The bacterium Helicobacter pylori (H. pylori) is a common pathogen adapted to survive in the acidic environment of the human stomach. This spiral-shaped bacterium burrows into the protective mucus layer, causing chronic inflammation of the stomach lining, known as gastritis. The infection is widespread globally, though most infected individuals remain without symptoms. When symptoms do arise, they are typically related to ulcers or inflammation in the upper gastrointestinal tract. The question is whether H. pylori can cause swollen lymph nodes, or lymphadenopathy.
The Direct Link: H. pylori and Lymphadenopathy
While H. pylori infection primarily resides in the stomach, the body’s immune system reacts strongly to its presence, which can lead to localized lymph node swelling. This reaction is a form of reactive lymphadenopathy, where the lymph nodes nearest the site of infection—such as the abdominal or cervical lymph nodes—become enlarged. The lymph nodes process immune cells responding to the chronic inflammation. The bacteria or the immune cells that have captured the bacteria can travel from the stomach to the regional gastric lymph nodes, stimulating this localized swelling.
The prolonged inflammatory state can also lead to a rare complication involving lymphoid tissue. Chronic H. pylori gastritis can cause the stomach lining to acquire Mucosa-Associated Lymphoid Tissue (MALT), which is not normally present. In a small fraction of cases, this acquired lymphoid tissue can transform into gastric MALT lymphoma, a slow-growing cancer. This condition is directly linked to H. pylori infection and involves the proliferation of lymphoid cells, sometimes including the infiltration of regional lymph nodes. Eradicating the infection often leads to the regression of this lymphoma.
Common Gastrointestinal Symptoms of H. pylori
Although the link to swollen lymph nodes is rare, the infection is better known for its direct effects on the digestive system. Gastritis, or inflammation of the stomach lining, can lead to a gnawing or burning ache in the upper abdomen. This discomfort may be more noticeable when the stomach is empty, but it can also worsen immediately after eating.
The constant irritation often manifests as frequent burping, bloating, and an upset stomach. In some instances, the infection progresses to cause peptic ulcers, which are open sores in the stomach or the first part of the small intestine. More severe symptoms suggesting a complication like a bleeding ulcer include unintentional weight loss or the passage of black, tarry stools due to digested blood.
Testing Methods for H. pylori
Confirming the presence of H. pylori involves both non-invasive and invasive diagnostic tools. Non-invasive methods are typically the first line of testing and include the urea breath test and the stool antigen test. The urea breath test requires the patient to swallow a capsule or liquid containing a carbon-tagged urea compound. If H. pylori is present, the bacteria’s urease enzyme breaks down the urea, releasing carbon dioxide that is exhaled and measured in a collected breath sample.
The stool antigen test is a highly accurate non-invasive option that looks for specific H. pylori proteins, or antigens, in a stool sample. Both the urea breath test and the stool antigen test are effective for confirming an active infection and checking the success of treatment after eradication therapy. For accurate results, the patient must stop taking proton pump inhibitors (PPIs) for at least one to two weeks prior to testing, as these medications can temporarily reduce the bacterial load and lead to a false-negative result.
Invasive testing involves an upper endoscopy, where a flexible tube with a camera is passed into the stomach and duodenum. This procedure allows a doctor to visually inspect the lining for ulcers or inflammation and to take small tissue samples, called biopsies. These samples are tested for the presence of the bacteria using methods like a rapid urease test or histological examination. Endoscopy is reserved for patients who have “alarm symptoms” like unexplained weight loss or difficulty swallowing, or for those over the age of 60.
Treatment and Eradication Strategies
The goal of treatment is to eliminate the H. pylori bacteria, a process known as eradication, which heals ulcers and prevents long-term complications. Standard therapy involves a combination of medications designed to kill the bacteria and reduce stomach acid production. The most common approach is a multi-drug regimen, often referred to as “triple therapy” or “quadruple therapy,” lasting 10 to 14 days.
Triple therapy consists of a proton pump inhibitor (PPI) to suppress acid, along with two different antibiotics, such as amoxicillin and clarithromycin. Due to increasing rates of antibiotic resistance, particularly to clarithromycin, “quadruple therapy” may be recommended as a first-line approach. Quadruple therapy involves a PPI, bismuth subsalicylate, and two antibiotics like metronidazole and tetracycline.
Adherence to the full course of medication is important, as incomplete treatment significantly lowers the chance of successful eradication. Clinicians recommend follow-up testing, such as a urea breath test or stool antigen test, at least four weeks after completing the antibiotic course to confirm the infection is gone. If the initial treatment fails, a different combination of drugs, or a “salvage regimen,” will be prescribed.