ICL 15.2: IBS and Constipation Flashcards
what are functional gastrointestinal disorders?
FGIDS are disorders, not a disease!!
they’re functional disorder so there’s not structural or biochemical abnormalities which means there will be normal x-rays, blood tests and endoscopies
they can affect any part of the GI tract
considered a disorder of the mind gut axis
what are the most common functional gastrointestinal disorders?
- irritable bowel syndrome
altered bowel habits combined with abdominal pain/bloating that’s usually relieved with BM
- functional dyspepsia
ulcer-like symptoms with upper-GI pain/indigestion/discomfort/fullness +/- nausea, soon after eating
who is affected by IBS?
affect 5-20% of population
females > males (1.5-2:1)
younger > Older (50% <35 y/o)
affects lower socioeconomic groups more
PCP: 12%, GI practices : 28% - 50%
how do you diagnose iBS?
Rome criteria
recurrent abdominal pain, on average of at least 1 day per week in the last 3 months, associated with two or more of the following:
- pain with defecation
- onset associated with a change in frequency of stool
- onset associated with a change in form of stool
criteria needs to be fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis
what is the pathophysiology of IBS?
PSYCHOSOCIAL FACTORS
1. life stress
- psychologic state
- coping ability
- social support
PHYSIOLOGY
1. motility
- sensation
EARLY LIFE
1. genetics
- environment
FGID
1. sypmptom experience
- behavior
patients have more sleep issues and somatic pain which all leads to a decreased quality of life and they’re hard to manage because there’s so many different components to try to have to manage because you have to manage the whole brain-gut axis
how are IBS patients hypersensitive?
if you post a balloon in their colon they’ll be more uncomfortable but the same happens when you put their hand in an ice bucket so they’re just really hypersensitive
also if you put the balloon in different parts of the colon, they have referred pain in larger areas of their abdomen in comparison to normal people
so they’re just really hypersensitive to pain so they report pain more often than normal patients with the balloon insertions
what are the subtypes of iBS?
they’re based on stool consistency
IBS-C = constipation predominant IBS
IBS-D = diarrhea predominant IBS
IBS-M = mixed-IBS with both diarrhea and constipation
IBS-U = unclassified IBS
what are the different types of stool consistency?
type 1 = separate hard lumps = severe constipation
type 2 = lumpy and sausage like = mild constipation
type 3 = sausage shape with cracks in the surface = normal
type 4 = smooth, soft sauce or snake = normal
type 5 = soft blobs with clear cut edges = lacking fibre
type 6 = mushy consistency with ragged edges = mild diarrhea
type 7 = liquid consistency with no solid pieces = severe diarrhea
IBS-D has types 5-7 more than 25% of the time and IBS-C has types 1 and 2 and IBS-M it has both
what is the clinical presentation of IBS?
- chronic abdominal pain
- bloating
- altered bowel habits
in the absence of red flags***
what are the red flags that would make something not IBS?
- unintended weight loss
- blood in the stools not caused by hemorrhoid or anal fissures
- abnormal labs = anemia, hypoalbuminemia, liver tests, elevated CRP or ESR
- fever
- family history of GI cancer, IBD or celiac disease
how do you workup someone who you think has IBS if there aren’t alarm signs?
- PE
- complete blood count
- stool for occult blood
- routine colorectal cancer screening if over 50
- blood tests
- fecal calprotectin
- check stool of C/S, ova and parasites if they’re having diarrhea
- diagnostic colonoscopy if poor response to treatment
CT scans should not be routinely performed in iBS patients unless they have alarm features
what characteristics of a patient presentation would suggest that they don’t have IBS?
- onset in old age
- steady progressive course
- frequent awakening by pain
- weight loss not attributed to depression
what do you need to do to diagnose IBS-D?
- stool cultures: little role in chronic diarrhea (except for Giardia).
- celiac disease: screening with serum TTG IgA
- 24 hour stool collection: if osmotic, secretory or malabsorptive diarrhea is suspected
- colonoscopy or flexible sigmoidoscopy & biopsy: rule out microscopic colitis
- radiography: a plain film of the abdomen can detect retained stool, (constipation)
which diseases mimic IBS-D?
I = intolerances, especially carbohydrates
B = bacterial overgrowth/dysbiosis
S = sprue and maybe gluten sensitivity
D = drugs, alcohol and laxative
what is post-infectious IBS?
20% of IBS patients describe acute infectious prodrome
occurs in 5-25% after bacterial enteritis and is mostly diarrhea predominant
can occur after most after most enteric pathogens (bacterial & viral) and after antibiotic treatment
more common in females
long duration of diarrhea (eventual resolution not certain but more likely than in non-PI-IBS)
occurs in subjects with anxiety, depression
what does CIC stand for?
chronic idiopathic constipation
no reliable radiologic, endoscopic, biomarkers abnormalities…
what is chronic idiopathic constipation?
infrequent or difficult evacuation of stool
normal stool frequency is three times weekly to as frequently as twice daily so infrequency is two or fewer times a week
difficult evacuation, less clearly defined but encompasses inability to initiate or complete evacuation, excess straining, or feeling of incomplete evacuation
hard stool definition varies and is subjective… but it’s stool that’s physically hard or hard to pass
how is stool formed?
approximately 1L fluid daily reaches the cecum:
derived of water, insoluble fiber and salts
during the next 24-30hrs 90% of water and salts are reabsorbed
fiber is fermented into gas
yield is 80-120g/24hrs feces
how does the gut move?
phasic contractions and background contractility
there are high amplitude propagated contractions contribute to mass movements
parasympathetic (+)
sympathetic (-)
external Sphincter is voluntary
ascending and transverse colon act as depot for stool
transit ~12 hours/segment
what is the pathophysiology of CIC?
it’s due to altered signalizing in the GI tract!!
1. defects in mucosal serotonin/ACh
- altered numbers of EC cells
- altered levels of serotonin transporters
this all leads to altered GI physiology like altered motility, altered sensitivity, and altered secretion which can result in chronic constipation or IBS-C
what populations are moe likely to have constipation?
- females
- older subjects (increases with age)
- lower socioeconomic status.
- linked to impaired quality of life
what are the 2 posible categories of constipation?
IDIOPATHIC
1. slow transit constipation
- functional outlet
- obstruction
obscure
SECONDARY
1. metabolic
- endocrine
- smooth muscle isorders
- CNS Disorders
- peripheral nervous
system Disorder - stenosis/obstruction
- painful anal lesions
RULE OUT THE SECONDARY CAUSES FIRST!!
what are the endocrine causes of constipation?
- hypothyroidism
2. DM
what are the metabolic causes of constipation?
- hypercalcemia
2. hypokalemia
what are the neurologic causes of constipation?
- Parkinson’s
- multiple sclerosis
- spinal cord lesions
- cerebrovascular accident
- muscular dystrophy
- autonomic myopathy
what are the rheumatologist causes of constipation?
- systemic sclerosis
what are the psychosocial causes of constipation?
- depression
2. eating disorders
what are the medication causes of constipation?
- narcotics
- anticholinergenics
- antipsychotics
- calcium channel blockers
- anti-Parkinson’s therapy
- anticonvulsants
- tricyclic antidepressants
- iron
- calcium
- aluminum antacids
- sucralfate
what is the ROME0IV diagnostic criteria for chronic idiopathic constipation?
presence of difficult stool passage with symptoms for 3 months with onset more than 6 months ago
during at least 25% of their defections, there must be 2+ of the following:
1. straining
- lumpy or hard stools
- sensation of incomplete evacuation
- sensation of anorectal obstruction/blockage
- manual maneuvers to facilitate defecation
- less than 3 delectations per week
how do you dignase CIC?
if they meet the ROME-IV criteria then you look for an abnormal balloon expulsion test or abnormal anorectal manometry or anal surface EMG.
what is the ROME clinical friendly definition for IBS and CIC?
IBS : abdominal discomfort/pain associated with altered bowel habits
CIC: unsatisfactory defecation that is characterized by infrequent stools, difficult stool passage, or both
how can you differentiate CIC and IBS-C?
CIC
must include 2+:
1. hard or lumpy stool
- straining
- incomplete evacuation
- sensation of anorectal obstruction/blockage
- manual maneuvers
- < 3 defecations/week
- pain not usually present
IBS-C
recurrent abdominal pain/discomfort with:
1. change in pain with defecation
- onset associated with change in frequency of stool
- onset associated with change in form (appearance) of stool
what are the different diagnostic tests you can do for IBS or CIC?
- anorectal manomety
- balloon-expulsion
- colonic-transit study
- defecography
what is anorectal manometry and what is it used for?
a pressure-sensitive catheter is inserted into the anus to measure resting and squeeze pressures of the sphincter
normally there is an increased pressure in the rectum and decrease in the anal canal as stool moves out but with anorectal dyssynergia there’s no increased pressure in the rectum and the anal canal pressure remains elevated
assesses the internal and external anal sphincters, pelvic floor, and associated nerves
what is a balloon-expulsion test and what is it used for?
a balloon with 50 ml of water or air is inserted into the rectum and then the patient is asked to expel the balloon –> if they expel within 1 minute that’s normal and more than 2 minutes is abnormal
helps detects defecatory disorders and is a simple, office-based screening test
sensitivity 88%, specificity 89%, PPV 67% and NPV 97%
what is a colonic-transit study and what is it used for?
the patient swallows a capsule filled with radiopaque markers and then serial abdominal radiographs are taken 120 hours later
ingesting 24 plastic markers with xrays on day 1 & day 6 (120 hours) <20% should be present at day 6
it measures rate at which fecal residue moves through colon
what is a defecography and what is it used for?
thickened barium is instilled into the rectum and then radiographic films are taken during defecation
it detects structural abnormalities of the rectum –> provides useful evaluation of prolapse
what is the finger test?
put your finger in someones rectum and feel for something abnormal which means you probably need to do a more invasive modality
how do you generally manage iBS?
- avoid narcotics!! they cause constipation
- patient education about exercise and stress reduction
- fiber supplements
- diet
- anticholinergic medications
- avoid antidepressants
- antibiotics
- serotonergic tangents and prosecretory agents
what are the dietary interventions for iBS?
- gluten free
- FODMAP
- lactose free diet
- exclusion of gas producing foods = beans, onions, celery, car
what is a FODMAP?
fermentable oligo-di- and monosaccharides and polyps
huge change in IBS symptoms just by trying a low FODMAP diet!
the theory is that there is impaired absorption of the FODMAPS that leads to intestinal fermentation of the carbohydrates by gut bacteria which leads to symptoms and increased intestinal permaeability
people who do a low FODMAP diet have improved pain, bloating, passing of satisfaction with stool consistency
what is non-celiac gluten sensitivity?
gut and other symptoms that respond to a gluten-free diet; wheat allergies are excluded
they do not fulfill criteria for Celiac disease
there’s no real way of determining that gluten is inducing the symptoms because there’s no biomarkers so it’s all symptom based and a lot of people feel better when they’re put on a gluten free diet
up to 13% of the population has some gluten sensitivity! but 20% of these people actually have Celiac
what medication do you treat IBS-C with?
Prosecratory:
- linactolide
- plecanatide
- lubiprostone
what medication do you treat IBS-D with?
- rifaximin 550mg tid x 2 weeks
- ntidepressants:
TCAs
SSRIs - eluxadoline (ópiod derivative)
- alosetron
what medication can you treat any type of IBS with?
antispasmodics:
- otilonium
- pineverium
- hyocine Bromide
- cimetroprium bromide
- drotaverine
- dicyclomine hydrochloride
- peppermint oil
how do you treat CIC?
- fiber supplements
- osmotic laxatives
- stimulate laxatives
- PEG
- prosecretory: lubiprostone linaclotide prucalopride
what classes of laxatives are there?
- bulk agents
- non absorbed substances
- diphenylmethanes
- anthraquinone
- secretory drugs
what non absorbed laxatives are there?
- PEG (polyethylene glycol)
2. lactulose
what bulk agent laxatives are there?
- psyllium
- methylcellulose
- calcium polycarbophil
- wheat dextrin
what anthraquinone laxatives are there?
senna
what secretory drug laxatives are there?
- lubiprostone
- linaclotide
- plecanatide
what are the benefits of using PEG?
polyethylene glycol improves stool frequency only in CIC
may not alleviate abdominal pain
what are the benefits of using lubiprostone? what are the side effects and MOA?
selectiveC-2 chloride channel activators so it releases a bunch of Cl into the glut which is then followed by water which drives stool motility
relief of IBS symptoms in female IBS-C patients
may cause nausea, diarrhea, abdominal pain, and headache, teratogenic risks
what are the benefits of using linaclotide? what are the side effects and MOA?
guanylate cyclase agonists which drives HCO3 excretion which is also followed by water –> on the nonluminal side it induces NO which relaxes the nerve and helps with IBS-C pain!
relief symptoms of IBS-C
long-term risks are unknown, severe uncontrolled diarrhea
what are the benefits of using prucalopride? what are the side effects and MOA?
5-HT4 receptor agonist
relief of symptoms of CIC
suicidal ideation, nausea and diarrhea
how do you treat long term CIC?
subtotal colectomy for colonic intertia
this is only for patients with severe intractable and disabling symptoms
they can’t have evidence of intestinal pseudo-obstruction and must have anorectal function
how do you workup refractory constipation?
when you start a patient on treatment for CIC, start with fibers and laxatives first
then you do anorectal manometry and balloon expulsion test and if both are normal you look at clonic transit – if it’s slow you see if you can medically manage it or if you need a partial colectomy but if they’re normal then it’s IBS-C –> if they’re abnormal then you refer to biofeedback which teaches the pelvic floor how to respond properly which usually helps a lot of people –> if the two tests don’t match do defecography to figure out specifically where is messed up
what is biofeedback treatment for CIC?
for pelvic floor dysfunction (dyssynergia).
biofeedback, performed by a trained and skilled therapist
how do you medically and dietary treat IBS-D?
DIETARY
- gluten free
- low FODMAP
MEDICATION
- tricyclics
- rifaximin
- eluxadoline
what is eluxadoline?
Mu and Kappa agonist, delta antagonist so it acts like an opioid without giving the high
good for treating IBS-D
contraindication: patients at risk for pancreatitis or have had their gallbladder removed
if someone has chronic constipation what is the differential and how would you treat each?
- slow transit/functional constipation –> treat with linaclotide, lobiprostone, prucalopride, PEG, or laxatives
- IBS-C normal transit –> treat with llinaclotide, lobiprostone, SSRI, or laxatives
- dyssynergic defecation –> biofeedback therapy
what drugs are used for iBS-C treatment?
- linaclotide*
- lubiprostone*
- CBT/hypnotherapy
- diet modification
- SSRIs
- probiotics
- elobixibat
what drugs do you use to treat IBS-D?
- CBT/hypnotherapy
- diet
- rifaximin*
- TCAs
- enterra-GAM*
- eluxadoline*
- alosetron*
- probiotics
- IBgard
