GI: Irritable Bowel Syndrome

What is an indication for imipramine in irritable bowel syndrome?

Imipramine can slow whole-gut transit in IBS-D, improving diarrhea, pain, and depression. These agents also require a lower dose than depression.

What are six anti-flatulence therapies?

1. Eat slowly. 2. Do not chew gum. 3. Avoid carbonated beverages. 4. Avoid dairy, fresh fruits, vegetables, and juice. 5. Simethicone or infant drops also improves symptoms. 6. Beano, or B-glucosidase, can break down cabbage, beans, and other legumes.

What are the three types of irritable bowel syndrome?

1. IBS-M (20-50%) 2. IBS-C (20-45%) 3: IBS-D (15-35%)

Guanylate cyclase C agonists can be used to treat ______.

IBS-C

Lubiprostone can be used in the treatment of _______.

IBS-C

Tegaserod can be used in the treatment of ______.

IBS-C * However, this drug has been withdrawn from the market.

SSRI may be useful in ______.

IBS-C This is questionable.

How does gastrointestinal motor abnormalities lead to irritable bowel syndrome?

Increased rectosigmoid activity can lead to irritable bowel syndrome.

True or False: Irritable bowel syndrome presents with normal gas production.

True

IBS ________ the quality of life.

decreases

Alosetron increases the risk of ______.

ischemic colitis

Clinical Features of IBS (4)

1. Abdominal Pain: Abdominal pain is the prerequisite clinical feature of IBS. The pain may waken patients up repeatedly at night in severe cases and may be worsened with eating and stress. 2. Altered Bowel Habits: Altered bowel habits is the most consistent feature of IBS. One feature becomes prominent. Constipation may lead to incomplete evacuation, and diarrhea may be aggravated by emotional stress or eating. 3. Gas and Flatulence: Patients often have gas and flatulence that leads to abdominal distension. However, gas production is normal, but gas produced exacerbates symptoms. 4. Upper Gastrointestinal Symptoms: Symptoms can include dyspepsia, heartburn, nausea, vomiting, and abnormal small intestine motility.

What are eight underlying pathophysiologic and/or psychosocial factors to irritable bowel syndrome?

1. Gastrointestinal Motor Abnormalities 2. Visceral Hypersensitivity 3. Abnormal Psychological Features 4. Post-Infectious IBS 5. Immune Activation and Mucosal Inflammation 6. Increased Intestinal Permeability with Inflammatory Cytokines 7. Altered Gut Flora 8. Abnormal Serotonin Pathways

Guanylate Cyclase C Agonists (2)

1. Linaclotide 2. Plecanatide

How is dysbiosis treated? (4)

1. Reassurance. 2. Carefully explain the functional nature of treatment. 3. Modify diet by excluding alcohol sweeteners (sorbitol), coffee, legumes, and cabbage. The FODMAP diet can be recommended. 4. High fiber diets and bulking agents such as psyllium can help both constipation and diarrhea.

Eluxadoline should be avoided in patients with (3):

1. constipation history. 2. pancreatitis. 3. alcohol abuse.

Management recommendations for IBS include:

1. making a positive diagnosis based on symptoms and the absence of alarm features. 2. determining the effect of illness on the patient and on the patient's psychosocial resources (family). 3. determining if there is a comorbid psychiatric disease or an unresolved major loss or trauma. 4. assessing the patient's expectations and hidden fears. 5. providing education, telling the patient is not alone and that their diagnosis is not benign. 6. providing firm reassurance, emphasizing that the symptoms are known to be real and not just "in patient's head" and that IBS is a recognized bowel disease. 7. avoiding giving mixed messages (i.e. patient reassurance/ordering extensive tests with adequate explanation). 8. avoiding repeated tests unless there is new development of structural disease that is suspected. 9. basing treatment on the principle of patient-based responsibility for care. 10. setting realistic treatment goals. 11. considering referral to a patient support group. 12. organizing a continuing care strategy if symptoms have been chronic or disabling. 13. considering psychological treatments for patients with moderate to severe symptoms.

Dysbiosis can be treated via (4):

1. probiotics. 2. diet. 3. prebiotics. 4. antibiotics.

Describe the bowel habits associated with irritable bowel syndrome.

Altered bowel habits is the most consistent feature of IBS. One feature, either constipation or diarrhea, becomes prominent. Constipation may lead to incomplete evacuation, and diarrhea may be aggravated by emotional stress or eating.

How does altered gut flora lead to irritable bowel syndrome?

Altered gut flora can lead to IBS via small intestinal bacterial overgrowth.

What is the mechanism of action of eluxadoline?

Eluxadoline is a μ and κ receptor agonist and δ receptor antagonist.

Epidemiology of Irritable Bowel Syndrome Sex: Incidence: Age:

Epidemiology of Irritable Bowel Syndrome Sex: women Incidence: 10-20% of adults and adolescents Age: Most present before the age of 45.

True or False: Irritable bowel syndrome can present with nocturnal diarrhea.

False

True or False: Tolerance can be developed against opioid-based agents such as loperamide (Imodium).

False: not much really

Alosetron can be used in the treatment of _____.

IBS-D

What is the conceptual model of irritable bowel syndrome?

In patients with IBS, early life events, genetics, and environment partner together to result in changes in physiology, motility, and sensation in the gut. When these three factors are combined with psychosocial factors, life stress, psychological state, coping strategies, and social support, these factors can develop IBS.

How do abnormal serotonin pathways lead to irritable bowel syndrome?

In patients with IBS-D, it has been found that 5-HT enterochromaffin cells are increased in number, which can contribute to the development of IBS.

What is the mechanism of action of linaclotide?

Linaclotide is a guanylate cyclase C agonist that increases cGMP, leading to anion secretion, fluid secretion, intestinal transit, and reduces abdominal pain.

What is lubiprostone?

Lubiprostone is a bicyclic fatty acid that stimulates chloride channels. Chloride secretion induces passive movement of sodium and water into the bowel lumen, improving constipation symptoms.

What is the mechanism of action of plecanatide?

Plecanatide is a structural analog of uroguanylin that is a guanylate cyclase C agonist that increases cGMP, leading to antion secretion, fluid secretion, intestinal transit, and decreases pain-sensing nerves of the intestine.

Explain the Bristol stool scale.

The Bristol stool scale demonstrates all possible stool types. Type I are constipated, dehydrated pellet stools that spent a while in the bowel to become so dehydrated. Type III and IV are sausages of stool that is associated with a medium passage through the GI tract. Type VII stool is seen in individuals with frank diarrhea.

What is the pathophysiologic sequence of irritable bowel syndrome? Explain.

The pathophysiologic sequence of IBS was developed by Mark Pimentel, MD. In some individuals, there is food poisoning from E. coli, Salmonella sp., Shigella sp., or Campylobacter sp. These species develop a bacterial toxin that results in cytolethal distending toxin. Then, there is a potential for autoimmunity. This results in gut nerve damage that results in reduced ICC generation of the MMC. As a result, this leads to bacterial overgrowth that can be detected through breath tests or culturing. As a result, this results in IBS, and patients are treated empirically with antibiotics.

How does visceral hypersensitivity lead to irritable bowel syndrome?

Visceral hypersensitivity is an exaggerated sensory response to visceral stimulation, such as gas in the small intestine and colon, often due to greater activation in the mid-cingulate cortex. This greater activation can lead to visceral hypersensitivity and then to irritable bowel syndrome.

Patients with an autoimmune component of IBS-D may have ______ antibodies.

anti-vinculin

Tegaserod increases the risk of ______.

cardiovascular events

Eluxadoline is contraindicated in patients with a ______.

cholecystectomy

The major adverse effect of eluxadoline is ______.

constipation

A change in the heightened sensorimotor activity can lead to a ______ in symptoms.

decrease

The passing of mucus may indicate ______.

irritable bowel syndrome

The symptoms of IBS come and go and overlap with (4).

other functional disorders (i.e. fibromyalgia, headache, backache, and genitourinary symptoms)

About 80% of patients with irritable bowel syndrome have _______.

psychiatric symptoms

Irritable bowel syndrome is more common in _______.

women

Describe the abdominal pain associated with irritable bowel syndrome.

Abdominal pain is the prerequisite clinical feature of IBS. The pain may waken patients up repeatedly at night in severe cases and may be worsened with eating and stress. It has a variable intensity, from mild to severe, and location, but is episodic or crampy or constant in nature.

FODMAP Diet

About 75% of individuals have an improvement of symptoms; however, nutritional deficiencies may occur.

Patients with irritable bowel syndrome are classified as constipation dominant or diarrhea dominant by ________.

the predominant stool on the Bristol stool scale

True or False: Painless constipation and diarrhea indicate irritable bowel syndrome.

False: Painless constipation and diarrhea does not indicate irritable bowel syndrome. However, defecation straining, urgency or feeling of incomplete bowel movement, passing mucus, or bloating may indicate IBS.

What is irritable bowel syndrome?

Irritable bowel syndrome is a chronic functional bowel disorder with a normal intestinal structure characterized by abdominal pain or discomfort and altered bowel habits. It has a poorly understood cause with few reliable treatments. It is a clinical presentation with no clear diagnostic markers to seal a diagnosis.

_______ can be given for anticipatory diarrhea.

Opioid-based agents such as loperamide (Imodium)

What is the initial therapy of choice for IBS-D?

Opioid-based agents such as loperamide (Imodium) is the initial therapy of choice for IBS-D. These opioid based agents segment colonic contractions, delay fecal transit, increase anal pressure, and reduce rectal perception.

What is post-infectious irritable bowel syndrome?

Post-infectious irritable bowel syndrome is irritable bowel syndrome caused by a previous gastroenteritis-like illness. You can see this in COVID!

Rome Criteria for Irritable Bowel Syndrome

Recurrent abdominal pain must occur once per week with two or more of the following: 1. related to defecation. 2. change in stool frequency at onset. 3. change in stool appearance at onset. * The criteria is fulfilled for the last three months with symptom onset at least six months prior to diagnosis.

What is a non-absorbable antibiotic that can be used in patients with autoimmune IBS-D?

Rifaximin is a non-absorbable antibiotic that can be used in patients with autoimmune IBS-D. This drug improves global IBS scores and has a short-term effect in some patients.

Peppermint oil increases the risk of ______.

reflux

Eluxadoline is indicated in ______.

refractory IBS-D patients

Peppermint oil is a smooth muscle ______.

relaxer