Irritable bowel syndrome (IBS) – causes, symptoms, risk factors, treatment, pathology

Irritable Bowel Syndrome, or IBS, describes
a pattern of recurrent bouts of abdominal pain and abnormal bowel motility causing things
like constipation or diarrhea, or a mixture of the two, and often times the abdominal
pain improves after a bowel movement. Although it sounds similar, IBS is different
from inflammatory bowel disease or IBD, which involves some of the same IBS symptoms, but
also includes inflammation, ulcers, or other damage to the bowel, whereas IBS does not
involve these, and instead can be thought of as a functional disorder. Right now, the underlying biological mechanisms
that produce the symptoms of irritable bowel syndrome aren’t well understood, so most
research is focused on these key symptoms: abdominal pain and abnormal bowel motility. With regard to abdominal pain, a lot of people
with irritable bowel syndrome have “visceral hypersensitivity,” which means that the
sensory nerve endings in the intestinal wall have an abnormally strong response to stimuli
like stretching during and after after a meal. This visceral hypersensitivity might explain
why people with the disease experience recurrent abdominal pain. With regard to abnormal bowel motility, the
underlying mechanism is a little less clear. One clue is that eating foods that contain
short chain carbohydrates such as lactose and fructose often trigger the symptoms. One possible explanation is that unabsorbed
short-chain carbohydrates act as solutes that draw water across the gastrointestinal wall
and into the lumen. In addition to triggering visceral hypersensitivity
which causes pain, that excess water can also cause smooth muscle lining the intestines
to spasm, and create diarrhea if the excess water’s not reabsorbed back into the body. To make matters worse, the unabsorbed short-chain
carbohydrates are often metabolized by gastrointestinal bacterial flora which produce gas that could
trigger more bloating, spasm, or pain. Now, there are also epidemiologic clues as
well. For example, in North America, irritable bowel
syndrome is most common among middle aged women, but in other parts of the world, it
affects both sexes equally. Also, one important risk factor is having
a bout of acute gastroenteritis, for example from norovirus or rotavirus, but also another
risk factor is being stressed, and both of these seem to be triggers for developing irritable
bowel syndrome in many individuals. Since the mechanism behind irritable bowel
syndrome is still unclear, most treatments target the symptoms. This includes things like diet modification,
like avoiding certain foods like apples, beans, and cauliflower, all of which have short-chain
carbohydrates. In addition, to treat constipation, soluble
fiber, stool softeners, and osmotic laxatives can help, whereas for gastrointestinal spasms
and pain, anti-diarrheals like serotonin antagonists and antimuscarinic medications can help. Finally, managing things like stress and controlling
feelings of anxiety and depression can all help symptoms irritable bowel syndrome symptoms. Okay, as a quick recap—patients with irritable
bowel syndrome have recurrent abdominal pain with constipation or diarrhea, and the pain
is usually relieved after bowel movements. The underlying pathophysiology isn’t well
understood, but seems to be related to visceral hypersensitivity and abnormal bowel motility,
and triggers or risk factors include short-chain carbohydrates, bouts of acute gastroenteritis,
and stress. Thanks for watching, you can help support
us by donating on patreon, or subscribing to our channel, or telling your friends about
us on social media.


  1. Hello Osmosis, love your channel and it's been helping me a lot in nursing school! 🙂

    One request (might have heard this one): Can you turn up the volume in your videos?

  2. This is what i was originally diagnosed with back in 2015, it progressively got worse and I had a few more tests and was diagnosed with Crohns disease this summer.

  3. I Love your videos! I also love that they follow information on UpToDate so that I can better understand those documents :). – a 4th year medical student

  4. Great videos!! Your videos are really helping me on my rotations. Keep up the good work!

    P.S: Please do carcinoid syndrome next.

  5. one interesting information regarding ibs is that its most common in drivers..2nd m/c in doctors..main driving force being stimulation of prefrontal correx and mid cingulate gyrus as a result of stress..

  6. I have watched lots of your videos, they are amazing.

    One suggestion i would make, is doing more recaps at the end of video.

    keeps up the good work it great to see the growth.

  7. Im doing my medical finals, and your videos are amazing! thank you. I will be donating to the channel right after I'm done with the exams.

  8. I have ibs I get pain when I'm standing too long or when I get up and stretch or after a meal im mostly always bloated its just a pain to have this

  9. A friend of mine is with this condition, and it gets triggered if he drinks beer. Than he has abdomen pain and farts like a horse in stables

  10. I got this crap all because of a colitis infection just a big burden I'm devastated I fear it may affect my career

  11. I had an appendectomy on Sunday July 31st and I have these symptoms:

    Irregular bowel movements(some are small, some are large, some are in small clumps, some are in 1 solid mass, some are frequent, some are infrequent)
    Constipation(but then again, I had chronic constipation long before I got appendicitis)
    Diarrhea(sometimes I have a little bit of bleeding and it burns(burning sensation means bleeding and I have only bled a tiny bit once since the appendectomy(so probably my internal hemorrhoids or something else minor)) and I end up with this yellow liquid that isn't urine along with the bowel movement(I don't know if that is blood plasma from bleeding or urobilinogen from bile))
    Abdominal pain

    And this abdominal pain I can separate into multiple types. Those are:

    Radiation from the rectum upwards(soon after this pain is when I try to have a bowel movement)
    Gas(common side effect of appendectomy)
    Outbursts of pain anywhere but typically in the lower abdomen where my incisions are
    Appendicitis-type pain(constant, high on pain scale, often feel hot(sometimes I even feel heat waves down my neck), pain only lasts for a maximum of 5 minutes)

    I have a few questions.

    1) Are these symptoms(bowel movement problems and radiating pain to be specific) due to IBS that is caused by my appendectomy?

    2) If it isn't my appendix, then why do I get appendicitis type pains? Am I having phantom appendix(phantom pain phenomena from nerves that used to send signals from my appendix to my brain)?

    3) What is this yellow liquid occasionally coming out of my intestines if I don't have a colovesicular fistula(fistula attaching colon to the bladder?

  12. Another IBS sufferer here. I've managed to keep mine under control with dietary changes and medication as needed. For me I find that certain fats trigger it as well as non-complex carbohydrates. Anyone else get IBS flare-ups with fats?

  13. I dont believe in this disease… I think there must be underlying cause… they kept telling me i have IBS .. till i discovered i have worms.. i treated that.. and im healthy never had suffered from this again

  14. I heard there is no cure for ibs sad. All i can do is, to go in remission from ibs. I'm having ibs from 9 years. Till 6 years i did not know that i has ibs because there is no blood test for ibs either. I was miss diagnosed by doctors they put me on wrong medication.
    Before i was having just ibs now i'm having depression, anxiety, stress, joints pain. I lost my weight, I'm loosing my hairs. Today i discover i has Acid Reflux too.
    But still hopeful, I want to complete my graduation for good job.

  15. hey i am 15 years old boy, i have grumbling and pain in the up and down left abdomen. could you suggest what i have

  16. thanks alot, this was super informative. I've had constipation and abdominal discomfort my whole life. And i was wondering if this had something to do with it. sometimes ill be in a really awefull mood and then I'll feel a strong bowel movement and start feeling alot more cheery. Then I think to myself "huh, well that's odd".

  17. I think mine is being caused by general anxiety. My gut never gets the blood flow it needs because I’m almost always in fight or flight. Blood just focuses on your lungs and heart when anxious.

  18. Hey all IBS sufferers!!! I was born with IBS and I found a way to help pain and irregularity!!! 1) cut back on your gluten intake 2) DRINK LOTS OF WATER EVERY DAY IT HELPS WITH PAIN 3) herbal medicine works wonders it is a life saver trust me marshmallow root and licorice root are my best friends 4) limit your lactose intake 5) don't drink coffee. Instead drink matcha or green tea. Yeah it'll make you poop anyway but it's a lot more gentle on your stomach and less acidic than coffee. Plus you still get your caffeine if you need it. 6) make sure you are on a consistent sleep schedule. 7) following 6, for breakfast drink a smoothie or a bunch of water. It lubricates your intestines and is less harsh on your digestive system. I HOPE THIS HELPS SOMEONE! IT TOOK ME DECADES TO FIGURE THIS OUT! DONT GIVE UP!!!❤️

  19. Thank you so much for all the helpful videos! You guys really helped me prepare for my exam. 😊 5/6/2018

  20. Plant based diet plus pelvic floor relaxation did it for me! You are welcome. Also practice exercise and meditation.

  21. I have ibs d and it’s caused by anxiety and stress but I get anxiety when leaving the house so I can’t leave my house because it plays up then I get depressed. It sucks cause it’s a long cycle.

  22. I discovered your video on Stomach Oracle Omnibus – there are many great  videos there that may help you

  23. I'm studying does ibs cause constipation and discovered a fantastic resource at Stomach Oracle Omnibus (check it out on google)

  24. Here is a blog post to know more on irritable bowel syndrome,

  25. Try MEGA DOSE of .probiotic…..reason it does not work for many people is NOT high enough dose…I use " Progurt" VERY expensive.
    But it did the trick re cramps….the diarrhea.NOT selling anything

  26. If you take an anti-diarrheal that acts as a serotonin antagonist, couldn’t that disrupt a patient who is taking an SSRI?

  27. Thanks for this video! Very well explained! But I guess the soul´s or psychic factor should be more emphasized. Many studies could show that treating the soul´s illness cures the bowl´s issues as well – without medication. But many docs just try to prescribe drugs instead of healing the disease´s root.


  29. i have this every morning before the bus i get really nauseous and stressed because i have social anxiety disorderand going on the bus is one of my triggers

  30. Sadly I have had Ibs for 14 years 😞 And still having it Actually I have it right now 😭 I recommend merolac I don’t know if I spelt it right

  31. This  caricature is of me. I have a subtype of IBS-D called Functional Diarrhoea. It has same symptoms except for constipation and abdominal pain)

  32. if you've found this and need some help, I'll leave you some references that have helped me.
    First and foremost find a gastroenterologist and present your symptoms. IBS is a diagnose of exclusion, meaning that you'll be diagnosed with IBS if you do not have any known condition. You may have another simpler condition. If your doctor does not test you (blood, fecal, endoscopy and colonoscopy), find another one. (more…)

    If you need some control back, I'll reference stuff that helped me with IBS-D:
    1. FODMAP diet. Try it out for 2 to 6 weeks. 3 out of 4 people feel better (monash university, has a unique app for this supporting android and iphone. It is not free but it is very useful.).
    2. Check if you're lactose intolerant; avoid lactose products for some days. Everyone develops lactose intolerance over time to some degree. Find yours.
    3. Bifidumbacterium infantins 35635 (Align). This probiotic helps with pain, bloating and other symptoms, by filling your gut with healthy bacteria.
    4. Peppermint oil, coated pills helps with bloating, and other gas related symptoms.
    5. Mebeverin (do not use this without medical advice).
    6. Consume rice and rice water (water extracted after rice has cooked).
    7. Vitamin D, if you have IBS you probably have a deficiency. Repleneshing may help with pain management. 30 minutes of sunlight will probably do the trick
    8. Eat smaller but regular meals. Do not skip meals. You'll probably feel worse.

    9. Be patient. IBS diagnosis exists for 150 years yet it is a poorly understood condition. Its being researched actively and many small pieces of the puzzle ar discovered every day. At one time, celiac disease was included in IBS. Be patient, solution will be found.
    10. If you have back pain, either pre-existent or contemporary to the IBS, please keep in mind that some IBS situations may be caused from herniated disks, particularly on the upper back. Keep you weight under check and exercise with caution. Check with your doctor.
    11. IBS seems related with serotonin. Exercise and relaxating activities may help regulate serotonin.
    12. you may try loving-kindness meditation. It'll help you aliviate the anxiety associated with this situation. Look for a meditation teacher.
    13. CBT (Cognitive behaviour Therapy) may help you aliviate the anxiety.
    14. Rest. You must rest and hydrate yourself. If you find yourself waking up to go to the toilet, this is not a common ibs-d symptom, nor is blood in stool or in vomit (granulate like coffee waste). Refer to a gastroneterologist.
    16. Keep a food diary. There are foods that trigger symptoms. Try to systematically identify and exchange them with other more tolerable foods. The Monash Univesity's FODMAP app may help you.

    Keep strong. Keep healthy. You can have a long, happy, fulfilling life with IBS. Look for support around you. There are others who suffer from this, probably in silence. You're not alone.

  33. My doctors keep telling me I have this but I don’t think so I have bodywide twitching and spinal pain???

  34. While i cant recommend it for its other adverse health effects smoking alleviates ibs symptoms for me, presumably by reducing stress and anxiety while relaxing the intestenal walls.

  35. I hear Noro virus and things got real. It took me A WHOLE FREAKING YEAR to be able to eat solid food. And It took me like 2 years to get off Ranitidine and GasX. I know the ins and outs of almost every common stommach medication. You have snot? Ranitidine and GasX for preventing issues. Acid? Ranitidine. General angry? Pepto. Liquid or chewables are my favorite. Off brand chewables are the best tasting and have the best texture. You have diarrhea due to stress? PEPTO LIQUID. Most sharp pain in the stommach/intestines? GasX! Coffee is bad unless you are om a good day. Avoid over drinking milk. Things that are richer like PB&J? Consume in small quantities only. Grease? Go ahead and take a proflactic Ranitidine. Oddly enough, I rarely have problems with Pizza or Mexican.
    Strong Ozone that day? Carry pills. Not enough sleep? Carry pills. Freaking anxious? CARRY PILLS. So many things can be fixed with the right amounts of Pepto, GasX Max Strength, and Ranitidine. Tums too, but they are hard to eat when your body is revolting.

  36. My symptims got a lot better once I went on an SSRI. They are mostly manigable now. Still have to go get diagnosed with an actual thing.

  37. Hey. Anyone with ibs has cronic diahreia? I am so tired of it. I have an appointment to a gastroenterologist in 10 days, i am so worried he will misdiagnose me.

  38. I want to lessen my belly fat but I have IBS. Everytime I do curl ups my abdomen hurts and I suddenly having a diarrhea.

  39. Sometimes when I am really stressed or angry I have a pressing pain in my left chest and back, is this normal? Is it because if IBS? Can it cause this pain with a headache ,depression and fear?

  40. Im so tired of this problem. I didnt experience it for 2 years atleast… thought i was ok. Here it is again. Just leave me alone already

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