IBS and Diverticulosis Flashcards
What is the criteria for IBS?
Recurrent abdominal pain or discomfort at least 3 days/month
Associated with 2 or more of the following:
- improvement with defecation
- change in stool frequency
- change in stool appearance
What are the subtypes of IBS?
IBS with constipation
IBS with diarrhea
Mixed IBS
Discuss the many factors that contribute to the pathophysiology of IBS
Dysfunction in Brain-Gut Axis Dysfunction in GI Motility Visceral Hypersensitivity Alteration in Fecal Flora Food Intestinal Inflammation Genetic Predisposition Psychosocial Factors
How does GI motility differ between IBS-C and IBS-D
IBS-C: slowed GI motility
IBS-D: increased GI motility and exaggerated motor response to CCK and meal ingestion
How does visceral hypersensitivity contribute to/manifest in IBS?
Normally: stimulation of receptors in gut wall –> dorsal horn of spinal cord –> brain
People with IBS have excess and prolonged stimulation of this pathway –> neuronal hypersensitization
What are some of the proposed causes of visceral hypersensitivity in IBS?
Increased sensation in response to stimuli (increased awareness at lower distention levels)
Abnormal stimulus (excessive gas, bloating)
Abnormal central pain processing (IBS pts. used pain and emotional arousal modulation centers more than pts. w/o IBS)
What is post-infectious IBS? What is the proposed pathophysiology?
Just like it sounds…Increased risk of IBS after infections
GI infection increases intestinal permeability –> inflammation and intestinal microbiota change –> intestinal dysfunction and infection-induced dysbiosis
FACT: Treating SIBO (Small Intestinal Bacterial Overgrowth) reduces IBS symptoms
SIBO = increased number and/or type of bacteria in upper GI tract
What kind of carbohydrates cause symptoms in IBS and why?
short chain, poorly absorbed, highly fermentable carbs (FODMAPs)
Since they are fermentable, they produce gas in the intestine
Does high fiber diet aggravate IBS?
Yes
In IBS, 2hat is the effect of lipids on GI tract in terms of motility and sensitivity
Small intestine - slows motility
Colon - increases motility
What is the relationship between gluten and IBS?
Gluten has been shown to cause increased symptoms and increase small bowel permeability in patients with IBS-D (particularly in HLA DQ2/8 positive patients)
*not necessarily people who have Celiac Disease though
How is intestinal inflammation related to IBS
changes in mucosal barrier and intestinal permeability- –> intestinal inflammation –> stimulation of enteric nervous system –> abnormal motor and visceral response
Is there a genetic predisposition to IBS?
YES
Do early adverse life events contribute to IBS?
YESSSS
Differentiate between diverticulum and diverticulosis
diverticulum = sac-like protrusion of colonic wall
diverticulosis just means diverticula are present
What is the difference between a false diverticulum and a true diverticulum?
False - does not contain all layers of the wall (more common)
True - contains all layers (congenital)
Most diverticula are acquired and diverticulosis increases with age
FACT
Differentiate between diverticulosis in Westernized nations and in Asia
West = acquired and left sided
Asia = genetic/congenital and right sided
Discuss the many factors that contribute to the pathophysiology of diverticulosis
Increased intraluminal pressure
Disordered motility
Neurotransmitters
Anatomic weakness
Dietary factors
Where do diverticula usually form?
Develop at points around the colon where vasa recta penetrate the inner circular muscle layer (weak points)
What are the muscle layers in the colon? What is their function?
Longitudinal muscle (taeniae coli) pull the colon to shorter functional length
Circular muscle (plicae circulares) control peristalsis
How is the muscle altered in diverticulosis because of increased elastin deposition?
Thickened taenia coli –> highly contractile normal muscle –> thickened circular muscle layer –> narrowing of the lumen –> bowel division into segments/compartments
How is the muscle altered in diverticulosis because of increased collagen?
Increased rigidity of colon –> decreased compliance –> inability to accommodate pressures
How do neurotransmitters play into diverticular disease?
increase in cholinergic activation –> increased motility and colonic pressure
Is diverticulosis asymptomatic?
YES it can be
Diverticulosis can be divided into two separate entities
- asymptomatic diverticulosis
- diverticular disease
Diverticular disease can be further divided into diverticulitis and symptomatic uncomplicated diverticular disease (SUDD)
What are influential factors in developing symptoms in diverticulosis aka developing to diverticular disease?
Diet
Lack of physical activity
Obesity
What are the different types of diverticular disease?
Diverticulitis (acute/chronic)
Segmental colitis associated diverticulosis (SCAD) - form of chronic diverticulitis
Symptomatic uncomplicated diverticular disease (SUDD) - persistent symptoms but no inflammation
What is the pathophysiology of diverticulitis?
Erosion of diverticular wall –> inflammation –> focal necrosis –> perforation that can be contained or not contained
What is the pathophysiology of diverticular bleeding?
Vasa recta exposed to injury in lumen –> intimal thickening and thinning of the media –> segmental weakness of artery –> rupture into lumen
