Recommendations for pharmacological clinical trials in children with functional constipation: The Rome foundation pediatric subcommittee on clinical trials

BACKGROUND

Evidence for the efficacy of commonly used drugs in the treatment of childhood functional constipation (FC) is scarce, studies are often of low quality and study designs are heterogeneous. Thus, recommendations for the design of clinical trials in childhood FC are needed.

PURPOSE

Members of the Rome Foundation and a member of the Pediatric Committee of the European Medicines Agency formed a committee to create recommendations for the design of clinical trials in children with FC.

KEY RECOMMENDATIONS

This committee recommends conducting randomized, double-blind, placebo-controlled, parallel-group clinical trials to assess the efficacy of new drugs for the treatment of childhood FC. Pediatric study participants should be included based on fulfilling the Rome IV criteria for FC. A treatment free run-in period for baseline assessment is recommended. The trial duration should be at least 8 weeks. Treatment success is defined as no longer meeting the Rome IV criteria for FC. Stool consistency should be reported based on the Bristol Stool Scale. Endpoints of drug efficacy need to be tailored to the developmental age of the patient population.

Spontaneous food allergy in Was-/- mice occurs independent of FcεRI-mediated mast cell activation

BACKGROUND

Food allergies are a growing health problem, and the development of therapies that prevent disease onset is limited by the lack of adjuvant-free experimental animal models. We compared allergic sensitization in patients with food allergy or Wiskott-Aldrich syndrome (WAS) and defined whether spontaneous disease in Was^-/- mice recapitulates the pathology of a conventional disease model and/or human food allergy.

METHODS

Comparative ImmunoCAP ISAC microarray was performed in patients with food allergy or WAS. Spontaneous food allergy in Was^-/- mice was compared to an adjuvant-based model in wild-type mice (WT-OVA/alum). Intestinal and systemic anaphylaxis was assessed, and the role of the high-affinity IgE Fc receptor (FcεRI) in allergic sensitization was evaluated using Was^-/- Fcer1a^-/- mice.

RESULTS

Polysensitization to food was detected in both WAS and food-allergic patients which was recapitulated in the Was^-/- model. Oral administration of ovalbumin (OVA) in Was^-/- mice induced low titers of OVA-specific IgE compared to the WT-OVA/alum model. Irrespectively, 79% of Was^-/- mice developed allergic diarrhea following oral OVA challenge. Systemic anaphylaxis occurred in Was^-/- mice (95%) with a mortality rate >50%. Spontaneous sensitization and intestinal allergy occurred independent of FcεRI expression on mast cells (MCs) and basophils.

CONCLUSIONS

Was^-/- mice provide a model of food allergy with the advantage of mimicking polysensitization and low food-antigen IgE titers as observed in humans with clinical food allergy. This model will facilitate studies on aberrant immune responses during spontaneous disease development. Our results imply that therapeutic targeting of the IgE/FcεRI activation cascade will not affect sensitization to food.

Intra- and interrater reliability of the Chicago Classification of achalasia subtypes in pediatric high-resolution esophageal manometry (HRM) recordings

BACKGROUND

Subtyping achalasia by high-resolution manometry (HRM) is clinically relevant as response to therapy and prognosis have shown to vary accordingly. The aim of this study was to assess inter- and intrarater reliability of diagnosing achalasia and achalasia subtyping in children using the Chicago Classification (CC) V3.0.

METHODS

Six observers analyzed 40 pediatric HRM recordings (22 achalasia and 18 non-achalasia) twice by using dedicated analysis software (ManoView 3.0, Given Imaging, Los Angeles, CA, USA). Integrated relaxation pressure (IRP4s), distal contractile integral (DCI), intrabolus pressurization pattern (IBP), and distal latency (DL) were extracted and analyzed hierarchically. Cohen's κ (2 raters) and Fleiss' κ (>2 raters) and the intraclass correlation coefficient (ICC) were used for categorical and ordinal data, respectively.

RESULTS

Based on the results of dedicated analysis software only, intra- and interrater reliability was excellent and moderate (κ=0.89 and κ=0.52, respectively) for differentiating achalasia from non-achalasia. For subtyping achalasia, reliability decreased to substantial and fair (κ=0.72 and κ=0.28, respectively). When observers were allowed to change the software-driven diagnosis according to their own interpretation of the manometric patterns, intra- and interrater reliability increased for diagnosing achalasia (κ=0.98 and κ=0.92, respectively) and for subtyping achalasia (κ=0.79 and κ=0.58, respectively).

CONCLUSIONS

Intra- and interrater agreement for diagnosing achalasia when using HRM and the CC was very good to excellent when results of automated analysis software were interpreted by experienced observers. More variability was seen when relying solely on the software-driven diagnosis and for subtyping achalasia. Therefore, diagnosing and subtyping achalasia should be performed in pediatric motility centers with significant expertise.

Simultaneous urodynamic and anorectal manometry studies in children: insights into the relationship between the lower gastrointestinal and lower urinary tracts

BACKGROUND

Children with urinary incontinence (UI) have associated functional constipation (FC) and fecal incontinence (FI). The physiology between lower urinary tract (LUT) and anorectum in children has not been elucidated.

AIMS

Observe the effect of rectal distention (RD) on LUT function, and bladder filling and voiding on anorectal function.

METHODS

Children with voiding dysfunction referred to Boston Children's Hospital were prospectively enrolled in combined urodynamic (UDS) and anorectal manometry (ARM). Anorectal and urodynamic parameters were simultaneously measured. Patients underwent two micturition cycles, first with rectal balloon deflated and second with it inflated (RD). Lower urinary tract and anorectal parameters were compared between cycles.

KEY RESULTS

Ten children (seven UI, four recurrent UTIs, nine FC ± FI) were enrolled. Postvoid residual (PVR) increased (p = 0.02) with RD. No differences were observed in percent of bladder filling to expected bladder capacity, sensation, and bladder compliance with and without RD. Bladder and abdominal pressures increased at voiding with RD (p < 0.05). Intra-anal pressures decreased at voiding (p < 0.05), at 25% (p = 0.03) and 50% (p = 0.06) of total volume of bladder filling.

CONCLUSIONS & INFERENCES

The PVR volume increased with RD. Stool in the rectum does not alter filling cystometric capacity but decreases the bladder's ability to empty predisposing patients with fecal retention to UI and UTIs. Bladder and abdominal pressures increased during voiding, demonstrating a physiological correlate of voiding dysfunction. Intra-anal pressures decreased during bladder filling and voiding. This is the first time intra-anal relaxation during bladder filling and voiding has been described.

Primary Graft Dysfunction After Zero-Mismatch Kidney Transplantation Secondary to Early Biopsy-Proven Acute Cell-Mediated Rejection: Case Report

We report a case of primary renal allograft dysfunction and early acute cell-mediated rejection after a 12/12 HLA antigen zero-mismatch (0MM) transplant. The recipient was a 40-year-old white man who was highly allosensitized, with a calculated panel reactive antibody score of 100%. In posteroperative day 1 the recipient remained anuric and underwent dialysis because of hyperkalemia. Graft biopsy showed early acute cellular rejection, Banff grade 2B. No evidence of antibody-mediated rejection was observed. To our knowledge, this case is the 1st to report early cell-mediated rejection after 12/12 HLA antigen 0MM kidney transplantation. This case suggests that highly sensitized candidates are at high immunologic risk even in the context of 0MM kidney transplantation.

Inter- and intrarater reliability of the Chicago Classification in pediatric high-resolution esophageal manometry recordings

BACKGROUND

The Chicago Classification (CC) facilitates interpretation of high-resolution manometry (HRM) recordings. Application of this adult based algorithm to the pediatric population is unknown. We therefore assessed intra and interrater reliability of software-based CC diagnosis in a pediatric cohort.

METHODS

Thirty pediatric solid state HRM recordings (13M; mean age 12.1 ± 5.1 years) assessing 10 liquid swallows per patient were analyzed twice by 11 raters (six experts, five non-experts). Software-placed anatomical landmarks required manual adjustment or removal. Integrated relaxation pressure (IRP4s), distal contractile integral (DCI), contractile front velocity (CFV), distal latency (DL) and break size (BS), and an overall CC diagnosis were software-generated. In addition, raters provided their subjective CC diagnosis. Reliability was calculated with Cohen's and Fleiss' kappa (κ) and intraclass correlation coefficient (ICC).

KEY RESULTS

Intra- and interrater reliability of software-generated CC diagnosis after manual adjustment of landmarks was substantial (mean κ = 0.69 and 0.77 respectively) and moderate-substantial for subjective CC diagnosis (mean κ = 0.70 and 0.58 respectively). Reliability of both software-generated and subjective diagnosis of normal motility was high (κ = 0.81 and κ = 0.79). Intra- and interrater reliability were excellent for IRP4s, DCI, and BS. Experts had higher interrater reliability than non-experts for DL (ICC = 0.65 vs ICC = 0.36 respectively) and the software-generated diagnosis diffuse esophageal spasm (DES, κ = 0.64 vs κ = 0.30). Among experts, the reliability for the subjective diagnosis of achalasia and esophageal gastric junction outflow obstruction was moderate-substantial (κ = 0.45-0.82).

CONCLUSIONS & INFERENCES

Inter- and intrarater reliability of software-based CC diagnosis of pediatric HRM recordings was high overall. However, experience was a factor influencing the diagnosis of some motility disorders, particularly DES and achalasia.

Elevated levels of leukotriene C4 synthase mRNA distinguish a subpopulation of eosinophilic oesophagitis patients

BACKGROUND

Cysteinyl leukotrienes contribute to Th2-type inflammatory immune responses. Their levels in oesophageal tissue, however, do not distinguish patients with eosinophilic oesophagitis (EoE) from controls.

OBJECTIVE

We asked whether mRNA levels of leukotriene C4 synthase (LTC4 S), a key regulator of leukotriene production, could serve as a marker for EoE.

METHODS

Digital mRNA expression profiling (nCounter(®) Technology) was performed on proximal and distal oesophageal biopsies of 30 paediatric EoE patients and 40 non-EoE controls. Expression data were confirmed with RT-qPCR. LTC4 S mRNA levels were quantified in whole blood samples. Leukotriene E4 was measured in urine.

RESULTS

LTC4 S mRNA levels were elevated in proximal (2.6-fold, P < 0.001) and distal (2.9-fold, P < 0.001) oesophageal biopsies from EoE patients. Importantly, increased LTC4 S mRNA transcripts identified a subpopulation of EoE patients (28%). This patient subgroup had higher serum IgE levels (669 U/mL vs. 106 U/mL, P = 0.01), higher mRNA transcript numbers of thymic stromal lymphopoietin (TSLP) (1.6-fold, P = 0.009) and CD4 (1.4-fold, P = 0.04) but lower IL-23 mRNA levels (0.5-fold, P = 0.04). In contrast, elevated levels of IL-23 mRNA were found in oesophageal biopsies of patients with reflux oesophagitis. LTC4 S mRNA transcripts in whole blood and urinary excretion of leukotriene E4 were similar in EoE patient subgroups and non-EoE patients.

CONCLUSION & CLINICAL RELEVANCE

Elevated oesophageal expression of LTC4 S mRNA is found in a subgroup of EoE patients, concomitant with higher serum IgE levels and an oesophageal transcriptome indicative of a more-pronounced allergic phenotype. Together with TSLP and IL-23 mRNA levels, oesophageal LTC4 S mRNA may facilitate diagnosis of an EoE subpopulation for personalized therapy.

Association of metabolic syndrome with kidney function and histology in living kidney donors

The selection of living kidney donors is based on a formal evaluation of the state of health. However, this spectrum of health includes subtle metabolic derangements that can cluster as metabolic syndrome. We studied the association of metabolic syndrome with kidney function and histology in 410 donors from 2005 to 2012, of whom 178 donors were systematically followed after donation since 2009. Metabolic syndrome was defined as per the NCEP ATPIII criteria, but using a BMI > 25 kg/m(2) instead of waist circumference. Following donation, donors received counseling on lifestyle modification. Metabolic syndrome was present in 50 (12.2%) donors. Donors with metabolic syndrome were more likely to have chronic histological changes on implant biopsies than donors with no metabolic syndrome (29.0% vs. 9.3%, p < 0.001). This finding was associated with impaired kidney function recovery following donation. At last follow-up, reversal of metabolic syndrome was observed in 57.1% of donors with predonation metabolic syndrome, while only 10.8% of donors developed de novo metabolic syndrome (p < 0.001). In conclusion, metabolic syndrome in donors is associated with chronic histological changes, and nephrectomy in these donors was associated with subsequent protracted recovery of kidney function. Importantly, weight loss led to improvement of most abnormalities that define metabolic syndrome.

Living donor kidney transplantation: an update on evaluation and medical implications of donation

As the number of potential transplant recipient candidates increases with a relatively fixed number of organ donors, waitlists for kidney donation continue to grow. The disparity has forced physicians to reconsider prospective living organ candidates who are advanced in age with some degree of illness burden as a viable option for donation. The 2004 Amsterdam Forum was established to create consensus guidelines for donor evaluation. The primary goal of the evaluation of the prospective living donor is to risk stratify disease burden to ensure the safety of the donor. This article underscores some of the most contentious aspects of living donor evaluation such as metabolic derangements, donor age, donor gender and kidney function among others. Outcomes of the allograft and recipient are reviewed in the context of these medical conditions. The evaluation of the prospective living donor requires that he/she has agreed to proceed with donation after obtaining informed consent which can only be acquired by understanding all the short and long term complications and risks associated with kidney donation. This review will discuss the immediate surgical complications and long-term implications. There may be additional risk for female donors who are at childbearing age and plan to start a family. However, living kidney donation is the best treatment option available for patients with end stage renal disease and it is a safe procedure for the donor after careful medical consideration in each particular case is given.

Coexistence of constipation and incontinence in children and adults

The coexistence of constipation and fecal incontinence has long been recognised in paediatric and geriatric populations, but is grossly underappreciated in the rest of the adult population. In children, functional fecal incontinence is usually associated with constipation, stool retention and incomplete evacuation, and is frequently allied to urinary incontinence. Pathophysiology of the incontinence is incompletely understood, although both in children and adults, it is thought to be secondary to overflow, while in adults it may also be related to pelvic floor dysfunction and denervation. Incontinence has an important impact on quality of life and daily functioning, and in children may be associated with behaviour problems. The treatment of underlying constipation usually results in improvement in incontinence. This review broadly addresses the epidemiology and pathophysiology of coexistent constipation and incontinence in both children and adults, and also reviews clinical presentation and treatment response in pediatrics.

Beneficial outcomes of a steroid-free regimen with thymoglobulin induction in pancreas-kidney transplantation

BACKGROUND

Steroid-free immunosuppressive regimens are becoming more common in pancreas transplantation, with persistent concerns regarding its safety and efficacy.

METHODS

We performed a retrospective chart review of 87 pancreas transplant recipients-22 simultaneous pancreas-kidney transplants, 48 pancreas-after-kidney transplants, and 17 pancreas transplant alone-who underwent transplantation within the period of January 2000 to November 2006 and who received induction therapy with thymoglobulin followed by maintenance immunosuppression with tacrolimus and mycophenolate mofetil. We compared one group on a steroid-free regimen (n = 25) with another on a steroid-based regimen (n = 62).

RESULTS

At 6 months, there was no kidney graft loss and no significant difference between groups (steroid-free vs steroid-based groups) in patient survival (100% vs 96.8%), pancreas graft survival (96.0% vs 93.5%), acute rejection (4.0% vs 11.3%), hospitalization for any cause (60.0% vs 51.6%), infection requiring hospitalization (16.0% vs 32.3%), or incidence of BK viremia (0% vs 3.2%). CMV viremia occurred less in the steroid-free group (0% vs 17.7% in the steroid-based group, P = .024). The estimated glomerular filtration rate (eGFR) at 6 months was higher in the steroid-free group (74.8 vs 55.7 mL/min/1.73 m2 in the steroid-based group, P = .001), with fewer occurrences of a 25% decline in eGFR (33.3% among the steroid-free group vs 61.7% among steroid-based group, P = .019), despite similar average tacrolimus exposure (11.7 +/- 3.7 vs 12.2 +/- 2.7 ng/dL, P = .478).

CONCLUSIONS

A steroid-free regimen with thymoglobulin induction followed by tacrolimus and mycophenolate mofetil for maintenance in pancreas transplantation was safe and effective in preventing rejection, with reduced incidence of CMV infection and better-preserved kidney function.

Prevalence and clinical course of BK virus nephropathy in pancreas after kidney transplant patients

The influence of BK virus nephropathy (BKVN) in pancreas after kidney (PAK) transplantation is unclear. A retrospective analysis of PAK transplants performed at our center was conducted to determine the impact of BKVN. Among 40 PAK transplants performed using sequential immunosuppression, four patients developed BKVN, as defined by a >20% rise in serum creatinine and BK viremia (BK plasma load >4 log copies/mL), at a median of 19 months following PAK. In all four patients, treatment of BKVN consisted of reduction in tacrolimus, cessation of mycophenolate mofetil, and introduction of leflunomide. With this approach, two patients experienced improvement or stabilization of renal function. The remaining two patients progressed to dialysis dependence despite treatment. Plasma BK load < or =5 log copies/mL was associated with graft preservation. Gender, age, delay between transplants, cumulative Thymoglobulin dose, and type of kidney donor were not associated with BK virus infection. Pancreas graft rejection or dysfunction was not observed with the above immunosuppression modification. Mean amylase and lipase > or =6 months following BKVN treatment remained normal. BKVN is an important cause of kidney allograft loss in PAK patients. Screening and early treatment of BKVN may enable preservation of kidney and pancreas grafts.

Diagnosis and management of MNGIE syndrome in children: case report and review of the literature

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) syndrome is a rare disorder that presents in childhood; however, marked delay in diagnosis is common. We report a case and review the literature describing the typical features that should alert pediatricians to the diagnosis. We also describe a novel management strategy for providing symptomatic relief.

Cysteine metabolism and whole blood glutathione synthesis in septic pediatric patients

OBJECTIVE

To investigate whole body in vivo cysteine kinetics and its relationship to whole blood glutathione (GSH) synthesis rates in septic, critically ill pediatric patients and controls.

DESIGN

Prospective cohort study.

SETTING

Multidisciplinary intensive care unit and pediatric inpatient units at a children's hospital.

PATIENTS

Ten septic pediatric patients and ten controls (children admitted to the hospital for elective surgery).

INTERVENTIONS

Septic patients (age, 31 months to 17 yrs) and controls (age, 24 months to 21 yrs) received a 6-hr primed, constant, intravenous tracer infusion of l-[1-13C]cysteine. Blood samples were obtained to determine isotopic enrichment of plasma cysteine and whole blood [1-13C]cysteinyl-glutathione by gas-chromatography mass spectrometric techniques. The plasma flux and oxidation rate of cysteine and the fractional and absolute synthesis rates of GSH were determined. Septic patients received variable protein and energy intake, as per routine clinical management, and controls were studied in the early postabsorptive state.

MEASUREMENTS AND MAIN RESULTS

Plasma cysteine fluxes were increased in the septic patients when compared with the controls (68.2 +/- 17.5 [sd] vs. 48.7 +/- 8.8 micromol x kg(-1) x hr(-1); p <.01), and the fraction of plasma cysteine flux associated with oxidative disposal was similar among the groups. The absolute rates of GSH synthesis in whole blood were decreased (p <.01) in the septic patients (368 +/- 156 vs. 909 +/- 272 micromol x L(-1) x day(-1)). The concentration of whole blood GSH also was decreased in the septic group (665.4 +/- 194 vs. 1059 +/- 334 microM; p <.01)

CONCLUSIONS

Whole blood glutathione synthesis rates are decreased, by about 60%, in critically ill septic children receiving limited nutritional support. Plasma cysteine fluxes and concentration of cysteine were increased in the septic patients, suggesting a hypermetabolic state with increased protein breakdown. The mechanisms whereby GSH synthesis rates are decreased in these patients are probably multifactorial, presumably involving an inflammatory response in the presence of limited nutritional support. The role of nutritional modulation and the use of cysteine prodrugs in maintaining GSH concentration and synthesis remain to be established.

Nonfixation of an atretic colon predicts Hirschsprung's disease

PURPOSE

After noting the colon to be nonfixed and coiled in the pelvis of a patient with colonic atresia and total colonic Hirschsprung's disease, the authors sought to determine whether this colonic position might be predictive of aganglionosis in the atretic colon.

METHODS

The authors reviewed all cases of colonic atresia treated in their institution over the past 2 decades with regard to colonic orientation and the presence of aganglionosis.

RESULTS

We identified 9 patients with colonic atresia. Two of these patients, as well as one patient with ileal atresia, also had long-segment Hirschsprung's disease. All 3 of these patients had foreshortened nonfixed colons located predominantly in the pelvis. None of the other 6 patients with colonic atresia had this configuration. Reviewing 12 reported cases from other institutions of total colonic aganglionosis associated with atresia, 7 appear to have had a pelvic nonfixed colon; colonic orientation could not be determined from the remaining reports. The diagnosis of Hirschsprung's disease was not established in any case before repair of the atresia, and each patient required a secondary enterostomy.

CONCLUSIONS

An early gestational atresia, occurring before secondary retroperitoneal fixation of the colon at approximately 11 weeks may result in interruption of caudal migration of enteric nerves manifesting as Hirschsprung's disease distal to the atresia. Moreover, the aganglionosis may be predicted by a foreshortened, nonfixed colon coiled in the pelvis. Thus, biopsy of the colon should be performed at initial exploration in all cases of atresia in which the colon is not properly fixated to avoid immediate or delayed anastomosis to an aganglionic colon.

Advances in the management of pediatric constipation

Constipation in children is a common concern. There is no single treatment; many children do not respond and continue to have chronic problems. This lack of response is multifactorial, but it is most likely related to the fact that the exact pathophysiology of constipation in children is not known. Diagnostic criteria (Rome II classification) and algorithms proposed by the North American Society for Pediatric Gastroenterology and Nutrition (NASPGN) for evaluation and treatment of children with constipation were recently published and are summarized here. The effectiveness of new treatments such as dietary interventions, prokinetic agents, biofeedback, and polyethylene-glycol electrolyte (PEG) solutions is discussed in this review.

Cisapride for the treatment of constipation in children: A double-blind study

OBJECTIVE

To determine whether cisapride is effective in the treatment of children with constipation.

STUDY DESIGN

Double-blind, placebo-controlled study in which children with chronic constipation were randomly assigned to treatment with cisapride or placebo for 12 weeks.

RESULTS

Forty children were enrolled, and 36 completed the therapy. Treatment successes occurred in 13 of 17 (76%) subjects in the cisapride group and 8 of 19 (37%) subjects in the placebo group (P <.03). The odds ratio for response after cisapride administration was 8.2 times higher (95% CI 1.3 to 49.4). During cisapride therapy, there was a significant improvement in number of spontaneous bowel movements per week (from 0.9 +/- 0.1 to 4.1 +/- 1.1), and there was a significant decrease in number of fecal soiling episodes per day (1.8 +/- 0.5 to 0.08 +/- 0.4), percent with encopresis (82% vs 23%), number of laxative doses per week (from 10.3 +/- 2.6 to 0.8 +/- 0.6), percent using laxatives (77% to 24%), and total gastrointestinal transit time (from 115.0 +/- 3.7 hours to 77.0 +/- 11.1 hours). With placebo, there were no significant changes in the number of spontaneous bowel movements (from 1.0 +/- 0.8 to 2.2 +/- 0.6), percent with encopresis (74% vs 47%), or total gastrointestinal transit time (from 112.5 +/- 4.9 hours to 95.4 +/- 9.8 hours); but there was a significant decrease in number of fecal soiling episodes per day (from 1.3 +/- 0.4 to 0.4 +/- 0.2) and number of laxative doses used per week (from 11.5 +/- 2.9 to 2.05 +/- 0.7). The final number of spontaneous bowel movements, fecal soiling episodes, laxatives used, or percent patients with encopresis was not different when patients receiving cisapride were compared with those receiving placebo.

CONCLUSION

Cisapride was effective in the treatment of children with constipation.

Constipation in infants and children: evaluation and treatment. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition

BACKGROUND

Constipation, defined as a delay or difficulty in defecation, present for 2 or more weeks, is a common pediatric problem encountered by both primary and specialty medical providers.

METHODS

The Constipation Subcommittee of the Clinical Guidelines Committee of the North American Society for Pediatric Gastroenterology and Nutrition has formulated clinical practice guidelines for the management of pediatric constipation. The Constipation Subcommittee, consisting of two primary care pediatricians, a clinical epidemiologist, and pediatric gastroenterologists, based its recommendations on an integration of a comprehensive and systematic review of the medical literature combined with expert opinion. Consensus was achieved through Nominal Group Technique, a structured quantitative method.

RESULTS

The Subcommittee developed two algorithms to assist with medical management, one for older infants and children and the second for infants less than 1 year of age. The guidelines provide recommendations for management by the primary care provider, including evaluation, initial treatment, follow-up management, and indications for consultation by a specialist. The Constipation Subcommittee also provided recommendations for management by the pediatric gastroenterologist.

CONCLUSIONS

This report, which has been endorsed by the Executive Council of the North American Society for Pediatric Gastroenterology and Nutrition, has been prepared as a general guideline to assist providers of medical care in the evaluation and treatment of constipation in children. It is not intended as a substitute for clinical judgment or as a protocol for the management of all patients with this problem.

Allergic colitis: a mimic of Hirschsprung disease

BACKGROUND

Allergy to cow milk protein is a common cause of gastrointestinal symptoms in infancy. Milk allergy is usually a clinical diagnosis, and thus there have been few reports of the radiographic findings.

OBJECTIVE

To describe the barium enema findings of allergic colitis and differentiate them from Hirschsprung disease. Materials and methods. Four infants (age range 7 days-5 weeks) with constipation underwent barium enema to exclude Hirschsprung disease. Radiographic findings were correlated with the pathologic specimens from suction rectal biopsy.

RESULTS

All enemas revealed irregular narrowing of the rectum and a transition zone. Rectal biopsies in each case demonstrated ganglion cells and evidence of an allergic colitis, with inflammatory infiltrates in the lamina propria. A diagnosis of milk allergy colitis was made and symptoms resolved after removal of milk from the diet.

CONCLUSIONS

Milk allergy is common in infancy. The rectum is a primary target organ, with allergic colitis often diagnosed on clinical grounds alone. However, a child with allergic colitis may be referred to radiology for barium enema, especially if constipation is present. The radiologist should be aware of the unique imaging findings of allergic colitis, so as to avoid confusion with Hirschsprung disease and perhaps an unnecessary rectal biopsy.

Intraduodenal hematoma complicating intestinal biopsy: case reports and review of the literature

We report two cases of postbiopsy duodenal hematoma and review 14 additional cases. Duodenal hematoma predominantly occurs in children and presents with abdominal pain, vomiting, and pancreatitis. Upper gastrointestinal series, abdominal ultrasound, and CT scan are useful in visualizing the hematoma. No comparative studies of the usefulness of these techniques are available, but a CT is indicated if perforation is suspected. The treatment is conservative if no perforation is detected, and resolution of symptoms generally occurs within 2 wk.

Schatzki ring in children and young adults: clinical and radiologic findings

BACKGROUND

The Schatzki ring is a well-known clinical and radiologic entity in adults, but is thought to be rare in childhood. Objective. To review the clinical presentations and radiologic findings of children and young adults with Schatzki rings.

MATERIALS AND METHODS

A retrospective review of all barium swallow examinations done between 1990 and 1996 revealed 20 patients with Schatzki rings.

RESULTS

The most frequent presenting symptoms of these patients were progressive dysphagia with solid food and acute food impaction. Radiographic findings of Schatzki rings were typical in all cases. Twelve patients had endoscopy and all had evidence of esophagitis.

CONCLUSION

Schatzki rings are not rare in childhood. The patients are symptomatic, presenting with either progressive dysphagia with solids or acute food impaction. A thorough evaluation of the distal esophagus should be performed in patients with a suggestive clinical history.

Benefit of uncooked cornstarch in the management of children with dumping syndrome fed exclusively by gastrostomy

OBJECTIVES

Children with dumping syndrome fed exclusively by gastrostomy are difficult to manage because liquid diets are given directly into the antrum. The gastric contents are emptied rapidly into the small intestine, with consequent hyperglycemia followed by a delayed hypoglycemia and multiple, often debilitating, symptoms. Uncooked cornstarch is a complex carbohydrate that provides a slow and continuous glucose source and may delay gastric emptying. The objective of this study was to determine the efficacy of uncooked cornstarch in the treatment of these children.

METHODS

The medical records of eight children with dumping syndrome fed exclusively by gastrostomy were reviewed. Dumping syndrome was diagnosed if there was consistent symptomatology, rapid gastric emptying, and abnormal glucose measurements after a glucose tolerance test. Enough uncooked cornstarch to match hepatic glucose production for 4 h was added to control hypoglycemia, and the feeding formula was modified to control hyperglycemia.

RESULTS

All patients had debilitating symptoms. Weight z-score on admission was -2.31 +/- 0.29. Glucose shifts were controlled in all. There was a significant difference between the maximum (221.3 +/- 19.3 mg/dl vs 121.3 +/- 6.9 mg/dl; p < 0.008) and minimum serum glucose (47 +/- 7.8 mg/dl vs 65.6 +/- 4 mg/dl; p < 0.04) before and after uncooked cornstarch. Weight increased from 11.87 +/- 1.4 kg to 15.10 +/- 2.3 kg (p = 0.06). In seven patients, bolus feedings were successfully administered, and symptoms improved or resolved.

CONCLUSIONS

Uncooked cornstarch controlled the glucose shifts, resolved most of the symptoms, allowed bolus feedings, and enhanced weight gain in these children.

Successful use of a chicken-based diet for the treatment of severely malnourished children with persistent diarrhea: a prospective, randomized study

OBJECTIVE

To evaluate the efficacy of a chicken-based diet for the treatment of persistent diarrhea in severely malnourished children.

STUDY DESIGN

Prospective, randomized, double-blind study that compared a chicken-based diet with elemental (Vivonex) and soy (Nursoy) diets. Hospitalized children with third-degree malnutrition and persistent diarrhea, aged 3 to 36 months, were included. Diets were isocaloric and given nasogastrically at 150 ml/kg per day in progressively increasing concentrations.

RESULTS

Fifty-six children were included (18 received Vivonex, 19 Nursoy, 19 chicken). They had a mean age of 6.4 +/- 4.4 months, a mean weight of 3604 +/- 1232 gm, and a mean weight-for-age percentage of 51.4% +/- 7.2%. Sixty-four percent had associated conditions on admission to the hospital. Forty-one children (73.2%) were successfully treated (13 Vivonex, 13 Nursoy, 15 chicken). There were no differences in diarrheal outcomes, and all groups had significant weight gain. Failure was independent of the diet and was associated with the presence of infection on admission. There was a significantly higher nitrogen balance in the children from the chicken group (358.2 +/- 13 mg/kg per day) than in those receiving Vivonex (226.6 +/- 61) or Nursoy (291-4 +/- 111.6; p < 0.05) groups.

CONCLUSIONS

The chicken-based diet was as effective as Vivonex or Nursoy. It is well tolerated, inexpensive, and widely available and thus represents an effective and inexpensive alternative to the treatment of severely malnourished children with persistent diarrhea.

Hyperhomocysteinemia: detection, risk assessment, and treatment

Homocysteine is formed by the demethylation of methionine in the course of its normal metabolism. Hyperhomocysteinemia is an independent risk factor for vascular disease. It develops most commonly from folate deficiency, genetic abnormalities, and chronic renal failure. Current models favor direct angiotoxicity involving endothelial and vascular smooth muscle cells, and impaired thrombolysis. Folic acid reduces hyperhomocysteinemia and thus provides an opportunity for risk-factor modification.

Calcium dependence of integrity of the actin cytoskeleton of proximal tubule cell microvilli

To better define the role of Ca2+ in pathophysiological alterations of the proximal tubule microvillus actin cytoskeleton, we studied freshly isolated tubules in which intracellular free Ca2+ was equilibrated with highly buffered, precisely defined medium Ca2+ levels using a combination of the metabolic inhibitor, antimycin, and the ionophore, ionomycin, in the presence of glycine, to prevent lethal membrane damage and resulting nonspecific changes. Increases of Ca2+ to > or = 10 microM were sufficient to initiate concurrent actin depolymerization, fragmentation of F-actin into forms requiring high-speed centrifugation for recovery, redistribution of villin to sedimentable fractions, and structural microvillar damage consisting of severe swelling and fragmentation of actin cores. These observations implicate Ca(2+)-dependent, villin-mediated actin cytoskeletal disruption in tubule cell microvillar damage under conditions conceivably present during pathophysiological states. However, despite prior evidence for cytosolic free Ca2+ increases of the same order of magnitude and similar structural microvillar alterations, Ca(2+)- and villin-mediated events did not appear to account for the initial microvillar damage that occurs during ATP depletion induced by antimycin alone or hypoxia.

Treatment of intractable constipation in children: experience with cisapride

To establish whether cisapride is beneficial in children with intractable constipation, an open trial was performed. Chronically constipated children who had failed at least 12 weeks of medical therapy received cisapride at a dose of 0.2 mg/kg/dose TID for 12 weeks. Children with pelvic floor dyssynergia were excluded. Patients were followed prospectively for at least 12 months. Thirty children were initially enrolled, and 27 (14 boys, 13 girls) completed the study. At the end of 12 weeks of cisapride treatment, there was a significant increase in the number of bowel movements per week (1.43 +/- 0.52 to 6.48 +/- 4.16; p < 0.05) and significant decreases in the number of accidents per day (2.86 +/- 2.71 to 0.52 +/- 1.23; p < 0.05) and doses of laxatives used per week (14.33 +/- 5.84 to 3.37 +/- 7.10; p < 0.05). Encopresis disappeared in 65.2% of cases (p < 0.0001) and improved in 26%. Sixty-nine percent of the patients stopped using laxatives (p < 0.001). After 12 weeks 18 patients (66.6%) were asymptomatic, seven (25.9%) showed some improvement in bowel movement frequency and number of accidents, and two (7.4%) showed no improvement. The cisapride was well tolerated. After long-term follow-up (20 +/- 9.8 months), 37% of patients had recovered (asymptomatic and off laxatives and cisapride) and 29.6% were still asymptomatic but were using laxatives or cisapride. There were no differences in baseline characteristics between recovered and nonrecovered patients. We conclude that cisapride is effective in the treatment of some children with intractable constipation without pelvic floor dyssynergia.

Contribution of actin cytoskeletal alterations to ATP depletion and calcium-induced proximal tubule cell injury

The actin cytoskeleton of rabbit proximal tubules was assessed by deoxyribonuclease (DNase) binding, sedimentability of detergent-insoluble actin, laser-scanning confocal microscopy, and ultrastructure during exposure to hypoxia, antimycin, or antimycin plus ionomycin. One-third of total actin was DNase reactive in control cells prior to deliberate depolymerization, and a similar proportion was unsedimentable from detergent lysates during 2.5 h at 100,000 g. Tubules injured by hypoxia or antimycin alone, without glycine, showed Ca(2+)-dependent pathology of the cytoskeleton, consisting of increases in DNase-reactive actin, redistribution of pelletable actin, and loss of microvilli concurrent with lethal membrane damage. In contrast, tubules similarly depleted of ATP and incubated with glycine showed no significant changes of DNase-reactive actin or actin sedimentability for up to 60 min, but, nevertheless, developed substantial loss of basal membrane-associated actin within 15 min and disruption of actin cores and clubbing of microvilli at durations > 30 min. These structural changes that occurred in the presence of glycine were not prevented by limiting Ca2+ availability or pH 6.9. Very rapid and extensive cytoskeletal disruption followed antimycin-plus-ionomycin treatment. In this setting, glycine and pH 6.9 decreased lethal membrane damage but did not ameliorate pathology in the cytoskeleton or microvilli; limiting Ca2+ availability partially protected the cytoskeleton but did not prevent lethal membrane damage. The data suggest that both ATP depletion-dependent but Ca(2+)-independent, as well as Ca(2+)-mediated, processes can disrupt the actin cytoskeleton during acute proximal tubule cell injury; that both types of change occur, despite protection afforded by glycine and reduced pH against lethal membrane damage; and that Ca(2+)-independent processes primarily account for prelethal actin cytoskeletal alterations during simple ATP depletion of proximal tubule cells.

Anorectal function in children after ileoanal pull-through

Mucosal proctectomy and ileoanal pull-through is increasingly used in children requiring total colectomy for ulcerative colitis or familial polyposis. Excellent continence can be achieved with this procedure, and it avoids proctocolectomy and permanent ileostomy. We have evaluated prospectively anorectal function in nine consecutively treated children who underwent ileoanal pull-through. Patients were 8 to 17.5 years of age (median, 11.3 years) at the time of surgery; seven had ulcerative colitis, and two had familial polyposis. Anorectal evaluation was performed before colectomy and ileoanal pull-through, following ileoanal pullthrough, after rectal training, and then at yearly intervals. A biofeedback "rectal training" program was instituted 6 weeks after ileoanal pull-through and a contrast study documenting integrity of the pouch. The program consisted of an initial biofeedback session with the motility unit, followed by daily instillations, through a catheter, of progressively larger volumes of water (from 1 to 6 oz, increasing 1 oz per week) into the ileal pouch. Patients were instructed to retain the water and participate in normal activities after the instillation. This protocol acclimated the patient to sensing distension of the pouch and using the sphincters. The follow-up period ranges from 1 to 4.5 years (median, 2.2 years). All patients are continent by day and night. One patient has nocturnal incontinence with episodes of pouchitis. Stool frequency is three to eight movements per day (median, four), with none at night. Preoperative resting rectal sphincter pressures averaged 74.3 +/- 23.1 mm Hg (mean +/- standard deviation), and a maximum squeeze pressure was 93.9 +/- 25.3 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of neuropeptide Y in opossum internal anal sphincter

The present investigation was undertaken to examine the effects and role of neuropeptide Y (NPY) on the internal anal sphincter (IAS). The studies were performed in alpha-chloralose-anesthetized opossums. Resting pressure in the IAS (IASP) was recorded using low-compliant continuously perfused catheters. The effect of NPY administered close intra-arterially on the resting IASP was examined before and after different neurohumoral antagonists and the neurotoxin tetrodotoxin (TTX). To examine the influence of sympathetic nerves, the ventral roots of lumbar sympathetic nerves were isolated in some experiments and stimulated electrically. The influence of NPY on the IAS relaxation in response to rectoanal reflex mimicked by rectal balloon distension (RD) was also examined. NPY caused dose-dependent rise in the IASP, which was not modified by different neurohumoral antagonists and TTX. The rise in IASP by electrical stimulation of ventral lumbar nerve root (L3) was suppressed but not abolished by phentolamine. However, guanethidine (which depletes both norepinephrine and NPY) caused complete obliteration of this response. The other effect of NPY on the IAS was significant antagonism of IAS relaxation caused by RD. From these results, we conclude that NPY exerts two different actions on the IAS. First, it causes a rise in IASP by its action directly at the IAS smooth muscle. Sympathetic nerve stimulation may cause a rise in IASP by its action directly at the IAS smooth muscle partially through release of NPY. Second, it inhibits IAS relaxation produced by rectoanal reflex. These findings would suggest an important regulatory role of NPY in rectoanal physiology.

Peptide histidine isoleucine and vasoactive intestinal polypeptide cause relaxation of opossum internal anal sphincter via two distinct receptors

The purpose of this investigation was to characterize the nature of peptide histidine isoleucine (PHI) and vasoactive intestinal polypeptide (VIP) receptors, and to examine the role of PHI in internal anal sphincter (IAS) relaxation. The studies were performed on opossums anesthetized with alpha-chloralose. The pressures in the IAS were recorded using continuously perfused catheters. The IAS responses to PHI analogues, PHI-27, PHM-27, PHI-(14-27)-NH2, PHI-(1-13), to VIP, to rectal balloon distention, sacral nerve stimulation, and local intramural stimulation were evaluated before and after PHI-(14-27)-NH2, PHI tachyphylaxis, and the VIP antagonists [4 Cl-D-Phe6, Leu17] VIP (VIP analogue) and (N-Ac-Tyr1, D-Phe2)-GRF(1-29)-NH2 (growth hormone releasing factor analogue). The inhibitory responses by all of the PHI analogues and VIP were not modified by tetrodotoxin. PHI-(14-27)-NH2 and PHI tachyphylaxis caused significant antagonism of the fall in internal anal sphincter pressure by PHI-27 and PHM-27 without modifying the IAS responses to VIP and rectal balloon distention, sacral nerve stimulation, and local intramural stimulation. On the other hand, VIP and growth hormone releasing factor analogues caused significant antagonism of VIP responses without modifying the responses to PHI-27. We conclude that distinct PHI and VIP receptors are present in the IAS smooth muscle and that PHI may not play a significant role in the IAS relaxation via the rectoanal reflex.

Role of vasoactive intestinal polypeptide in the internal anal sphincter relaxation of the opossum

The nature of the inhibitory neurotransmitter responsible for internal anal sphincter (IAS) relaxation in response to rectoanal reflex is not known. The objective of the present investigation was to examine the role of VIP in IAS relaxation in response to the rectoanal reflex in intact opossums with the use of VIP antagonists, [4CI-D-Phe6,Leu17] VIP and (N-AC-Tyr1,D-Phe2)-GRF (1-29)-NH2. Intraluminal pressures from the sphincter were monitored using low-compliance, continuously perfused catheters. VIP and the antagonists were administered close-intraarterially. The responses to VIP, rectoanal reflex, sacral nerve stimulation, and local intramural stimulation were examined before and after the VIP antagonists. The present studies in intact animals show: (a) VIP causes a dose-dependent fall in the IAS pressures by a direct action at the IAS smooth muscle; (b) VIP antagonists selectively and significantly antagonized the inhibitory action of VIP; and (c) VIP antagonists caused significant antagonism of the IAS relaxation caused by rectoanal reflex and the other neural stimuli. The antagonism of the IAS relaxation by the VIP antagonists, depending upon the volume of rectal distension used, ranged from 40% to 62% (P less than 0.05). From these results, we conclude that VIP acts as an inhibitory neurotransmitter for IAS relaxation during the rectoanal reflex.

Pectus carinatum and pectus excavatum: are they the same disease?

Eighty cases of anterior chest wall deformities were reviewed. The group consisted of 47 patients with pectus carinatum and 33 patients with pectus excavatum. This 1.4:1 distribution has not been reported in the literature, where a 1:10 distribution is regularly cited. Important bronchopulmonary changes were found by chest x-rays in both groups. Formerly, alterations in pectus excavatum were attributed to the mechanical effect of the depressed sternum. The presence of the same symptoms and bronchopulmonary radiographic changes in patients with pectus carinatum suggests a primary pulmonary defect in both entities. However, bronchopulmonary changes were more prominent in patients with pectus excavatum than in patients with carinatum, which suggests that mechanical compression enhances the problem. Postoperative radiologic improvement was similar in both groups. The patients underwent a surgical procedure that included a sternal osteotomy and a complete removal of the costal cartilages. All patients survived. There were two recurrences. Considerable postoperative overgrowth of the unresected second costal cartilages was observed, hence our recommendation for routine removal of these structures. The habitus of prominent abdomen and stooped shoulders was not modified by the operation, but important symptomatic improvement and some radiologic improvement were observed in both groups.