Diarrhea pathophysiology

From Spruill WJ, Wade WE. Diarrhea, constipation and irritable bowel syndrome. In DiPiro JT, Talbert RL, Yee CC, et al, (eds.) Pharmacotherapy A Pathophysiologic Approach. 6th ed. New York McGraw-Hill, Inc 677-692, with permission. 

Any event that leads to a significant increase in the amount of fluid retained in the stool may result in diarrhea. Large-stool diarrhea often signifies small intestinal involvement, whereas small-stool diarrhea usually originates in the colon. Diarrhea may be classified according to pathophysiologic... 

C. difficile overgrowth is present in only 15-25% of cases of AAD thus, other explanations are needed to understand the pathophysiology of diarrhea. There are multiple mechanisms which can account for the diarrhea associated with antibiotics. These include altered fermentation of the flora, changes in dietary fiber and overgrowth of other potential pathogens. 

Abrupt discontinuation of TCAs commonly results in diarrhea, increased sweating, anxiety, and dizziness. These symptoms were previously attributed to cholinergic rebound, but the occurrence of similar symptoms after the discontinuation of many of the newer serotonergic antidepressants suggests that the pathophysiology may be more closely related to changes in serotonin. 

Cholinesterase inhibitors are the only class of drugs currently approved by most Health Authorities and recommended by professional associations (e.g. Doody et al.. 2001) for the symptomatic treatment of AD. However, ChE-Is intervene at a late stage of the pathophysiological cascade leading to AD (Fig. 7.2) furthermore, their efficacy is limited and they may cause a number of side effects, most frequently nausea, vomiting, diarrhea, anorexia and dizziness. For these reasons, major efforts are being made to alter the biological processes... 

Camilleri M Chronic diarrhea A review of pathophysiology and management for the clinical gastroenterologist. Clin Gastroenterol Hepatol 2004 2 198. [PMID 15017602]... 

Four general pathophysiologic mechanisms disrupt water and electrolyte balance, leading to diarrhea. These four mechanisms are the basis of diagnosis and therapy. They are (1) a change in active ion transport by either decreased sodium absorption or increased chloride secretion (2) a change in intestinal motility (3) an increase in luminal osmolarity and (4) an increase in tissue hydrostatic pressure. These mechanisms have been related to four broad clinical diarrheal groups secretory, osmotic, exudative, and altered intestinal transit. 

Saliba F, Hagipantelli R, Misset JL, Bastian G, Vassal G, Bonnay M, Herait P, Cote C, Mahjoubi M, Mignard D, Cvitkovic E. Pathophysiology and therapy of irinotecan-induced delayed-onset diarrhea in patients with advanced colorectal cancer a prospective assessment. J Clin Oncol 1998 16(8) 2745-51. 

The four pathophysiologic mechanisms of diarrhea have been linked to the four broad diarrheal groups, which are secretory, osmotic, exudative, and altered intestinal transit. The three mechanisms by which absorption occurs from the intestines are active transport, diffusion, and solvent drag. 

Diarrhea may be associated with a specific disease of the intestines or secondary to a disease outside the intestines. For instance, baciUary dysentery directly affects the gut, whereas diabetes meUitus causes neuropathic diarrheal episodes. Furthermore, diarrhea can be considered as acnte or chronic disease. Infectious diarrhea is often acnte diabetic diarrhea is chronic. Whether acute or chronic, diarrhea has the same pathophysiologic canses that help identification of specific treatments. 

Field M (2003) Intestinal ion transport and the pathophysiology of diarrhea. J Clin Invest 111 931-943... 

Kulkami H, Mamtani M, Patel A. Roles of zinc in the pathophysiology of acute diarrhea. Curr Infect Dis Rep 2012 14(l) 24r-32. 

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