Can Helicobacter pylori (H. pylori) cause diarrhea?

H. pylori and Diarrhea: Clinical Evidence and Management

H. pylori infection is not directly associated with diarrhea as a primary symptom, and there is no strong evidence supporting H. pylori as a causative agent for diarrhea in clinical practice. 1

Relationship Between H. pylori and Gastrointestinal Symptoms

• H. pylori is primarily associated with gastritis, peptic ulcer disease, gastric cancer, and MALT lymphoma, but not with diarrhea as a primary manifestation 1
• The infection typically causes chronic gastritis and is linked to upper gastrointestinal symptoms rather than lower gastrointestinal symptoms like diarrhea 2
• H. pylori colonizes the gastric mucosa and primarily affects the stomach and proximal duodenum, not the intestines where diarrheal processes typically originate 3

Clinical Manifestations of H. pylori Infection

• The main clinical manifestations of H. pylori infection include:

  • Chronic gastritis 1, 2
  • Peptic ulcer disease (gastric and duodenal) 1
  • Gastric MALT lymphoma 1
  • Gastric cancer 1, 2
  • Functional dyspepsia (in some patients) 1

• H. pylori eradication is recommended for these conditions but not specifically for diarrhea 1, 4

Potential Indirect Mechanisms

While H. pylori does not directly cause diarrhea, there are several indirect mechanisms that could potentially link H. pylori infection with altered bowel habits:

• H. pylori infection can alter gastric acid secretion (either increase or decrease depending on the distribution of gastritis), which might indirectly affect intestinal motility 1
• Treatment for H. pylori (antibiotics) can cause diarrhea as a side effect, which might be mistakenly attributed to the infection itself 5, 2
• H. pylori may influence the gastric microbiome, potentially leading to dysbiosis that could affect intestinal function 2

Extragastric Manifestations of H. pylori

• The Maastricht IV/Florence Consensus Report recognizes several extragastric manifestations of H. pylori infection, but diarrhea is not among them 1
• Recognized extragastric manifestations include:
  • Iron-deficiency anemia 1, 2
  • Idiopathic thrombocytopenic purpura (ITP) 1, 2
  • Vitamin B12 deficiency 1, 2
  • Impaired absorption of certain drugs (thyroxine and l-dopa) 1

Clinical Approach to Patients with Diarrhea and H. pylori

• In patients presenting with diarrhea who are found to have H. pylori infection, clinicians should:
  • Consider that the diarrhea likely has a cause other than H. pylori 1, 3
  • Evaluate for other common causes of diarrhea (infections, inflammatory bowel disease, irritable bowel syndrome, etc.) 3, 6
  • Recognize that H. pylori eradication is not specifically indicated for the treatment of diarrhea 1, 4
  • Be aware that antibiotics used for H. pylori eradication can themselves cause diarrhea as a side effect 5, 2

Common Pitfalls in Clinical Practice

• Attributing diarrhea directly to H. pylori infection without considering other more likely causes 3, 6
• Treating H. pylori solely for the purpose of resolving diarrhea, which lacks evidence-based support 1, 4
• Failing to recognize that diarrhea occurring during H. pylori treatment is likely an antibiotic side effect rather than a manifestation of the infection 5, 2
• Overlooking the established indications for H. pylori testing and treatment, which are based on upper gastrointestinal symptoms and disease prevention 1, 2, 4