??? IBS is a common GI disorder
??? IBS is a chronic disease
??? IBS etiology is unknown
??? IBS symptoms need not be daily, weekly or even monthly
??? No diagnostic test is necessary if Rome Criteria for IBS are met in the absence of Alarm symptoms
??? Multiple treatment modalities are recommended, none very effective.

In the majority of cases IBS is not a real disease entity, almost always symptoms are due to a treatable disease; dietary indiscretions and/or food intolerance.

Conditions that can cause IBS symptoms/ differential diagnosis of IBS includes but not limited to the followings:

1- Dietary Habits, food high in FODMAP and carbohydrates
2- Lactose intolerance, 25% US, 75% World population
and milk protein allergy, or fat intolerance
3- Fructose intolerance, 33% can't tolerate >25 gm fructose daily
4- Celiac Sprue, 4.6% of IBS patients
5- Food Intolerance (allergy, non-allergy)
6- Small intestine bacterial overgrowth (SIBO), 4% of IBS patients
7- Bile acid malabsorption due to overproduction, malabsorption or rapid small bowel transit
8- Chronic pancreatitis
9- Enteric neuropathy and myopathy like in Diabetes mellitus and gastroparesis
10- GI infection, Blastocystis Hominis , Giardiasis, Amebiasis
11- Alcohol intolerance
12- Idiopathic constipation
13- Diverticulosis
14- Dyspepsia
15- Acid Reflux disease
16- Medication side effects by increasing or decreasing SB transit time or secretions
17- Inflammatory bowel disease like ulcerative colitis and Crohn’s
18- Microscopic colitis, 5% of IBS-D pts
19- Hyper or Hypothyroidism
20- Malignancy
21- Incompetent ileocecal valve, back up bacteria, colon gas
22- Rapid small bowel transit time delivering undigested food to colon
23- Metabolic diseases
24- Other functional GI disorders, biliary dyskinesia, dyspepsia
25- Circular muscle hypertrophy of sigmoid colon, true IBS
26- Salicylate sensitivity and foods with high salicylate
27- Terminal ileum resection for ileitis, adhesion with blockage, cecal cancer, or decreased absorption surface due to disease or resection causing poor bile acid absorption and diarrhea
28- Drugs that interfere with carbohydrate absorption like acarbose and metformin
29- Antibiotics interfering with colonic salvage of malabsorbed or physiologically incompletely absorbed Carbs by reducing bacteria
30- Gluten sensitivity but not Celiac disease
31- Excess fiber in diet causing bloating, pain and constipation
32- overuse of caffein, and monosodium glutamate present in some Chinese food
33- Achlorhydria or hypo-chlorhydria causing bacterial overgrowth
34- Incompetent pyloric sphincter allowing food to pass from stomach into duodenum before ready, resulting Maldigestion
35- S/P Bilroth ll gastric surgery same as 34
36- S/P Cholecystectomy with bile induced diarrhea
37- S/P Hiatal hernia surgery / Nissen's fundoplication with gas- bloat syndrome
38- Post-gastroenteritis IBS-D.
39- Leaky Bowel Syndrome caused by NSAID, gastroenteritis, autoimmune enteritis, etc.
40- Combination of two or more in the majority of patients.