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Diarrhea is defined as having stools that occur more than three times a day and are looser than usual.
Learn about diarrhea causes, types, and how to differentiate organic vs functional and acute vs chronic diarrhea.
Key Takeaways
- Diarrhea causes can be acute or chronic, with chronic further divided into organic and functional.
- Organic diarrhea often presents with blood, weight loss, and extraintestinal symptoms, unlike functional diarrhea.
- Pathophysiological types of diarrhea help guide diagnosis and treatment, including osmotic, secretory, exudative, and motility-related diarrhea.
- Clinical evaluation includes stool characteristics, symptom timing, and associated systemic signs to narrow down causes.
- Diagnostic procedures like endoscopy and biopsy are important for identifying organic causes.
Summary
- Diarrhea is defined as having stools more than three times a day and looser than usual, with 200 grams in 24 hours considered diagnostic.
- Causes of diarrhea are divided into acute (less than 4 weeks) and chronic (more than 4 weeks).
- Acute diarrhea is mostly viral or toxin-mediated infections and usually resolves spontaneously.
- Chronic diarrhea is classified into organic (detectable by tests) and functional (not detectable by tests) causes.
- Organic causes include celiac disease, inflammatory bowel disease, infections, pancreatic insufficiency, and intestinal neoplasms.
- Functional causes include irritable bowel syndrome, lactose intolerance, food allergy, and drug or alcohol abuse.
- Distinguishing organic from functional diarrhea involves assessing duration, volume, presence of blood, timing, stress association, extra symptoms, weight loss, and cramping pain.
- Small bowel diarrhea typically has high volume, low frequency, and yellow/gray stools; large bowel diarrhea is frequent, low volume, and often has blood and mucus.
- Types of diarrhea based on pathophysiology include osmotic, secretory, exudative, and altered motility diarrhea.
- Diagnostic follow-up may include endoscopy, colonoscopy, and biopsies depending on clinical findings.
Full Transcript — Download SRT & Markdown
Speaker A
Specifically, 200 grams in 24 hours is considered diagnostic, but as you can imagine, trying to measure the weight of stools in everyone referring diarrhea would be a mess. Literally. So first off, the causes of diarrhea. We can divide
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them into acute and chronic causes for a start. Acute diarrhea is defined as lasting less than four weeks and is often caused by infections that are usually either viral or toxin mediated.
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Typically, they will resolve spontaneously. Chronic cases, i.e., cases lasting more than four weeks, need to be divided into either organic or functional causes, and the difference between them is that organic causes can be detected or quantified through testing, while functional causes cannot.
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Examples of organic causes include: celiac disease, inflammatory bowel disease like ulcerative colitis or Crohn's disease. We can also have bacterial and parasitic infections, pancreatic insufficiency, and of course intestinal neoplasms. On the other hand, functional causes of chronic diarrhea
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include irritable bowel syndrome, lactose intolerance, food allergy, and abuse of drugs or alcohol. How then can we begin to narrow down the causes when we encounter a patient with diarrhea? Let's first tackle how to distinguish functional from organic
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diarrhea. Firstly, the duration of organic ranges between weeks and years, while functional is over six months. Secondly, the volume of organic diarrhea is usually larger than in functional. Next, we look for the presence or absence of blood—functional will never have blood,
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while organic often does. We can also ask about the timing—organic doesn't have any specific pattern but may wake the patient up at night, while functional is usually in the morning and will not wake the patient up.
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This is also closely tied to stress, where organic diarrhea doesn't have much association to stress, but functional diarrhea often coincides with stress. Extra symptoms like fever, arthritis, and skin lesions are often seen in organic causes but not commonly
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seen in functional causes. The last two are weight loss and cramping pain. Organic usually has weight loss, while functional only has it alongside anorexia, and cramping pain is usually present in an organic cause but not as frequently seen in a functional cause,
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although it is there often. After making the distinction between organic and functional, you want to evaluate whether it's a small or large bowel problem.
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Small bowel-related diarrhea usually has a higher volume and a lower frequency and is often yellow or even gray in color. Large bowel-related diarrhea instead often is very frequent with a low volume and much more frequently features blood and mucus.
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After addressing these two questions, you would then look at doing a follow-up based on your findings, including potential esophagogastroduodenoscopy or colonoscopy and biopsies. So that's it for the clinical side of things, but it's worth knowing about the different types
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of diarrhea based on the pathophysiology. First off, we have osmotic diarrhea where there is an increased concentration of osmotically active solutes in the lumen, and so water remains in the lumen. Here the causes are malabsorptive diseases like celiac disease or things like
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osmotic laxatives. Interestingly, the symptoms will resolve if the patient fasts. The osmotic gap here is often greater than 100 milliosmoles per kilo.
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Next is secretory diarrhea where we have active secretion of water and electrolytes into the lumen via activation of adenylyl or guanylyl cyclase. Usually, this type is caused by bacterial endotoxins such as with E. coli and cholera. Here there is no response to
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fasting and no osmotic gap. Third is exudative diarrhea resulting from extended inflammatory damage to the intestinal mucosa. It may often feature blood and mucus, and it will not respond to fasting. Lastly, we have diarrhea of altered motility where we
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have an increase in peristalsis and therefore less time for reabsorption. [Music]
Topics:diarrheaacute diarrheachronic diarrheaorganic diarrheafunctional diarrheadiarrhea causesosmotic diarrheasecretory diarrheaexudative diarrheaintestinal diseases
