Syncope was defined as an abrupt decrease in blood pressure and often, heart rate, requiring termination of the tilt study. Statistical analysis utilized Fisher's exact test and Student's t test, as appropriate.

RESULTS

Of 810 patients referred for postural tachycardia syndrome, 185 met criteria while another 328 patients had orthostatic hypotension. Of the postural tachycardia syndrome patients, 38% had syncope on head-up tilt, compared with only 22% of those with orthostatic hypotension (P<.0001). In the postural tachycardia group, syncope on head-up tilt was associated with a clinical history of syncope in 90%, whereas absence of syncope on head-up tilt was associated with a clinical history of syncope in 30% (P<.0001). In contrast, syncope on head-up tilt did not bear any relationship to clinical history of syncope in the orthostatic hypotension group (41% vs 36%; P=.49).

CONCLUSION

Our results demonstrate that syncope (both tilt table and clinical) occurs far more commonly in patients who have postural tachycardia syndrome than in patients with orthostatic hypotension. These findings suggest that one should be clinically aware of the high risk of syncope in patients with postural tachycardia syndrome, and the low-pressure baroreceptor system that is implicated in postural tachycardia syndrome might confer more sensitivity to syncope than the high pressure system implicated in orthostatic hypotension.

Food protein sensitivity with partial villous atrophy after pediatric liver transplantation with tacrolimus immunosuppression

We report three pediatric liver transplant recipients receiving tacrolimus immunosuppression presented with vomiting, heme-positive stools and failure to thrive, who had subtotal villous atrophy in their histology because of food protein sensitivity. Case findings and current literature of the casual relationship between tacrolimus and food allergies briefly reviewed.

Helicobacter pylori in children and adolescents

There is now considerable evidence that suggests that the H. pylori organism isa human pathogen. The strong association between H. pylori and gastroduodenal disease is well documented. A number of hypotheses have been suggested for the pathogenic mechanisms of H. pylori-induced gastroduodenal disease, including the presence of bacterial virulence factors, the production of inflammatory mediators, disregulation of acid secretion, and the host immune response. At the present time, treatment with a combination of a proton pump inhibitor and antimicrobial agents continues to be recommended for the treatment of H. pylori-associated peptic ulcer disease.

Pneumatosis intestinalis and diarrhea in a child following renal transplantation

Pneumatosis intestinalis is an uncommon finding beyond the neonatal period, but it has been reported in immunocompromized pediatric patients. The association of pneumatosis intestinalis in children following renal transplantation has to the best of our knowledge been only reported once in children. We describe a 4-year-old female who developed intermittent emesis, weight loss, and intermittently loose bloody stools after cadaveric renal transplantation at age 3.5 years. An abdominal x-ray demonstrated extensive pneumatosis in the colon. The infectious work-up was negative. Histologically, she had increased eosinophils throughout the lamina propria in the rectum. A glucose breath test was suggestive of small bowel bacterial overgrowth. She was treated with 10 days of metronidazole with resolution of the diarrhea and occult blood in stools. One month after the treatment she had radiologic resolution of her pneumatosis. Based on this report, pneumatosis intestinalis should be considered in the differential diagnosis of children after organ transplant suffering from diarrhea, abdominal pain, or blood in the stool.

Evaluation and Treatment of Autonomic Disorders of the Gastrointestinal Tract

Despite the extensive impact of autonomic function on the gastrointestinal system, there is little understanding of the mechanisms by which specific autonomic abnormalities translate into particular gastrointestinal complaints. Three logical alternatives include: (1) the underlying disorder affects the autonomic and gastrointestinal systems independently; (2) autonomic dysfunction alters gastrointestinal processing directly; (3) gastrointestinal manifestations arise as a delayed, indirect consequence of autonomic dysfunction. The major gastrointestinal manifestations of dysautonomia include esophageal dysmotility such as achalasia, gastroparesis, and small bowel bacterial overgrowth in the upper tract. Lower tract disorders include diarrhea, fecal incontinence, and constipation. Sorting through the varied causes of these disorders requires a careful history and examination in each patient. Supportive diagnostic studies may include radionuclide imaging, motility examination, and electrogastrography. Autonomic studies can (1) distinguish a purely enteric from a more generalized dysautonomia; (2) provide surrogate information about motility; (3) differentiate primary (e.g., multiple system atrophy) from secondary (e.g., irritable bowel syndrome) dysautonomias as the etiology of gastrointestinal symptoms. Several new strategies are available for the treatment of gastroparesis, constipation, irritable bowel, and sphincteric incontinence.

Hair relaxers: a benign caustic ingestion?

BACKGROUND

Despite federally legislated safety regulations, caustic ingestions remain a significant problem in the pediatric population. The current standard of care for caustic ingestion includes upper gastrointestinal endoscopy in most cases. Hair relaxers are a common caustic ingestion at our institution, yet few data have been published describing the clinical or endoscopic outcome. We explored the relative frequency of hair relaxer ingestion, the incidence of associated upper gastrointestinal injury, and the adverse clinical sequelae resulting from these ingestions.

METHODS

Consecutive caustic ingestions admitted to our institution between January 1990 and January 2001 were identified. The data were collected through retrospective physician chart review, were analyzed, and were pooled with the existing literature to evaluate for the presence of esophageal injury.

RESULTS

96 charts were reviewed, 29 (30%) of which were hair relaxer ingestions that underwent esophagogastroduodenoscopy; these ingestions served as our study cohort. The median age of the cohort was 14.0 months and patients were evenly divided in gender. The most common symptoms at presentation were drooling and emesis. At endoscopy, lip and oropharyngeal mucosa were most commonly affected. While six patients (20.7%) had Grade I esophageal mucosal injury and five patients (17.2%) had Grade I gastric mucosal injury, none had greater than Grade I mucosal damage. No adverse clinical events were identified. When our data were combined with all previously published cohort data, the findings were similar and no adverse clinical outcomes were reported.

CONCLUSIONS

Hair relaxer is the most common childhood caustic ingestion presenting to our large metropolitan tertiary care center. Symptoms are common at presentation. However, despite the high pH of these products, no clinically significant esophageal or gastric mucosal injuries and no long-term sequelae were identified.

Familial association of autonomic and gastrointestinal symptoms

Autonomic dysfunction occurs in the adult population with irritable bowel syndrome, but this association is not recognized in children. A mother and son with functional abdominal pain unresponsive to conventional treatment had complete resolution of symptoms with treatment directed at the autonomic dysfunction identified by testing. The authors recommend autonomic testing in patients with functional abdominal pain and suggest that autonomic dysfunction plays a direct and intrinsic role in the mechanism of these disorders and their symptoms.

Autonomic abnormalities in children with functional abdominal pain: coincidence or etiology?

BACKGROUND

There is increasing evidence that autonomic neuropathies may adversely affect gastrointestinal motility by involving the extrinsic nerves of the gut. The authors' hypothesize that functional abdominal pain in children is associated with generalized autonomic dysfunction.

METHODS

The authors performed detailed autonomic testing in eight patients with functional abdominal pain, including deep breathing, Valsalva, tilting (to assess parasympathetic and sympathetic adrenergic function), and axon-reflex function and thermoregulatory sweat testing to assess sympathetic cholinergic function. Patients also completed a questionnaire regarding other autonomic symptoms.

RESULTS

Results of autonomic testing were abnormal in seven patients. Parasympathetic function was normal in all, and the abnormalities were restricted to sympathetic cardiac, vasomotor, and sudomotor function. Abnormal results of axon-reflex testing in six were consistent with peripheral nervous system dysfunction. Five had decreased sweating over the abdomen, determined by thermoregulatory sweat testing. Five eight had nongastrointestinal autonomic symptoms, primarily palpitations and flushing.

CONCLUSIONS

Functional abdominal pain in the current patients is associated with generalized dysfunction of the autonomic nervous system. This dysfunction can be peripheral or central in different individuals but seems to be restricted to the sympathetic branch. The known function of the sympathetic nervous system as the motility "brake" suggests that pain could be a manifestation of unmodulated peristalsis, resulting in abdominal cramps.