Diseases of the Intestine

Diseases of the IntestineDiarrhea alteration in GI function in digestion, absorption or secretion

Diarrheal Disease

Osmotic factors overfeeding, malabsorption, ingestion of nonsoluble compounds (lactulose/MgSO4)

Decrease absorption or increase secretion of water & electrolytes- infectious diarrhea, free bile acid & hydroxyl fatty acid accumulation,presence of humoral factors, inflammatory bowel dse, mucosal dse (celiac)Mechanism of PathogenesisDiminished anatomic or functional intestinal surface area- short bowel syndrome, mucosal dse

Altered motility hypermotility, hypomotility

Diarrhea can be: infectious or non-infectious

1. Infectious> acute diarrhea are generally infectious> viruses/bacteria/parasites/fungietc

TYPES of DIARRHEA1. Adherence & enterotoxin production- V. cholera & Enterotoxic E. coli (ETEC)

* adherenceexotoxin releaseadenyl cyclase activationcAMPCl secretion, Na absorption

* ETEC heat stable toxinguanylate cyclase activationcGMPNa absorption inhibition without Cl secretion- cAMP + cGMP = profuse, watery diarrhea & dehydration

a) Interactions of enteric pathogen to intestinal mucosa

2. Enteroinvasion with damage to epithelial cells- Shigella dysenteriae enteroinvasive E. coli (EIEC)Yersinia enterolytica Campylobacter jejuni- mucosal inflammation with damage enterocytes ensues = bloody, mucoid stools

3. Enteroinvasion with penetration of lamina propria & systemic spread- Salmonella sp.- invades the lamina propria inflammation (prostaglandin release) + enterotoxins lead to increase intestinal fluid production which are generally loose and watery and sometimes with blood & mucus4. Adherence without enterotoxin production nor damage to enterocytes- enteropathogenic E. coli (EPEC)- disruption of microvilli and blunting of intestinal villi = profuse & watery stool without blood/mucus

- Entamoeba histolytica & Giardia lamblia --- considered in a diarrheic child especially if the dse course is chronicE. histolitica enteroinvasive- usually bloody, mucoid stools; with tenesmus and abdominal painG. lamblia interaction not yet identified,- acute watery, non-bloody gastroenteritis that may become chronic (pale, bulky & malodorous stool)

b) Parasitic dses- associated with chronic debilitating illnesses & prolonged intake of antimicrobials, corticosteroids or immunosuppresssives- Candida albicans is the most prevalent

c) Fungal infection2. Non-infectious> intolerance (lactose/other CHO)> overfeeding> drug-induced(antibiotics)> food allergy> poisons> inflammatory bowel dse

TYPES of DIARRHEA1. Cholera like watery, non bloody diarrheaVibrio Colera, Rotavirus ETECEPECC. PerfringensB. cereus S. aureusC. difficileG.Lamblia

2 Major Clinical Syndromes in Diarrhea

Dysentery like blood- streaked or mucoid diarrheaS.dysenteriaeE.histolyticaEIECSalmonella sp.Yersinia enterocoliticaC. jejuni

Persistent diarrhea- 3rd clinical syndrome by WHO, under chronic diarrhea

Good description of diarrheic stool + knowing the associated symptoms classification into clinical syndromesThe character of the stools may indicate the site of involvement of gut and offending agent.Pathogens affecting Upper gut watery, non-bloody diarrhea + anorexia and vomitingLower gut bloody or blood streaked, mucoid diarrhea + abdominal pain abd tenesmus

Principles:

Rests chiefly on the recognition of the clinical syndromes in diarrheas interactions of the enteropathogens with the intestinal mucosa.

Bloody diarrheas have been describes by studies to be predominantly secondary to shigella.

PRACTICAL DIAGNOSIS OF ACUTE DIARRHEANon-bloody diarrheas or so-called acute watery diarrheas generally respond well to fluid and nutritional therapyno need to identify pathogen

Laboratory confirmation of amebiasis and giardiasis Detection of the vegetative form (trophozoite) especially in the presence of ingested RBC, is more specific for amebiasis.