Submitted by geekonthemoon t3_z14kbc in askscience
Title really says it. Quick Google searches simply list stomach cramps as a symptom, but what exactly are they? What's happening in the body that results in a stomach cramp?
Do they serve a purpose in the sick/healing process? Or are they just a painful reaction to the sickness?
I’ve seen this described as: If the caboose of a train (food in your stomach) has a bomb (spoiled food or toxins from a pathogen), the whole train needs to start moving faster to get the bomb out of town (your body).
Since muscles are what moves that “train,”moving faster can cause cramps, just like quickly overexercising any muscle can.
If you don’t then experience any loose stools or frequent bowel movements, it may be more likely that the pain is directly from the toxins instead of cramping from diarrhea
If the body identifies toxic food while it's in the stomach, the most efficient route out is back out the way it came in, i.e. vomiting. Once it passes into the intestines, though, then you're right that the best way out is forward (quickly).
Right, and the body will empty the GI tract to deprive the toxin of additional nutrients while the immune system mounts a defense. The belly pain might also be from the lymph nodes that act as the body's sewer system, purging unwanted toxins out.
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The human body cannot identify toxins i.e. the human body cannot think. The human body can only react to exogenous stimulus. It's such a common misconception that our bodies can actively find and know noxious stimuli. It's likely because growing up, we likely all had parents who told us vomiting or diarrhea was our body's way of getting rid of the bad stuff. However, that is just not the case...it's comforting to hear that as a child, but it's actually quite the opposite in reality. Reality is that bacteria and viruses have evolved proteins that bind to and activate certain receptors in our gastrointestinal tract and cause a multitude of different effects. For instance, in the majority of food poisoning cases, the toxin is likely an emetic toxin that literally binds to and activates the 5HT-3 receptor in the small intestine. This is a serotonin receptor that directly activates the vomiting center in the brain, so when you consume a food that has been improperly stored/contaminated by a bacterium that produces an emetic toxin, that toxin directly activates your vomiting center. These toxins and the genes that encode them have been highly conserved over time as they allow the bacteria that make them to spread rapidly through the environment. That's really all a bacteria or virus wants to do....multiply and spread...but please don't take that as me saying that bacteria and viruses are thinking. They are not...haha.
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Hmm that makes me wonder if IBS is really just the digestive system stuck in fight mode.
Just a note: Normal peristalsis only goes one direction - increased peristalsis causes diarrhea. It does not cause the vomiting that is characteristic of these illnesses. Vomiting is very forceful use of muscles in the opposite direction than what they are used to being used for. Reverse peristalsis is the muscular mechanism for vomiting, but it is abrupt and very forceful.
There are 2 aspects at play here.
Microorganisms and/or their toxins do their actions on stomach cells and cause cellular destruction, which creates pain that is perceived as stomach cramps.
The destruction causes inflammation of the stomach mucosa. The afferent portion of the vagus nerve will be stimulated by either :
… the inflammation, like with Fusarium infection with its vomitoxin.
… or by the toxin itself, like with Bacillus infection with its emetic toxin.
Either way, a nervous signal is sent to multiple structures in the hindbrain, including the reticular formation and the dorsal motor nucleus of the vagus. These respond by sending an efferent influx through the vagus nerve to have the stomach muscles contract, in an effort to induce the emetic reflex (vomiting). This also causes stomach cramps.
Vomiting the microorganisms and their toxins is a protective mechanism that helps prevent the passage of theses substances to the small intestines, where they could be absorbed to the blood stream and cause much more damage.
Wow! Thank you for explaining this. I have another question. Should anyone try and take vomit relief/stopping medication? If it works, then could you be setting yourself up for more severe consequences if the body cannot rid itself of whatever is making it sick? Thank you.
It depends on what's causing the vomit, but yes it's possible that's it is not helping, the same way that anti coughing medicine is usually not a good idea (unless you're coughing because of an irritation)
During N/V bouts, the toxins are being evacuated as well fluids and electrolytes. On top of dehydration, electrolytes such as Sodium, Potassium will be severely out of balance, which can then lower the threshold for critical dysthymias. College students do the same thing by overloading on energy drinks!
For vomiting, yes. For diarrhea, ehhh not so much...but the jury is still out on that. It really depends what bacteria or virus has infected your gastro tract. With diarrhea, the main concern is the strain of E. coli that produces a toxin that can cause kidney damage if not treated...although this does not happen to everyone that is infected by that bacteria.
If you go to the ER for vomiting, chances are they will give you ondansetron (or a similar anti-emetic). In most people, this will stop the vomiting within 15 to 30 minutes and allow the person to drink fluids. Obviously, if it didn't stop, they would give you an IV.
The point here is that the toxins causing the sickness are unlikely to cause harm to your body if you block the 5HT-3 receptor they are binding to and activating. Vomiting as it relates to the gastro tract is controlled pretty much exclusively by serotonin and the 5HT-3 receptor.
For example, if you eat something and it irritates your stomach and small intestinal mucosa (not because of bacteria or viruses....think eating like a whole carolina reaper pepper or something similar that is irritating), certain immune cells will become activated by the inflammation and will release serotonin. That serotonin will then bind to and activate the 5HT-3 receptors which will directly stimulate the vomiting center in the brain. Obviously, the reason animals evolved this mechanisms was help expel noxious foods and make us adverse to them in the future.
Now, another example is food poisoning. There are many types, and I won't go into crazy detail. Let's consider the most common...Staph food poisoning. Certain strains of Staph that find their way into food (think somebody handling food with their bare hands) will grow and produce an emetic toxin (if the food is not stored properly). This toxin, if ingested, directly binds to and activates that 5HT-3 receptor...i.e. it directly activates the vomiting center in the brain. These bouts tend to be short in duration with no lasting effects. Therefore, taking a damn anti-emetic (like generic Zofran...ondansetron) is fine. All it does is bind to and inactivate the 5HT-3 receptor in the gut. It literally just blocks either serotonin or toxins from binding and activating the receptor.
So, the next time you are sick to your stomach and it is dragging on, call your doctor and ask for ondansetron. The huge benefit to this medication is that it normally works very well and will allow you to re-hydrate...and we all know that is the most critical part of gatro illnesses.
Great post and explanation!
However, I would like to discuss the last sentence. Wouldn't you agree that "Vomiting the microorganisms and their toxins is a protective mechanism that helps prevent the passage of theses substances to the small intestines...." is not necessarily a protective mechanism in animals but is, in reality, a mechanism evolved by microorganisms to facilitate their spread in the environment?
I would argue that animals evolved the vomiting reflex to deal with toxic and irritating chemicals found in plants and the environment in general. My evidence would be that the vomiting reflex is controlled by our own endogenous serotonin and 5HT-3 receptors. If we ingest an irritating chemical, the inflammatory response causes an acute release of serotonin in the gastro tract which can lead to activation of the 5HT-3 receptors and vomiting.
When it comes to microorganisms, some have evolved proteins over time that can also bind to and activate the 5HT-3 receptor directly.
However, I will concede that infection by microorganisms themselves can cause localized gastric irritation (by way of activation or our own immune system) which can lead to release of gastric serotonin. But, again, this inflammation is just a localized immune response....same thing that could happen with an irritating chemical from a plant.
In the case of vomiting directly from the toxins produced by microorganisms, I still say that is not a protective mechanism. The human body does not "know" it has been invaded by a toxin, so it therefore is not itself activating the vomiting reflex spontaneously because of the toxin. The toxin is literally binding to the receptor that activates the vomiting center.
I suppose it's a bit of which came first...the chicken or the egg.
I would not agree that the vomiting reflex doesn’t protect the animal. Clearly, the sooner the irritating substances are cleared of the gastrointestinal tract, the better for the animal’s health. The animal doesn’t have to « know » anything to be protected by a reflex, just like taking your hand off the hot stove protects you before the brain event feels the heat.
I would also not agree that the vomiting reflex of animals was evolved by the microorganisms, because that’s not how evolution works. The development of the sensory apparatus needed to sense the irritation, and then to provoke the necessary contractions to induce the vomiting is the result of the animal (not the microorganisms) population’s genetic changes and selection, with the animals that developed that reflex being fitter to face off infections.
I’ll agree that some microorganisms may have evolved to produce increasingly irritating substances so as to provoke vomiting with evermore efficiency because this could benefit them with the dispersion aspect.
I can’t speak much on the stomach contractions. I imagine they are a result of spasming muscles and your body wanting to get stuff out… BUT
As a pain neuroscientist I can speak generally on the pain felt in the stomach. Interestingly, visceral pain (pain of organs) is communicated to the brain with these really messy nociceptive (pain) paths. With this, descriptive location accurate visceral pain is not very evolutionary necessary. So visceral pain is almost never reflective of it’s quality or location. This is why bloat can burn and stomach ulcers can feel like you’ve been punched. It’s also why heart attacks (a pain causes by lack of oxygen) can feel like an elephant on your chest, a knife or a burn.
That is super interesting. I have a chronic pain condition and I’ve always wished we understood it better so it could just be cured
Hopefully the research I do will help! Not to get to into it too much but what I want to do is understand how systems that represent negative affect (feeling bad) become disordered in addiction, anxiety and chronic pain. A lot of time chronic pain is a result of abnormalities in the brain that cause a persistence of negative affect… it becomes nearly impossible to not constantly think about your pain and feel awful. This is why cbt and meditation can be so helpful. I want to figure out how these systems that generate our affective awareness work.
I’ve seen relief from migraines with supplements like B2 that are known to impact mitochondrial function but you’re the expert I dunno what else might be going on.
But absolutely yes I’ve also seen that mindset change from things like meditation or therapy can seemingly sometimes literally reduce pain.
It’s no surprise I guess that migraine and anxiety are so often linked, although of course you have to ask if it’s due to some underlying common etiology (word?) or whether it’s simply that chronic pain induces a state of fear… probably a little of both.
Addiction, even if not literal physical dependence I think is common in migraine too… video games addiction or porn or whatever it is, seems very common…
You have no idea how much joy you could spread to the world in figuring these things out, probably over a billion people are suffering from chronic pain and just want it to end, Godspeed to you I wish you the best, many of us need help
I think the reason there’s so much overlap between chronic pain, anxiety, depression, addiction… is because pain is, among other things, an emotion. More specifically it is an emotion driven by internal sensations.
To understand this overlap let’s take anxiety as an example. Imagine you are walking home and want to take a turn down an alley that will get you home faster. Your stomach drops, and you decide it’s best to take the long way. Here a sensory experience led to negative affect (anxiety) that turned you away from a bad choice. In an anxiety disorder however, an individual is hyper sensitive to changes in their body— this means that this negative affect/anxiety is likely to come up a lot more often when it’s unnecessary
In pain, a painful experience leads to a negative affective state, the kind that might make you feel awful, groan or cry. In a typical situation this negative affect might help you, it may, for example keep you from playing soccer when you should be healing. But In chronic pain we (just like anxiety!) become overly sensitive to signals in our body and we become a lot more likely to produce negative affect. This means instead of helping us chronic pain serves virtually no purpose. Right now the best way to address this cognitive/affective aspect of pain is through therapy or meditation but in the future there may be drugs that allow you to blunt these processes. This would mean that you could be aware of pain with out feeling bad because of it. Actually this has been achieved through deep brain stimulation in like 1 person… we’ll see where that goes.
Hope u enjoy my infodump. I’m obsessed with this (and further implications into how these affective systems play a role in social cognition)
Yeah I mean I’ve followed a lot of the research and what you’re saying makes some sense but also is obviously a bit of a simplification right — theories about migraines talk about signals misprocessed as pain, or over-sensitization, but also mitochondrial dysfunction or even things as simple as TMJ causing tension which triggers a migraine after a tension headache… it seems like it’s a complicated picture since some people respond to certain therapies but not others…
I also wonder how much you’ve researched about dopamine imbalances. One thing I’ve wondered is how much pain or anxiety could have to do with compulsive, addictive behavior that is often used to get a rush when one is feeling down. I’ve read theories that things like anxiety or migraines are sometimes linked to dopamine issues. Maybe if someone is frying those receptors by constantly stimulating them, whether it’s hardcore porn or just their favorite video game for 8 hours a day, could they be impacting how their brain processes other info?
And in that case, maybe for some people it’s as simple as “stop doing those things and let your brain readjust to a lower level of dopamine”. And in this case, I’d think difficulty actually stopping could be indicative of finding a source of a problem right? If someone is experiencing chronic pain for example, and tries to stop doing certain behaviors because they think it may be a causative factor, but despite their brutal pain they’re unable to stop (I know someone like this) it makes me think — okay that’s truly addictive behavior. If you are literally disabled by your pain and the prospect of being pain free isn’t enough to prevent you from seeking that high, you’re hardcore addicted.
There’s a shocking dearth of research on addictive behaviors, their correlations with chronic pain conditions, and the association between cessation of the behaviors with reduction in pain levels. I can’t find a single study that, for example, took a group of pain sufferers, compared their internet surfing behaviors with a control group of pain free people, then attempted an intervention of stopping the surfing, and measuring the effects of that.
Just food for thought. I’d personally like to think pain levels are something we can modulate with behavior, and someone with pain isn’t simply doomed to always be overly sensitive. I’d like to think we can make lifestyle choices, even things as simple as getting good sleep, that will lower that threshold
Absolutely a simplification (kinda gotta do that when you look at the brain). Affects the part I wanna look at though.
I’m actually doing addiction research now too and think that addiction is similar to chronic pain in that it results in this increased affect — people with addictive disorders feel strong cravings they can not crave, they over emphasize the good feeling on the drug and perhaps most importantly they feel awful when withdrawing. Withdrawal causes increased sensitivity to pain and negative affect and likely drives addictive behavior.
Real interesting stuff
Hmmmm, but what about before withdrawal, during the addiction phase? Can that cause pain issues?
> This would mean that you could be aware of pain with out feeling bad because of it.
Also just wanted to mention — this is the theory of mindfulness and meditation which is perhaps why it has seen some success. You can genuinely be aware of pain but experience it without suffering.
The proof is in the pudding right? We’ve all seen that photo of the Buddhist monk sitting still while burning himself to death.
Why does pain spread to non affected areas sometimes? For example period pain spreading and feeling like it’s coming from the legs
I know the answer to this one! It can actually be a several things but its most likely to be complications with endometriosis. It could have spread to press on your sciatic nerve or your ovaries (which share some nerves with your legs.)
Definitely an example of messy pain signaling. Pain can also generally increase sensitivity to pain or negative affect so being in consistent pain on your period might just make other pain more salient to you. There are some other reasons why visceral pain is poorly localized but it’s hard to get into in a comment
What about menstrual cramps? Why do I feel like I’m getting stabbed in the stomach and someone is twisting the knife? 😭
When you start your period, your endometrium begins to slough off since no egg has been fertilized. At the same time that your endometrium is shedding, prostaglandins are released. These prostaglandins play a role in the contraction of the uterus in order to adequately shed the endometrium for the current cycle. With these contractions, people can have pain, especially if someone's uterus contracts frequently. There's also thoughts that certain stretch receptors can get activated when this happens, and that can also contribute to pain.
TLDR; a chemical is released when you start your period that causes your uterus to contract and that hurts
Thank you for the explanation. Loathe the body for punishing me for no baby
>messy nociceptive (pain) paths
You talking type C fibers?
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I uh think I have a stomach ulcer after reading this. I’ve been having these attacks that feel like i’ve had the breath knocked out of me that last 10-45 mins and it’s severe and it stops with zantac and phenergan. Yikes
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Hey pain neuroscientist. I'm so glad you said this and especially the last part. I've been getting sharp stab pains on my chest come and go for years at random times, very sparsely; but here's the problem I'm a teen! And this has been happening since I was 13 normally I'd be concerned it's angina , but I'm so very young. Checkups aren't really so available.. would be quite expensive af I Imagine
Yeah please don’t interpret anything I say as medical advice. If anything what I’m saying is not to trust the locality and quality of your pain. I have had an esophageal ulcer and thought I was having a heart attack.
Also (again don’t trust my advice and please go to a doctor if you’re concerned) it could be precordial catch syndrome (I experience this) or costochondritis.
I'm embarrassed to not know this properly considering that I'm a medical student in their fifth year but tolerate me for a sec. We have two main things that can cause your cramps. It can either be preformed toxins which are seen in spoilt food and responsible for food poisoning, or it can due to viruses and bacteria which may have certain enzymes or proteins that causes Chloride channels in the lining of the G.I. tract, I believe it's the intestine (I think) and I believe there's reduced reabsorption of water.(Usually water you ingest is reabsorbed in the small intestines along with other nutrients and minerals) Generally people confuse food poisoning and stomach flu but there's a lot of differences like food poisoning lasting very briefly and being caused by pre formed toxins while stomach flu being caused by pathogens like bacteria, viruses, fungi etc.
In layman's term.
The same thing happen to your skin when it inflamed, red, swollen, and itchy.
However your stomach can't scratch itself, and your brain didn't register it as itchy. But the stomach did only one thing it can, contracted until it clamped.
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Everything about our bodies keep microorganisms out, wax in ur ears, tears in ur eyes, acidic skin..u get the point, the only real way we interact with the world is thru our mouth. So our immune system is in the gastro-intestinal tract and when it recognizes an attack from a microorganism that doesn’t play by our regular gi gang of microorganisms, it will set the alarm and create inflammation, increase temp, and so on. Inflammation creates pressure. Pain that arises from pressure doesnt respond to pain medicine —because its pressure. Thats why its soooo painful. Inflammation also makes tissue have more water and ergo the watery stool.
Wrong. You aren’t eating 24/7. You are breathing 24/7, and always inhaling bacteria, viruses and spores into your lungs.
Also we don’t have acidic skin, there germs that live on our skin and the skin has its own microbiome.
The guy microbiome is the largest and that’s why you got 70% of your immune system in. Also imflammation doesn’t cause pain. There are smooth muscles all along your bowels that contract and expand to help move things along. Those can cramp and cause pain too.
pH of skin is between 4.7 and 5.75
pH of sweat is 4-4.5.
<7 is acidic.
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Idobehere t1_ix9r5gl wrote
The body says “damn I gotta get this out of me”. The body also knows that the GI tract is basically a long tube so it increases peristalsis (the normal contractions of the stomach and intestines). This increased peristalsis really gets going, causing cramping.
Also as a general thing of infection, inflammation happens. This causes the pain causing nerves to be triggered. Pain being the evolutionary thing of “damn somethings happening do something about it”