Detection of Gastroesophageal Reflux in Children Using Combined Multi-Channel Intraluminal Impedance and pH Measurement: Data From the German Pediatric Impedance Group
Pilic D, Fröhlich T, Nöh F, et al
J Pediatr. 2011;158:650-654
The measurement of pH is the predominant modality used to diagnose gastroesophageal reflux (GER) in children. However, pH monitoring provides only part of the answer with respect to whether a child has reflux episodes. Multichannel intraluminal impedance monitoring can measure acidic and nonacidic reflux episodes using pressure-sensing electrodes along the length of the probe. Although impedance testing is becoming more prominent, head-to-head comparisons with pH monitoring to date have included only small numbers of children.
Methods. This study enrolled children from 2004-2008 at 4 centers in Germany, with the goal of comparing the validity of impedance monitoring with pH monitoring alone in detecting GER in infants and children. They enrolled 700 children who were referred to the 4 centers and could be divided into groups of those with predominantly gastrointestinal symptoms (325 children), patients with respiratory symptoms (329 children), or patients with neurologic syndrome symptoms such as seizure-like episodes (46 children). The catheters used for the studies each contained 7 impedance electrodes and 1 pH monitoring electrode. At least 18 hours of monitoring data were recorded for all children. Parents and patients were asked to record in a log when they experienced symptoms, so that these data could be correlated with monitor findings.
The criteria for a positive pH study were age dependent:
Children > 1 year old: gastric pH ≤ 4 for ≥ 5% of the time; or
Infants < 1 year old: gastric pH ≤ 4 for ≥ 10% of the time.;
The criteria for a positive impedance probe were:
Reflux-related symptoms comprised > 50% of all symptoms; or
The number of episodes is > 70 per 24 hours for > 1 year or > 100 episodes in children < 1 year old.
Findings. The ages of the children ranged from 3 weeks to 16 years, with a median age of 4 years. There were 291 (42%) girls and 409 (58%) boys. Abnormal studies were found in 270 children (38.6%). Among children with abnormal test results, 18% had abnormal pH monitoring results, 45% had only abnormal impedance results, and in 37% both monitoring studies were abnormal. When stratified by symptom, 35% of the children with gastrointestinal symptoms had abnormal test results, 40% of those with pulmonary symptoms had abnormal results, and 50% of the children who presented with neurologic symptoms had abnormal results.
Pilic and coworkers concluded that nonacidic or weakly acidic reflux is often present in patients referred for and tested by impedance probe and pH monitoring. They also concluded that combination monitoring with impedance and pH is superior to pH monitoring alone and suggest that combined testing should be considered the gold standard.
Pilic and coworkers comment that 81% of the children who were positive for GER would have been identified using only impedance testing, whereas 55% of the children who were positive for GER would have been identified using only pH testing. It seems evident that the combination approach is more sensitive, and it appears that it is slowly becoming the norm in the United States. However, these data show the complexity of issues when diagnosing. To begin, children presented with 3 different symptom groupings, and the tests performed differently in each of these groups of children. In addition, the number of reflux episodes and the symptoms used for the cut-offs are in some ways set arbitrarily, so that even the classification of positive or negative tests requires clinical correlation.
Medscape Pediatrics © 2011 WebMD, LLC
Cite this: William T. Basco. Diagnosing GER in Children - Medscape - May 20, 2011.