IBS Flashcards
How is irritable bowel syndrome (IBS) defined?
Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder that is characterized by recurrent abdominal pain and altered bowel habits and/or abdominal distension that occur in the absence of detectable structural and biochemical abnormalities.
What alarm symptoms and signs are absent in IBS?
Weight loss, iron-deficiency anemia, malnutrition, melena, or blood in the stools are absent.
What is the most important element in IBS diagnosis?
Since irritable bowel syndrome is a functional entity, clinical symptomatology is the most important element, the anamnesis being essential for providing diagnostic criteria.
What is the impact of IBS on patients and physicians?
Although irritable bowel does not endanger the patient’s life, irritable bowel syndrome is a condition that creates great discomfort for the patient and often therapeutic failure for the attending physician.
Contributing factors to the development of IBS
➢ altered gastrointestinal motility,
➢ visceral hypersensitivity,
➢ psychosocial distress,
➢ genetic predisposition,
➢ environmental agents,
➢ alteration of the intestinal
colonic microbiota.
Factors that increase the risk of developing IBS include
➢ Genetic factors
➢ Psychosocial factors
➢ Environmental factors
Factors that trigger the onset or exacerbation of IBS symptoms
include:
➢ previous episodes of gastroenteritis
➢ food intolerance
➢ chronic stress
➢ episode of diverticulitis
➢ surgery
The pathophysiological mechanisms are independent of the patient and include:
➢ Altered gastrointestinal motility
➢ Visceral hyperalgesia
➢ Increased intestinal permeability
➢ Immune activation
➢ Alteration of the intestinal flora
➢ Disturbances of neuronal function in the brain-gut axis
In what conditions is an increased prevalence of IBS symptoms observed?
chronic inflammatory conditions (inflammatory bowel disease, celiac disease) or after an episode of acute gastroenteritis (post-infection IBS), suggesting a role for altered intestinal immune activation and permeability.
How common are true food allergies in IBS, and what other food-related issues are common?
uncommon
However, food intolerances are often present in persons with IBS
resulting in osmotic diarrhea or increased fermentation, thereby leading to bloating and pain.
What is a characteristic feature of pain perception in IBS patients?
Heightened visceral pain sensitivity is a characteristic feature of patients with IBS.
Patients typically perceive the sensation of a balloon
During distention, they are seen to have increased activation of regions of the brain associated with emotional arousal and pain modulation.
What role do 5-Hydroxytryptamine (5-HT, or serotonin) receptors play in IBS?
5-Hydroxytryptamine (5-HT, or serotonin) receptors have been shown to play an important role in diarrhea as well as pain perception. This finding has led to the development of 5-HT3 antagonists as a therapy for diarrhea-predominant IBS.
How might early life experiences contribute to the development of IBS?
Early parental response to an individual’s pain in childhood or adolescence may lead to permanent alterations of the brain–gut axis with the development of associated poor coping behavioral responses as an adult.
What type of disorder is IBS suggested to be, and what role does inflammation play?
Primary mechanoreceptor disorder possibly related to the presence of a chronic, small-scale inflammatory process with a sensitizing role.
What are the possible causes of hypersensitivity in IBS?
Hypersensitivity may be caused by an alteration in the extrinsic nervous system or the influence of the CNS.
How does hypervigilance relate to IBS?
Hypervigilance to abdominal stimuli.
What have modern imaging methods revealed about IBS?
Modern imaging methods (positron emission tomography – PET-CT) have described cortical differences in IBS.
Where else has sensitization been suggested to occur in IBS?
Other studies have suggested that sensitization occurs at the level of splanchnic afference.
Are there specific changes in intestinal motility that can distinguish IBS-related diarrhea or constipation from other causes?
No, there is NO specific change for diarrhea or constipation from irritable bowel syndrome (IBS).
What type of antibiotic has been shown to be effective in treating some forms of IBS, particularly diarrhea-predominant IBS?
The administration of a non-absorbable antibiotic (e.g., Rifaximin) has proven to be effective in the treatment of some forms of IBS, especially in the case of the predominance of diarrhea.
How do serotonin levels differ in IBS patients with diarrhea predominance versus those with constipation predominance?
In the case of IBS with the predominance of diarrhea, some individuals have an increased level of circulating serotonin, while patients who have the variant of IBS with the predominance of constipation have a low level of circulating serotonin
What types of comorbidities are associated with IBS?
Somatic pain syndromes (fibromyalgia, chronic fatigue syndrome, chronic pelvic pain)
Psychiatric disorders (major depression, anxiety)
several factors are incriminated, including:
➢ food intolerance / food allergies,
➢ carbohydrates and poorly absorbed fibers
➢ obesity as comorbidity
What dietary changes can lead to a net and sustainable improvement of IBS symptoms?
Diets restrictive in fructose and sorbitol along with other FODMAPs.
ESSENTIAL ELEMENTS FOR THE
DIAGNOSIS OF IBS
➢ Abdominal pain associated with defecation disorders
➢ Abdominal pain relieved by defecation
➢ Imperious defecation
➢ Feeling of incomplete evacuation after defecation
➢ Mucus presence in the stool
➢ Obvious abdominal distention/bloating
➢ Investigations to exclude an organic disease: normal sigmoidoscopy/colonoscopy/barium enema (irrigography) and negative biochemical screening tests
Manifestations of IBS are?
➢ Recurrent abdominal pain
➢ Altered bowel habits
➢ Abdominal bloating/distention
Recurrent abdominal pain, on average, at least 1day/week in the last 3 months, associated with two or more of the following criteria:
➢ Related to defecation
➢ Associated with a change in the frequency of stool
➢ Associated with a change in the consistency (form of the stool)
Other symptoms that support a diagnosis of IBS include:
➢ altered stool frequency,
➢ altered stool form,
➢ altered stool passage (straining and/or urgency),
➢ mucus in the stool,
➢ abdominal bloating or subjective distention
Four bowel patterns of irritable bowel syndrome may be seen and these remain in the Rome IV classification
➢ IBS-D (diarrhea predominant)
➢ IBS-C (constipation predominant)
➢ IBS-M (mixed diarrhea and constipation)
➢ IBS-U (unclassified; the symptoms cannot be categorized into one of the above three subtypes)
