Family doctor

Overview:

• Helicobacter pylori infects the human stomach and causes a variety of diseases - gastritis, peptic ulcers, gastric cancer
• Infection rates vary with age, country of origin and present residence, ethnicity and socio-economic status
• Most people have no symptoms
• 25-40% of people with dyspepsia who test positive have a peptic ulcer
• Gastric cancer is rare - less than 0.5% of people with dyspepsia, mostly found in those older than 50 years of age
• Helicobacter pylori can be diagnosed by non-invasive methods in people with dyspepsia who are at low risk of gastric cancer
• It can be successfully eradicated by using a combination of antibiotics

What is helicobacter pylori?

Helicobacters are bacteria. An important member of this family of bacteria is "Helicobacter Pylori", often abbreviated to "H.Pylori".

H.Pylori bacteria live in the mucous layer that covers the inner surface of the human stomach. They survive in this very acid environment by producing and surrounding themselves by ammonia which neutralises the acid normally produced by the stomach lining.

Who is infected by helicobacter pylori?

About 30% of people have H.Pylori. It is spread by close contact - it is not certain whether the actual route is oral-oral (bacteria present in the saliva and transferred to an uninfected person's mouth) or oral-faecal (bacteria excreted in the faeces). Both routes may be important.

Rates of infection vary with many different factors:

• Geography: infection in New Zealand is less common in those living in the South Island, more common in the North Island. Infection rates are very high in Asia.
• Age: rate of infection increases with age - more common with increasing age
• Ethnicity: infection is more common in those of Maori or Polynesian ethnicity
• Socio-economic: infection is more common with lower socio-economic status

How does H.Pylori cause disease?

Most people have no symptoms.

H.Pylori causes inflammation in the lining of the stomach (called the "mucosa") and one consequence of this may be Gastritis, with symptoms of dyspepsia (pain or discomfort in the upper abdomen), nausea and bloating.

Another more serious consequence is a "peptic ulcer" which is an ulcer forming in the lining (mucosa) of the stomach or in the duodenum (the connection between the stomach and the small intestine). Not everyone with H.Pylori will develop an ulcer, up to 15% may do so at some time in their lives. Symptoms of an uncomplicated ulcer are very similar to those of gastritis, with dyspepsia, nausea and bloating. A peptic ulcer may become complicated and cause bleeding, perforation of the stomach, or obstruction due to scaring.

Various medications may interact with the H.Pylori infection to increase the risk of an ulcer. Examples are aspirin, disprin, steroids (e.g. prednisone), warfarin and non-steroidal anti-inflammatory drugs (e.g. voltaren, naprosyn, synflex, brufen etc).

Smoking, alcohol and stress increase the risk of an ulcer.

Gastric cancer is associated with infection with H.Pylori, although the lifetime risk is very low. Less than 0.5% of people with dyspepsia (usually these are in people older than 50-55years) have gastric cancer.

There seem to be genetic factors in determining the outcome of H.Pylori infection. An example is that persons of Japanese, Maori and Polynesian descent have a higher lifetime risk of gastric cancer, and younger age of onset. Certain strains of H.Pylori are more virulent than others.

Who should be tested for H.Pylori?

There is no evidence that testing healthy people with no symptoms is useful.

Patients with symptoms should see their doctor to discuss testing, as other tests and examination may also be needed.

People with dyspepsia (pain or discomfort in the upper abdomen) should first be screened by their family doctor for symptoms and physical signs of possible serious disease (including gastric cancer), and those at higher risk referred to a specialist for further investigation, usually gastroscopy.

Those suffering from dyspepsia who should be referred to a gastroenterologist would include those 50-55 years old and older, and those with other serious symptoms and physical signs such as anaemia, vomiting blood, loss of weight, trouble swallowing, palpable mass, vomiting, etc.

People with obvious symptoms of Gastro-Oesophageal Reflux (acid rising from the stomach into the oesophagus - see specific article) do not benefit from treatment for H.Pylori and are not routinely tested for infection with H.Pylori.

What non-invasive tests are available?

The most accurate test (about 98%) is the Urea Breath Test, which involves drinking a small amount of labeled urea solution and then breathing into a test tube. This is currently not funded in New Zealand and costs about $85 to the patient. It is useful in both diagnosis of present infection and confirmation of cure after treatment.

Serology is a blood test, about 90% accurate, involving a small sample of blood. It is useful in diagnosing if the person has ever been infected with H.Pylori, (i.e. present and past infection). However it remains positive for several years after eradication of H.Pylori and thus cannot be used to confirm a cure.

Who should be offered antibiotic treatment to eradicate H.Pylori?

Everyone with dyspepsia (pain or discomfort in the upper abdomen ongoing for some time) who tests positive for H.Pylori should be offered eradication.

A positive test in the presence of dyspepsia means a 25% - 40% chance of an ulcer being present. Successful eradication of H.Pylori will result in the ulcer healing. The ulcer will not heal in the ongoing presence of H.Pylori infection. Gastritis will also heal with successful eradication.

What antibiotics are used?

H.Pylori is difficult to eradicate, so three medications are used simultaneously.

This is called "Triple Therapy".

The best treatment at present is called OAC, taken for 7 days:

• O = Omeprazole (which decreases the acid level in the stomach)
• A = Amoxicillin (a penicillin antibiotic).
• C = Clarithromycin (an antibiotic related to erythromycin)

OMC is used in those who are penicillin allergic, where M = Metranidazole.

Both OAC and OMC give eradication rates of about 90%.

H.Pylori is rapidly developing increased resistance to various antibiotics, and antibiotic combinations which were highly successful several years ago now only result in 60% cure rates. Clarithromycin containing therapy is currently the "gold-standard". Older, less effective therapies are no longer recommended as first line treatment.

Should testing be repeated to confirm a cure?

If the symptoms of dyspepsia disappear after completing the course of treatment, it is not necessary to repeat the urea breath test, which may be used to confirm eradication. The resolution of symptoms is a reliable predictor of healing of an ulcer.

If symptoms persist after the course of treatment, the urea breath test should be repeated.

If still positive, a gastroenterologist should be consulted either to select another combination of antibiotics or investigate further.

If the urea breath test is negative, referral to a gastroenterologist is recommended for assessment and further investigation.