Irritable Bowel Synfrome Flashcards
(34 cards)
is a functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habits in the absence of detectable structural abnormalities.
is a functional bowel disorder characterized by abdominal pain or discomfort and altered bowel habits in the absence of detectable structural abnormalities.
Clinical features:
affects all ages,
although most patients have their first symptoms
before age 45
Women are diagnosed with IBS two to three times
pain is a key symptom for the diagnosis of IBS
Rome IV criteria is more stringent, requiring abdominal pain to occur at a minimum of once a week and eliminates “discomfort” as one of the criteria
Supportive symptoms
not included diagnosis
defecation straining, urgency or a feeling of incomplete bowel movement, passing mucus, and bloating.
prerequisite clinical feature of IBS.
Abdominal pain
episodic and crampy, but it may be superimposed on a background of constant ache
s, malnutrition due to inadequate caloric intake is exceedingly rare with IBS.
Abdominal pain present only using the waking hours
nocturnal pain is a poor discriminating factor between organic and functional bowel disease.
Pain is often exacerbated by eating or emotional stress and improved by passage of flatus or stools.
Rome IV Diagnostic Criteria for Irritable Bowel Syndrome Recurrent
Criteria fulfilled for the last 3 months with symptom onset at least 6 months prior to diagnosis.
Recurrent abdominal pain, on average, at least 1 day per week in the last 3 months, associated with ≥2 of the following criteria:
- Related to defecation
- Associated with a change in frequency of stool
- Associated with a change in form (appearance) of stool
Clinical manifestation
2. Altered bowel habits
most consistent clinical feature in IBS
First: episodic constipation—-> intractable
sense of incomplete evacuation,
:
- Predominant constipation: IBS-C
- Predominant symptoms is diarrhoea
-stool volumes: less than 200ml: 33%
IBS-D - IBS-M: mixed
Nocturnal diarrhoea does not occur.
Bleeding is not a feature of IBS
Gas and Flatulence
IBS frequently complain of abdominal distention and increased belching or flatulence, all of which they attribute to increased gas.
Most IBS patients have impaired transit and tolerance of intestinal gas loads
with IBS tend to reflux gas from the distal to the more proximal intestine, which may explain the belching.
Upper GI symptoms:
20-50%: IBS complained with dyspepsia, heartburn, and vomiting IBS show a high incidence of abnormalities in the small bowel during the diurnal (waking) period
IBS show a high incidence of abnormalities in the small bowel during the diurnal (waking) period
Prevalence of IBS is higher among patients with dyspepsia (31.7%)
IBS 55.6% reported symptoms of dyspepsia
pathophysiolodgy of IBS
- Bile malabsorption
- Brain-gut interaction
HPA axis
Autonomic dysfunction - Motility abnormality
4.leaky gut dyes bios is
5.visceral hypersensitivity
6.pyschologi
Anxiety/panic
Depression
Somatization
GI motor abnormality
-myolectrical an emoter
contrast, colonic motor abnormalities are more prominent under stimulated conditions in IBS
Increases rectosigmoid motor activity up to 3 hours after eating
- prolonged distention-evoked contractile activity
- rapid colonic transit and abdominal pain
Visceral hypersensitivity
-vesiral afferent dysfuction
frequency of perceptions of food intolerance is at least twofold more
- post prandial pain has been temporally related to food entry into the caecum.
- prolonged fasting in IBS associated with relief of symptoms
Lipids lower the thresholds for the first sensation of gas, discomfort, and pain in IBS patients
-postprandial symptoms: nutrient dependent exaggerated sensory component of gastroclolic response
Mechanisms of visceral hypersensitivity
(1) increased end-organ sensitivity with recruitment of “silent” nociceptors
(2) spinal hyperexcitability with activation of nitric oxide and possibly other neurotransmitters;
(3) endogenous (cortical and brainstem) modulation of caudad nociceptive transmission; and
(4) over time, the possible
development of longterm hyperalgesia due to development of neuroplasticity, resulting in permanent or semipermanent changes in neural responses to chronic or recurrent visceral stimulation.
Central neural dysregulation
shown that in response to distal colonic stimulation, the mid-cingulate cortex—a brain region concerned with attention processes and response selection—shows greater activation in IBS patients.
preferential activation of the prefrontal lobe, which contains a vigilance network within the brain that increases alertness.
Abnormal psychological features
Abuse is associated with greater pain reporting, psychological distress, and poor health outcome
posterior and middle dorsal cingulate cortex, which is implicated in affect processing in IBS patients with a past history of sexual abuse.
Postinfectious IBS
more commonly in females and affects younger rather than older patients.
Capylobacter, shigella, salmonella’s
Campylobacter infection who are toxin-positive are more likely to develop postinfective IBS
Immune activation and mucosal inflammation
peripheral blood mononuclear cells (PBMCs)
Mucosal Inflammation Some patients with IBS display persistent signs of low-grade mucosal inflammation with activated lymphocytes, mast cells, and enhanced expression of proinflammatory cytokines.
IL6,Il1b, and TNF
TRPV1 channels in the sensory neurons of the gut has been observed in IBS
shown increased intestinal permeability in patients with IBS-D
,
Altered Gut flora
s, in general IBS patients had
decreased proportions of the genera Bifidobacterium and Lactobacillus and
increased ratios of Firmicutes:Bacteroidetes
Firmicutes is the dominant phylum in adults consuming a diet high in animal fat and protein
Abnormal serotonin pathways
serotonin (5-HT)-containing enterochromaffin cells in the colon are increased in a subset of IBS-D patients compared to healthy individuals or patients with ulcerative colitis.
postprandial plasma 5-HT levels were significantly higher
Tryptophan hydroxylase 1 (TPH1) is the rate-limiting enzyme in enterochromaffin cell 5-HT biosynthesis,
Approach to the patient with Irritable bowel syndrome
its diagnosis relies on recognition of positive clinical features and elimination of other organic diseases.
IBS: recurrence of lower abdominal pain with altered bowel habits over a period of time without progressive deterioration, onset of symptoms during periods of stress or emotional upset, absence of other systemic symptoms such as fever and weight loss, and small-volume stool without any evidence of blood.
major symptoms of IBS—abdominal pain,
abdominal bloating,
and alteration in bowel habits—are common complaints of many GI organic disorders, the list of differential diagnoses is a long one.
Pain due to IBS:
Epigastric or periumbilical are must be differentiated from biliary tract disease, peptic ulcer disorder, intestinal ischemia, carcinoma of the stomach and pancreas.
Pain: occur mainly in the lower abdomen, the possibility of diverticula disease of the colon, inflammatory bowel disease (including ulcerative colitis and Crohn’s disease) and carcinoma of the colon must be considered.
Intestinal infestation: giardia lamblia
Diarrhoea: major complaint the possibility of lactase deficiency, laxative abuse, malabsorption, celiac spruce hyperthyroidism, inflammatory bowel disease and infectious arrhea..
Diagnostic work up
Diarrhoea—: sigmoid colon biopsy— to rule out microscopic colitis.
Age more than 40: air contrast barium enema
Diarrhoea + increase gas: possibility of lactase deficiency, ruled out by hydrogen breath test or with evaluation after a 3-week lactose-free diet.
Celiac sprue: respond with gluten free diet
In patients with dyspepsia: upper GI radiographs or esophagogastroduodenoscopy
Post prandial right upper quadrant: ultrasound of the gall bladder
Laboratory features that argue against IBS include evidence of anemia, elevated sedimentation rate, presence of leukocytes or blood in stool, and stool volume >200–300 mL/d. These findings would necessitate other diagnostic consideration
Treatment : irritable bowel syndrome:
- Patient counselling and dietary alterations
- excessive fructose and artificial sweeteners such as sorbitol or mannitol
Diet: FODMAPs ( fermentable oligosaccharides, disaccharides, monosaccharides and polyols ( helpful in IBS patients)
-dietary fibre
Effective treatment for for IBS
Increase stool weight decrease
colonic transit time
Psyllium: produce less bloating and distension
20-30grams of total dietary and supplementary fibre per dAY.
TREATMENT;
Antispasmodic: provide temporary relief for symptoms such as painful cramps related to intestinal spasm
postprandial pain is best managed by giving antispasmodics 30 min before meals so that effective blood levels are achieved shortly before the anticipated onset of pain
Belladonna alkaloids: ceros Tomis, urinary. Hesitancy, and retention, blurred vision and drowsiness.
Dicyclomine: lesser side effects
Treatment: antidiarrheal Agents:
1. Opiate-based agents are initial therapy of choice for IBS D
painless diarrhea variant of IBS, small doses of loperamide, 2–4 mg every 4–6 h up to a maximum of 12 g/d, can be prescribed
antidiarrheal agent that may be used in IBS patients is the bile acid binder cholestyramine resin as up to 30% of IBS-D patients may have bile acid malabsorption
