Contaminated small bowel syndrome (small intestinal bacterial overgrowth, SIBO)
SIBO means the growth of bacterial strains in small bowel that are normally present only in the large bowel. It leads to impaired intestinal absorption of carbohydrate type foods.
Overgrowth of such bacteria in the small bowel may be induced by several factors. These include fistulas (abnormal passageways) between certain bowel sections, taking particular medicines, previous surgeries of stomach or bowels, stressful, hectic lifestyle, endoscopic examinations, reduced production of digestive enzymes.
Which symptoms may occur in contaminated small bowel syndrome?
Symptoms are variable and may cause significant discomfort. Among others, these can be the following: abdominal bloating, abdominal distension, colic, increased gas production in the bowels, nausea (feeling of sickness), diarrhoea, constipation or combination of the above.
This condition can be identified indirectly, by the help of hydrogen breath test, following the consumption of a lactulose test solution. Basic principle of the test is that lactulose is a synthetic disaccharide that normally starts to be fermented in the large bowel only. This process is induced by large bowel bacteria and produces lactic acid, acetic acid, methane and hydrogen. If there is a significant overgrowth of large bowel bacteria in the small bowels digestion of lactulose already begins in here - producing hydrogen. This phenomenon will be detected during the examination.
Lactose intolerance
Lactose intolerance means disturbed digestion, absorption of lactose. Lactose is a disaccharide found in milk and dairy products, consisting of two components, namely galactose and glucose. In persons without lactose intolerance, lactose is broken down to galactose and glucose by a so called lactase enzyme produced by epithelial cells of the small bowel. Should this degradation process fail in the small bowel due to insufficient, impaired function of lactase enzyme, lactose gets into the large bowel and is degraded into organic acids and hydrogen through a fermentation process, causing undesired symptoms.
Just to give an example, up to 3 litres of gas may be produced after consumption of 100 ml milk.
Three types of lactose intolerance may be distinguished:
1. Congenital
It is very uncommon. The newborn does not produce any lactase enzyme already from birth so breastfeeding provokes the symptoms.
2. Primary
Typically begins in adolescents and young adults characterized by gradual decrease of lactase production for genetic reasons. It is diagnosed with genetic tests.
3. Secondary
It is the acquired, reversible form of lactose intolerance. The patient is genetically able to produce sufficient quantities of lactase enzyme but it is temporarily or permanently hindered by a certain factor. Such interfering factor may be inflammation diseases, bacterial or parasitic infections in the bowels, tumours, side effects of certain medicines.
What are the symptoms of lactose intolerance?
Lactose passes through the small intestine without being degraded, digested. In the large bowel it absorbs high quantities of water, producing thin stool and gases. This process results in numerous uncomfortable symptoms, such as diarrhoea, abdominal bloating and spasms, loud abdominal gurgles, intestinal colic, burning sensation during defecation. These symptoms appear relatively short time (0.5-2 hours) after consuming foods or drinks with lactose-content. Once a lactose-free diet is started, these undesired symptoms cease spontaneously after a day or two.
Hydrogen breath test is also suitable for diagnosing lactose intolerance, with previous consumption of a lactose test solution. It should be noted that approximately 30-40% of the Hungarian population is affected by lactose intolerance.
Fructose intolerance
Two types of fructose (fruit sugar) intolerance are distinguished.
Hereditary (existing immediately from birth) form is very rare, with an occurrence rate of approximately 1:30,000 in average. In this form, fructose is absorbed in the bowels but due to the lack of a specific hepatic enzyme that should convert it to glucose, metabolic products accumulate, leading to variable symptoms. These include hypoglycaemia (reduced blood glucose level) following the consumption of fructose; spasms, somnolence (drowsiness); on the long term it may cause an impairment of renal, hepatic and/or cognitive functions. Symptoms occur already after the end of the breast-feeding period; consequently, the condition is usually diagnosed in very early life, using blood tests and liver biopsy.
The other form is far more common than the above and is related to hydrogen breathe test. It is called fructose malabsorption which refers to disturbed intestinal digestion and absorption of this substance. Fructose is not degraded and absorbed in the small bowel; instead, it is forwarded to the large intestine and starts to be fermented by the bacteria of this bowel section. During this fermentation process, gases and acids are produced, leading to diarrhoea, abdominal bloating and abdominal spasms (colic).
About the H2 exhalation test device
It is a palm device with colour LCD touch screen. During the test procedure it is connected to a so called mouthpiece, through which exhaled air is led to the measuring unit.
The test procedure lasts 180 minutes; the patient should blow the air into the device about every 20-30 minutes. Of course, if the device is used by several patients simultaneously, every patient has his/her own mouthpiece.
Prior to this painless and informative procedure, the patient performs mouth-rinsing with a disinfectant solution and drinks a test solution with lactose-, lactulose- or fructose-content. The device measures and digitally displays the hydrogen concentration of the exhaled air. After a comprehensive evaluation of the detected parameters and symptoms, intolerance can be diagnosed or excluded.
How to prepare for the examination?
Prior to the examination, detailed information is provided for the patient on what to do and what to avoid before the procedure. Particular instructions related to the diet and medication should be observed. In a 12-hour period before the test, it is not allowed to wash one's teeth or smoke. Necessarily, all of these instructions are provided to the patient in writing at a preliminary consultation with the specialist.
Further information about hydrogen breathe test
If the value measured by the device already after the first test exhalation it might be necessary to postpone the examination (making a new appointment). The specialist decides it on the basis of the detected value.
Some people's intestinal flora contains methane- or hydrogen sulphide-producing bacteria. It may result that the hydrogen produced in the bowel is converted into methane or hydrogen sulphide so hydrogen concentration of the exhaled air does not rise. In such cases, the test may give false negative results.
