Flashcards in Diarrhea Deck (31):
What constitutes diarrhea?
>200 grams or 200 mL per 24 hour period
Inadequate nutrient absorption
Associated with steatorrhea
Relieved by fasting
Due to inflammatory disease
Purulent, bloody stools
Continue during fasting
What constitutes a normal bowel movement?
One BM every 3 days to 3 BM every day
What are some history clues to investigate with diarrhea?
4. Nocturnal BM
Diarrhea due to small bowel disease
Watery diarrhea, large volume, less frequent
Abdominal cramping, bloating, gas and weight loss
Evidence of malabsorption, vitamin or nutrient deficiencies
Fever is rare
Rare stool WBCs or occult blood
Diarrhea due to large bowel disease
Inflamed dysfunctional colon/rectum cannot perform this function
Frequent, small, regular stools
Tenesmus (rectal "dry heaves")
Fever, bloody, mucoid stools
RBCs and WBC on stool smear
Small intestine and colon cannot maintain an osmotic gradient against serum
Unabsorbed ions remain in the lumen --> pull water into the lumen of bowel
Maintain intraluminal osmolality = 290 mOsm/kg
What are some things that may cause osmotic diarrhea?
Ingestion of poorly absorbed ions or sugars or sugar alcohols -- Mannitol, sorbitol, magnesium, sulfate and phosphate
Monosaccharides but not disaccharides can be absorbed
Disappears with fasting
Many causes --> net secretion of anions (chloride/bicarb) or inhibition of net sodium absorption
Most common cause is infection
What constitutes acute, persistent and chronic diarrhea?
Acute: 28 days
What are some causes of acute diarrhea?
Infection -- bacteria, parasites, protozoa, viruses
Initial presentation of chronic diarrhea
What are some causes of chronic fatty diarrhea?
Mucosal diseases (celiac, Whipple's)
Short bowel syndrome
Small intestinal bacterial overgrowth
What are some causes of inflammatory chronic diarrhea?
Invasive bacterial/parasitic infections
What are some main things you must address during the history in a patient who presents with diarrhea?
Assess volume status (symptomatic, orthostatis, fluid intake)
Try to assess constancy
Blood in stool (never normal)
What are some medications that may cause diarrhea?
NSAIDs and Olmesartan (anti-htn) -- sprue like illness
What are some possible causes if diarrhea presents with a fever?
Cytotoxic organism (C. diff or Entamoeba histolytica)
What are some causes if diarrhea begins w/i six hours?
Suggests ingestion of toxin
Staph aureus or Bacillus cereus
What are some of the causes of diarrhea if it began within 8-15 hours?
Suggests infection with Clostridium perfringens
What are some of the possible causes of diarrhea if it began more than 14 hours?
Result of viral or bacterial infection, non-specific
How should you focus your physical exam with a patient who is presenting with diarrhea?
Initially focus on volume status
Check for signs of other systemic disease -- DH in Celiac disease or EN in arthritis/IBD
Rectal exam for (fistula, blood stool)
When do you order a stool sample for pathogens?
When a patient is very ill or has risk factors for infection
When do you use ELISAs or DFA microscopy on stool samples?
To test for Giardiasis and Cryptosporidium
-Sensitivities greater than 90%
-Specificities approaching 100%
Useful if proper history or immune compromised
What is the osmotic gap?
Osmotic gap = Serum Osm - Est Stool Osm (290)
The osmolality of colonic fluid contents is in equilibrium with body fluids (290 mOsm/kg)
What is the osmotic gap like in secretory vs osmotic diarrhea?
In secretory diarrhea -- the osmotic gap is small (100 mOsm/kg)
What does it mean if the osmotic gap is negative?
There is a poorly absorbed multivalent anion, such as phosphate or sulfate
The measured stool osmolality is of little value -- stool osmolality tends to rise once the stool has been collected b/c of continuing bacterial fermentation in vitro.
How can you test for surreptitious laxative ingestion?
There will be a large osmotic gap -- suggesting magnesium ingestion
Or a negative osmotic gap
Stool can be analyzed for laxatives by chemical or chromatographic methods
What are some common causes of chronic diarrhea that should be pursued early?
Celiac disease (caucasians)
When is it appropriate to pursue endoscopy for chronic diarrhea?
Persistent and chronic with significant lab abnormalities -- obtain biopsies of even normal appearing mucosa is essential