Diagnosing stomach problems: Check your breath
They're looking for signs of Helicobacter pylori (HP), a bacteria that has been linked to a host of gastrointestinal problems.
For many years doctors and researchers thought ulcers were caused by stomach acids, spicy food, stress or alcohol. Then in 1982 Robin Warren and Barry Marshall made the significant discovery of bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease. They went on to receive the Nobel Prize in Physiology or Medicine in 2005 for this important medical breakthrough.
Since then, researchers have discovered that HP bacteria can lead to an array of problems when it makes a home in a person's gastrointestinal tract. It can cause infection of the stomach, as well as contribute to the development of diseases such as dyspepsia (heartburn, bloating and nausea), gastritis (inflammation of the stomach), and ulcers in the stomach and duodenum. It has also been linked to stomach cancer.
Helicobacter pylori is a treatable affliction, but the trick is determining whether it's truly the culprit when a patient reports stomach problems.
In the past, endoscopy, biopsy, blood tests and stool sampling were used to make a diagnosis. Today, more effective and less invasive urea breath tests are becoming a more common diagnostic tool.
There are two main forms of the breath test, commonly referred to as C13 and C14. They look for changes that HP can cause in the chemical composition of a person's breath.
According to a report titled The urea breath test for Helicobacter pylori infection: taking the wind out of the sails of endoscopy, "H. pylori possesses a very active and specific urease enzyme. The patient ingests an isotope-labelled urea solution, which is broken down by the urease enzyme into carbon dioxide and ammonia. A high level of labelled CO2 in the patient's breath suggests H. pylori infection."
The C14-UBT test involves a radioactive isotope, so it can be performed only in accredited nuclear medicine facilities. For the most part, these are located at larger hospitals.
The C14 test is available throughout the country, but mainly through university medical centres, due to the high cost of equipment needed. Provincial health plans and insurance generally reimburse little of the cost if any, which has also limited the number of facilities offering the test.
"The C14 urea breath test is highly accurate both for diagnosis and for proof of eradication of H. pylori infection and plays an important role in patient management," says Freeman, who also works with Mount Sinai Hospital and Women's College Hospital.
"We started using the C-14 breath test approximately 13 years ago," he adds. "We performed over 1,200 studies last year in the Greater Toronto Area. The C-14 urea breath test is the most specific non-invasive test to detect Helicobacter pylori, with reported sensitivity and specificity rates of 90 per cent and 95 per cent, respectively. Overall, the C-14 urea breath test is an accurate, rapid and easily administered examination to diagnose initial H. pylori infection and to monitor its eradication."
How does HP spread?
"The exact route of transmission of HP has not been proven, but is thought to be oral-oral," says Dr. John K. Marshall of McMaster University Medical Centre. Oral-oral transmission refers to the regurgitation of stomach contents that are later ingested (inadvertently) by another individual.
"Children can certainly be infected," he adds. "Indeed, we think most people acquire their infection as infants and carry it throughout their lives. It is extremely unusual for an adult to acquire the infection … The majority of people we see with HP infection were born overseas in areas of higher incidence like Eastern Europe, Asia and South America."
There are no hard statistics on the prevalence of HP in Canada, adds Marshall. He says that among children born in Canada, HP infection is thought to be rare, likely less than one per cent of the population, with the exception of First Nations individuals.
"No one really knows why First Nations individuals are at increased risk. Epidemiologically, HP infection is associated with childhood crowding and poor sanitation, which — unfortunately — are more prevalent among the First Nations. There is no evidence that drinking water is the source. There have been attempts to isolate HP from drinking water, but the results are inconclusive."
"It will depend on where an individual spent his/her childhood and his/her age. We believe HP is acquired in childhood, and so its occurrence will depend on the childhood environment and will consider factors like sanitation and crowding."
The Safe Drinking Water Foundation (SDWF) is a Canadian charity that conducts research and uses scientific solutions to procure safe drinking water in rural and First Nation communities in Canada and abroad . It has compiled Canadian H. Pylori stats per province based on the number of people who have become ill and have died in each province due to stomach ulcers, but the group does not have figures on the number of people with HP infections.
The C13-UBT test uses a non-radioactive isotope.
"As a result, the sample can be collected anywhere and mailed to a central lab for processing," says Dr. John K. Marshall, associate professor of medicine, division of gastroenterology, at McMaster University in Hamilton. "Many private labs offer this test — for example, Lifelabs in Ontario — but it is not covered by OHIP and individuals must pay for the test approximately $60." Melanie Wolfe, a research lab technician at McMaster, says, "The C13 test is very important for many reasons. It is non-radioactive like the C-14 test, it is less invasive than an endoscopy and it is very patient-friendly. It only takes a half hour to do the test. Currently we test approximately 750 patients per year for our local gastroenterologist."
A background document on the C13-Urea Breath Test for Detection of Helicobacter pylori says, "The performance of these two tests is virtually identical, therefore practical considerations should determine the choice between either one in a given context for a particular patient."
To eradicate HP infection typically requires a one- to two-week regimen that combines two antibiotics with a proton pump inhibitor. Proton pump inhibitors are medications that block acid production in the stomach.
But treatment can take time. Nat Filice, 61, born in Italy and now living in Ancaster, Ont., had stomach discomfort, heartburn and gastritis for several years until HP was identified in his system as a result of a test at McMaster University. He says the diagnosis was a surprise because, "as far as I know no one else in my family has this bacteria."
"I've had at least three if not four treatments and still the HP is not gone. I currently have to do another breath test to determine the presence of HP or not," Filice says.
He says that identifying his stomach problems as being the result of a treatable HP infection has given him peace of mind. "I really don't worry much about this condition. I can comfortably live with [it]. I don't believe I will get stomach cancer: the odds are apparently quite slim, plus I eat well and I get a lot of exercise. "
The key to outcomes like Felice's is early detection, before this tiny bacteria causes bigger problems. Both the C-13 and the C-14 are equally effective when diagnosing H. pylori and in assessing the success for treatment for H. pylori after a course of antibiotic therapy, according to researchers, and the urea breath test has the potential to save costs and improve patient care.