Clin Med IBS & Constipation Flashcards
IBS
- define
- recurrent abd pain associated with disordered bowel habits
- no structural abnormalities
- bloating and distention are typical
- disorder of gut-brain axis
- most frequently dx GI condition
- “central sensitivity syndrome”
Common comorbidities seen with IBS
- functional somatic syndromes (fibromyalgia, chronic fatigue syndrome, chronic pelvic pain, TJM, chronic back pain)
- other GI (GERD, dyspepsia)
- psych (major depression, generalized anxiety disorder, somatization, panic disorder, PTSD)
Symptom patterns IBS
- intermittent
- duration of episodes vary
- 67% have functional dyspepsia
- diarrhea, constipation or alternating between
- bloating
what is often the most bothersome symptom in IBS
bloating
7 contributing factors to IBS
- family/env
- psych disorders
- genetic predisposition
- prior infectious gastroenteritis
- alterations in gut microbiome
- bile salt overproduction
- diet
IBS Pathophys: major abnormalities (4)
- colon stimulation causes motor abnormalities
- increased rectosigmoid motor activity after meals
- increased contraction amplitude in colon
- rectal balloon inflation causes prolonged contractile activity
IBS Pathophys: visceral hypersensitivity
- not well understood
- exaggerated response to visceral stimulation (lower threshold for visceral pain)
- pain is perceived when food bolus enters cecum (exaggerated response to stimuli that are not normally pain-producing)
- up-regulated connectivity in emotional arousal circuitry = increased sympathetic arousal, anxiety, vigilance
What eating situation improves IBS, what type of food makes it worse
- fasting improves
- lipids make it worse
How is colorectal distention different in patients with IBS (2)
- activates brain stress response
- deactivates brain areas that modulate stress response
IBS Pathophys: Central neural dysregulation (2)
- greater activation of mid-cingulate cortex after colonic stimulation = subjective unpleasantness of pain
- activation of prefrontal lobe = increased alertness, possibly increased perception of pain
IBS Pathophys: Abnormal psych features (5)
- mood disorders
- anxiety disorders
- somatization
- hypervigilance
- catastrophizing
IBS Pathophys: Postinfectious
- may be induced by gastroenteritis
- campylobacter, salmonella, shigella were studied, all toxin producers
IBS Pathophys: immune activation/mucosal inflammation
- activated lymphocytes, mast cells, increased cytokines = inflammation
Cycle:
stress - cytokines - mucosal inflammation enhanced expression sensory neurons in gut - visceral hypersensitivity - chronic abd pain
IBS Pathophys: altered gut flora
differences of fecal microbiota are speculated to contribute
- unsure if causal, consequential, or result of IBS
IBS Pathophys: abnormal serotonin pathways
- 5-HT receptors for serotonin play role in GI motility and visceral perception
- Increased enterochromaffin cells with 5-HT receptors are seen in IBS-D and UC
- abnormal serotonin reuptake and variations in gene that encodes serotonin reuptake transport system are found in IBS
- likely polymorphism of 5-HT2A receptor gene may be associated with IBS
IBS Pathophys: Brain-Gut Axis
- homeostatic info sent to brain via afferent neural and humoral “gut-brain” pathways
- most signals not consciously perceived under normal conditions
- strong gut-brain signaling, triggered by noxious stimuli warns of potential treats to homeostasis that require a response
- in IBS, problems with top down modulation of pain sensation
- stress contributes to dysfunction
IBS
- sx onset age
- male vs. female
- cardinal sx
- onset before 45
- women 2-3x men
- always pain
- usually bloating
IBS
- nutrient deficiencies and weight change
- pertinent negatives
- major contributors to sx
- no nutrient deficiencies, no weight loss despite diarrhea
- no nocturnal sx
- no bleeding (except from hemorrhoids potentially)
- aggravated by stress or eating
IBS altered bowel habits
- painful defectation
- small stools
- frequent or infrequent stools
- urgency
- inconsistant/alternating
- diarrhea: small volume
- narrow stool shape
IBS abdominal pain
- usually diffuse
- LLQ most common
- worse with meals
- gas pain
IBS other common sx
- dyspepsia
- heartburn
- n/v
- sexual dysfunction :(
- urinary freq.
- fibromyalgia
- fatigue
- perimenstrual exacerbation
What is name for IBS criteria
Rome IV (2016 update)
Rome IV sx criteria
Recurrent abd pain => 1 day/week in last 3 months associated with two or more of:
- defecation
- assoc. with change in stool frequency
- assoc. with change in stool form
Rome IV IBS diagnosis time requirements
must be active for last 3 months with symptoms over at least the last 6 months total (chronicity)
What symptoms is urgency seen with in IBS
- BOTH diarrhea and constipation
How is IBS diff from functional constipation or functional diarrhea
- IBS has alternation of the two, bloating, and pain!
IBS: clinical hx
- hallmark: abd pain, esp lower abdomen
- altered bowel habits
- unpredictable pattern
- sx of bloat +/- distention
IBS: PE
- tenderness on palpation of lower abdomen
- rectal exam to r/o rectal disease, check stool for blood if indicated
IBS ddx
- celiac dz
- IBD
- microscopic colitis
- bile acid diarrhea
- dyssynergic defecation / pelvic floor dysfunction
True false: there are no clear diagnostic markers for IBS
true!! it is a clinical dx
Use stool markers/blood tests to r/o other things on ddx
Lab studies in IBS
- CBC
- CRP
- Thyroid
- stool analysis for infection if diarrhea
- stool calprotectin and/or lactoferrin which are inflammation markers
IBS: when is colonoscopy approrpaite
- ALARM sx
- fam hx colon ca
- persistent diarrhea
ALARM sx big three
- person/fam hx of colorectal ca, intestinal polyposis, IBD, celiac
- new onset of sx after age 50
- recent change in bowel movement habit
ALARM sx - additional
- nocturnal sx
- fever
- anemia
- weight loss
- fecal blood
- severe abd pain
- palpable mass
- occult stool +
IBS Treatment overview
- relationship is key! assure them they won’t die and let them know you care
- direct tx towards dominant sx
IBS Treatment - lifestyle
- avoid food precipitants (food diary)
- ask about artificial sweeteners
- increase soluble fiber
- gluten restriction
- FODMAP restriction
- make sure explain why all these changes
What does FODMAP stand for
Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyhydric alcohols
IBS Fiber tx
SOLUBLE ONLY
- bulks stool
- constipated: speeds colonic transit time
- diarrhea: absorbs water, delays colon transit time
- reduces perception rectal distention
- better results IBC-C
- psyllium is best option
- start low, titrate up to goal 20-30 grams/day
IBS and Probiotics
- proven to be slightly helpful with pain/bloating
- no help with bowel regularity
- bifidobacterium breve, b. longum, lactobacillus acidophilus
IBS and prebiotics
- promote proliferation of bifidobacteria
- not proven useful for IBS
IBS - common medication
- Rifaximin (Xifaxin)
- non-absorbable abx
- IBS-D and IBS_M
- modest improvements, mostly to bloat
- sx tent to return over time
IBS - psych interventions
- ID triggers and feelings (self monitoring)
- cognitive strategies: modify thinking errors
- problem solving to manage and cope with stress
- relaxation techniques
- hypnosis
- exposure therapy
IBS Treatment - Anti-depressant meds
- tricyclic anti-depressants
- SSRI
- SNRI
IBS tx with tricyclic anti-depressants
- slow jejunal transit, delay gut transit time
- may alter visceral hypersensitivity
- lower dose
- anticholinergic side effects that help diarrhea
- best with IBS-D
IBS tx with SSRI
- paroxetine accelerates transit time, better for IBS-C
- efficacy needs more study
Treatment of IBS-D
- Mu Opioid receptor agonist (Imodium and Lomotil)
- bile acid sequestrants (Cholestyramine, Colesevelam, Colestipol)
- 5-HT3 receptor antagonists (Lotronex)
what medication is sometimes used but has no FDA approval to treat IBS-D
Ondansetron
Three additional potential future IBS-D treatments
- Mast cell stabilizers
- muscarinic type 3 receptor antagonists
- glutamine
IBS-C treatment first line
soluble fiber
IBS-C treatment after soluble fiber
- Osmotic laxatives (don’t help pain)
- Intestinal Secretagogues (Lubiprostone, Linaclotide, Pecanatide)
IBS Pain tx
- Anti-cholinergic drugs (PRN): dicyclomine, hyoscyamine, don natal, clidinium bromide, peppermint oil
- Gas pain: gas-x, beans, lactaid
Chronic Idiopathic Constipation (CIC)
- Dx
- must rule out all other organic causes before idiopathic label
- usually requires specialist
- some will have intractable constipation
Common meds that can cause constipation
- opioids
- antiemetics
- antipsychotics
- antihypertensives (CCB, atenolol, furosemide, clonidine)
- ibuprofen
- ca and iron supplements
** also ask about laxative use/abuse: rebound constipation can occur
Chronic Idiopathic Constipation (CIC) ddx
SO MANY, big list on the lecture
Chronic Idiopathic Constipation (CIC)
- tests
- plain abd film
- Sitz Marker study for colonic transit time
- SmartPill to measure overall GI transit time
- Anorectal motility testing to determine if evacuation problem exists
- colonoscopy if >50, fam hx, alarm sx
Chronic Idiopathic Constipation (CIC)
- non-pharm tx
- toileting habits, positioning (squatty potty)
- exercise
- hydration
- dc meds that cause
- soluble fiber (usually doesn’t work though)
Chronic Idiopathic Constipation (CIC)
- pharm tx
- Osmotic laxatives (Miralax, lactulose, magnesium salts)
- Stimulant laxatives (Cascara, Senna/ex-lax/perdiem, Bisacodyl)
- Intestinal secretagogues
- Enema/suppository (Fleet, glycerine support, mineral oil enema, milk of molasses enema)
When might biofeedback therapy for Chronic Idiopathic Constipation (CIC) be needed?
- anorectal motility issue
- difficulty evacuating rectum
- manual extraction is required
When is surgery required for Chronic Idiopathic Constipation (CIC)
- rarely required, only if true colonic inertia
- subtotal colectomy
