Helicobacter pylori Stages: From Infection to Chronic Gastritis

Helicobacter pylori which is known as H. pylori which is a bacteria that infects the stomach lining of the individual and is the most common cause of chronic gastritis everywhere around the globe. In many people, this infection is for years without any visible symptoms which is why it is left unnoticed. Basically, the problem starts when this bacteria settles inside the stomach and slowly irritates the stomach lining. Over-time, this irritation becomes long-term inflammation, known as chronic gastritis. This condition takes place when the infection is not treated properly on time. 

Let’s understand the stages of H. pylori to know more about this silent infection and how it can lead to chronic and other serious gastric conditions.

Stage 1: Initial H. pylori Infection and Colonization

The first stage of H. pylori infection^[1] is settlement of bacteria in the stomach. This usually happens during childhood and spreads through contaminated food, water, or close personal contact. What happens here is that H. pylori moves through the stomach’s protective mucus layer and attaches itself to the stomach lining. It produces an enzyme called urease, which helps it survive stomach acid.

In simple words, the bacteria creates a safer environment for itself inside the stomach. At this stage, most people do not feel sick at all, even though the bacteria is already present. This is why many people don’t realize they have this infection.

Stage 2: Acute Gastritis 

Once the bacteria settles in the stomach, the body’s immune system starts reacting to it. This leads to acute inflammation of the stomach lining, also called acute gastritis.

Basically, the stomach lining becomes irritated and swollen. Some people may experience mild symptoms like stomach discomfort, nausea, or indigestion, while many still feel completely normal.

Because the symptoms are often mild or temporary, this stage is frequently ignored.

Stage 3: Chronic Gastritis

If H. pylori remains in the stomach for a long time, the inflammation does not go away. Instead, it becomes chronic, meaning long-lasting.

In this stage, the immune system keeps trying to fight the bacteria but is unable to remove it completely. As a result, the stomach lining stays inflamed for years.

This is why chronic gastritis caused by H. pylori is very common and often diagnosed accidentally during tests for other stomach problems.

Stage 4: Chronic Atrophic Gastritis

If the condition is left untreated, the inflammation can cause atrophy^[2] which means the individual might lose normal gastric glands under this condition. In simple words, the stomach lining will start becoming thin, the production of acid and enzyme will decrease and digestive function will not work properly.

This stage reflects permanent tissue damage rather than just inflammation.

Stage 5: Intestinal Metaplasia (Precancerous Change)

In some individuals, prolonged atrophic gastritis progresses to intestinal metaplasia^[3]. This means that stomach cells are replaced by intestine-like cells and if the infection is not treated it might increase the risk of gastric cancer. This is important to mind that not all patients with intestinal metaplasia have cancer but instead it signals higher long-term risks.

These long term risks of untreated H. pylori infection are: 

• Peptic ulcer disease
• Upper gastrointestinal bleeding
• MALT lymphoma^[4]
• Gastric adenocarcinoma^[5]

Early diagnosis and eradication therapy significantly reduce these risks.

Final Thoughts

H. pylori infection usually begins silently, but its long-term presence can slowly damage the stomach lining. From early infection to chronic gastritis and, in some cases, more severe changes, the process happens gradually and often without clear warning signs. The important thing to understand is that early diagnosis and treatment can stop this progression. Treating H. pylori not only relieves inflammation but also helps prevent long-term complications related to chronic gastritis.

Chronic Helicobacter pylori infection is a major cause of antral gastritis, explained in detail in Antral Gastritis: Everything You Need to Know.

FAQs: Helicobacter pylori and Chronic Gastritis

Q1. What is the first stage of H. pylori infection?

The first stage is colonization of the stomach lining, usually in childhood, often without symptoms.

Q2. Does H. pylori always cause chronic gastritis?

No, H. pylori always causes some inflammation.

Q3. How long does it take for H. pylori to cause chronic gastritis?

It may take months to years, and in many cases, the process is silent and gradual.

Q4. Can chronic gastritis caused by H. pylori be reversed?

Yes, H. pylori can be reversed if treated before atrophy develops.

Q5. Is intestinal metaplasia reversible?

It may be partially reversible in early stages, but advanced changes are often permanent, which is why early treatment is important.

you can also read: Gastric Antral and Oxyntic Mucosa: What It Means in Endoscopy Reports