What is helicobacter pylori?

Helicobacter pylori (H. pylori) is a bacterium that commonly infects the gastrointestinal tract. It can damage the stomach lining, causing inflammation, ulcers and even stomach cancer.

H. pylori is the main cause of peptic ulcers (stomach and duodenal ulcers). Around 95% of duodenal ulcers and 80% of gastric ulcers are caused by H. pylori. The bacterium was discovered in 1983 by two Australian researchers, who ingested the organism themselves to prove their theory.

H. pylori lives in the sticky mucus that coats the lining of the stomach and duodenum. The stomach environment is very acidic; H. pylori neutralises this acid by producing an enzyme called urease. To counteract this, the stomach increases its production of acid, causing inflammation of the lining of the stomach. Acid secretion returns to normal once H. pylori is eliminated.
H. Pylori can also attach itself to the stomach cells, weakening the stomach’s defence system and causing inflammation.

H. Pylori is a very common infection. More than 25% of people are infected with it, although only a few (15%) develop ulcers. The reason why some people develop ulcers and others do not is not known.  
 
How do you get H. pylori infection?

The exact way in which H. pylori gets passed from one individual to another is uncertain, but person to person transmission is most likely. The bacteria are acquired mainly in childhood, especially in areas of poor hygiene and overcrowding. H. pylori is 2-3 times more prevalent in developing, non-industrialized countries. Re-infection can occur, especially in areas of overcrowding.

The bacteria can survive for years within the stomach and causes a form of chronic inflammation.
 
What are the symptoms?

Some people don’t have any symptoms and may not even realise that they have gastritis or a peptic ulcer. Mild symptoms are often put down to indigestion.

Symptoms of peptic ulcer disease include:

• Abdominal pain, usually in centre of the upper abdomen, sometimes spreading to the back. Pain commonly occurs in the early hours of the morning and is described as burning or "gnawing". Food and antacids may help but the pain may return again a few hours after eating.
• Indigestion/heartburn
• Nausea
• Vomiting
• Difficulty in swallowing/regurgitation
• Bloating
• Loss of appetite and weight loss

Occasionally ulcers may bleed. This can cause:

• Vomiting blood (‘coffee grounds’).
• Dark, tarry, black stools.
• Severe abdominal pain.
• Weakness/dizziness/palpitations/pallor (caused by anaemia due to blood loss).
An ulcer can also perforate (break through the wall of the stomach or duodenum). This causes severe abdominal pain and the person may collapse. Occasionally, an ulcer can obstruct the normal passage of food.

How would I know if I had it?

H. pylori infection is diagnosed by:
• Blood test. Your GP can take a blood test to measure antibodies to H. pylori in the blood. Antibody levels can also be measured several months after treatment to see if the infection has cleared. However, it can take 6 months or more for the blood test to become negative.
• Breath test. This involves drinking a radioactive or non-radioactive form of urea, which is normally broken down by H. pylori. If H.pylori is present, the urea will be changed into a chemical that can be detected with a breathalyser. The breath test is the best way of checking that H. pylori infection has cleared and can be used within 30 days of treatment.
• Biopsy specimen. A sample of tissue (biopsy) obtained at gastroscopy (examination of the stomach and duodenum using a special illuminated tube) can be examined under a microscope for H. pylori. H. pylori may also be grown (cultured) from the specimen (H. pylori is not easy to culture). Specimens may also be placed on a special card that changes colour if urease is present.
• Stool test. A small sample of stool is tested for antibodies to H. pylori.

 
How is it treated?

H. pylori is usually treated with 2 high doses of antibiotics and a proton pump inhibitor (PPI), which cuts down acid production in the stomach. This is called triple therapy.

The antibiotics most commonly used are amoxicillin, clarithromycin, metronidazole, and tetracycline.

Triple therapy kills H. pylori, reduces ulcer symptoms, and prevents ulcer recurrence in over 90% of patients.

The main drawback of triple therapy is the large number of pills a patient has to take and side effects from the antibiotics (diarrhoea, dizziness, headache, a metallic taste in the mouth, nausea, vomiting, and yeast infections).

For most people, one week of treatment is usually enough (sometimes a 2 week course is used). Some people may need to continue taking an acid reducing medicine for 2-4 weeks.

Most ulcers usually heal in 4-8 weeks, but are likely to recur if H. pylori infection is not completely eliminated.
 
Are there any complications of H. pylori infection?

H pylori infection is a common cause of gastritis and peptic ulcers. Besides causing abdominal pain and other symptoms, peptic ulcers can bleed or perforate.

H. pylori infection is 9 times more common in patients with stomach cancer and 7 times more common in patients with lymphoma of the stomach. It is thought that prolonged inflammation leads to changes in cell growth and the development of tumours.

How can I prevent H. pylori infection?

Good hygiene and sanitation decrease the incidence of H. pylori infection. In the future a vaccine may be available which may be useful in areas where H. pylori infection and occurrence of stomach cancer is high e.g. Japan.