chronic diarrhea. diarrhea loosely defined as passage of abnormally liquid or unformed stools at an...
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Chronic DiarrheaChronic Diarrhea
DiarrheaDiarrhea
Loosely defined as passage of abnormally liquid or unformed stools at an increased frequency.
Adults (typical western diet) stool weight > 200g/d
caused by an imbalance in the physiologic mechanisms of the GI tract, resulting in impaired absorption and/or excessive secretion.
2 common conditions (<200 g/d) must be distinguished from diarrhea:
◦Pseudodiarrhea Frequent passage of small volumes of stool Associated with rectal urgency ; accompanies
IBS/proctitis
◦Fecal Incontinence involuntary discharge of rectal contents
most often caused by neuromuscular disorder/structural/anorectal problems
DiarrheaDiarrhea
Type Duration
Acute < 2 weeks
Persistent 2-4 weeks
Chronic > 4 weeks
Chronic DiarrheaChronic Diarrhea
Warrants evaluation to exclude serious underlying pathology
Most of the causes: NON- infectious
Classification by pathophysiological mechanism rational approach to management
Approach to Chronic Approach to Chronic Diarrhea:Diarrhea:Laboratory tools are extensive
costly and invasive rationally directed by a careful History and PE.
When this strategy is unrevealing, simple triage tests (Hx, PE, routine blood studies) are often warranted.◦Characterize the mechanism of diarrhea◦ Identify diagnostically helpful assoc.◦Assess px’s fluid/electrolyte &
nutritional status
HISTORYHISTORY
Family History:
IBD
Sprue
Presence of:
fecal incontinencefeverweight losspain exposure(travel, medications, contacts) common extraintestinal manifestations (skin, arthralgias, oral aphtous ulcers
Diarrhea
Onset
Duration
Pattern
Aggravating and relieving factors (diet)
Characteristics
Physical Findings
Thyroid mass Wheezing Murmurs Edema
Hepatomegaly Abdominal
masses
Lymphadenopathy
Mucocutaneous abnormalities Perianal
fistula Anal sphincter
laxity
Celiac disease
Blood Studies
Peripheral blood leukocytosis↑sedimentation rateC- reactive protein
Anemia
Eosinophilia
Tissue transglutaminase Ab
Inflammation
Blood loss/nutritional
deficiency
Parasites, neoplasia, collagen
vascular disease, allergy,
eosinophilic gastroenteritis
Celiac disease
Chronic DiarrheaChronic Diarrhea2/3 of cases, the causes remain
unclear after the initial encounter further testing is required:◦Quantitative stool collection and
analyses important objective data and establish a diagnosis/characterize the type of diarrhea as a triage for focused additional studies
◦Stool ( >200g/d ) electrolyte concentration, pH, occult blood testing, leukocyte inspection/protein assay, fat quantitation, and laxative screens.
Chronic DiarrheaChronic DiarrheaWhen a specific diagnosis is suggested on the
initial encounter, therapeutic trial is often appropriate, definitive, and highly cost effective. Examples:
◦ Chronic watery diarrhea ceases with fasting in an otherwise healthy young adult may justify a trial of lactose-restricted diet
◦ Bloating w/ diarrhea after a mountain backpacking trip trial of metronidazole (giardiasis)
Any patient with chronic diarrhea + hematochezia evaluated with stool microbiologic studies and colonoscopy
Chronic DiarrheaChronic DiarrheaSecretory diarrheas
◦Microbiologic studies should be done, including: fecal bacterial cultures, inspection for ova and parasites and Giardia antigen assay
◦Suggested history & other findings screening for peptide hormones (gastrin, VIP, calcitonin, TH/TSH, urinary 5-HIAA, and histamine)
◦Upper endoscopy, colonoscopy w/ biopsy and small bowel barium x-rays rule out structural/occult inflammatory disease
Chronic DiarrheaChronic DiarrheaOsmotic diarrhea
◦Tests for 2 most common causes: Lactose intolerance/malabsorption lactose breath
testing or therapeutic trial w/ lactose exclusion & lactose challenge
Magnesium ingestion fecal magnesium levels◦pH low fecal pH suggests CHO malabsorption
Steatorrhea◦Endoscopy w/ small bowel biopsy(includes
aspiration for Giardia and quantitative cultures)◦Small-bowel radiograph◦(-) radiograph/ pancreatic exocrine disease
Pancreatic exocrine insufficiency ruled out secretin-cholecystokinin stimulation test
Chronic DiarrheaChronic DiarrheaChronic inflammatory-type of
diarrheas (presence of blood/leukocytes in the stool)◦Stool cultures◦Inspection for ova/parasites◦C. difficile toxin in assay◦Colonoscopy w/ biopsies◦Small-bowel contrast studies
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