Diagnostic tests for childhood Helicobacter pylori infection: invasive, noninvasive or both?

Helicobacter pylori infection is still one of the most common infections worldwide. It is almost always acquired in childhood, becomes chronic unless treated and may be the cause of duodenal ulcer or gastric cancer later in life. Improved hygienic conditions in the western world in recent decades have decreased the prevalence of the infection in the younger population. This is not the case in developing countries where the majority of children continue to acquire H. pylori at an early age. Early acquisition is considered one risk factor for development of gastric cancer in adulthood (1). There are several tests to diagnose H. pylori infection. Tests may be invasive, requiring upper gastrointestinal endoscopy and gastric biopsies, or noninvasive. Tests of infection have advantages and disadvantages and different indications for use. No single test is a fully reliable method for detection of H. pylori in all instances. Even histology is not positive in 100% of infected children. In symptomatic children, the diagnosis of H. pyloriassociated disease should always be performed with endoscopy, as clearly stated by task force reports from the European Task Force for H. pylori Infection in Children (2) and NASPGN (3). Noninvasive tests to screen children with abdominal pain for H. pylori are not recommended, as endoscopy provides more complete information on the entire differential diagnosis. Endoscopy allows the identification of causes of pain such as esophagitis and peptic ulceration and is the only method by which biopsies can be obtained to diagnose gastritis (including H. pylori), eosinophilic gastroduodenitis and celiac disease. Gastric biopsies can be cultured to grow H. pylori and test for antibiotic susceptibility, which may be important in choosing treatment (4). Clearly, endoscopy should be justified by symptoms indicating organic disease. The use of endoscopy might decrease the over use of noninvasive tests and the use of anti-H. pylori therapy in children with nonspecific symptoms, particularly in populations with a high prevalence of H. pylori where the infection may not play any role in causing symptoms. Compliance with eradication therapy may be better after endoscopy, and better compliance may result in a lower rate of treatment failures and therefore in a reduced risk of therapy-induced antibiotic resistance of the surviving bacteria. Noninvasive tests (serology, C-urea breath test (UBT), and stool antigen determination) have the advantages of low cost, the possibility of repeat testing and minimal patient discomfort. Their use for screening patients before endoscopy or before treatment to implement the so called test-and-treat strategy, as suggested for young adults (5), is discouraged in children because in the pediatric age there is no specific clinical picture indicating a need to screen children with dyspeptic symptoms for H. pylori infection (2). An eradication treatment in a child with abdominal pain and a positive noninvasive test is not recommended because diagnoses other than H. pyloriassociated peptic ulcer are more likely (6). Moreover, noninvasive tests give no information on the mucosal lesion, its distribution or its severity. Noninvasive tests for H. pylori infection are helpful in epidemiologic studies of incidence, mode of transmission and reinfection and spontaneous clearance to develop preventitive measures in early life. In clinical practice noninvasive tests are useful in monitoring treatment efficacy. Non-invasive tests should be easy to perform, inexpensive and have a high diagnostic accuracy. Serology and the C-urea breath test (UBT) do not fulfill all of these requirements. Serology, although not expensive, is not totally noninvasive, and venipuncture can cause pain and fear in children. Serology cannot distinguish between current and past infection. Sensitivity of most commercial kits is lower in children than in adults as children may respond to some H. pylori antigens only. Antibody titers may become Address correspondence and reprint requests to Prof. Giuseppina Oderda, Clinica Pediatrica, Universita del Piemonte Orientale, Via Solaroli 17, 281000 Novara, Italy (e-mail: oderda@med.unipmn.it). Journal of Pediatric Gastroenterology and Nutrition 39:482–484 November 2004 Lippincott Williams & Wilkins, Philadelphia