10/12- Functional GI Disorders Flashcards

1
Q

What are Functional GI disorders?

A
  • Defined by symptoms
  • Biochemical, radiologic and endoscopic tests cannot identify an organic cause of symptoms
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2
Q

Prevalence of Functional GI disorders?

  • Adult vs. pediatric
  • __% of adult Americans
  • __% of office visits in GIM
  • __% of referrals to GI
A
  • 28 adult and 17 pediatric
  • Highly prevalent
  • 40% of adult Americans
  • 20% of office visits in GIM
  • 40-50% of referrals to GI
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3
Q

What are some of the classes of Functional GI Disorders?

A
  • Functional Esophageal (4)
  • Functional Gastroduodenal (7)
  • Functional Bowel (5)
  • Functional Abdominal Pain
  • Functional Gallbladder and Sphincter of Oddi (3)
  • Functional Anorectal Disorders (8)
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4
Q

What are the ROME III Criteria for IBS? (Exam Question!)

A

Recurrent abdominal pain or discomfort at least 3 days/mo in the last 3 mo associated with 2+ of the following:

  • Improvement with defecation
  • Onset associated with change in stool frequency
  • Onset associated with change in form of stool

Criteria fulfilled for last 3 mo with symptom onset at least 6 mo prior to diagnosis

(Essential combo = abdominal discomfort + changes in bowel habits)

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5
Q

What is the most common FGID?

  • Prevalence
  • Epidemiology
A

Irritable Bowel Syndrome

  • 12% in US (but not all seek healthcare)
  • Women 1.5x more likely (to present, not to be affected)
  • Significant impact on Quality of Life
  • Significant economic impact
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6
Q

When is the typical onset of IBS?

A
  • Typical onset in 20s-30s
  • There is a childhood variant
  • Onset decreases with age
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7
Q

Pathophysiology of Functional GI Disorders?

A

Starting point:

  • Genetic factors
  • Environment

Progression

  • Abuse
  • Acute gastroenteritis
  • Other precipitating factors (stress, anxiety, depression, Abx use)

Physiologic Abnormalities

  • Enteric Neuropathy (inflammation of nerve endings and disruption of conduction)
  • GI motor disturbances
  • Visceral hypersensitivity
  • Abnormal central processing of sensations
  • Psychological disturbances

Flares/exacerbations:

  • Food
  • Stress Result = symptoms -> consultation
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8
Q

Describe the brain-gut axis and the control of GI function

A

Central factors

  • Brain activation pattern (disordered in FGIDs)

Autonomic factors

  • Parasympathetic and sympathetic nervous systems (PNS and SNS)

Peripheral factors

  • Serotonin signaling
  • Activation of mast cells
  • Altered cytokine levels

RESULTS

  • Changes in GI motility
  • Changes in GI secretion
  • Visceral hypersensitivity
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9
Q

T/F: Irritable bowel syndrome and ulcerative colitis are FGIDs?

A

False

  • IBS is a FGID, but ulcerative colitis is not
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10
Q

How are IBS and ulcerative colitis similar?

A

They have an abnormal response to normal GI stimulus

  • IBS pts activated limbic and paralimbic regions; may facilitate perceptual response to the stimulus
  • Pts with IBS have increased response to stress/unpleasantness than control; cannot return to same degree of relaxation even with removal of stressful stimuli
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11
Q

T/F: A significant number of IBS pts have anxiety or depressive disorder, but it is unlikely that IBS is secondary to these

A

True

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12
Q

Is there a degree of genetics behind IBS? (monozygotic vs. dizogytic twin studies)

A

Stronger association for monozygotic twins; thus, there is some genetic component

  • May be mediated by hereditability of anxiety and depression
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13
Q

Case)

  • 38 yo ME man c/o intermittent “diarrhea” and “constipation” for past 2 yrs
  • Cramps, post-cibal and morning episodes
  • Bloating
  • No weight loss, fever, GI bleeding
  • No family h/o GI cancer
  • Overweight
  • Diabetes on glipizide
  • Normal CBC, CMP, TSH Diagnosis?
A

This man fulfills criteria for GFID (pain + bowel habit symptoms for > 3 mo)

  • This is irritable bowel syndrome (IBS)
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14
Q

What are the different patient groups with IBS/constipation?

A
  • IBS-C: IBS with constipation
  • CC: chronic constipation
  • IBS-M: mixed/alternating symptoms of constipation and diarrhea
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15
Q

What history and physical exam findings are expected in IBS?

A
  • Site and radiation of pain
  • Relief with BM
  • Diarrhea/constipation
  • Onset and duration: typically subacute onset
  • Nocturnal symptoms
  • Organic bowel disease (e.g. cancer) may produce pain that wake people from sleep
  • FGID/IBS do NOT typically have nocturnal symptoms; absence of Sx that wake from sleep (sign of impaired brain-gut axis)
  • Association with meals, medications
  • Often the pain results from overactive gastric reflexes
  • Blood from up or down
  • Weight loss
  • Family history
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16
Q

T/F: IBS commonly occurs with co-morbidities

A

True!

Many:

  • Depression (39%)
  • Migraine (37%)
  • Anxiety (35%)
  • Neuralgia
  • Headache
  • Chronic fatigue
  • Chronic pain
  • Fibromyositis
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17
Q

What signs/symptoms are NOT typical of a functional GI disorder?

A
  • Bleeding
  • Anemia
  • Unexplained weight loss (>10% body wt)
  • Nocturnal symptoms
  • Progressive dysphagia, odynophagia
  • Persistent vomiting
  • Lymphadenopathy
  • Abdominal mass
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18
Q

T/F: Organic diseases are found with increased prevalence in pt with IBS

A

False

  • These (colorectal cancer, lactose malabsorption, thyroid dysfunction…) do not occur more with IBS
  • Exception: celiac disease may be over-represented in pts with IBS who have diarrhea
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19
Q

IBS pharmacologic therapies are organized by symptoms. What symptoms are treated?

A
  • Abdominal pain/discomfort
  • Bloating/distension
  • Altered bowel function
20
Q

What is the emerging consensus concerning the microbiota in IBS?

A
  • Decreased proportions of the genera Bifidobacterium and Lactobacillus
  • Increased ratios of Firmicutes:Bacteroidetes, at the phylum level (Some problems with studies: small, heterogeneous samples, not controlled for age/sex/meds/diet…)
21
Q

What is the most extensively studied antibiotic for IBS?

  • Distribution
  • ASEs
  • Efficacy
A

Rifaximin

  • Gut-directed antibiotic; functions on the assumption that the microbiota plays a role in IBS
  • Pretty broad spectrum
  • Not systemically absorbed
  • Generally well-tolerated

ASEs:

  • Headache
  • Abdominal pain

Results:

  • 40% with antibiotic vs. 32% describe adequate relief of global symptoms
22
Q

What are probiotics?

A

Microorganisms that are believed to provide health benefits

23
Q

What are some probiotics used for IBS?

  • Characteristics
A
  • Lactobacilli (anaerobic gm + rods)
  • Casei
  • Plantarum
  • Acidophilus
  • Reuteri
  • Bifidobacteria (anaerobic gm + rods)
  • VSL #3 (8 organisms: 3 bifido, 1 streptococcus, 4 lactobacilli)
  • Enteroccoccus
  • Streptococcus salivarius
  • Saccharomyces
24
Q

What is the mechanism of action of probiotics?

A
  • Competitive inhibition
  • Barrier protection
  • Immune effects
  • Anti-inflammatory effects
  • Production of various substances (enzymes, SCFA, bacteriocidal agents)
  • Ability to alter local pH and physiology
  • Provides nutrition to colonocytes
25
Q

What is Lubiprostone?

  • Mechanism of action
A
  • Fatty acid derived from prostaglandin E1
  • Acts by activating CIC-2 chloride channels on the apical aspect of gastrointestinal epithelial cells, producing a chloride-rich fluid secretion
26
Q

What is Linaclotide? - Mechanism of action

A
  • Peptide agonist of the guanylate cyclase 2 C.
  • Reduces activation of colonic sensory neurons, reducing pain; and activates colonic motor neurons –> increases smooth muscle contraction and thus promotes bowel movements
  • Most common ASE = diarrhea
27
Q

T/F: Diet affects IBS

A

True

28
Q

What is the difference between a food allergy and a food intolerance? Aversion?

A
  • Allergy- immunologic
  • Intolerance- adverse reaction; non-immunologic
  • Aversion: psychological avoidance to a specific food or foods
29
Q

Characteristics of food allergy

  • Prevalence
  • More common in
  • Timing
  • Mechanism
  • Common food allergies
A
  • 30-50% of GI clinic pts believe their symptoms to be related to food allergy/intolerance but true food allergies are uncommon (1-3%)
  • More common in atopic individuals
  • Symptoms develop after eating
  • IgE mediated (type 1) – rapid in onset
  • Cell mediated (type 4) – delayed hypersensitivity

Worst offenders:

  • Peanuts, tree nuts
  • Eggs
  • Cow’s milk
  • Soy, wheat
  • Fish, shellfish
30
Q

Characteristics of food intolerance?

  • Prevalence
  • Gender
A
  • 20% complain of intolerance
  • More women report symptoms
  • Prevalence in IBS ranges from 20-67%
31
Q

Why might food cause GI symptoms?

A
  • Stimulation of mechanoreceptors
  • Stimulation of chemoreceptors
  • Release of hormones/peptides
  • Alterations in secretion
  • Changes in osmolarity
  • Fermentation of foods
  • Subsequent luminal distention
32
Q

What foods commonly cause/exacerbate IBS?

A
  • Lactose
  • Fructose
  • Non-absorbable sugars
  • Fibers
  • Wheat
  • Other fermentable foods
33
Q

What is lactose?

  • Metabolism
  • Mechanism
A
  • Lactose = disaccharide
  • Broken down into glucose and galactose
  • Lactase deficiency leads to fermentation in the colon
  • Excess hydrogen, CO2, methane
34
Q

__% of US adults are lactose intolerant

__% worldwide prevalence

  • Prevalence in IBS pts is ___ (higher/lower)
A

30-35% of US adults are lactose intolerant

70% worldwide prevalence

  • Prevalence in IBS pts is higher
35
Q

What is the Goal in lactose-free diet?

Treatment options for lactose intolerance?

A

Goals:

  • Maintain calcium
  • Vitamin D

Treatment options:

Dairy free

  • Lactaid
  • Rice, Almond, Coconut, Hemp, Soy, Quinoa, Oat, Hazelnut
36
Q

How is lactose intolerance diagnosed?

A
  • Breath test
  • Challenge (e.g. 3 big glasses of milk)
  • Elimination
37
Q

What is fructose?

  • Metabolism
  • Present in what foods
A

Fructose = monosaccharide

  • Exists as free hexose or after sucrose hydrolysis
  • No enzyme present in human small intestine
  • Very poorly absorbed by itself (GLUT5)
  • Efficiently absorbed in conjunction with glucose (GLUT2)

Found in:

  • Fruits
  • Honey
  • Table sugar
  • High fructose corn syrup
38
Q

Describe fructose intolerance

  • Prevalence
  • Association with IBS
  • Treatment strategies
A
  • 11-70% fructose intolerance
  • 40% of IBS pts may be fructose intolerance

Treatment strategies

  • Minimize
  • Avoid
  • Ingest with glucose
  • (no high fructose corn syrup!)
39
Q

What is gluten?

  • Genetics
  • Prevalence
  • Association with IBS
A

Gluten = storage protein in wheat, barley, rye

  • Genetically susceptible individuals (HLA-DQ2 and HLA-DQ8) develop an immune response
  • Worldwide prevalence of celiac disease in IBS patients = 4% (US = 0.4%)
  • KEY POINT: The vast majority of IBS patients don’t have celiac disease.
40
Q

What were the effects of a low gluten diet on IBS?

A
  • Prior symptom improvement on gluten-free diet
  • Primary endpoint = adequate symptom relief
  • Gluten group had less improvement in symptoms than those on gluten free (pain, bloating, satisfaction with stool consistency, tiredness)
41
Q

What are FODMAPs?

A

Fermentable Oligo, Di, Monosaccharides and Polys

  • Excess fructose (honey, apples, pears…)
  • Fructans (wheat, rye, onions, leeks, zucchini)
  • Sorbitol (apricots peaches, artificial sweeteners, gums)
  • Raffinose (lentils, cabbage, Brussel sprouts, asparagus, green beans, legumes)
42
Q

What can be eaten in a FODMAP diet?

A
  • Lean proteins
  • Gluten-free breads, rolls, pasts
  • Rice, corn, and oat products
  • Quinoa
  • Safe fruits and veggies: snow peas, bok choy, carrots, mandarin
43
Q

What were the effects of FODMAP diet on IBS? (test question)

A
  • FODMOP diet compared to typical Australian diet; measured stool frequency and water content
  • Low FODMOP diet -> lower global GI symptom scores
  • Symptoms of bloating, gas, and abdominal pain were all improved on FODMAP
44
Q

What is the mechanism of action of antidepressents?

How does this relate to GI function?

A
  • Antidepressent action works in CNS
  • May have visceral analgesia
  • Changes in GI motility; smooth muscle relaxation
45
Q

What is a prediction error about expected interoceptive state?

A

Worrying about pain (worried it will be unbearable)

  • Cognitive behavioral therapy functions on the relationship that thoughts -> feelings (manage thoughts to help)
46
Q

What are psychological therapies?

A
  • Cognitive behavioral therapy
  • Relaxation training
  • Dynamic psychotherapy
  • Hypnotherapy