IBS Flashcards
Irritable Bowel Syndrome
-GI syndrome characterized by chronic abdominal pain and altered bowel habits in the absence of any known organic cause
Epidemiology of IBS
- most prevalent GI disease
- Female: Male 2:1
- most patients develop symptoms at <1% of IBS patients have refractory disease
- usually associated with psychosocial distress
- become chronic healthcare users
Pathophysiology of IBS
- uncertain etiology
- motility disorder
- visceral hypersensitivity
- intestinal inflammation
- intestinal microbial changes
- psychological
Motility Disorder
- colonic motility is considered the main culprit
- no particular motility pattern has been identified
- treatment is aimed at altering the underlying dominant motility pattern
- mostly constipation
Visceral Hypersensitivity
- increased sensitivity to pressure and pain stimulus
- Distention
- Bloating: half of patients have this complaint results from slow transit
Intestinal Inflammation
certain patients show increased inflammatory markers (TNF and other cytokines)
Microbial Alterations
- Post infectious IBS
- Alterations in Gut microbes
- Bacterial Overgrowth
Psychological Causes
- IBS patients tend to have more psychological diagnoses
- various studies have shown abuse as an independent risk factor for IBS
- corticotropin releasing factor (CRF) as possible mediating factor
Rome III Diagnostic Criteria IBS
- recurrent abdominal pain or discomfort for 3 consecutive days a month in last 3 months associated with 2 or more:
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
Manning Criteria for IBS
- likelihood of IBS increases with number of criteria present
1. pain relieved with defecation
2. more frequent stools at onset of pain
3. looser stool at the onset of pain
4. visible abdominal distention
5. passage of mucus
6. sensation of incomplete evacuation
IBS Subtypes
IBS-C: hard stool >25% of stool
IBS-D: loose/watery stool>25% of stool
Mixed IBS: loose and hard stool alternate>25% each
Unsubtyped
Diarrhea in IBS
> 3 stools/day
frequent non-bloody stools of small volume
usually AM or post-prandial
does not awaken patient
may be associated with urgency or feeling of incomplete evacuation
Constipation in IBS
<3 stools/week
may be constant or intermittent
stools may be hard or pellet-shaped
Alternating Constipation/Diarrhea
-most frequent type of altered bowel habits seen in IBS
Red Flags in Diagnosis of IBS
- signs/symptoms suggest organic disease is present and symptoms are not IBS
- history-weight loss, severe chronic diarrhea or constipation, rectal bleeding, onset of sx in patient >50, recent travel or abx use, family history of GI cancer, sprue, IBD
Red Flags in Physical Exam/Lab Diagnosis of IBS
- arthritis, lymphadenopathy, abdominal mass
- anemia, abnormal thyroid test, abnormal Ca, abnormal liver tests, leukocytosis
Evaluation of IBS
- good H&P
- CBC, stool for hemoccult
- clinical diagnosis, therapeutic trial
- further work-up if indicated or symptoms persist
IBS Symptoms: Pain
- abdominal X-ray
- CT scan
- ultrasound
- small bowel X-ray
IBS Symptoms: Constipation
- TSH, Ca
- Colonoscopy if >50
IBS Symptoms: Diarrhea
- Hx of lactose intolerance
- stool studies with recent travel or abx use
- stool for fat
- serology for sprue
- sigmoidoscopy with biopsies
Treatment of IBS
- based on nature/severity of symptoms & whether psychosocial impairment is also present
- therapeutic relationship is important
- Education, Reassurance, Dietary Modification, Drug (abdominal pain, constipation, diarrhea)
- psychological treatment
Dietary Treatment of IBS
- certain foods may cause symptoms in some individuals-fatty foods, alcohol, caffeine, beans
- Food dairy- may help determine exacerbating foods
Drug Treatment of IBS
- fiber: may help with constipation
- Loperamide: symtomatic control of diarrhea
- Anti-cholinergics: pain & bloating
- will control in most patients
Treatment for IBS with more severe symptoms
- anti-depressants: used for more severe pain, psychotrophic effect, modulated GI motility, may modulate visceral hyperesthesia
- tricyclic antidepressants (amitriptyline, imipramine, nortriptyline, desipramine) used at doses lower than for depression
- SSRI (especially with psychiatric disorders), give for 3-4 weeks
Other Therapies for IBS
- Lubiprostone: locally acting chloride channel activator that enhances chloride-rich intestinal fluid secretion used in constipation predominant IBS
- Abx
- Guanylate Cyclase -2c (GCS-2C)
- Laniclotide (Linzess)
- Plecanatide
Psychological Treatment in IBS
- useful for severe symptoms, especially associated with psychiatric disorders or past history of abuse
- cognitive-behavioral treatment, stress management, and behavioral modification may all be useful
