AstraZeneca has delivered this text only version of the course to serve those users who have difficulty accessing the interactive version.
You can access it here: Demo Interactive Version
Welcome to the “Irritable Bowel Syndrome” course.
Before beginning, please take a moment to read the course details.
Course Length: Approximately 2 hours. Your
time may vary based on modem speed, prerequisite knowledge and
other factors.
Prerequisites: Anatomy & Physiology of the
Gastrointestinal (GI) System.
Date Published: November 2003
Valid Until: November, 2006
Irritable Bowel Syndrome, or IBS, is a common condition that affects between 10 and 20% of the population in developed countries. Almost ¾ of those reporting symptoms are female. However, only 20-30% of IBS sufferers consult a doctor. The common symptoms of IBS include pain, bloating, defecatory symptoms and non-intestinal symptoms. The first three symptoms are the most frequent and comprise part of the Rome criteria for diagnosing IBS. There are no structural lesions or pathophysiological explanations for IBS, although there is an obvious malfunction of the intestine. Throughout the course, we will be examining the symptoms, possible causes, and treatments for this condition.
This course, “Irritable Bowel Syndrome”, presents basic medical background information about bowel habits, symptoms and causes of IBS, and the currently available treatments.
The first section, AETIOLOGY, introduces the possible causes of IBS. It also covers the possible diseases that may present as IBS, but are actually more serious in nature and pathophysiology.
The second section, EPIDEMIOLOGY, summarises some of the epidemiological data relating to IBS.
The third section, DIAGNOSIS, covers the clinical features of IBS. It also reviews the differential diagnosis of the disease and explains the laboratory, imaging, and pathology findings associated with the disease.
The fourth section, TREATMENT, covers the various non-pharmacological and pharmacological treatments that are currently utilised to treat IBS.
Irritable bowel syndrome (IBS) is an illness characterised by several symptoms, including abdominal pain and discomfort, intermittent abdominal cramps, and constipation with alternating periods of diarrhoea. These symptoms appear to be due to intestinal dysfunction, but there is no underlying structural cause. This section explores some of the possible causes of IBS.
These are the objectives for this section.
After you finish this section, you should be able to:
The specific cause of IBS is unknown. Some of the causes that have been suggested include a neurological disorder leading to problems with GI motility, diet, previous exposure to an enteric infection, visceral hypersensitivity, and psychological factors. The possible role of the nervous system in IBS is discussed in this section.
The digestive system is endowed with its own, local nervous system referred to as the enteric or intrinsic nervous system. In patients with IBS, there appears to be a misconnection between the brain (the central nervous system) and the enteric nervous system.
In order for material to pass through the colon, a series of intestinal muscle contractions needs to occur. This is termed ‘colon motility.’ These contractions are controlled by nerves, hormones, and electrical activity in the muscle. In a healthy colon, strong muscle contractions move down the colon. This pushes faecal matter to the rectum and sometimes results in a bowel movement. Thus, an incorrect or failed impulse to the colonic muscles will result in an altered ability to pass material through the colon to the rectum.
Diet is a possible cause of IBS. Various foods can induce intestinal symptoms if eaten in anything but small amounts, and a lack of fibre can cause constipation which can evoke many of the same symptoms of IBS. Dietary causes of IBS and differentiation between symptoms of IBS and true IBS are delineated in this lesson.
The human large intestine has evolved to handle up to 40 grams of fibre everyday, yet most people do not consume that amount. Lack of fibre can lead to constipation, and constipation evokes many of the symptoms of IBS. However, most people with IBS consume as much fibre as those without the symptoms. Various foods can induce intestinal symptoms if taken in anything but small amounts: chocolate, caffeine, milk products, alcohol, and unripe fruit. But this is the case in many people who do not have IBS, and it is possible that IBS just exaggerates a preexisting response.
Gastroenteritis is an illness that can be caused by bacteria or a virus. Recent studies have shown that between 24 and 32% of patients post-gastroenteritis develop IBS. IBS as a result of gastroenteritis is discussed in this lesson.
Recent studies have shown that between 24 and 32% of patients recovering from acute gastroenteritis develop IBS. Gastroenteritis is an illness that can be caused by bacteria or a virus, and the symptoms are a combination of diarrhoea, vomiting, fever, and dehydration. Postinfection IBS (PI-IBS) is more likely to develop in women than men. In addition, the severity and duration of the gastroenteritis infection is often indicative of PI-IBS development. PI-IBS has a better prognosis than other types of IBS, but the treatment regimen is the same after elimination of the original infective organism.