10/12- Functional GI Disorders Flashcards Preview

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Flashcards in 10/12- Functional GI Disorders Deck (46)

What are Functional GI disorders?

- Defined by symptoms

- Biochemical, radiologic and endoscopic tests cannot identify an organic cause of symptoms


Prevalence of Functional GI disorders?

- Adult vs. pediatric

- __% of adult Americans

- __% of office visits in GIM

- __% of referrals to GI

- 28 adult and 17 pediatric

- Highly prevalent

- 40% of adult Americans

- 20% of office visits in GIM

- 40-50% of referrals to GI


What are some of the classes of Functional GI Disorders?

- Functional Esophageal (4)

- Functional Gastroduodenal (7)

- Functional Bowel (5)

- Functional Abdominal Pain

- Functional Gallbladder and Sphincter of Oddi (3)

- Functional Anorectal Disorders (8)


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

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)


What is the most common FGID?

- Prevalence

- Epidemiology

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


When is the typical onset of IBS?

- Typical onset in 20s-30s

- There is a childhood variant

- Onset decreases with age


Pathophysiology of Functional GI Disorders?

Starting point:

- Genetic factors

- Environment


- 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


- Food

- Stress Result = symptoms -> consultation


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

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


- Changes in GI motility

- Changes in GI secretion

- Visceral hypersensitivity


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


- IBS is a FGID, but ulcerative colitis is not


How are IBS and ulcerative colitis similar?

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


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



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

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

- May be mediated by hereditability of anxiety and depression



- 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?

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

- This is irritable bowel syndrome (IBS)


What are the different patient groups with IBS/constipation?

- IBS-C: IBS with constipation

- CC: chronic constipation

- IBS-M: mixed/alternating symptoms of constipation and diarrhea


What history and physical exam findings are expected in IBS?

- 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


T/F: IBS commonly occurs with co-morbidities



- Depression (39%)

- Migraine (37%)

- Anxiety (35%)

- Neuralgia

- Headache

- Chronic fatigue

- Chronic pain

- Fibromyositis


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

- Bleeding

- Anemia

- Unexplained weight loss (>10% body wt)

- Nocturnal symptoms

- Progressive dysphagia, odynophagia

- Persistent vomiting

- Lymphadenopathy

- Abdominal mass


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


- 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


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

- Abdominal pain/discomfort

- Bloating/distension

- Altered bowel function


What is the emerging consensus concerning the microbiota in IBS?

- 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...)


What is the most extensively studied antibiotic for IBS?

- Distribution

- ASEs

- Efficacy


- Gut-directed antibiotic; functions on the assumption that the microbiota plays a role in IBS

- Pretty broad spectrum

- Not systemically absorbed

- Generally well-tolerated


- Headache

- Abdominal pain


- 40% with antibiotic vs. 32% describe adequate relief of global symptoms


What are probiotics?

Microorganisms that are believed to provide health benefits


What are some probiotics used for IBS?

- Characteristics

- 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


What is the mechanism of action of probiotics?

- 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


What is Lubiprostone?

- Mechanism of action

- 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


What is Linaclotide? - Mechanism of action

- 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


T/F: Diet affects IBS



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

- Allergy- immunologic

- Intolerance- adverse reaction; non-immunologic

- Aversion: psychological avoidance to a specific food or foods


Characteristics of food allergy

- Prevalence

- More common in

- Timing

- Mechanism

- Common food allergies

- 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


Characteristics of food intolerance?

- Prevalence

- Gender

- 20% complain of intolerance

- More women report symptoms

- Prevalence in IBS ranges from 20-67%


Why might food cause GI symptoms?

- Stimulation of mechanoreceptors

- Stimulation of chemoreceptors

- Release of hormones/peptides

- Alterations in secretion

- Changes in osmolarity

- Fermentation of foods

  • Subsequent luminal distention


What foods commonly cause/exacerbate IBS?

- Lactose

- Fructose

- Non-absorbable sugars

- Fibers

- Wheat

- Other fermentable foods


What is lactose?

- Metabolism

- Mechanism

- Lactose = disaccharide

  • Broken down into glucose and galactose

- Lactase deficiency leads to fermentation in the colon

  • Excess hydrogen, CO2, methane


__% of US adults are lactose intolerant

__% worldwide prevalence

- Prevalence in IBS pts is ___ (higher/lower)

30-35% of US adults are lactose intolerant

70% worldwide prevalence

- Prevalence in IBS pts is higher


What is the Goal in lactose-free diet?

Treatment options for lactose intolerance?


- Maintain calcium

- Vitamin D

Treatment options:

Dairy free

- Lactaid

- Rice, Almond, Coconut, Hemp, Soy, Quinoa, Oat, Hazelnut


How is lactose intolerance diagnosed?

- Breath test

- Challenge (e.g. 3 big glasses of milk)

- Elimination


What is fructose?

- Metabolism

- Present in what foods

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


Describe fructose intolerance

- Prevalence

- Association with IBS

- Treatment strategies

- 11-70% fructose intolerance

- 40% of IBS pts may be fructose intolerance

Treatment strategies

- Minimize

- Avoid

- Ingest with glucose

- (no high fructose corn syrup!)


What is gluten?

- Genetics

- Prevalence

- Association with IBS

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.


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

- 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)


What are FODMAPs?

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)


What can be eaten in a FODMAP diet?

- Lean proteins

- Gluten-free breads, rolls, pasts

- Rice, corn, and oat products

- Quinoa

- Safe fruits and veggies: snow peas, bok choy, carrots, mandarin


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

- 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


What is the mechanism of action of antidepressents?

How does this relate to GI function?

- Antidepressent action works in CNS

- May have visceral analgesia

- Changes in GI motility; smooth muscle relaxation


What is a prediction error about expected interoceptive state?

Worrying about pain (worried it will be unbearable)

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


What are psychological therapies?

- Cognitive behavioral therapy

- Relaxation training

- Dynamic psychotherapy

- Hypnotherapy