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Eur Respir J . 2007; 30: 48–55. IV. Infection, Inflammation & Other Topics IV.1. Infection, Inflammation & Other Topics – Gastroesophageal reflux IV.1.1 The clinical manifestations of GER in children M. Ghezzi, O. Sacco, D. Girosi, N. Ullmann, G.A. Rossi. Pulmonary and Allergy Units, Giannina Gaslini Institute, Genoa, Italy Gastroesophageal reflux (GER) is a physiological process occurring with different frequency and characteristics in healthy infants, children and adults, most episodes being brief and asymptomatic. In contrast, GER disease (GERD) occurs when this normal event results in the occurrence of symptoms/signs or complications [1]. The most common clinical manifestations of GERD caused by gastric contents reflux include “typical symptoms”, related to the upper portion of the gastroenteral tract, and “atypical supraoesophageal” respiratory symptoms, affecting the respiratory tract [1,2]. Typical symptoms include regurgitation, vomiting, abdominal or retrosternal pain, dysphagia and hematemesis. Upper respiratory tract symptoms comprise, chronic sinusitis, laryngitis, hoarseness, vocal cord nodules, granulomas and ulcers, feeding- related choking, pharyngonasal reflux and/or cyanosis, recurrent croup/spasmodic croup, stridor, “pseudolaryngomalacia”, subglottic stenosis, posterior glottic erythema and oedema [1–3]. Involvement of the lower respiratory tract may be associated with apnoea, ALTE, recurrent aspiration pneumonia, persistent and/or nocturnal cough, wheezy bronchitis and “difficult-to-treat” asthma. Less commonly recognized presentation of GERD include Sandifer’s syndrome and unexplained “feeding problems”. One difficult task in managing reflux is to determine to what extent it is physiologic or constitutes a pathological condition. Indeed, some nocturnal aspirations of gastric refluxate occur periodically also in normal healthy subjects, but clearly may result in recurrent and/or progressive lung disease in others. An association between GER and respiratory symptoms has been well documented, but a causal relationship between GER and respiratory symptoms is difficult to determine in an individual child since there are no gold- standard diagnostic tests [4]. Currently, the diagnosis of aspiration is made clinically with some supporting diagnostic evaluations. During the past 2 decades, GER has been recognized more frequently be- cause of an increased awareness of the condition and also because of the more sophisticated diagnostic techniques that have been devel- oped for both identifying and quantifying the disorder and to relate acid and weakly acid GER events with respiratory symptoms [5]. References [1] Rudolph CD, Mazur LJ, Liptak GS, Baker RD, Boyle JT, Coletti RB, Gerson WT, Werlin SL. Guidelines for evaluation and treatment of gastroesophageal reflux in infants and children. Recommendations of the North American Society for Pediatric Gastroenterology and Nutrition. J Pediatr Gastroenterol Nutr 2001; 32(Suppl 2): S1–31. [2] Vandenplas Y, Hassall E. Mechanisms of gastroesophageal reflux and gastroesophageal reflux disease. J Pediatr Gastroenterol Nutr 2002; 35: 119–36. [3] Sacco O, Mattioli G, Girosi D, Battistini E, Jasonni V, Rossi GA. Gastroesophageal reflux and its clinical manifestation at gastro-enteric and respiratory levels in childhood: physiology, signs and symptoms, diagnosis and treatment. Expert Review of Respiratory Medicine 2007; 1: 391–401. [4] Vakil N, Van Zanten SV, Kahrilas P, Dent J, Jones R; Global Con- sensus Group. The Montreal definition and classification of gastroe- sophageal reflux disease: a global evidence based consensus. Am J Gastroenterol 2006; 101: 1900–1920. [5] Ghezzi M, Silvestri M, Guida E, Pistorio A, Sacco O, Mattioli G, Jasonni V, Rossi GA. Acid and weakly acid gastroesophageal refluxes and type of respiratory symptoms in children. Respir Med 2011; 105: 972-8. IV.1.2 Why monitor the pH and/or impedance in the esophagus? Y. Vandenplas. Universitair Kinderziekenhuis Brussel, Brussels, Belgium Gastro-esophageal reflux (GER) is the involuntary passage of gastric contents into the esophagus. GER is a physiological event occurring in every individual several times during the day, particularly after meals. Most reflux episodes are asymptomatic, brief and limited to the distal esophagus. GER may be a primary gastro-intestinal motility disorder, but may be secondary to other conditions, such as cow’s milk protein allergy. According to recent literature, cow’s milk protein allergy is a frequent cause of GER during infancy [1,2]. This review will discuss both the advantages and disadvantages of pH and impedance techniques to measure GER. The idea that pH measurement in the esophagus may be of clinical importance started with the observation that acid perfusion- induced heartburn coincides with a fall of intraesophageal pH below 4.0 [3]. This simple historical observation points out one of the major pitfalls of pH monitoring: the cut-off of “pH 4.0” was defined to separate reflux causing heartburn from reflux causing no heartburn. However, “heartburn” is only one of the indications