Chronic diarrhea pathophysiology: Difference between revisions
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==Overview== | ==Overview== | ||
The fundamental [[pathophysiology]] of all diarrhea is incomplete [[absorption]] of water from the [[lumen]] because of either a reduced rate of net water [[absorption]] or [[osmotic]] retention of water intraluminally. The causes of chronic diarrhea include [[inflammatory]], [[osmotic]], [[Secretory component|secretory]], [[iatrogenic]], [[motility]], and functional [[Disease|diseases]]. [[Osmotic]] chronic [[diarrhea]] involves an unabsorbed substance that draws water from the [[plasma]] into the [[intestinal]] lumen along [[osmotic]] gradients. If excessive amounts of unabsorbed substance are retained in the [[intestinal]] lumen, water will not be absorbed and [[diarrhea]] will result. Secretory chronic [[diarrhea]] on the other hand, results from disordered [[electrolyte]] transport and, despite the term, is more commonly caused by decreased [[absorption]] rather than net [[secretion]]. A disruption of the normal colonic [[epithelial]] barrier by microorganisms is mainly responsible for [[inflammatory]] chronic [[diarrhea]]. This disruption can lead to exudative, secretory, or malabsorptive components of inflammatory chronic [[diarrhea]]. Both rapid transit time and slow transit time are associated with motility [[disorders]] causing chronic [[diarrhea|diarrhea.]] Some [[iatrogenic]] causes of chronic diarrhea are seen after [[abdominal]] [[surgeries]] such as [[cholecystectomy]], where about 5%–10% of patients develop chronic diarrhea. In general, the causes of chronic [[diarrhea]] are multifactorial. | |||
== | ==Pathogenesis== | ||
[[Diarrhea]] is a condition of altered [[intestinal]] water and [[electrolyte]] transport. The physiological mechanisms of [[diarrhea]] include [[osmotic]], secretory, [[inflammatory]], altered motility, and [[iatrogenic]] mechanisms.<ref name="pmid22677080">{{cite journal| author=Sweetser S| title=Evaluating the patient with diarrhea: a case-based approach. | journal=Mayo Clin Proc | year= 2012 | volume= 87 | issue= 6 | pages= 596-602 | pmid=22677080 | doi=10.1016/j.mayocp.2012.02.015 | pmc=3538472 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=22677080 }} </ref> | |||
===Osmotic chronic diarrhea=== | |||
[[Osmotic]] chronic [[diarrhea]] involves an unabsorbed substance that draws water from the [[plasma]] into the [[intestinal]] lumen along [[osmotic]] gradients. If excessive amounts of unabsorbed substance are retained in the [[intestinal]] lumen, water will not be absorbed and [[diarrhea]] will result. | |||
*Chronic [[diarrhea]] due to an [[osmotic]] cause includes [[osmotic]] [[laxatives]] such as [[lactose intolerance]] [[Antacid|antacids]], [[fructose]], [[lactulose]], [[laxatives]] [[magnesium]], [[phosphate]], and [[sorbitol]].<ref name="pmid7776987">{{cite journal| author=Suarez FL, Savaiano DA, Levitt MD| title=A comparison of symptoms after the consumption of milk or lactose-hydrolyzed milk by people with self-reported severe lactose intolerance. | journal=N Engl J Med | year= 1995 | volume= 333 | issue= 1 | pages= 1-4 | pmid=7776987 | doi=10.1056/NEJM199507063330101 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7776987 }} </ref> | |||
*[[Maldigestion]] [[syndromes]] such as [[disaccharidase]] deficiency and [[Pancreatic insufficiency|pancreatic exocrine insufficiency]] can also result in [[osmotic]] chronic [[diarrhea]]. | |||
*[[Osmotic]] diarrheas might result in [[steatorrhea]] and [[azotorrhea]] (passage of [[fat]] and nitrogenous substances into the [[stool]]), but they typically do not cause any [[rectal bleeding]].<ref name="pmid467934">{{cite journal| author=Morris AI, Turnberg LA| title=Surreptitious laxative abuse. | journal=Gastroenterology | year= 1979 | volume= 77 | issue= 4 Pt 1 | pages= 780-6 | pmid=467934 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=467934 }} </ref> | |||
===Secretory chronic diarrhea=== | |||
Secretory chronic [[diarrhea]] results from disordered [[electrolyte]] transport and, despite the term, is more commonly caused by decreased [[absorption]] rather than net [[secretion]]. | |||
*Secretory [[Diarrhea|diarrheas]] include [[congenital]] abnormalities such as [[congenital]] chloridorrhea, in which an abnormality in the [[genetic]] control of [[Chloride-bicarbonate exchanger|chloride-bicarbonate exchange]] in the [[ileum]] results in the loss of [[chloride]] into the [[stool]]. | |||
*Another example is the loss of α2-adrenergic function in [[enterocytes]] of patients with [[autonomic neuropathy]] caused by [[diabetes mellitus]]. | |||
*The typical features of secretory [[diarrhea]] include the persistence of the [[diarrhea]] with fasting and the absence of [[steatorrhea]], [[azotorrhea]], or [[Rectal bleeding|blood per rectum]]. | |||
*Secretory diarrheas caused by [[neuroendocrine tumors]] have been identified by measurement of [[plasma]] levels of the [[hormone]] or its [[metabolite]] in the [[urine]]. | |||
*Investigations include measurements of [[VIP]], [[gastrin]], or [[calcitonin]] in [[plasma]] or 24-hour collections of urine for [[5-Hydroxyindoleacetic acid|5-hydroxyindoleacetic acid]].<ref name="pmid8371728">{{cite journal| author=von der Ohe MR, Camilleri M, Kvols LK, Thomforde GM| title=Motor dysfunction of the small bowel and colon in patients with the carcinoid syndrome and diarrhea. | journal=N Engl J Med | year= 1993 | volume= 329 | issue= 15 | pages= 1073-8 | pmid=8371728 | doi=10.1056/NEJM199310073291503 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8371728 }} </ref> | |||
===Inflammatory chronic diarrhea=== | |||
Disruption of the normal colonic [[epithelial]] barrier by microorganisms is mainly responsible for [[inflammatory]] chronic [[diarrhea]]. This disruption can lead to exudative, secretory, or malabsorptive components of inflammatory chronic [[diarrhea]]. | |||
*[[Inflammatory]] causes of chronic [[diarrhea]] might present with features that suggest [[malabsorption]] or [[rectal bleeding]]. | |||
*The nature of the [[malabsorption]] depends on the regions affected (e.g., [[proximal]] vs. distal small bowel), and [[rectal bleeding]] is usually a manifestation of colonic or rectal [[ulcerations]]. | |||
*Anti-inflammatory agents, including [[bismuth subsalicylate]] or other, more potent [[Anti inflammatory medications|anti-inflammatory medications]], appear to benefit patients with [[microscopic]] or [[collagenous colitis]].<ref name="pmid12003412">{{cite journal| author=Pardi DS, Smyrk TC, Tremaine WJ, Sandborn WJ| title=Microscopic colitis: a review. | journal=Am J Gastroenterol | year= 2002 | volume= 97 | issue= 4 | pages= 794-802 | pmid=12003412 | doi=10.1111/j.1572-0241.2002.05595.x | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12003412 }} </ref> | |||
===Motility disorders causing chronic diarrhea=== | |||
Both rapid transit time and slow transit time are associated with motility [[disorders]] causing chronic [[diarrhea]]. | |||
*Rapid transit time delivers [[fluid]] secreted during digestion to the distal [[small bowel]] or [[colon]]. This prevents reabsorption of normally secreted fluid in the [[small bowel]], overwhelming the re-absorptive capacity of the [[colon]]. | |||
*Slow transit time results in [[bacterial overgrowth]] with [[bile acid]] deconjugation, poor [[micelle]] formation, and [[steatorrhea]]. | |||
*The clinical manifestations of chronic [[diarrhea]] caused by motility disorders include [[steatorrhea]], usually up to 14 g per day. | |||
*Osmotic [[laxatives]] result in acceleration of transit through the [[bowel]], which is associated with up to 14 g of fat in the [[stool]]. | |||
*Presence of more than 14 g per day of [[fat]] in the stool suggests the presence of [[bacterial overgrowth]] or associated [[disease]] such as [[celiac disease]].<ref name="pmid2794043">{{cite journal| author=Hammer HF, Santa Ana CA, Schiller LR, Fordtran JS| title=Studies of osmotic diarrhea induced in normal subjects by ingestion of polyethylene glycol and lactulose. | journal=J Clin Invest | year= 1989 | volume= 84 | issue= 4 | pages= 1056-62 | pmid=2794043 | doi=10.1172/JCI114267 | pmc=329760 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2794043 }} </ref> | |||
===Iatrogenic causes of chronic diarrhea=== | |||
After [[abdominal]] surgeries such as [[cholecystectomy]], about 5%–10% of patients develop chronic diarrhea. | |||
*Most of these cases resolve completely or significantly improve within a couple of months. | |||
*[[Iatrogenic]] diarrhea is related to excessive [[Bile acid|bile acids]] being delivered into the [[intestine]].<ref name="pmid3731987">{{cite journal| author=Breuer NF, Jaekel S, Dommes P, Goebell H| title=Fecal bile acid excretion pattern in cholecystectomized patients. | journal=Dig Dis Sci | year= 1986 | volume= 31 | issue= 9 | pages= 953-60 | pmid=3731987 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3731987 }} </ref><ref name="pmid3606289">{{cite journal| author=Arlow FL, Dekovich AA, Priest RJ, Beher WT| title=Bile acid-mediated postcholecystectomy diarrhea. | journal=Arch Intern Med | year= 1987 | volume= 147 | issue= 7 | pages= 1327-9 | pmid=3606289 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3606289 }} </ref> | |||
*After a [[cholecystectomy]], bile is delivered directly into the [[small bowel]], overcoming the [[terminal ileum]]'s ability to reabsorb adequately, leading to cholerheic diarrhea. | |||
*Some other [[iatrogenic]] causes of chronic diarrhea might result from [[vagal]] [[injury]] and [[Ileum|ileal]] resection. | |||
==Genetics, Associated Conditions, Gross Pathology, and Microscopic Pathology== | |||
For the details of the [[genetics]], associated conditions, [[Gross examination|gross]] and [[microscopic]] [[pathology]] of the following causes of chronic [[diarrhea]], click the links below. | |||
*[[Ulcerative colitis pathophysiology#Pathphysiology|Ulcerative colitis]] | |||
*[[Crohn's disease pathophysiology#Pathophysiology|Crohn's disease]] | |||
*[[Lactose intolerance pathophysiology#Pathophysiology|Lactose intolerance]] | |||
*[[Celiac disease pathophysiology#Pathophysiology|Celiac disease]] | |||
*[[Chronic pancreatitis pathophysiology#Pathophysiology|Chronic pancreatitis]] | |||
*[[Cholera pathophysiology#Pathophysiology|Cholera]] | |||
*[[Microsporidiosis pathophysiology#Pathophysiology|Microsporidiosis]] | |||
*[[Giardiasis pathophysiology#Pathophysiology|Giardiasis]] | |||
*[[Cryptosporidiosis pathophysiology#Pathophysiology|Cryptosporidiosis]] | |||
*[[Hyperthyroidism pathophysiology#Pathophysiology|Hyperthyroidism]] | |||
==References== | ==References== | ||
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[[Category:Emergency medicine]] | |||
[[Category:Disease]] | |||
[[Category:Up-To-Date]] | |||
[[Category:Infectious disease]] | |||
[[Category:Gastroenterology]] | |||
[[Category:Pediatrics]] | |||
[[Category:Up-To-Date]] | |||
Latest revision as of 14:13, 15 January 2021
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Chronic diarrhea Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Omodamola Aje B.Sc, M.D. [2]
Overview
The fundamental pathophysiology of all diarrhea is incomplete absorption of water from the lumen because of either a reduced rate of net water absorption or osmotic retention of water intraluminally. The causes of chronic diarrhea include inflammatory, osmotic, secretory, iatrogenic, motility, and functional diseases. Osmotic chronic diarrhea involves an unabsorbed substance that draws water from the plasma into the intestinal lumen along osmotic gradients. If excessive amounts of unabsorbed substance are retained in the intestinal lumen, water will not be absorbed and diarrhea will result. Secretory chronic diarrhea on the other hand, results from disordered electrolyte transport and, despite the term, is more commonly caused by decreased absorption rather than net secretion. A disruption of the normal colonic epithelial barrier by microorganisms is mainly responsible for inflammatory chronic diarrhea. This disruption can lead to exudative, secretory, or malabsorptive components of inflammatory chronic diarrhea. Both rapid transit time and slow transit time are associated with motility disorders causing chronic diarrhea. Some iatrogenic causes of chronic diarrhea are seen after abdominal surgeries such as cholecystectomy, where about 5%–10% of patients develop chronic diarrhea. In general, the causes of chronic diarrhea are multifactorial.
Pathogenesis
Diarrhea is a condition of altered intestinal water and electrolyte transport. The physiological mechanisms of diarrhea include osmotic, secretory, inflammatory, altered motility, and iatrogenic mechanisms.[1]
Osmotic chronic diarrhea
Osmotic chronic diarrhea involves an unabsorbed substance that draws water from the plasma into the intestinal lumen along osmotic gradients. If excessive amounts of unabsorbed substance are retained in the intestinal lumen, water will not be absorbed and diarrhea will result.
- Chronic diarrhea due to an osmotic cause includes osmotic laxatives such as lactose intolerance antacids, fructose, lactulose, laxatives magnesium, phosphate, and sorbitol.[2]
- Maldigestion syndromes such as disaccharidase deficiency and pancreatic exocrine insufficiency can also result in osmotic chronic diarrhea.
- Osmotic diarrheas might result in steatorrhea and azotorrhea (passage of fat and nitrogenous substances into the stool), but they typically do not cause any rectal bleeding.[3]
Secretory chronic diarrhea
Secretory chronic diarrhea results from disordered electrolyte transport and, despite the term, is more commonly caused by decreased absorption rather than net secretion.
- Secretory diarrheas include congenital abnormalities such as congenital chloridorrhea, in which an abnormality in the genetic control of chloride-bicarbonate exchange in the ileum results in the loss of chloride into the stool.
- Another example is the loss of α2-adrenergic function in enterocytes of patients with autonomic neuropathy caused by diabetes mellitus.
- The typical features of secretory diarrhea include the persistence of the diarrhea with fasting and the absence of steatorrhea, azotorrhea, or blood per rectum.
- Secretory diarrheas caused by neuroendocrine tumors have been identified by measurement of plasma levels of the hormone or its metabolite in the urine.
- Investigations include measurements of VIP, gastrin, or calcitonin in plasma or 24-hour collections of urine for 5-hydroxyindoleacetic acid.[4]
Inflammatory chronic diarrhea
Disruption of the normal colonic epithelial barrier by microorganisms is mainly responsible for inflammatory chronic diarrhea. This disruption can lead to exudative, secretory, or malabsorptive components of inflammatory chronic diarrhea.
- Inflammatory causes of chronic diarrhea might present with features that suggest malabsorption or rectal bleeding.
- The nature of the malabsorption depends on the regions affected (e.g., proximal vs. distal small bowel), and rectal bleeding is usually a manifestation of colonic or rectal ulcerations.
- Anti-inflammatory agents, including bismuth subsalicylate or other, more potent anti-inflammatory medications, appear to benefit patients with microscopic or collagenous colitis.[5]
Motility disorders causing chronic diarrhea
Both rapid transit time and slow transit time are associated with motility disorders causing chronic diarrhea.
- Rapid transit time delivers fluid secreted during digestion to the distal small bowel or colon. This prevents reabsorption of normally secreted fluid in the small bowel, overwhelming the re-absorptive capacity of the colon.
- Slow transit time results in bacterial overgrowth with bile acid deconjugation, poor micelle formation, and steatorrhea.
- The clinical manifestations of chronic diarrhea caused by motility disorders include steatorrhea, usually up to 14 g per day.
- Osmotic laxatives result in acceleration of transit through the bowel, which is associated with up to 14 g of fat in the stool.
- Presence of more than 14 g per day of fat in the stool suggests the presence of bacterial overgrowth or associated disease such as celiac disease.[6]
Iatrogenic causes of chronic diarrhea
After abdominal surgeries such as cholecystectomy, about 5%–10% of patients develop chronic diarrhea.
- Most of these cases resolve completely or significantly improve within a couple of months.
- Iatrogenic diarrhea is related to excessive bile acids being delivered into the intestine.[7][8]
- After a cholecystectomy, bile is delivered directly into the small bowel, overcoming the terminal ileum's ability to reabsorb adequately, leading to cholerheic diarrhea.
- Some other iatrogenic causes of chronic diarrhea might result from vagal injury and ileal resection.
Genetics, Associated Conditions, Gross Pathology, and Microscopic Pathology
For the details of the genetics, associated conditions, gross and microscopic pathology of the following causes of chronic diarrhea, click the links below.
- Ulcerative colitis
- Crohn's disease
- Lactose intolerance
- Celiac disease
- Chronic pancreatitis
- Cholera
- Microsporidiosis
- Giardiasis
- Cryptosporidiosis
- Hyperthyroidism
References
- ↑ Sweetser S (2012). "Evaluating the patient with diarrhea: a case-based approach". Mayo Clin Proc. 87 (6): 596–602. doi:10.1016/j.mayocp.2012.02.015. PMC 3538472. PMID 22677080.
- ↑ Suarez FL, Savaiano DA, Levitt MD (1995). "A comparison of symptoms after the consumption of milk or lactose-hydrolyzed milk by people with self-reported severe lactose intolerance". N Engl J Med. 333 (1): 1–4. doi:10.1056/NEJM199507063330101. PMID 7776987.
- ↑ Morris AI, Turnberg LA (1979). "Surreptitious laxative abuse". Gastroenterology. 77 (4 Pt 1): 780–6. PMID 467934.
- ↑ von der Ohe MR, Camilleri M, Kvols LK, Thomforde GM (1993). "Motor dysfunction of the small bowel and colon in patients with the carcinoid syndrome and diarrhea". N Engl J Med. 329 (15): 1073–8. doi:10.1056/NEJM199310073291503. PMID 8371728.
- ↑ Pardi DS, Smyrk TC, Tremaine WJ, Sandborn WJ (2002). "Microscopic colitis: a review". Am J Gastroenterol. 97 (4): 794–802. doi:10.1111/j.1572-0241.2002.05595.x. PMID 12003412.
- ↑ Hammer HF, Santa Ana CA, Schiller LR, Fordtran JS (1989). "Studies of osmotic diarrhea induced in normal subjects by ingestion of polyethylene glycol and lactulose". J Clin Invest. 84 (4): 1056–62. doi:10.1172/JCI114267. PMC 329760. PMID 2794043.
- ↑ Breuer NF, Jaekel S, Dommes P, Goebell H (1986). "Fecal bile acid excretion pattern in cholecystectomized patients". Dig Dis Sci. 31 (9): 953–60. PMID 3731987.
- ↑ Arlow FL, Dekovich AA, Priest RJ, Beher WT (1987). "Bile acid-mediated postcholecystectomy diarrhea". Arch Intern Med. 147 (7): 1327–9. PMID 3606289.