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Clinical medicine: acute and chronic diarrhea (Rehfield)
Terms in this set (52)
physiologic definition of diarrhea
Decreased absorption or increased secretion, or both, causing > 200 ml or gram stool excretion/ 24 hr. day in a person on a Western diet.
lasts < 2-3 weeks
what is the most common cause of acute diarrhea?
infection, usually self-limiting
> 14 days in duration
lasting at least 4 weeks and > 6-8 weeks or longer
what are the subcategories of chronic diarrhea?
osmotic (malabsorptive) diarrhea
inflammatory vs. non inflammatory diarrhea
what are the remainder causes of diarrhea?
ingestion of medications
poorly absorbed sugars (fructose polymers or sorbitol)
what does diarrhea result from?
imbalance of the intestines to handle water and electrolytes
what is the required evaluation of bloody acute diarrhea?
must evaluate ALL bloody diarrhea
C & S stool
sigmoidoscopy (limited or colonoscopy (
: if you think you need a tissue sample due to chronic diarrhea that is not infectious, do this = only way for tissue diagnosis)
what is the required evaluation of nonbloody acute diarrhea?
most are viral
most resolve on own without definite diagnosis
rarely further complications unless remission of a chronic condition
if symptoms progress to fever, pus, dehydration, then needs more evaluation
clinical clues for infectious diarrhea
=> Bacterial: Sx onset
WHILE IN visited country
=> Parasitic: Sx onset
clinical clues for noninfectious diarrhea
what are the short-lived watery diarrheas diagnosed as "viral gastroenteritis" likely to be?
mild, sporadic, food-borne bacterial infections
why may you not be able to label the exact etiology of the acute diarrhea?
since diagnostic work up is not always indicated
what nutritional supplements should be reviewed in patient history?
the intake of "sugar-free" foods (containing nonabsorbable carbohydrates),
heavy intake of fruits, fruit juices,
what is one of the most frequent adverse effects of prescription medications?
when does drug-related diarrhea usually occur?
after a new drug is initiated or the dosage is increased
which antibiotics most commonly cause diarrhea?
macrolides = erythiromycin (activates motilin)
what is the pertinent history for diagnosing acute diarrhea?
recent antibiotic use or inpatient therapy for many acute disorders
timing of symptoms = initially diarrhea with progressive symptoms such as fever, HA, myalgias, stiff neck
what are risk factors for acute diarrhea?
immunocompramised pts (HIV)
noninfectious causes of diarrhea
ischemic bowel disease
partial small bowel obstruction
pelvic abscess in the rectosigmoid area
fecal impaction (impacted stool distally, hard for the pt to pass that, so stool seeps around it = fecal soiling)
ingestion of poorly absorbable sugars, such as lactulose and acute alcohol ingestion
when is medical evaluation of acute diarrhea
symptoms are mild, moderate
spontaneously improve within 48 hours
not accompanied by fever, chills, severe abdominal pain, or blood in the stool.
when is diagnostic evaluation indicated for acute diarrhea?
Symptoms are severe or prolonged
The patient appears "toxic"
There is evidence of colitis (occult or gross blood in the stools, severe abdominal pain or tenderness, and fever)
Hospitalized patients or recent use of antibiotics
Diarrhea in the elderly (≥70 years of age) or the immunocompromised
Systemic illness with diarrhea, especially in pregnant women (in which case listeriosis should be suspected)
Empirical therapy has failed
Treatment of acute diarrhea
rehydration = ORS, liquids, salts and sugars
- nondiet cola
- IV fluids, such as lactated rings or saline solution
- frequent sips of OR may avoid IV therapy
absorbent preparations = Kaolin/pectin and busmuth subsalicylate
inhibition of motility = opioid agonists: loperamide and diphenoxylate with atropine
antibiotic = depends on specific causative agent
what absorbent preparations are used for tx of acute diarrhea?
Kaolin/pectin = kaopectat
Bismuth subsalicylate (Pepto-Bismol)
what drugs that inhibit motility are used for tx of acute diarrhea?
diphenoxylate with atropine (lomotil)
what diet protocols are used for acute diarrhea?
total food abstinence is unnecessary and not recommended = food provides calories necessary to facilitate renewal of enterocytes
take frequent feeding of fruit drinks, tea, "flat" carbonated bevs, soft, easily digested foods = BRAT diet, potatoes, noodles, crackers, soups
what products should be avoided in acute diarrhea?
dairy products = b/c transient lactase deficiency can be caused by enteric, viral, and bacterial infections
caffeinated beverages and alcohol = enhance motility and secretions
what should be added to diet when diarrhea has resolved for at least 24 hours?
proteins and fats
allow the bowel to rest
who must be treated regardless of cause of infectious diarrhea? (3)
extremely young or old
specific diagnosis of culture proven bacterial infections
what are probiotics?
live, nonpathogenic, human microorganisms that provide a health benefit
most species are lactic acid bacteria
what is the effect of adding lactobacillus to an ORS?
decreases the duration of diarrhea in children with acute diarrhea, particularly with rotavirus infection
what can yogurt containing live lactobacillus decrease?
incidence of antibiotic induced diarrhea
what is the empiric treatment while clinician is awaiting stool culture?
fluoroquinolones = ciproflaxacin
what is second-line empiric treatment?
what organisms are likely to cause chronic diarrhea?
> 4 weeks
Giardia or enzyme immunossay (ELISA) for Giardia
Cryptosporidium and Cyclospora
Aeromonas and Plesiomonas
Candida albicans (think immunosuppression)
what are noninfectious etiologies of chronic diarrhea?
malabsorption of fat
what is the evaluation for suspected inflammatory or infectious cause of chronic diarrhea?
Blood tests incl. CBC with diff (anemia and parasitic infections), electrolytes, amylase (pancreatitis), liver function tests and PT (hepatobiliary disease), serum calcium and glucose
Fecal leukocytes (these are all specific for IBD, UC, Crohn's)
72 hour quantitative stool fat determination: >6 gm/d while on a test diet of 100 gm of fat /24 hrs. indicates fat malabsorption
Stool for occult blood
(office procedure right when you see the pt, is there blood or no blood, is it inflammatory or not)
Stool O&P and Giardia antigen
Stool for C. difficile toxin
celiac sprue (gluten intolerance) tests
Antiendomesial , antitransglutaminase, and antigliadin antibodies
Small bowel biopsy for confirmation
CBC for anemia, chem panel for liver function, electrolytes, serum calcium, glucose, alkaline phosphatase, and Vitamin D
what imaging tests should be done in chronic diarrhea evaluation?
sigmoidoscopy or colonoscopy with biopsies for IBD/Crohn's/UC
CT scan of abdomen
primary causes of malabsorption
Congenital defects in membrane transport systems of the small intestinal epithelium
secondary causes of malabsorption
acquired defects in the epithelial absorptive surface (e.g. Crohn's, celiac disease, intestinal bypass surgery
what malabsorption can cause exocrine pancreatic insufficiency?
impaired digestion of nutrients within intestinal lumens
what can cause lactose maldigestion?
impaired digestion of nutrients at the terminal digestive site of the brush border of mucosal epithelial cells
Malabsorption clinical presentation
pale, greasy, voluminous, foul-smelling stools
despite adequate food intake
Anorexia and flatulence
abdominal distension and borborygmi
symptoms suggestive of irritable bowel syndrome
what common disorders are associated with malabsorption?
bacterial overgrowth of the small intestine
Diffuse damage to proximal small intestinal mucosa causes malabsorption of most nutrients
removal of gluten from diet results in disappearance of symptoms and healing in most
who presents with celiac?
more commonly in infancy
also between 20-40 and > 60
what is the pathogenesis of gluten?
elicits both humoral and cellular inflammatory responses in mucosal lining
inflammation => destruction
how are osmotic diarrheas and secretory diarrheas differentiated? (
with fasting, while secretory diarrheas
what does carcinoid syndrome cause?
endocrine tumor diarrheas
what does vilous adenomas cause?
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