This document defines and classifies functional bowel disorders, including irritable bowel syndrome (IBS), functional constipation, functional diarrhea, and unspecified functional bowel disorders. IBS is further described in terms of pathophysiology, clinical features, diagnostic criteria, subtypes, diagnosis supporting features, associated problems, investigations, and management approaches. Functional constipation and diarrhea are also defined and their diagnostic criteria, clinical evaluation, and treatment are outlined.

1. Functional Bowel Disorders
Zaryab Ghauri
Batch E

2. Definition
Functional bowel disorders are functional
gastrointestinal disorders with symptoms
attributable to the middle or lower
gastrointestinal tract.

3. Classification
These include the following:
1.IBS (Irritable Bowel Syndrome)
2.Functional bloating
3.Functional constipation
4.Functional diarrhea
5.Unspecified functional bowel disorder

4. When to label a bowel disorder as
Functional Bowel Disorder…
Symptoms must have occurred for the first time
> 6 months before the patient presents, and
their presence on >3 days a month during the
last 3 months.

5. 1.IBS (Irritable bowel Syndrome)
IBS is a functional bowel disorder in which
abdominal pain or discomfort is associated with
defecation or a change in bowel habit.

6. IBS (Pathophysiology)
Psychosocial Factors
Altered Gastrointestinal Motility
Abnormal Visceral Perception
Infection and Allergy

9. IBS (Clinical Features)
Colicky Abdominal Pain(lower Abdomen
relieved by defecation)
Abdominal Distention (worsens throughout the
day)
Altered Bowel Habit
Defecation straining or urgency
Rectal Mucus
Feeling of incomplete defecation

10. IBS (Diagnostic Criteria)
Recurrent abdominal pain or discomfort at least
>3 days per month in the last >3 months
associated with 2 or more of the following:
1. Improvement with defecation
2. Onset associated with a change in frequency
of stool
3. Onset associated with a change in form
(appearance) of stool

11. IBS-C
Infrequent pellety stools, usually in association with
abdominal pain or proctalgia
IBS-D
Frequent defecation but produce low volume stools +
mucus
Mixed IBS (IBS-M)
hard or lumpy stools and loose (mushy) or watery stools
Unsubtyped IBS
Insufficient abnormality of stool consistency to meet
criteria for IBS-C, D, or M.

13. IBS(Diagnosis Supporting Features)
Symptoms >6months
Previous medically unexplained symptoms
Frequent Consultation for non-GI problems
Stress worsen symptoms

14. IBS (Associated Problems)
Heartburn(Non ulcer dyspepsia)
Fibromyalgia
Chronic Fatigue Syndrome
No weight loss
Unremarkable physical Examination but abdominal
tenderness may be present.
Tensing the abdominal wall increases local
tenderness associated with abdominal wall pain,
whereas it lessens visceral tenderness by protecting
the abdominal organs (Carnett test).

15. IBS(Investigations)
Few tests are required for patients who have typical
IBS symptoms.
Full Blood Count
Faecal Calprotectin Normal
Sigmoidoscopy
Patient’s age >50years; Male gender
Family history of Colon Cancer
Weight Loss Alarming
Rectal Bleeding Features
Anemia
Nocturnal Symptoms

16. Older Patients+Rectal Bleeding History should
undergo Colonoscopy to rule out Malignancy or
IBD
In IBS-D to exclude organic GI Disease
Microscopic Colitis
Lactose Intolerance
Bile Acid Malabsorption
Coeliac Disease
Thyrotoxicosis
Parasitic Infection(Stool examination for ova
and parasites eg Giardia)

17. IBS (management)
Reassurance
Elimination of Diets(Lactose exclusion, wheat
free diet, excess caffeine intake or artificial
sweeteners such as sorbitol)
Symptoms Resolve
If Symptoms persist…

18. IBS-D Avoid legumes excessive dietary
fibers
Symptoms Persist Anti Diarrheal Drugs
Loperamide
2-8 mg daily
Codeine Phosphate
30-90 mg daily
Cholestyramine 1 Sachet daily
Symptoms Persist Amitriptyline 10-25mg at
night
Symptoms Persist Relaxation therapy
Biofeedback
Hypnotherapy

19. IBS-C High Roughage Diet
Symptoms Persist Isapghol(Psyllium)
Lactulose
Symptoms Persist Relaxation therapy
Biofeedback
Hypnotherapy

20. Pain and Bloating Spasmolytic Drugs
Mebeverine
Pepperment oil
Alverine
Symptoms Persist Amitriptyline 10-25mg at night
Probiotics
Dietry changes (exclude wheat,
Dairy Products)
Symptoms Persist Relaxation therapy
Biofeedback
Hypnotherapy

22. 2.Functional Bloating
Functional bloating is a recurrent sensation of
abdominal distention that may or may not be
associated with measurable distention, but is not
part of another functional bowel or gastro
duodenal disorder.

23. It is about twice as common in women as men and
is often associated with menstruation. Typically, it
worsens after meals and throughout the day and
improves or disappears overnight.
IBS associated.
Both increased intestinal gas accumulation and
abnormal gas transit.
Functional Bloating(Symptoms)
Diurnal Pattern
Due to ingestion of specific food
Excessive burping or flatus
Diarrhea, weight loss, or nutritional deficiency
should prompt investigation for intestinal disease.

24. Functional Bloating(Diagnostic Criteria)
Must include both of the following:
1. Recurrent feeling of bloating or visible
distention
at least 3 days/month in 3 months
2. Insufficient criteria for a diagnosis of
functional
dyspepsia, IBS, or other functional GI disorder.

25. Functional Bloating(Treatment)
Associated gut syndrome such as IBS or
constipation is improved.
If bloating is accompanied by diarrhea and
worsens after ingesting dairy products, fresh
fruits, or juices, further investigation or a dietary
exclusion trial is worthwhile.

26. 3.Functional Constipation
Functional constipation is a functional bowel
disorder that presents as persistently difficult,
infrequent, or seemingly incomplete defecation,
which do not meet IBS criteria.
Also known as chronic idiopathic constipation.
It is due to colonic inertia or anorectal
dyssynergia.
Depressed patients may have constipation.

27. Functional Constipation(Diagnostic Criteria)
1. Must include 2 or more of the following:
a. Straining during defecations
b. Lumpy or hard stools
c. Sensation of incomplete evacuation
d. Sensation of anorectal obstruction/blockage
e. Manual maneuvers to facilitate defecations
(e.g., support of the pelvic floor)
f. Fewer than 3 defecations per week
2. Loose stools are rarely present without the use
of laxatives
3. There are insufficient criteria for IBS

28. Functional Constipation(Clinical Evaluation)
Patient’s gut symptoms
General health
Psychological status
Use of constipating medications
Dietary fiber intake
Signs of medical illnesses (e.g., hypothyroidism) should
guide investigation.
Perianal and anal examination to detect fecal impaction,
anal stricture, rectal prolapse, mass, or abnormal
perineal descent with straining.
Laboratory tests are rarely helpful. Endoscopic
evaluation of the colon may be justified for patients 50
with new symptoms or patients with alarm features or a
family history of colon cancer.

29. Functional Constipation(Investigation-Transit
studies)
If fiber supplementation fails to help or worsens
the constipation, measurements of whole gut
transit time may identify cases of anorectal
dysfunction or colonic inertia.
Using radiopaque markers, measurement of
whole gut transit time (primarily colon transit)
is inexpensive, simple, and safe. Retention of
markers in the proximal or transverse colon
suggests colonic dysfunction, and retention in
the recto sigmoid area suggests obstructed
defecation.

31. Functional Constipation(Treatment)
Physicians should stop or reduce any
constipating medication the patient may be
taking and treat depression and hypothyroidism
when present.
Pharmacologic therapy is not advisable until
general and dietary measures are exhausted.
Bulking agents(Psyllium, methyl cellulose and
calcium polycarbophil)
Laxatives(Bisacodyl, sodium picosulphate, or
sennosides)

32. 4.Functional Diarrhea
Functional diarrhea is a continuous or recurrent
syndrome characterized by the passage of loose
(mushy) or watery stools without abdominal pain or
discomfort.
Functional Diarrhea(Diagnostic Criteria)
Loose (mushy) or watery stools without pain
Decreased non-propagating colonic
contractions(ring contractions) and increased
propagating colonic contractions.
Accelerated colonic transit inducible by acute stress.

33. Functional Diarrhea(Clinical Evaluation)
Dietary history can disclose poorly absorbed
carbohydrate intake, such as lactose or “sugar-
free” products containing fructose, sorbitol, or
mannitol.
Alcohol can cause diarrhea by impairing sodium
and water absorption from the small bowel.

34. Physical examination should seek signs of
anemia or malnutrition.
An abdominal mass suggests Crohn’s disease in
the young patient and cancer in the elderly
patient.
Rectal examination, colonoscopy, and biopsy can
exclude microscopic colitis, and IBD.

35. Abnormal results of blood or stool tests or other
alarm features necessitate further tests. Features
of malabsorption (malnutrition, weight loss,
non–blood-loss anemia, or electrolyte
abnormalities) should provoke the appropriate
antibody tests and/or duodenal biopsy for celiac
disease. Where relevant, giardiasis and tropical
sprue should be excluded.
Barium small bowel radiography may be
necessary. Rarely, persistent diarrhea may
require tests for bile acid malabsorption or,
more practically, a trial of the bile acid-binding
resin Colestyramine.

36. Functional Diarrhea(Treatment)
Reassurance is important.
Restriction of foods, such as those containing
sorbitol or caffeine, which seem provocative, may
help.
Antidiarrheal therapy (e.g., diphenoxylate or
Loperamide) is usually effective, especially if taken
prophylacticaly, such as before meals.
Cholestyramine, an ion-exchange resin that binds
bile acids and renders them biologically inactive, is
occasionally very effective.
The prognosis of functional diarrhea is uncertain,
but it is often self-limited

37. 5.Unspecified Functional Bowel
Disorders
Individual symptoms discussed in the previous sections
are very common in the population. These occasionally
lead to medical consultation, yet are unaccompanied by
other symptoms that satisfy criteria for a syndrome. Such
symptoms are best classified as unspecified.
Unspecified Functional Bowel Disorder
Bowel symptoms not attributable to an organic
etiology that do not meet criteria for the
previously defined categories.

38. Thank You

39. References
Davidson
http://www.fascrs.org/physicians/education/co
re_subjects/2005/functional_bowel_disorders/
http://www.romecriteria.org/
http://www.medscape.com/viewarticle/717346_
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