eMedicine Specialties > Pediatrics: General Medicine > Gastroenterology
Helicobacter Pylori Infection
Updated: Oct 30, 2009
Introduction
Background
Helicobacter pylori (Hp) is a gram-negative bacillus responsible for one of the most common infections found in humans worldwide.1 Warren and Marshall first cultured and identified the organism as Campylobacter pylori in 1982. By 1989, it was renamed and recognized to be associated closely with antral gastritis (gastric and duodenal ulcers in adults and children). In recognition of this crucial discovery, they were awarded the Nobel Prize for medicine in 2005. By the early-to-mid 1990s, further evidence supported a link between chronic gastritis of H pylori infection in adults and malignancy, specifically gastric lymphoma and adenocarcinoma.
Objectives of current and future research on H pylori include improving the understanding of the immunopathogenesis of gastric disease associated with H pylori infection, elucidating the modes of transmission, and improving the safety and efficacy of vaccines to prevent H pylori infection.
Pathophysiology
H pylori organisms are spiral-shaped gram-negative bacteria that are highly motile because of multiple unipolar flagella. They are microaerophilic and potent producers of the enzyme urease. H pylori inhabits the mucus adjacent to the gastric mucosa.
Important adaptive features that enhance survival of the organism in an acidic environment include its shape and motility, its reduced oxygen requirement, its adhesion molecules that are trophic to certain gastric cells, and its urease production. Bacterial urease converts urea to ammonium and bicarbonate, neutralizing gastric acid and providing protection in the hostile, highly acidic gastric environment. Some of the lipopolysaccharide of the organism mimics the Lewis blood group antigens in structure. This molecular mimicry also helps in the continued existence of H pylori in the unfavorable gastric environment.2
H pylori produces suspected disease-inducing factors, including urease, vacuolating cytotoxin, catalase, and lipopolysaccharide (LPS). Urease, a potent antigen, induces increased immunoglobulin G and immunoglobulin A production. Expression of vacuolating cytotoxin, which induces inflammatory cytokines, may be associated with more pronounced inflammation and increased propensity to cause disease. Catalase helps H pylori survive in the host by preventing the formation of reactive oxygen metabolites from hydrogen peroxide. The LPS outer membrane of H pylori is a less potent inducer of the host complement cascade.
Cytotoxin-associated antigen (CagA) is probably the most important virulence factor in H pylori. Translocating the CagA protein into the gastric epithelial cells causes rearrangement of the host cytoskeleton and alters cell signaling and perturbs cell cycle control. Furthermore, CagA-positive strains are known to induce the expression of a DNA-editing enzyme, which leads to accumulation of mutations in the tumor suppressor p53.3
Two Japanese groups demonstrated the important role of Peyer patches (PPs) in the development of H pylori– induced gastritis. Kiriya et al showed that Helicobacter– induced gastritis was impaired in PP-null mice.4 Another study by Nagai et al also supports the notion that PPs are inductive sites for generating CD4 T-cell responses in the gastric mucosa.5
H pylori colonizes the stomach, induces inflammatory cytokines, and causes gastric inflammation. Individuals with H pylori– associated antral-predominant gastritis with increased gastric acid production are prone to peptic ulcer disease (PUD).6 In contrast, H pylori pan-predominant gastritis or corpus-predominant gastritis with decreased gastric acid production are more prone to developing gastric atrophy (intestinal metaplasia and gastric adenocarcinoma).
H pylori has been associated with iron-deficiency anemia. The 2 main hypotheses that potentially explain this relation are (1) sequestration of iron due to antral H pylori infection and (2) decreased non-heme iron absorption caused by hypochlorhydria.
H pylori infection and its association with gastric malignancy have been well described in several epidemiologic studies.7 However, the course of progression from inflammation to cancer remains unclear. One model describes the stepwise progression of H pylori infection to hypochlorhydria, chronic gastritis, atrophic gastritis, intestinal metaplasia, and gastric cancer. Increased production of the cytokine interleukin 1β has been linked to an increased risk of hypochlorhydria and gastric cancer in infected subjects.
Frequency
United States
Overall, approximately one-third of the population is infected with H pylori, increasing with age. See Age.
International
In general, the prevalence is high in developing countries and the infection is acquired at a young age. The prevalence of H pylori infection is not only lower in industrialized countries than in developing countries, but the incidence of H pylori infection, gastric cancer, and ulcer disease are also declining. Worldwide, more than 1 billion people are estimated to be infected with H pylori. See Age.
Mortality/Morbidity
Most children infected with H pylori are asymptomatic. Antral gastritis is the most common manifestation in children. Duodenal and gastric ulcers may be associated with H pylori gastritis in adults but is uncommon in children. The risk of gastric cancers, including non-Hodgkin lymphoma (eg, mucosa-associated lymphoid tissue [MALT]) and adenocarcinoma, is increased in adults.
The relationship between H pylori gastritis and recurrent abdominal pain (RAP) is controversial. The incidence of H pylori gastritis in patients with RAP is not significantly higher than the incidence of H pylori infection in the general population. Although some studies demonstrate an improvement in symptoms in children with RAP and H pylori gastritis after eradication therapy for H pylori, data from a recent double-blind controlled trial did not confirm that finding.8 The heterogenicity of their definition of RAP and the varying study methodologies may have led to different results and conclusions. The medical positional statement of the North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition regarding H pylori infection in children also found no convincing data to support the routine testing of children with RAP for H pylori.9
Some studies suggest that H pylori protects human subjects from developing gastroesophageal reflux disease, whereas others postulate a causative association between them. A recent retrospective study revealed a significantly higher prevalence of reflux esophagitis in children with H pylori infection.10 H pylori infection has also been associated with extraintestinal manifestations, such as short stature, immune thrombocytopenic purpura, and migraine with varying level of evidence.
Race
The prevalence is increased in black, Hispanic, Asian, and Native American populations.
Sex
Infection rates are similar in males and females.
Age
In developed countries, less than 10% of children younger than 12 years are infected; however, seropositivity increases with age at a rate of 0.3-1% per year. Studies of seropositivity in adults in developed countries revealed prevalences of 30-50%. In the United States, the estimated prevalence is 20% for people younger than 30 years and 50% for those older than 60 years. In developing countries, the prevalence rates are much higher. The serological prevalence rates of H pylori were 15% and 46% in Gambian children younger than 20 months and age 40-60 months, respectively.11
Clinical
History
When obtaining the history of patients with Helicobacter pylori infection, one should pay particular attention to anorexia and weight loss, pallor or laboratory findings of anemia, vomiting, abdominal pain associated with meals or nighttime, and any description of GI bleeding. A history of such findings raises the concern of peptic ulcer disease (PUD).
In the child in whom H pylori infection is suspected, the history should include the following:
- Character, location, frequency, duration, severity, and exacerbating and alleviating factors of abdominal pain
- Bowel habits and description of stool
- Appetite, diet, and weight changes
- Halitosis, vomiting, and description of gastric material
- Family history of ulcer disease or GI conditions (eg, Crohn disease)
- Medications (prescribed and over the counter)
- Previous diagnostic testing and specific therapy in the GI tract
Physical
Physical examination of an asymptomatic child with H pylori infection usually yields unremarkable findings. In the child with chronic gastritis, duodenitis, and PUD, important examination findings include epigastric tenderness or findings consistent with GI bleeding (eg, guaiac-positive stools, tachycardia, pallor).
Children with PUD leading to complications (eg, severe blood loss in the GI tract, perforation, obstruction) can appear ill and have evidence of hemodynamic instability or signs of an acute abdomen. Children with long-standing PUD from H pylori may become profoundly anemic from undetected chronic bleeding and have no complaints.
- Assess the general appearance of the child.
- Assess perfusion, with attention to mental status, heart rate, pulses, and capillary refill.
- Assess the skin and conjunctivae for pallor.
- Perform a thorough heart and lung examination.
- Inspect, auscultate, and palpate the abdomen.
- Perform rectal examination and a stool guaiac test.
Causes
Epidemiologic studies have addressed various factors, such as bacterial, host, genetic, and environmental factors, to determine the causative links to H pylori infection. Data support person-to-person spread of infection, possibly related to dental plaque, but knowledge of reservoirs and transmission modes is incomplete.
Causes of H pylori infection include the following:
- Person-to-person transmission of H pylori infection is noted.
- Infection clusters are noted, particularly in families with infected children. The possible routes are fecal-oral, oral-oral and gastro-oral. Mother-to-child transmission was strongly suggested in a study of DNA analysis of the H pylori strains.12 The data showed identical H pylori strains between mothers and their toddler-aged children. Moreover, the mother’s symptoms of nausea and vomiting and the use of pacifier were significantly associated with the risk of H pylori infection in children.
- Crowding and poor personal hygiene may also play a role.
- An increased prevalence of H pylori infection is noted in developing countries. This may reflect the combined effects of poor living conditions, poor hygiene, and crowding.
- In the United States, socioeconomic level is strongly and inversely related to the prevalence of H pylori infection, a finding that may also reflect the same factors as those noted in developing countries.
- Bacterial factors may play a role in the clinical manifestations of H pylori infection.
- Patients with H pylori infection have 2 basic phenotypes based on the presence or absence of a vacuolating cytotoxin.
- People with cytotoxin-positive infection have endoscopically proven inflammation that is more pronounced than those of patients with cytotoxin-negative H pylori infection.
- Host factors may play a role in the acquisition of H pylori infection.
- Children may be better able to clear acute infection than adults (2% per year).
- Hypochlorhydria may be necessary to allow H pylori to colonize in the stomach.
- Normal gastric epithelial cells that line the stomach are necessary for H pylori persistence. H pylori is not found in atrophied metaplastic epithelium.
- Genetic factors may play a role in H pylori infection.
- Concordance for PUD is higher in monozygotic than in dizygotic twins.
- Data from only one study links an increased prevalence of H pylori infection with a community's water supply.13
- Other possible ways of transmission include vector-borne transmission.14
- H pylori isolates are found more often in personnel who work in the endoscopy suite than in the general population.
More on Helicobacter Pylori Infection |
Overview: Helicobacter Pylori Infection |
| Differential Diagnoses & Workup: Helicobacter Pylori Infection |
| Treatment & Medication: Helicobacter Pylori Infection |
| Follow-up: Helicobacter Pylori Infection |
| Multimedia: Helicobacter Pylori Infection |
| References |
| Next Page » |
References
Blecker U. Helicobacter pylori-associated gastroduodenal disease in childhood. South Med J. Jun 1997;90(6):570-6; quiz 577. [Medline].
Appelmelk BJ, Simoons-Smit I, Negrini R, et al. Potential role of molecular mimicry between Helicobacter pylori lipopolysaccharide and host Lewis blood group antigens in autoimmunity. Infect Immun. Jun 1996;64(6):2031-40. [Medline].
Figueiredo C, Machado JC, Yamaoka Y. Pathogenesis of Helicobacter pylori Infection. Helicobacter. 2005;10 Suppl 1:14-20. [Medline].
Kiriya K, Watanabe N, Nishio A, et al. Essential role of Peyer's patches in the development of Helicobacter-induced gastritis. Int Immunol. Apr 2007;19(4):435-46. [Medline].
Nagai S, Mimuro H, Yamada T, et al. Role of Peyer's patches in the induction of Helicobacter pylori-induced gastritis. Proc Natl Acad Sci U S A. May 22 2007;104(21):8971-6. [Medline].
Baysoy G, Ertem D, Ademoglu E, et al. Gastric histopathology, iron status and iron deficiency anemia in children with Helicobacter pylori infection. J Pediatr Gastroenterol Nutr. Feb 2004;38(2):146-51. [Medline].
Williams MP, Pounder RE. Helicobacter pylori: from the benign to the malignant. Am J Gastroenterol. Nov 1999;94(11 Suppl):S11-6. [Medline].
Ashorn M, Rago T, Kokkonen J, et al. Symptomatic response to Helicobacter pylori eradication in children with recurrent abdominal pain: double blind randomized placebo-controlled trial. J Clin Gastroenterol. Sep 2004;38(8):646-50. [Medline].
[Guideline] Gold BD, Colletti RB, Abbott M, et al. Helicobacter pylori infection in children: recommendations for diagnosis and treatment. J Pediatr Gastroenterol Nutr. Nov 2000;31(5):490-7. [Medline].
Moon A, Solomon A, Beneck D, Cunningham-Rundles S. Positive association between Helicobacter pylori and gastroesophageal reflux disease in children. J Pediatr Gastroenterol Nutr. Sep 2009;49(3):283-8. [Medline].
Sullivan PB, Thomas JE, Wight DG, et al. Helicobacter pylori in Gambian children with chronic diarrhoea and malnutrition. Arch Dis Child. Feb 1990;65(2):189-91. [Medline].
Konno M, Fujii N, Yokota S, et al. Five-year follow-up study of mother-to-child transmission of Helicobacter pylori infection detected by a random amplified polymorphic DNA fingerprinting method. J Clin Microbiol. 43(5):2246-50. [Medline]. [Full Text].
Ahmed KS, Khan AA, Ahmed I, et al. Impact of household hygiene and water source on the prevalence and transmission of Helicobacter pylori: a South Indian perspective. Singapore Med J. Jun 2007;48(6):543-9. [Medline].
Grubel P, Huang L, Masubuchi N, Stutzenberger FJ, Cave DR. Detection of Helicobacter pylori DNA in houseflies (Musca domestica) on three continents. Lancet. Sep 5 1998;352(9130):788-9. [Medline].
Bourke B, Ceponis P, Chiba N, et al. Canadian Helicobacter Study Group Consensus Conference: Update on the approach to Helicobacter pylori infection in children and adolescents--an evidence-based evaluation. Can J Gastroenterol. Jul 2005;19(7):399-408. [Medline].
Booka M, Okuda M, Shin K, et al. Polymerase chain reaction--restriction fragment length polymorphism analysis of clarithromycin-resistant Helicobacter pylori infection in children using stool sample. Helicobacter. Jun 2005;10(3):205-13. [Medline].
Bonamico M, Strappini PM, Bonci E, et al. Evaluation of stool antigen test, PCR on ORAL samples and serology for the noninvasive detection of Helicobacter pylori infection in children. Helicobacter. Feb 2004;9(1):69-76. [Medline].
Bujanover Y, Konikoff F, Baratz M. Nodular gastritis and Helicobacter pylori. J Pediatr Gastroenterol Nutr. Jul 1990;11(1):41-4. [Medline].
Bhasin DK, Sharma BC, Ray P, et al. Comparison of seven and fourteen days of lansoprazole, clarithromycin, andamoxicillin therapy for eradication of Helicobacter pylori: a report from India. . Helicobacter. Jun 2000;5(2):84-7.
Khurana R, Fischbach L, Chiba N, et al. Meta-analysis: Helicobacter pylori eradication treatment efficacy in children. Aliment Pharmacol Ther. Mar 1 2007;25(5):523-36. [Medline].
Chan KL, Zhou H, Ng DK, Tam PK. A prospective study of a one-week nonbismuth quadruple therapy for childhood Helicobacter pylori infection. J Pediatr Surg. Jul 2001;36(7):1008-11. [Medline].
Bahremand S, Nematollahi LR, Fourutan H, et al. Evaluation of triple and quadruple Helicobacter pylori eradication therapies in Iranian children: a randomized clinical trial. Eur J Gastroenterol Hepatol. May 2006;18(5):511-4. [Medline].
Francavilla R, Lionetti E, Castellaneta SP, et al. Improved efficacy of 10-Day sequential treatment for Helicobacter pylori eradication in children: a randomized trial. Gastroenterology. Nov 2005;129(5):1414-9. [Medline].
Lionetti E, Miniello VL, Castellaneta SP, et al. Lactobacillus reuteri therapy to reduce side-effects during anti-Helicobacter pylori treatment in children: a randomized placebo controlled trial. Aliment Pharmacol Ther. Nov 15 2006;24(10):1461-8. [Medline].
Goldman CG, Barrado DA, Balcarce N, et al. Effect of a probiotic food as an adjuvant to triple therapy for eradication of Helicobacter pylori infection in children. Nutrition. Oct 2006;22(10):984-8. [Medline].
Zojaji H, Talaie R, Mirsattari D, et al. The efficacy of Helicobacter pylori eradication regimen with and without vitamin C supplementation. Dig Liver Dis. Sep 2009;41(9):644-7. [Medline].
Ables AZ, Simon I, Melton ER. Update on Helicobacter pylori treatment. Am Fam Physician. Feb 1 2007;75(3):351-8. [Medline].
Blecker U, Hauser B, Lanciers S, et al. The prevalence of Helicobacter pylori-positive serology in asymptomatic children. J Pediatr Gastroenterol Nutr. Apr 1993;16(3):252-6. [Medline].
Cammarota G, Cianci R, Cannizzaro O, et al. High-dose versus low-dose clarithromycin in 1-week triple therapy, including rabeprazole and levofloxacin, for Helicobacter pylori eradication. J Clin Gastroenterol. Feb 2004;38(2):110-4. [Medline].
Chan KL, Zhou H, Ng DK, Tam PK. A prospective study of a one-week nonbismuth quadruple therapy for childhood Helicobacter pylori infection. J Pediatr Surg. Jul 2001;36(7):1008-11. [Medline].
Chong SK, Lou Q, Asnicar MA, et al. Helicobacter pylori infection in recurrent abdominal pain in childhood: comparison of diagnostic tests and therapy. Pediatrics. Aug 1995;96(2 Pt 1):211-5. [Medline].
Czinn SJ. Helicobacter pylori infection: detection, investigation, and management. J Pediatr. Mar 2005;146(3 Suppl):S21-6. [Medline].
Drumm B. Helicobacter pylori in the pediatric patient. Gastroenterol Clin North Am. Mar 1993;22(1):169-82. [Medline].
El-Omar EM, Oien K, Murray LS, et al. Increased prevalence of precancerous changes in relatives of gastric cancer patients: critical role of H. pylori. Gastroenterology. Jan 2000;118(1):22-30. [Medline].
Ernst PB, Gold BD. Helicobacter pylori in childhood: new insights into the immunopathogenesis of gastric disease and implications for managing infection in children. J Pediatr Gastroenterol Nutr. May 1999;28(5):462-73. [Medline].
Farrell MK. Dr. Apley meets Helicobacter pylori. J Pediatr Gastroenterol Nutr. Feb 1993;16(2):118-9. [Medline].
Feydt-Schmidt A, Kindermann A, Konstantopoulos N, et al. Reinfection rate in children after successful Helicobacter pylori eradication. Eur J Gastroenterol Hepatol. Oct 2002;14(10):1119-23. [Medline].
Fiedorek SC, Casteel HB, Pumphrey CL, et al. The role of Helicobacter pylori in recurrent, functional abdominal pain in children. Am J Gastroenterol. Mar 1992;87(3):347-9. [Medline].
Gillen D, el-Omar EM, Wirz AA, et al. The acid response to gastrin distinguishes duodenal ulcer patients from Helicobacter pylori-infected healthy subjects. Gastroenterology. Jan 1998;114(1):50-7. [Medline].
Glassman MS. Helicobacter pylori infection in children. A clinical overview. Clin Pediatr (Phila). Aug 1992;31(8):481-7. [Medline].
Gormally S, Drumm B. Helicobacter pylori and gastrointestinal symptoms. Arch Dis Child. Mar 1994;70(3):165-6. [Medline].
Graham DY, Rakel RE, Fendrick AM, et al. Practical advice on eradicating Helicobacter pylori infection. Postgrad Med. Mar 1999;105(3):137-40, 145-8. [Medline].
Graham DY, Shiotani A. The time to eradicate gastric cancer is now. Gut. Jun 2005;54(6):735-8. [Medline].
Guo CY, Wu YB, Liu HL, et al. Clinical evaluation of four one-week triple therapy regimens in eradicating Helicobacter pylori infection. World J Gastroenterol. Mar 1 2004;10(5):747-9. [Medline].
Hardikar W, Feekery C, Smith A, et al. Helicobacter pylori and recurrent abdominal pain in children. J Pediatr Gastroenterol Nutr. Feb 1996;22(2):148-52. [Medline].
Heldenberg D, Wagner Y, Heldenberg E, et al. The role of Helicobacter pylori in children with recurrent abdominal pain. Am J Gastroenterol. Jun 1995;90(6):906-9. [Medline].
Horvitz G, Gold BD. Gastroduodenal diseases of childhood. Curr Opin Gastroenterol. Nov 2006;22(6):632-40. [Medline].
Huang FC, Chang MH, Hsu HY, et al. Long-term follow-up of duodenal ulcer in children before and after eradication of Helicobacter pylori. J Pediatr Gastroenterol Nutr. Jan 1999;28(1):76-80. [Medline].
Huebner ES, Surawicz CM. Probiotics in the prevention and treatment of gastrointestinal infections. Gastroenterol Clin North Am. June 2006;35:355-65. [Medline].
Israel DM, Hassall E. Treatment and long-term follow-up of Helicobacter pylori-associated duodenal ulcer disease in children. J Pediatr. Jul 1993;123(1):53-8. [Medline].
Judd RH. Helicobacter pylori, gastritis, and ulcers in pediatrics. Adv Pediatr. 1992;39:283-306. [Medline].
Kimia A, Zahavi I, Shapiro R, et al. The role of Helicobacter pylori and gastritis in children with recurrent abdominalpain. Isr Med Assoc J. Feb 2000;2(2):126-8. [Medline].
Kiyota K, Habu Y, Sugano Y, et al. Comparison of 1-week and 2-week triple therapy with omeprazole, amoxicillin,and clarithromycin in peptic ulcer patients with Helicobacter pylori infection: results of a randomized controlled trial. J Gastroenterol. 1999;34 Suppl 11:76-9. [Medline].
Knippig C, Arand F, Leodolter A, et al. Prevalence of H. pylori-infection in family members of H. pylori positive and its influence on the reinfection rate after successful eradication therapy: a two-year follow-up. Z Gastroenterol. Jun 2002;40(6):383-7. [Medline].
Koivisto TT, Rautelin HI, Voutilainen ME, et al. First-line eradication therapy for Helicobacter pylori in primary health care based on antibiotic resistance: results of three eradication regimens. Aliment Pharmacol Ther. Mar 15 2005;21(6):773-82. [Medline].
Logan RP, Gummett PA, Schaufelberger HD, et al. Eradication of Helicobacter pylori with clarithromycin and omeprazole. Gut. Mar 1994;35(3):323-6. [Medline].
Long SS, Pickering LK, Prober CG, eds. Helicobacter pylori. In: Principles and Practice of Pediatric Infectious Diseases. New York, NY: Churchill Livingstone; 1997:1029-33.
Moshkowitz M, Reif S, Brill S, et al. One-week triple therapy with omeprazole, clarithromycin, and nitroimidazole for Helicobacter pylori infection in children and adolescents. Pediatrics. Jul 1998;102(1):e14. [Medline]. [Full Text].
Nista EC, Candelli M, Cremonini F, et al. Levofloxacin-based triple therapy vs. quadruple therapy in second-line Helicobacter pylori treatment: a randomized trial. Aliment Pharmacol Ther. Sep 15 2003;18(6):627-33. [Medline].
Parsonnet J. Helicobacter pylori. Infect Dis Clin North Am. Mar 1998;12(1):185-97. [Medline].
Parsonnet J, Hansen S, Rodriguez L, et al. Helicobacter pylori infection and gastric lymphoma. N Engl J Med. May 5 1994;330(18):1267-71. [Medline]. [Full Text].
Siberry GK, Iannone R, eds. Formulary: drug doses. In: The Harriet Lane Handbook. 15th ed. St Louis, MO: Mosby; 2000:622, 630, 645-6, 674-5, 772-3, 795, 837.
Helicobacter pylori. In: Feigin RD, Cherry JD, Fletcher J, eds. Textbook of Pediatric Infectious Diseases. 1998. Philadelphia, PA: WB Saunders; 1488-94.
Vinette KM, Gibney KM, Proujansky R, Fawcett PT. Comparison of PCR and clinical laboratory tests for diagnosing H. pylori infection in pediatric patients. BMC Microbiol. Jan 27 2004;4:5. [Medline]. [Full Text].
Wewer V, Andersen LP, Paerregaard A, et al. Treatment of Helicobacter pylori in children with recurrent abdominal pain. Helicobacter. Sep 2001;6(3):244-8. [Medline].
Windle HJ, Kelleher D, Crabtree JE. Childhood Helicobacter pylori infection and growth impairment in developing countries: a vicious cycle?. Pediatrics. Mar 2007;119(3):e754-9. [Medline].
Further Reading
Keywords
infection, Hp, Hp infection, antral gastritis, type B gastritis, autoimmune gastritis, type A gastritis, peptic ulcer disease, PUD, , recurrent abdominal pain, RAP, anorexia, Crohn disease




Overview: Helicobacter Pylori Infection