Irritable Bowel Syndrome - Chapter 327 Flashcards

1
Q

Definition of IBS

A

Irritable bowel syndrome (IBS) is
* a functional bowel disorder
* characterized by abdominal pain or discomfort and altered bowel habits
* in the absence of detectable structural abnormalities.

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2
Q

How to diagnose IBS

A

based on clinical presentation

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3
Q

IBS is a disorder that affects all ages, although most patients have their first symptoms before what age

A

before age 45

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4
Q

________ is a key symptom for the diagnosis of IBS.

A

pain is a key symptom for the diagnosis of IBS.

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5
Q

3 differenes of Rome IV criteria from Rome III

A
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6
Q

prerequisite clinical feature of IBS
vs
most consistent clinical feature in IBS

A
  • abdominal pain – prerequisite clinical feature of IBS
  • altered bowel habis – most consistent clinical feature in IBS
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7
Q

in IBS, abnormalities in the small bowel occur during the night

True or False

A

False….

abnormalities in the small bowel during the diurnal (waking) period; nocturnal motor patterns are not different from those of healthy controls.

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8
Q

colonic motor abnormalities are more prominent under unstimulated conditions in IBS.

True or False

A

FALSE…
* Studies of colonic myoelectrical and motor activity under unstimulated conditions have not shown consistent abnormalities in IBS.
* In contrast, colonic motor abnormalities are more prominent under stimulated conditions in IBS.

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9
Q

Inflation of rectal balloons BOTH in IBS-D and IBS-C patients leads to marked and prolonged distention-evoked contractile activity.

True or False

A

True

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9
Q

prolonged fasting in IBS patients is often associated with significant WORSENING of symptoms.

A
  • IBS patients frequently exhibit exaggerated sensory responses to visceral stimulation.
  • On the other hand, prolonged fasting in IBS patients is often associated with significant improvement in symptoms.
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9
Q

Lipids RAISE the thresholds for the first sensation of gas, discomfort, and pain in IBS patients.

True or False

A

Lipids lower the thresholds for the first sensation of gas, discomfort, and pain in IBS patients.

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10
Q

Apart from enhanced gut sensitivity, IBS patients also exhibit heightened sensitivity at what part of the body

A

In contrast to enhanced gut sensitivity, IBS patients do not exhibit heightened sensitivity elsewhere in the body

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10
Q

Functional brain imaging studies such as magnetic resonance imaging (MRI) have shown that in response to distal colonic stimulation THIS PART OF THE BRAIN shows greater activation in IBS patients.

A

Functional brain imaging studies such as magnetic resonance imaging (MRI) have shown that in response to distal colonic stimulation, the mid-cingulate cortex—a brain region concerned with attention processes and response selection—shows greater activation in IBS patients.

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11
Q

In addition to mid cingulate cortex, IBS patients also show preferential activation of the THIS PART OF BRAIN, which contains a vigilance network within the brain that increases alertness.

A

prefrontal lobe

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12
Q

Abnormal psychiatric features are recorded in up to 80% of IBS patients, especially in referral centers…. WHAT psychiatric diagnosis predominates.

A

Abnormal psychiatric features are recorded in up to 80% of IBS patients, especially in referral centers; however, no single psychiatric diagnosis predominates

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13
Q

Brain functional MRI studies show greater activation of the WHAT PART OF THE BRAIN of IBS patients with a past history of sexual abuse.

A

Brain functional MRI studies show greater activation of the posterior and middle dorsal cingulate cortex, which is implicated in affect processing in IBS patients with a past history of sexual abuse.

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14
Q

“postinfective” IBS occurs more commonly in males

True or False

A

“postinfective” IBS occurs more commonly
* in females
* and affects younger rather than older patients

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15
Q

“postinfective” IBS occurs more commonly in older people

True or False

A

“postinfective” IBS occurs more commonly
* in females
* and affects younger rather than older patients

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16
Q

Age older than ____years might protect against postinfectious IBS,

A

Age older than 60 years might protect against postinfectious IBS,

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17
Q

treatment with antibiotics has been associated with increased risk of postinfectious IBS

True or False

A

True

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18
Q

The microbes involved in the initial infection leading to postinfectious GBS are (3)

A

The microbes involved in the initial infection are
* Campylobacter
* Salmonella
* Shigella

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19
Q

Increased rectal mucosal enteroendocrine cells, T lymphocytes, and gut permeability are acute changes following THIS GUT INFECTION that could persist for more than a year and may contribute to postinfective IBS.

A

Increased rectal mucosal enteroendocrine cells, T lymphocytes, and gut permeability are acute changes following Campylobacter enteritis that could persist for more than a year and may contribute to postinfective IBS.

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20
Q

This cation channel play a central role to the initiation and persistence of visceral hypersensitivity.

A

cation channels such as TRPV1 (vanilloid) channels are central to the initiation and persistence of visceral hypersensitivity.

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21
Q

These cells have a prominent role in the pathogenesis of visceral hypersensitivity.

A

Mast cells

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22
Q

A high prevalence of small-intestinal bacterial overgrowth in IBS patients has been noted based on WHAT TEST

A

A high prevalence of small-intestinal bacterial overgrowth in IBS patients has been noted based on positive lactulose hydrogen breath test.

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23
Q

A high prevalence of small-intestinal bacterial overgrowth in IBS patients has been noted based on positive lactulose hydrogen breath test.

HOWEVER, Abnormal H2 breath test can occur because of ________ and may lead to erroneous interpretation

A

Abnormal H 2 breath test can occur because of small-bowel rapid transit and may lead to erroneous interpretation

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24
Q

IBS patients generally had decreased proportions of these bacteria
(2)

A
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25
Q

IBS patients generally had increased proportions of these bacteria
(3)

A
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26
Q

These bacteria are anti-inflammatory organisms (2) and may reduce mucosal inflammation in IBS patients

A
  • Bifidobacterium
  • Faecalibacterium
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27
Q

Bacteria capable of injuring epithelium lining and inducing mucosal inflammation via a lipopolysaccharide-dependent pathway

A
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28
Q

Bacteria that can produce toxin to dissolve glycoproteins and induce mucosal inflammation

A
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29
Q

Bacteria that can produce gas and organic acids from glucose and fructose fermentation, resulting in bloating and abdominal pain.

A
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30
Q

The serotonin-containing enterochromaffin cells in the colon are increased in a subset of IBS-C patients

True or False

A

False….

The serotonin-containing enterochromaffin cells in the colon are increased in a subset of IBS-D patients

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31
Q

WHAT is the rate-limiting enzyme in enterochromaffin cell serotonin biosynthesis

A

Tryptophan hydroxylase 1 (TPH1) is the rate-limiting enzyme in enterochromaffin cell serotonin biosynthesis

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32
Q

Effect of gut microbes on colonic serotonin production

A

gut microbes promote colonic serotonin production through an effect of short-chain fatty acids on enterochromaffin cells.

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32
Q

In IBS patients, the expression of THIS TRANSPORTER is downregulated due to gram negative gut dysbiosis.

A

In IBS patients, the expression of mucosal serotonin reuptake transporter (SERT) is downregulated due to gram negative gut dysbiosis.

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33
Q

4 clinical features that argue against the diagnosis of IBS

A
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34
Q

Postprandial pain accompanied by bloating, nausea, and vomiting suggests what 2 diseases

A
  • gastroparesis
  • or partial intestinal obstruction
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35
Q

this possibility should be ruled out before making a diagnosis of IBS

A

Patients with small intestinal bacteria overgrowth can present with abdominal pain, nausea, and bloating, and this possibility should be ruled out before making a diagnosis of IBS.

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36
Q

These 2 conditions are DDx for IBS-C. They can present with painful constipation as the major complaint

A
  • Acute intermittent porphyria
  • Lead poisoning
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37
Q

In patients with persistent diarrhea not responding to simple antidiarrheal agents, a sigmoid colon biopsy should be performed to rule out what disease….

A

In patients with persistent diarrhea not responding to simple antidiarrheal agents, a sigmoid colon biopsy should be performed to rule out microscopic colitis.

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38
Q

the possibility of lactase deficiency should be ruled out HOW (2)

A

the possibility of lactase deficiency should be ruled out with
* a hydrogen breath test
* or with evaluation after a 3-week lactose-free diet

39
Q

Excessive gas with bloating also raises the possibility of small-bowel bacteria overgrowth and should be
ruled out with WHAT TEST

A

Excessive gas with bloating also raises the possibility of small-bowel bacteria overgrowth and should be
ruled out with a glucose hydrogen breath test

40
Q

In patients with IBS with concurrent symptoms of dyspepsia, the ff tests are advisable (2)

A
  • upper GI radiographs or
  • esophagogastroduodenoscopy
41
Q

In IBS patients with postprandial right upper quadrant pain, this imaging should be obtained.

A

In patients with postprandial right upper quadrant pain, an ultrasonogram of the gallbladder should be obtained.

42
Q

Laboratory features that argue against IBS (4)

A

Laboratory features that argue against IBS include
* evidence of anemia,
* presence of leukocytes or blood in stool,
* elevated sedimentation rate,
* and stool volume >200–300 mL/d.

43
Q

FODMAP stands for…

A

fermentable oligosaccharides, disaccharides, monosaccharides, and polyols

44
Q

Stool-bulking agents bind water and thus prevent both excessive hydration and dehydration of stool.

True or False

A

True

45
Q

This fiber has been shown to reduce perception of rectal distention

A

Psyllium

46
Q

Which type of fiber tend to produce less bloating and distention.

Insoluble or soluble

A

Compared to insoluble dietary fiber such as wheat bran, soluble fibers such as psyllium preparations tend to produce less bloating and distention.

47
Q

Target dose of total dietary and supplementary fiber per day

A

targeted dose of 20–30 g of total dietary and supplementary fiber per day.

48
Q

These 2 kinds of constipation do not respond to fiber supplementation

A
  • drug-induced constipation
  • slow colonic transit constipation
49
Q

Best timing to give antispamsmodics in order to prevent or control postprandial pain

A

Physiologic studies demonstrate that anticholinergic drugs inhibit the gastrocolic reflex; hence, postprandial pain is best managed by giving antispasmodics 30 min before meals so that effective blood levels are achieved shortly before the anticipated onset of pain.

50
Q

Most anticholinergics contain ____, which may cause xerostomia, urinary hesitancy and retention, blurred vision, and drowsiness.

A

Most anticholinergics contain natural belladonna alkaloids, which may cause xerostomia, urinary hesitancy and retention, blurred vision, and drowsiness.

51
Q

Example of synthetic anticholinergics causing less effect on mucous membrane secretion and produce fewer undesirable side effects

A

Dicyclomine

52
Q

Peppermint oil appears to reduce abdominal cramps by WHAT mechanism.

A

Peppermint oil appears to reduce abdominal cramps by some undefined mechanism.

53
Q

The most commonly reported adverse event with the use of peppermint oil is …..

A

Heartburn

54
Q

initial therapy of choice for IBS-D

A

Peripherally acting opiate-based agents

55
Q

Usual dose of loperamide
vs
Max dose per day

A
55
Q

Why is increasing the dose of opiates not required to maintain antidiarrheal potency

A

In general, the intestines do not become tolerant of the antidiarrheal effect of opiates, and increasing doses are not required to maintain antidiarrheal potency.

56
Q

Why can cholestyramine resin be useful sometimes in diarrhea in IBS

A

up to 30% of IBS-D patients may have bile acid malabsorption.

cholestyramine is a bile acid binder

57
Q

This tricyclic antidepressant slows jejunal migrating motor complex transit propagation and delays orocecal and whole-gut transit

A

imipramine

58
Q

Tricyclic antidepressants are useful in both IBS-D and IBS-C patients

True or False

A

False.

59
Q

The beneficial effects of the tricyclic compounds in the treatment of IBS appear to be dependent of their effects on depression.

True or False

A

FALSE…

The beneficial effects of the tricyclic compounds in the treatment of IBS appear to be independent of their effects on depression.

60
Q

In contrast to tricyclic agents, THIS DRUG accelerates orocecal transit, raising the possibility that this drug class may be useful in IBS-C patients

A

In contrast to tricyclic agents, the selective serotonin reuptake inhibitor (SSRI) paroxetine accelerates orocecal transit, raising the possibility that this drug class may be useful in IBS-C patients

tricyclic antidepressant imipramine kasi slows jejunal migrating motor complex transit propagation and delays orocecal and whole-gut transit… TCAs known to be effective in IBS-D talaga

61
Q

This antidepressant blunts perception of rectal distention and reduces the magnitude of the gastrocolonic response in healthy volunteers.

A

The SSRI citalopram blunts perception of rectal distention and reduces the magnitude of the gastrocolonic response in healthy volunteers.

62
Q

____, an over-the-counter oral β-glycosidase solution, may reduce rectal passage of gas without decreasing bloating and pain.

A

Beano, an over-the-counter oral β-glycosidase solution, may reduce rectal passage of gas without decreasing bloating and pain.

63
Q

____ reduce bloating, gas, and fullness during and after high-calorie, high-fat meal ingestion.

A

Pancreatic enzymes reduce bloating, gas, and fullness during and after high-calorie, high-fat meal ingestion.

64
Q

These serotonin receptors (2) are found throughout the GI tract.

A

Serotonin 5-HT 3 and 5-HT 4 receptors are found throughout the GI tract.

65
Q

____, a dihydrobenzo-furancarboxamide derivative, is a new selective agonist of 5-HT4 .

A

Prucalopride, a dihydrobenzo-furancarboxamide derivative, is a new selective agonist of 5-HT4 . Used for constipation. Parang Tegaserod

66
Q

Advantage of Prucalopride from Tegaserod

A
67
Q

Prucalopride was approved by the European Medicines Agency and the U.S. Food and Drug Administration (FDA) for treatment of ……

A

chronic constipation

68
Q

In 2007, this 5-HT4 receptor agonist was voluntarily withdrawn from the market after a greater number of cardiovascular complications

A

Tegaserod

69
Q

____ is the only major side effect of Tegaserod

Tegaserod a 5-HT4 receptor agonist

A

Diarrhea

70
Q

Tegaserod was withdrawn initially from the market but in 2019 the FDA approved the use of tegaserod in women provided they meet these 3 conditioons

A
71
Q

secretagogues that stimulate net efflux of ions and water into the intestinal lumen and thus enhance transit and facilitate ease of defecation (3)

A

Lubiprostone, linaclotide, and plecanatide are secretagogues that stimulate net efflux of ions and water into the intestinal lumen and thus enhance transit and facilitate ease of defecation.

72
Q

Secretagogues increase intestinal secretion of this electrolyte

A

Secretagogues increase intestinal chloride secretion

73
Q

This secretatgogue is a bicyclic fatty acid derived from prostaglandin E 1 that activates type 3 chloride channels in the apical membrane of intestinal epithelial cells.

A
74
Q

These secretagogouges are minimally absorbed 14-amino-acid peptide guanylate cyclase-C (GC-C) agonists that bind to and activate GC-C on the luminal surface of intestinal epithelium. (2)

A
75
Q

Oral lubiprostone was effective in the treatment of patients with IBS-D

True or False

A

False….

Oral lubiprostone was effective in the treatment of patients with IBS-C

76
Q

recommended daily dose of lubiprostone

A

Lubiprostone recommended daily dose is 24 mg twice daily

77
Q

major side effects of lubiprostone (2)

A

nausea and diarrhea

78
Q

These drugs are similar to endogenous peptides secreted by the small intestine (uroguanylin) or colon (guanylin).
(2)

A

Linaclotide and plecanatide

79
Q

Differentiate Lubiprostone, Linaclotide, and Plecanatidde in terms of dosing

A
80
Q

This secretagogue is small-molecule inhibitor of GI sodium-hydrogen exchange-3

A

Tenapanor

80
Q

Dose of secretagogue Tenapanor

small-molecule inhibitor of GI sodium-hydrogen exchange-3

A

Tenapanor 50 mg BID

81
Q

How is PEG-based solution different from other osmotic laxatives in terms of action

A

polyethylene glycol (PEG)–based solution is iso-osmotic and induces bowel movement by high-volume lavage.

82
Q

chronic use of THIS LAXATIVE may result in severe hypermagnesemia in patients with renal impairment.

A

chronic use of magnesium hydroxide may result in severe hypermagnesemia in patients with renal impairment.

83
Q

Frequent sodium phosphate–based bowel cleansing should be avoided as this is associated with 3 elec abnormalities

A

Frequent sodium phosphate–based bowel cleansing should be avoided as this is associated with
* Hyperphosphatasemia
* Hypocalcemia
* Hypokalemia

84
Q

Frequent use of this LAXATIVE should be avoided as this is associated with hyperphosphatasemia , Hypocalcemia, Hypokalemia

A

sodium phosphate–based bowel cleansing

85
Q

most thoroughly studied antibiotic for the treatment of IBS.

A

Rifaximin

85
Q

Dosing of Rixamin vs Neomycin for patients with IBS

A
86
Q

These are nondigestible food ingredients that stimulate growth and/or activity of bacteria in the GI tract.

A

Prebiotics

87
Q

only antibiotic with demonstrated sustained benefit beyond therapy cessation in IBS patients

A

Rifaximin

88
Q

live microorganisms that when administered in adequate amounts in IBS patients confer a health benefit on the host.

A

Probiotics

89
Q

These 3 bacteria are used or found in probiotic agents

A
  • Bifidobacterium breve
  • Bifidobacterium longum
  • Lactobacillus acidophilus
90
Q

Effect of probiotics in each the ff IBS symptoms:
* abdominal pain
* bloating
* stool frequency
* stool consistency

A
91
Q

These FODMAPs (2) induce IBS symptoms in a dose-dependent manner.

A

Fructose and fructans

92
Q

For patients with more severe constipation, may use these drugs (3)

A
  • chloride channel opener (lubiprostone)
  • GC-C agonist (linaclotide or plecanatide)
93
Q

For IBS patients with predominant gas and bloating, may give these… (3)

A

For IBS patients with predominant gas and bloating, a
* low-FODMAP diet
* Probiotics
* Rifaximin

94
Q

Prevalence of mild vs moderate vs severe IBS

A
95
Q

3 drugs that can be given for diarreha predominant IDS

A
96
Q

3 drug classes that can be given for abdominal pain predominant IDS

A
97
Q

3 drug classes that can be given for bloating predominant IDS

A